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st (Suckless Terminal)のソースコードリーディング

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st (Suckless Terminal)のソースコードリーディング

stはC言語で書かれた、とてもシンプルなX用ターミナル実装です。 (archlinux wikiのページ)

コンフィグの設定は config.h を編集する、機能拡張にはパッチを適用 するなどといった(コードベース的に)徹底的なシンプルさを持ちます。 そのため、ターミナル実装の作り方を知るためには一番良い教材になりそうだと感じ たのでコードを読んでみることとします。

使用するコードのバージョン

[2022-11-04 Fri 20:24] 現在の最新のコミットを使用します。

  • hash: e5e959835b195c023d1f685ef4dbbcfc3b5120b2

この記事の構成について

この記事では、ソースコードが MIT/X ライセンスであるため 実際のコードを引用してきて、各関数・型毎にコメントを書いていきます。 (ライセンスは

又、全体の処理の流れ等は分かり次第別のヘディングに分割して 記載する予定です。

コードリーディング

st.h

ヘッダファイル内でのみ定義されているものについてのみ解説し、 st.c のシグネチャは省く。

#define MIN(a, b)		((a) < (b) ? (a) : (b))
#define MAX(a, b)		((a) < (b) ? (b) : (a))
#define LEN(a)			(sizeof(a) / sizeof(a)[0])
#define BETWEEN(x, a, b)	((a) <= (x) && (x) <= (b))
#define DIVCEIL(n, d)		(((n) + ((d) - 1)) / (d))
#define DEFAULT(a, b)		(a) = (a) ? (a) : (b)
#define LIMIT(x, a, b)		(x) = (x) < (a) ? (a) : (x) > (b) ? (b) : (x)
#define ATTRCMP(a, b)		((a).mode != (b).mode || (a).fg != (b).fg || \
                                (a).bg != (b).bg)
#define TIMEDIFF(t1, t2)	((t1.tv_sec-t2.tv_sec)*1000 + \
                                (t1.tv_nsec-t2.tv_nsec)/1E6)
#define MODBIT(x, set, bit)	((set) ? ((x) |= (bit)) : ((x) &= ~(bit)))

#define TRUECOLOR(r,g,b)	(1 << 24 | (r) << 16 | (g) << 8 | (b))
#define IS_TRUECOL(x)		(1 << 24 & (x))

glyph_attribute

enum glyph_attribute {
        ATTR_NULL       = 0,
        ATTR_BOLD       = 1 << 0,
        ATTR_FAINT      = 1 << 1,
        ATTR_ITALIC     = 1 << 2,
        ATTR_UNDERLINE  = 1 << 3,
        ATTR_BLINK      = 1 << 4,
        ATTR_REVERSE    = 1 << 5,
        ATTR_INVISIBLE  = 1 << 6,
        ATTR_STRUCK     = 1 << 7,
        ATTR_WRAP       = 1 << 8,
        ATTR_WIDE       = 1 << 9,
        ATTR_WDUMMY     = 1 << 10,
        ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
};

selection_mode

  • SEL_IDLE

    • セレクションを初期化した時

    • セレクションを消した時

    • セレクションの移動が終わった時

enum selection_mode {
        SEL_IDLE = 0,
        SEL_EMPTY = 1,
        SEL_READY = 2
};

selection_type

enum selection_type {
        SEL_REGULAR = 1,
        SEL_RECTANGULAR = 2
};

selection_snap

enum selection_snap {
        SNAP_WORD = 1,
        SNAP_LINE = 2
};

uchar, uint, ulong, ushort

typedef unsigned char uchar;
typedef unsigned int uint;
typedef unsigned long ulong;
typedef unsigned short ushort;

Rune

1文字のキャラクターコードを示す (Glyphのコメントより)

typedef uint_least32_t Rune;

Glyph, Glyph_

#define Glyph Glyph_
typedef struct {
        Rune u;           /* character code */
        ushort mode;      /* attribute flags */
        uint32_t fg;      /* foreground  */
        uint32_t bg;      /* background  */
} Glyph;

Line

Glyphの横並び=一列。 ポインタで可変長配列、という感じ? メモリ管理をきちんとしないと死にそう。

typedef Glyph *Line;

Arg

typedef union {
        int i;
        uint ui;
        float f;
        const void *v;
        const char *s;
} Arg;


/* config.h globals */
extern char *utmp;
extern char *scroll;
extern char *stty_args;
extern char *vtiden;
extern wchar_t *worddelimiters;
extern int allowaltscreen;
extern int allowwindowops;
extern char *termname;
extern unsigned int tabspaces;
extern unsigned int defaultfg;
extern unsigned int defaultbg;
extern unsigned int defaultcs;

st.c

ヘッダー

  /* See LICENSE for license details. */
  #include <ctype.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <limits.h>
  #include <pwd.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <signal.h>
  #include <sys/ioctl.h>
  #include <sys/select.h>
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <termios.h>
  #include <unistd.h>
  #include <wchar.h>

  #include "st.h"
  #include "win.h"

  #if   defined(__linux)
   #include <pty.h>
  #elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
   #include <util.h>
  #elif defined(__FreeBSD__) || defined(__DragonFly__)
   #include <libutil.h>
  #endif

  /* Arbitrary sizes */
  #define UTF_INVALID   0xFFFD
  #define UTF_SIZ       4
  #define ESC_BUF_SIZ   (128*UTF_SIZ)
  #define ESC_ARG_SIZ   16
  #define STR_BUF_SIZ   ESC_BUF_SIZ
  #define STR_ARG_SIZ   ESC_ARG_SIZ

  /* macros */
  #define IS_SET(flag)		((term.mode & (flag)) != 0)
  #define ISCONTROLC0(c)		(BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
  #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
  #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
  #define ISDELIM(u)		(u && wcschr(worddelimiters, u))

  enum term_mode {
          MODE_WRAP        = 1 << 0,
          MODE_INSERT      = 1 << 1,
          MODE_ALTSCREEN   = 1 << 2,
          MODE_CRLF        = 1 << 3,
          MODE_ECHO        = 1 << 4,
          MODE_PRINT       = 1 << 5,
          MODE_UTF8        = 1 << 6,
  };

  enum cursor_movement {
          CURSOR_SAVE,
          CURSOR_LOAD
  };

  enum cursor_state {
          CURSOR_DEFAULT  = 0,
          CURSOR_WRAPNEXT = 1,
          CURSOR_ORIGIN   = 2
  };

  enum charset {
          CS_GRAPHIC0,
          CS_GRAPHIC1,
          CS_UK,
          CS_USA,
          CS_MULTI,
          CS_GER,
          CS_FIN
  };

  enum escape_state {
          ESC_START      = 1,
          ESC_CSI        = 2,
          ESC_STR        = 4,  /* DCS, OSC, PM, APC */
          ESC_ALTCHARSET = 8,
          ESC_STR_END    = 16, /* a final string was encountered */
          ESC_TEST       = 32, /* Enter in test mode */
          ESC_UTF8       = 64,
  };

  typedef struct {
          Glyph attr; /* current char attributes */
          int x;
          int y;
          char state;
  } TCursor;

  typedef struct {
          int mode;
          int type;
          int snap;
          /*
* Selection variables:
* nb – normalized coordinates of the beginning of the selection
* ne – normalized coordinates of the end of the selection
* ob – original coordinates of the beginning of the selection
* oe – original coordinates of the end of the selection
*/
          struct {
                  int x, y;
          } nb, ne, ob, oe;

          int alt;
  } Selection;

  /* Internal representation of the screen */
  typedef struct {
          int row;      /* nb row */
          int col;      /* nb col */
          Line *line;   /* screen */
          Line *alt;    /* alternate screen */
          int *dirty;   /* dirtyness of lines */
          TCursor c;    /* cursor */
          int ocx;      /* old cursor col */
          int ocy;      /* old cursor row */
          int top;      /* top    scroll limit */
          int bot;      /* bottom scroll limit */
          int mode;     /* terminal mode flags */
          int esc;      /* escape state flags */
          char trantbl[4]; /* charset table translation */
          int charset;  /* current charset */
          int icharset; /* selected charset for sequence */
          int *tabs;
          Rune lastc;   /* last printed char outside of sequence, 0 if control */
  } Term;

  /* CSI Escape sequence structs */
  /* ESC '[' [[ [<priv>] <arg> [;]] <mode> [<mode>]] */
  typedef struct {
          char buf[ESC_BUF_SIZ]; /* raw string */
          size_t len;            /* raw string length */
          char priv;
          int arg[ESC_ARG_SIZ];
          int narg;              /* nb of args */
          char mode[2];
  } CSIEscape;

  /* STR Escape sequence structs */
  /* ESC type [[ [<priv>] <arg> [;]] <mode>] ESC '\' */
  typedef struct {
          char type;             /* ESC type ... */
          char *buf;             /* allocated raw string */
          size_t siz;            /* allocation size */
          size_t len;            /* raw string length */
          char *args[STR_ARG_SIZ];
          int narg;              /* nb of args */
  } STREscape;

  static void execsh(char *, char **);
  static void stty(char **);
  static void sigchld(int);
  static void ttywriteraw(const char *, size_t);

  static void csidump(void);
  static void csihandle(void);
  static void csiparse(void);
  static void csireset(void);
  static void osc_color_response(int, int, int);
  static int eschandle(uchar);
  static void strdump(void);
  static void strhandle(void);
  static void strparse(void);
  static void strreset(void);

  static void tprinter(char *, size_t);
  static void tdumpsel(void);
  static void tdumpline(int);
  static void tdump(void);
  static void tclearregion(int, int, int, int);
  static void tcursor(int);
  static void tdeletechar(int);
  static void tdeleteline(int);
  static void tinsertblank(int);
  static void tinsertblankline(int);
  static int tlinelen(int);
  static void tmoveto(int, int);
  static void tmoveato(int, int);
  static void tnewline(int);
  static void tputtab(int);
  static void tputc(Rune);
  static void treset(void);
  static void tscrollup(int, int);
  static void tscrolldown(int, int);
  static void tsetattr(const int *, int);
  static void tsetchar(Rune, const Glyph *, int, int);
  static void tsetdirt(int, int);
  static void tsetscroll(int, int);
  static void tswapscreen(void);
  static void tsetmode(int, int, const int *, int);
  static int twrite(const char *, int, int);
  static void tfulldirt(void);
  static void tcontrolcode(uchar );
  static void tdectest(char );
  static void tdefutf8(char);
  static int32_t tdefcolor(const int *, int *, int);
  static void tdeftran(char);
  static void tstrsequence(uchar);

  static void drawregion(int, int, int, int);

  static void selnormalize(void);
  static void selscroll(int, int);
  static void selsnap(int *, int *, int);

  static size_t utf8decode(const char *, Rune *, size_t);
  static Rune utf8decodebyte(char, size_t *);
  static char utf8encodebyte(Rune, size_t);
  static size_t utf8validate(Rune *, size_t);

  static char *base64dec(const char *);
  static char base64dec_getc(const char **);

  static ssize_t xwrite(int, const char *, size_t);

  /* Globals */
  static Term term;
  static Selection sel;
  static CSIEscape csiescseq;
  static STREscape strescseq;
  static int iofd = 1;
  static int cmdfd;
  static pid_t pid;

  static const uchar utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
  static const uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
  static const Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
  static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};

xwrite

write 関数のラッパーみたいなもの。 writelen で与えた文字数を書き込むわけですが、 必ず全てが書き込まれるわけではありません。 man 2 write によると、

  • ファイルシステムに十分な空き容量が無い時

  • RLIMIT_FSIZE の制限にかかった時

  • 途中でシグナルハンドラに割り込みされた時

に、一部のみの書き込みで終わってしまうことがあるようです。

そこで、この関数では全てが書き込まれることを保証するために書き込まれた文字数(r)と 書き込みたい文字数の長さ(len)を比べ、全てが書き込まれるまで write を続けるようです。

ssize_t
xwrite(int fd, const char *s, size_t len)
{
        size_t aux = len;
        ssize_t r;

        while (len > 0) {
                r = write(fd, s, len);
                if (r < 0)
                        return r;
                len -= r;
                s += r;
        }

        return aux;
}

xmalloc

mallocに失敗したらログを残してアプリケーションを終了させます。

void *
xmalloc(size_t len)
{
        void *p;

        if (!(p = malloc(len)))
                die("malloc: %s\n", strerror(errno));

        return p;
}

xrealloc

reallocに失敗したらログを残してアプリケーションを終了する

void *
xrealloc(void *p, size_t len)
{
        if ((p = realloc(p, len)) == NULL)
                die("realloc: %s\n", strerror(errno));

        return p;
}

xstrdup

xstrdupに失敗したらログを残してアプリケーションを終了する

char *
xstrdup(const char *s)
{
        char *p;

        if ((p = strdup(s)) == NULL)
                die("strdup: %s\n", strerror(errno));

        return p;
}

utf8decode

size_t
utf8decode(const char *c, Rune *u, size_t clen)
{
        size_t i, j, len, type;
        Rune udecoded;

*u = UTF_INVALID;
        if (!clen)
                return 0;
        udecoded = utf8decodebyte(c[0], &len);
        if (!BETWEEN(len, 1, UTF_SIZ))
                return 1;
        for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
                udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
                if (type != 0)
                        return j;
        }
        if (j < len)
                return 0;
*u = udecoded;
        utf8validate(u, len);

        return len;
}

utf8decodebyte

Rune
utf8decodebyte(char c, size_t *i)
{
        for (*i = 0; *i < LEN(utfmask); ++(*i))
                if (((uchar)c & utfmask[*i]) == utfbyte[*i])
                        return (uchar)c & ~utfmask[*i];

        return 0;
}

utf8encode

size_t
utf8encode(Rune u, char *c)
{
        size_t len, i;

        len = utf8validate(&u, 0);
        if (len > UTF_SIZ)
                return 0;

        for (i = len - 1; i != 0; --i) {
                c[i] = utf8encodebyte(u, 0);
                u >>= 6;
        }
        c[0] = utf8encodebyte(u, len);

        return len;
}

utf8encodebyte

char
utf8encodebyte(Rune u, size_t i)
{
        return utfbyte[i] | (u & ~utfmask[i]);
}

utf8validate

size_t
utf8validate(Rune *u, size_t i)
{
        if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
*u = UTF_INVALID;
        for (i = 1; *u > utfmax[i]; ++i)
                ;

        return i;
}

base64dec_getc

char
base64dec_getc(const char **src)
{
        while (**src && !isprint((unsigned char)**src))
                (*src)++;
        return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
}

base64dec

char *
base64dec(const char *src)
{
        size_t in_len = strlen(src);
        char *result, *dst;
        static const char base64_digits[256] = {
                [43] = 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
                0, 0, 0, -1, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
                13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0,
                0, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
                40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
        };

        if (in_len % 4)
                in_len += 4 - (in_len % 4);
        result = dst = xmalloc(in_len / 4 * 3 + 1);
        while (*src) {
                int a = base64_digits[(unsigned char) base64dec_getc(&src)];
                int b = base64_digits[(unsigned char) base64dec_getc(&src)];
                int c = base64_digits[(unsigned char) base64dec_getc(&src)];
                int d = base64_digits[(unsigned char) base64dec_getc(&src)];

                /* invalid input. 'a' can be -1, e.g. if src is "\n" (c-str) */
                if (a == -1 || b == -1)
                        break;

*dst++ = (a << 2) | ((b & 0x30) >> 4);
                if (c == -1)
                        break;
*dst++ = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
                if (d == -1)
                        break;
*dst++ = ((c & 0x03) << 6) | d;
        }
*dst = '\0';
        return result;
}

selinit

`Selection' 型変数の `sel' 変数を初期化する?

void
selinit(void)
{
        sel.mode = SEL_IDLE;
        sel.snap = 0;
        sel.ob.x = -1;
}

tlinelen

与えられた y 行目にある文字数を返す。

iは横幅。最後の文字から順々に見ていき、空白でない文字の indexを返す。

int
tlinelen(int y)
{
        int i = term.col;

        if (term.line[y][i - 1].mode & ATTR_WRAP)
                return i;

        while (i > 0 && term.line[y][i - 1].u == ' ')
                --i;

        return i;
}

つまり、左上の文字を term.line[0][0] と仮定すると、以下の内容のとき:

$ echo "This is test" # line 0?
This is test
$ cat /tmp/foo
Foo text!
$ 
tlinelen(0) // -> 31

ってなる。と思う。

selstart

指定した位置にセレクションを初期化する

void
selstart(int col, int row, int snap)
{
        selclear();
        sel.mode = SEL_EMPTY;
        sel.type = SEL_REGULAR;
        sel.alt = IS_SET(MODE_ALTSCREEN);
        sel.snap = snap;
        sel.oe.x = sel.ob.x = col;
        sel.oe.y = sel.ob.y = row;
        selnormalize();

        if (sel.snap != 0)
                sel.mode = SEL_READY;
        tsetdirt(sel.nb.y, sel.ne.y);
}

selextend

void
selextend(int col, int row, int type, int done)
{
        int oldey, oldex, oldsby, oldsey, oldtype;

        if (sel.mode == SEL_IDLE)
                return;
        if (done && sel.mode == SEL_EMPTY) {
                selclear();
                return;
        }

        oldey = sel.oe.y;
        oldex = sel.oe.x;
        oldsby = sel.nb.y;
        oldsey = sel.ne.y;
        oldtype = sel.type;

        sel.oe.x = col;
        sel.oe.y = row;
        selnormalize();
        sel.type = type;

        if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
                tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));

        sel.mode = done ? SEL_IDLE : SEL_READY;
}

selnormalize

選択範囲の正規化を行う。正規化(normalize)と言ってはいるが、0~1の正規化ではなく 「始点」の座標が「終点」よりも前にくるようにする。

void
selnormalize(void)
{
        int i;

        if (sel.type == SEL_REGULAR && sel.ob.y != sel.oe.y) {
                sel.nb.x = sel.ob.y < sel.oe.y ? sel.ob.x : sel.oe.x;
                sel.ne.x = sel.ob.y < sel.oe.y ? sel.oe.x : sel.ob.x;
        } else {
                sel.nb.x = MIN(sel.ob.x, sel.oe.x);
                sel.ne.x = MAX(sel.ob.x, sel.oe.x);
        }
        sel.nb.y = MIN(sel.ob.y, sel.oe.y);
        sel.ne.y = MAX(sel.ob.y, sel.oe.y);

        selsnap(&sel.nb.x, &sel.nb.y, -1);
        selsnap(&sel.ne.x, &sel.ne.y, +1);

        /* expand selection over line breaks */
        if (sel.type == SEL_RECTANGULAR)
                return;
        i = tlinelen(sel.nb.y);
        if (i < sel.nb.x)
                sel.nb.x = i;
        if (tlinelen(sel.ne.y) <= sel.ne.x)
                sel.ne.x = term.col - 1;
}

selected

int
selected(int x, int y)
{
        if (sel.mode == SEL_EMPTY || sel.ob.x == -1 ||
                        sel.alt != IS_SET(MODE_ALTSCREEN))
                return 0;

        if (sel.type == SEL_RECTANGULAR)
                return BETWEEN(y, sel.nb.y, sel.ne.y)
                    && BETWEEN(x, sel.nb.x, sel.ne.x);

        return BETWEEN(y, sel.nb.y, sel.ne.y)
            && (y != sel.nb.y || x >= sel.nb.x)
            && (y != sel.ne.y || x <= sel.ne.x);
}

selsnap

  void
  selsnap(int *x, int *y, int direction)
  {
          int newx, newy, xt, yt;
          int delim, prevdelim;
          const Glyph *gp, *prevgp;

          switch (sel.snap) {
          case SNAP_WORD:
                  /*
* Snap around if the word wraps around at the end or
* beginning of a line.
*/
                  prevgp = &term.line[*y][*x];
                  prevdelim = ISDELIM(prevgp->u);
                  for (;;) {
                          newx = *x + direction;
                          newy = *y;
                          if (!BETWEEN(newx, 0, term.col - 1)) {
                                  newy += direction;
                                  newx = (newx + term.col) % term.col;
                                  if (!BETWEEN(newy, 0, term.row - 1))
                                          break;

                                  if (direction > 0)
                                          yt = *y, xt = *x;
                                  else
                                          yt = newy, xt = newx;
                                  if (!(term.line[yt][xt].mode & ATTR_WRAP))
                                          break;
                          }

                          if (newx >= tlinelen(newy))
                                  break;

                          gp = &term.line[newy][newx];
                          delim = ISDELIM(gp->u);
                          if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
                                          || (delim && gp->u != prevgp->u)))
                                  break;

*x = newx;
*y = newy;
                          prevgp = gp;
                          prevdelim = delim;
                  }
                  break;
          case SNAP_LINE:
                  /*
* Snap around if the the previous line or the current one
* has set ATTR_WRAP at its end. Then the whole next or
* previous line will be selected.
*/
*x = (direction < 0) ? 0 : term.col - 1;
                  if (direction < 0) {
                          for (; *y > 0; *y += direction) {
                                  if (!(term.line[*y-1][term.col-1].mode
                                                  & ATTR_WRAP)) {
                                          break;
                                  }
                          }
                  } else if (direction > 0) {
                          for (; *y < term.row-1; *y += direction) {
                                  if (!(term.line[*y][term.col-1].mode
                                                  & ATTR_WRAP)) {
                                          break;
                                  }
                          }
                  }
                  break;
          }
  }

getsel

  char *
  getsel(void)
  {
          char *str, *ptr;
          int y, bufsize, lastx, linelen;
          const Glyph *gp, *last;

          if (sel.ob.x == -1)
                  return NULL;

          bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
          ptr = str = xmalloc(bufsize);

          /* append every set & selected glyph to the selection */
          for (y = sel.nb.y; y <= sel.ne.y; y++) {
                  if ((linelen = tlinelen(y)) == 0) {
*ptr++ = '\n';
                          continue;
                  }

                  if (sel.type == SEL_RECTANGULAR) {
                          gp = &term.line[y][sel.nb.x];
                          lastx = sel.ne.x;
                  } else {
                          gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
                          lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
                  }
                  last = &term.line[y][MIN(lastx, linelen-1)];
                  while (last >= gp && last->u == ' ')
                          --last;

                  for ( ; gp <= last; ++gp) {
                          if (gp->mode & ATTR_WDUMMY)
                                  continue;

                          ptr += utf8encode(gp->u, ptr);
                  }

                  /*
* Copy and pasting of line endings is inconsistent
* in the inconsistent terminal and GUI world.
* The best solution seems like to produce '\n' when
* something is copied from st and convert '\n' to
* '\r', when something to be pasted is received by
* st.
* FIXME: Fix the computer world.
*/
                  if ((y < sel.ne.y || lastx >= linelen) &&
                      (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
*ptr++ = '\n';
          }
*ptr = 0;
          return str;
  }

selclear

void
selclear(void)
{
        if (sel.ob.x == -1)
                return;
        sel.mode = SEL_IDLE;
        sel.ob.x = -1;
        tsetdirt(sel.nb.y, sel.ne.y);
}

die

ログを書き残して終了させる

void
die(const char *errstr, ...)
{
        va_list ap;

        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);
        exit(1);
}

execsh

void
execsh(char *cmd, char **args)
{
        char *sh, *prog, *arg;
        const struct passwd *pw;

        errno = 0;
        if ((pw = getpwuid(getuid())) == NULL) {
                if (errno)
                        die("getpwuid: %s\n", strerror(errno));
                else
                        die("who are you?\n");
        }

        if ((sh = getenv("SHELL")) == NULL)
                sh = (pw->pw_shell[0]) ? pw->pw_shell : cmd;

        if (args) {
                prog = args[0];
                arg = NULL;
        } else if (scroll) {
                prog = scroll;
                arg = utmp ? utmp : sh;
        } else if (utmp) {
                prog = utmp;
                arg = NULL;
        } else {
                prog = sh;
                arg = NULL;
        }
        DEFAULT(args, ((char *[]) {prog, arg, NULL}));

        unsetenv("COLUMNS");
        unsetenv("LINES");
        unsetenv("TERMCAP");
        setenv("LOGNAME", pw->pw_name, 1);
        setenv("USER", pw->pw_name, 1);
        setenv("SHELL", sh, 1);
        setenv("HOME", pw->pw_dir, 1);
        setenv("TERM", termname, 1);

        signal(SIGCHLD, SIG_DFL);
        signal(SIGHUP, SIG_DFL);
        signal(SIGINT, SIG_DFL);
        signal(SIGQUIT, SIG_DFL);
        signal(SIGTERM, SIG_DFL);
        signal(SIGALRM, SIG_DFL);

        execvp(prog, args);
        _exit(1);
}

sigchld

void
sigchld(int a)
{
        int stat;
        pid_t p;

        if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
                die("waiting for pid %hd failed: %s\n", pid, strerror(errno));

        if (pid != p)
                return;

        if (WIFEXITED(stat) && WEXITSTATUS(stat))
                die("child exited with status %d\n", WEXITSTATUS(stat));
        else if (WIFSIGNALED(stat))
                die("child terminated due to signal %d\n", WTERMSIG(stat));
        _exit(0);
}

stty

void
stty(char **args)
{
        char cmd[_POSIX_ARG_MAX], **p, *q, *s;
        size_t n, siz;

        if ((n = strlen(stty_args)) > sizeof(cmd)-1)
                die("incorrect stty parameters\n");
        memcpy(cmd, stty_args, n);
        q = cmd + n;
        siz = sizeof(cmd) - n;
        for (p = args; p && (s = *p); ++p) {
                if ((n = strlen(s)) > siz-1)
                        die("stty parameter length too long\n");
*q++ = ' ';
                memcpy(q, s, n);
                q += n;
                siz -= n + 1;
        }
*q = '\0';
        if (system(cmd) != 0)
                perror("Couldn't call stty");
}

ttynew

int
ttynew(const char *line, char *cmd, const char *out, char **args)
{
        int m, s;

        if (out) {
                term.mode |= MODE_PRINT;
                iofd = (!strcmp(out, "-")) ?
                          1 : open(out, O_WRONLY | O_CREAT, 0666);
                if (iofd < 0) {
                        fprintf(stderr, "Error opening %s:%s\n",
                                out, strerror(errno));
                }
        }

        if (line) {
                if ((cmdfd = open(line, O_RDWR)) < 0)
                        die("open line '%s' failed: %s\n",
                            line, strerror(errno));
                dup2(cmdfd, 0);
                stty(args);
                return cmdfd;
        }

        /* seems to work fine on linux, openbsd and freebsd */
        if (openpty(&m, &s, NULL, NULL, NULL) < 0)
                die("openpty failed: %s\n", strerror(errno));

        switch (pid = fork()) {
        case -1:
                die("fork failed: %s\n", strerror(errno));
                break;
        case 0:
                close(iofd);
                close(m);
                setsid(); /* create a new process group */
                dup2(s, 0);
                dup2(s, 1);
                dup2(s, 2);
                if (ioctl(s, TIOCSCTTY, NULL) < 0)
                        die("ioctl TIOCSCTTY failed: %s\n", strerror(errno));
                if (s > 2)
                        close(s);
#ifdef __OpenBSD__
                if (pledge("stdio getpw proc exec", NULL) == -1)
                        die("pledge\n");
#endif
                execsh(cmd, args);
                break;
        default:
#ifdef __OpenBSD__
                if (pledge("stdio rpath tty proc", NULL) == -1)
                        die("pledge\n");
#endif
                close(s);
                cmdfd = m;
                signal(SIGCHLD, sigchld);
                break;
        }
        return cmdfd;
}

ttyread

size_t
ttyread(void)
{
        static char buf[BUFSIZ];
        static int buflen = 0;
        int ret, written;

        /* append read bytes to unprocessed bytes */
        ret = read(cmdfd, buf+buflen, LEN(buf)-buflen);

        switch (ret) {
        case 0:
                exit(0);
        case -1:
                die("couldn't read from shell: %s\n", strerror(errno));
        default:
                buflen += ret;
                written = twrite(buf, buflen, 0);
                buflen -= written;
                /* keep any incomplete UTF-8 byte sequence for the next call */
                if (buflen > 0)
                        memmove(buf, buf + written, buflen);
                return ret;
        }
}

ttywrite

  void
  ttywrite(const char *s, size_t n, int may_echo)
  {
          char *str, *ptr;
          int y, bufsize, lastx, linelen;
          const Glyph *gp, *last;

          if (sel.ob.x == -1)
                  return NULL;

          bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
          ptr = str = xmalloc(bufsize);

          /* append every set & selected glyph to the selection */
          for (y = sel.nb.y; y <= sel.ne.y; y++) {
                  if ((linelen = tlinelen(y)) == 0) {
*ptr++ = '\n';
                          continue;
                  }

                  if (sel.type == SEL_RECTANGULAR) {
                          gp = &TLINE(y)[sel.nb.x];
                          lastx = sel.ne.x;
                  } else {
                          gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
                          lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
                  }
                  last = &TLINE(y)[MIN(lastx, linelen-1)];
                  while (last >= gp && last->u == ' ')
                          --last;

                  for ( ; gp <= last; ++gp) {
                          if (gp->mode & ATTR_WDUMMY)
                                  continue;

                          ptr += utf8encode(gp->u, ptr);
                  }

                  /*
* Copy and pasting of line endings is inconsistent
* in the inconsistent terminal and GUI world.
* The best solution seems like to produce '\n' when
* something is copied from st and convert '\n' to
* '\r', when something to be pasted is received by
* st.
* FIXME: Fix the computer world.
*/
                  if ((y < sel.ne.y || lastx >= linelen) &&
                      (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
*ptr++ = '\n';
          }
*ptr = 0;
          return str;
  }

ttywriteraw

void
ttywriteraw(const char *s, size_t n)
{
        fd_set wfd, rfd;
        ssize_t r;
        size_t lim = 256;

        /*
* Remember that we are using a pty, which might be a modem line.
* Writing too much will clog the line. That's why we are doing this
* dance.
* FIXME: Migrate the world to Plan 9.
*/
        while (n > 0) {
                FD_ZERO(&wfd);
                FD_ZERO(&rfd);
                FD_SET(cmdfd, &wfd);
                FD_SET(cmdfd, &rfd);

                /* Check if we can write. */
                if (pselect(cmdfd+1, &rfd, &wfd, NULL, NULL, NULL) < 0) {
                        if (errno == EINTR)
                                continue;
                        die("select failed: %s\n", strerror(errno));
                }
                if (FD_ISSET(cmdfd, &wfd)) {
                        /*
* Only write the bytes written by ttywrite() or the
* default of 256. This seems to be a reasonable value
* for a serial line. Bigger values might clog the I/O.
*/
                        if ((r = write(cmdfd, s, (n < lim)? n : lim)) < 0)
                                goto write_error;
                        if (r < n) {
                                /*
* We weren't able to write out everything.
* This means the buffer is getting full
* again. Empty it.
*/
                                if (n < lim)
                                        lim = ttyread();
                                n -= r;
                                s += r;
                        } else {
                                /* All bytes have been written. */
                                break;
                        }
                }
                if (FD_ISSET(cmdfd, &rfd))
                        lim = ttyread();
        }
        return;

write_error:
        die("write error on tty: %s\n", strerror(errno));
}

ttyresize

void
ttyresize(int tw, int th)
{
        struct winsize w;

        w.ws_row = term.row;
        w.ws_col = term.col;
        w.ws_xpixel = tw;
        w.ws_ypixel = th;
        if (ioctl(cmdfd, TIOCSWINSZ, &w) < 0)
                fprintf(stderr, "Couldn't set window size: %s\n", strerror(errno));
}

ttyhangup

void
ttyhangup(void)
{
        /* Send SIGHUP to shell */
        kill(pid, SIGHUP);
}

tattrset

int
tattrset(int attr)
{
        int i, j;

        for (i = 0; i < term.row-1; i++) {
                for (j = 0; j < term.col-1; j++) {
                        if (term.line[i][j].mode & attr)
                                return 1;
                }
        }

        return 0;
}

tsetdirt

void
tsetdirt(int top, int bot)
{
        int i;

        LIMIT(top, 0, term.row-1);
        LIMIT(bot, 0, term.row-1);

        for (i = top; i <= bot; i++)
                term.dirty[i] = 1;
}

tsetdirtattr

void
tsetdirtattr(int attr)
{
        int i, j;

        for (i = 0; i < term.row-1; i++) {
                for (j = 0; j < term.col-1; j++) {
                        if (term.line[i][j].mode & attr) {
                                tsetdirt(i, i);
                                break;
                        }
                }
        }
}

tfulldirt

void
tfulldirt(void)
{
        tsetdirt(0, term.row-1);
}

tcursor

void
tcursor(int mode)
{
        static TCursor c[2];
        int alt = IS_SET(MODE_ALTSCREEN);

        if (mode == CURSOR_SAVE) {
                c[alt] = term.c;
        } else if (mode == CURSOR_LOAD) {
                term.c = c[alt];
                tmoveto(c[alt].x, c[alt].y);
        }
}

treset

void
treset(void)
{
        uint i;

        term.c = (TCursor){{
                .mode = ATTR_NULL,
                .fg = defaultfg,
                .bg = defaultbg
        }, .x = 0, .y = 0, .state = CURSOR_DEFAULT};

        memset(term.tabs, 0, term.col * sizeof(*term.tabs));
        for (i = tabspaces; i < term.col; i += tabspaces)
                term.tabs[i] = 1;
        term.top = 0;
        term.bot = term.row - 1;
        term.mode = MODE_WRAP|MODE_UTF8;
        memset(term.trantbl, CS_USA, sizeof(term.trantbl));
        term.charset = 0;

        for (i = 0; i < 2; i++) {
                tmoveto(0, 0);
                tcursor(CURSOR_SAVE);
                tclearregion(0, 0, term.col-1, term.row-1);
                tswapscreen();
        }
}

tnew

void
tnew(int col, int row)
{
        term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
        tresize(col, row);
        treset();
}

tswapscreen

void
tswapscreen(void)
{
        Line *tmp = term.line;

        term.line = term.alt;
        term.alt = tmp;
        term.mode ^= MODE_ALTSCREEN;
        tfulldirt();
}

tscrolldown

void
tscrolldown(int orig, int n)
{
        int i;
        Line temp;

        LIMIT(n, 0, term.bot-orig+1);

        tsetdirt(orig, term.bot-n);
        tclearregion(0, term.bot-n+1, term.col-1, term.bot);

        for (i = term.bot; i >= orig+n; i--) {
                temp = term.line[i];
                term.line[i] = term.line[i-n];
                term.line[i-n] = temp;
        }

        selscroll(orig, n);
}

tscrollup

void
tscrollup(int orig, int n)
{
        int i;
        Line temp;

        LIMIT(n, 0, term.bot-orig+1);

        tclearregion(0, orig, term.col-1, orig+n-1);
        tsetdirt(orig+n, term.bot);

        for (i = orig; i <= term.bot-n; i++) {
                temp = term.line[i];
                term.line[i] = term.line[i+n];
                term.line[i+n] = temp;
        }

        selscroll(orig, -n);
}

selscroll

void
selscroll(int orig, int n)
{
        if (sel.ob.x == -1)
                return;

        if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig, term.bot)) {
                selclear();
        } else if (BETWEEN(sel.nb.y, orig, term.bot)) {
                sel.ob.y += n;
                sel.oe.y += n;
                if (sel.ob.y < term.top || sel.ob.y > term.bot ||
                    sel.oe.y < term.top || sel.oe.y > term.bot) {
                        selclear();
                } else {
                        selnormalize();
                }
        }
}

tnewline

void
tnewline(int first_col)
{
        int y = term.c.y;

        if (y == term.bot) {
                tscrollup(term.top, 1);
        } else {
                y++;
        }
        tmoveto(first_col ? 0 : term.c.x, y);
}

csiparse

void
csiparse(void)
{
        char *p = csiescseq.buf, *np;
        long int v;

        csiescseq.narg = 0;
        if (*p == '?') {
                csiescseq.priv = 1;
                p++;
        }

        csiescseq.buf[csiescseq.len] = '\0';
        while (p < csiescseq.buf+csiescseq.len) {
                np = NULL;
                v = strtol(p, &np, 10);
                if (np == p)
                        v = 0;
                if (v == LONG_MAX || v == LONG_MIN)
                        v = -1;
                csiescseq.arg[csiescseq.narg++] = v;
                p = np;
                if (*p != ';' || csiescseq.narg == ESC_ARG_SIZ)
                        break;
                p++;
        }
        csiescseq.mode[0] = *p++;
        csiescseq.mode[1] = (p < csiescseq.buf+csiescseq.len) ? *p : '\0';
}

tmoveato

/* for absolute user moves, when decom is set */
void
tmoveato(int x, int y)
{
        tmoveto(x, y + ((term.c.state & CURSOR_ORIGIN) ? term.top: 0));
}

tmoveto

void
tmoveto(int x, int y)
{
        int miny, maxy;

        if (term.c.state & CURSOR_ORIGIN) {
                miny = term.top;
                maxy = term.bot;
        } else {
                miny = 0;
                maxy = term.row - 1;
        }
        term.c.state &= ~CURSOR_WRAPNEXT;
        term.c.x = LIMIT(x, 0, term.col-1);
        term.c.y = LIMIT(y, miny, maxy);
}

tsetchar

void
tsetchar(Rune u, const Glyph *attr, int x, int y)
{
        static const char *vt100_0[62] = { /* 0x41 - 0x7e */
                "↑", "↓", "→", "←", "█", "▚", "☃", /* A - G */
                0, 0, 0, 0, 0, 0, 0, 0, /* H - O */
                0, 0, 0, 0, 0, 0, 0, 0, /* P - W */
                0, 0, 0, 0, 0, 0, 0, " ", /* X - _ */
                "◆", "▒", "␉", "␌", "␍", "␊", "°", "±", /* ` - g */
                "␤", "␋", "┘", "┐", "┌", "└", "┼", "⎺", /* h - o */
                "⎻", "─", "⎼", "⎽", "├", "┤", "┴", "┬", /* p - w */
                "│", "≤", "≥", "π", "≠", "£", "·", /* x - ~ */
        };

        /*
* The table is proudly stolen from rxvt.
*/
        if (term.trantbl[term.charset] == CS_GRAPHIC0 &&
           BETWEEN(u, 0x41, 0x7e) && vt100_0[u - 0x41])
                utf8decode(vt100_0[u - 0x41], &u, UTF_SIZ);

        if (term.line[y][x].mode & ATTR_WIDE) {
                if (x+1 < term.col) {
                        term.line[y][x+1].u = ' ';
                        term.line[y][x+1].mode &= ~ATTR_WDUMMY;
                }
        } else if (term.line[y][x].mode & ATTR_WDUMMY) {
                term.line[y][x-1].u = ' ';
                term.line[y][x-1].mode &= ~ATTR_WIDE;
        }

        term.dirty[y] = 1;
        term.line[y][x] = *attr;
        term.line[y][x].u = u;
}

tclearregion

void
tclearregion(int x1, int y1, int x2, int y2)
{
        int x, y, temp;
        Glyph *gp;

        if (x1 > x2)
                temp = x1, x1 = x2, x2 = temp;
        if (y1 > y2)
                temp = y1, y1 = y2, y2 = temp;

        LIMIT(x1, 0, term.col-1);
        LIMIT(x2, 0, term.col-1);
        LIMIT(y1, 0, term.row-1);
        LIMIT(y2, 0, term.row-1);

        for (y = y1; y <= y2; y++) {
                term.dirty[y] = 1;
                for (x = x1; x <= x2; x++) {
                        gp = &term.line[y][x];
                        if (selected(x, y))
                                selclear();
                        gp->fg = term.c.attr.fg;
                        gp->bg = term.c.attr.bg;
                        gp->mode = 0;
                        gp->u = ' ';
                }
        }
}

tdeletechar

void
tdeletechar(int n)
{
        int dst, src, size;
        Glyph *line;

        LIMIT(n, 0, term.col - term.c.x);

        dst = term.c.x;
        src = term.c.x + n;
        size = term.col - src;
        line = term.line[term.c.y];

        memmove(&line[dst], &line[src], size * sizeof(Glyph));
        tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
}

tinsertblank

void
tinsertblank(int n)
{
        int dst, src, size;
        Glyph *line;

        LIMIT(n, 0, term.col - term.c.x);

        dst = term.c.x + n;
        src = term.c.x;
        size = term.col - dst;
        line = term.line[term.c.y];

        memmove(&line[dst], &line[src], size * sizeof(Glyph));
        tclearregion(src, term.c.y, dst - 1, term.c.y);
}

tinsertblankline

void
tinsertblankline(int n)
{
        if (BETWEEN(term.c.y, term.top, term.bot))
                tscrolldown(term.c.y, n);
}

tdeleteline

void
tdeleteline(int n)
{
        if (BETWEEN(term.c.y, term.top, term.bot))
                tscrollup(term.c.y, n);
}

tdefcolor

int32_t
tdefcolor(const int *attr, int *npar, int l)
{
        int32_t idx = -1;
        uint r, g, b;

        switch (attr[*npar + 1]) {
        case 2: /* direct color in RGB space */
                if (*npar + 4 >= l) {
                        fprintf(stderr,
                                "erresc(38): Incorrect number of parameters (%d)\n",
*npar);
                        break;
                }
                r = attr[*npar + 2];
                g = attr[*npar + 3];
                b = attr[*npar + 4];
*npar += 4;
                if (!BETWEEN(r, 0, 255) || !BETWEEN(g, 0, 255) || !BETWEEN(b, 0, 255))
                        fprintf(stderr, "erresc: bad rgb color (%u,%u,%u)\n",
                                r, g, b);
                else
                        idx = TRUECOLOR(r, g, b);
                break;
        case 5: /* indexed color */
                if (*npar + 2 >= l) {
                        fprintf(stderr,
                                "erresc(38): Incorrect number of parameters (%d)\n",
*npar);
                        break;
                }
*npar += 2;
                if (!BETWEEN(attr[*npar], 0, 255))
                        fprintf(stderr, "erresc: bad fgcolor %d\n", attr[*npar]);
                else
                        idx = attr[*npar];
                break;
        case 0: /* implemented defined (only foreground) */
        case 1: /* transparent */
        case 3: /* direct color in CMY space */
        case 4: /* direct color in CMYK space */
        default:
                fprintf(stderr,
                        "erresc(38): gfx attr %d unknown\n", attr[*npar]);
                break;
        }

        return idx;
}

tsetattr

void
tsetattr(const int *attr, int l)
{
        int i;
        int32_t idx;

        for (i = 0; i < l; i++) {
                switch (attr[i]) {
                case 0:
                        term.c.attr.mode &= ~(
                                ATTR_BOLD       |
                                ATTR_FAINT      |
                                ATTR_ITALIC     |
                                ATTR_UNDERLINE  |
                                ATTR_BLINK      |
                                ATTR_REVERSE    |
                                ATTR_INVISIBLE  |
                                ATTR_STRUCK     );
                        term.c.attr.fg = defaultfg;
                        term.c.attr.bg = defaultbg;
                        break;
                case 1:
                        term.c.attr.mode |= ATTR_BOLD;
                        break;
                case 2:
                        term.c.attr.mode |= ATTR_FAINT;
                        break;
                case 3:
                        term.c.attr.mode |= ATTR_ITALIC;
                        break;
                case 4:
                        term.c.attr.mode |= ATTR_UNDERLINE;
                        break;
                case 5: /* slow blink */
                        /* FALLTHROUGH */
                case 6: /* rapid blink */
                        term.c.attr.mode |= ATTR_BLINK;
                        break;
                case 7:
                        term.c.attr.mode |= ATTR_REVERSE;
                        break;
                case 8:
                        term.c.attr.mode |= ATTR_INVISIBLE;
                        break;
                case 9:
                        term.c.attr.mode |= ATTR_STRUCK;
                        break;
                case 22:
                        term.c.attr.mode &= ~(ATTR_BOLD | ATTR_FAINT);
                        break;
                case 23:
                        term.c.attr.mode &= ~ATTR_ITALIC;
                        break;
                case 24:
                        term.c.attr.mode &= ~ATTR_UNDERLINE;
                        break;
                case 25:
                        term.c.attr.mode &= ~ATTR_BLINK;
                        break;
                case 27:
                        term.c.attr.mode &= ~ATTR_REVERSE;
                        break;
                case 28:
                        term.c.attr.mode &= ~ATTR_INVISIBLE;
                        break;
                case 29:
                        term.c.attr.mode &= ~ATTR_STRUCK;
                        break;
                case 38:
                        if ((idx = tdefcolor(attr, &i, l)) >= 0)
                                term.c.attr.fg = idx;
                        break;
                case 39:
                        term.c.attr.fg = defaultfg;
                        break;
                case 48:
                        if ((idx = tdefcolor(attr, &i, l)) >= 0)
                                term.c.attr.bg = idx;
                        break;
                case 49:
                        term.c.attr.bg = defaultbg;
                        break;
                default:
                        if (BETWEEN(attr[i], 30, 37)) {
                                term.c.attr.fg = attr[i] - 30;
                        } else if (BETWEEN(attr[i], 40, 47)) {
                                term.c.attr.bg = attr[i] - 40;
                        } else if (BETWEEN(attr[i], 90, 97)) {
                                term.c.attr.fg = attr[i] - 90 + 8;
                        } else if (BETWEEN(attr[i], 100, 107)) {
                                term.c.attr.bg = attr[i] - 100 + 8;
                        } else {
                                fprintf(stderr,
                                        "erresc(default): gfx attr %d unknown\n",
                                        attr[i]);
                                csidump();
                        }
                        break;
                }
        }
}

tsetscroll

void
tsetscroll(int t, int b)
{
        int temp;

        LIMIT(t, 0, term.row-1);
        LIMIT(b, 0, term.row-1);
        if (t > b) {
                temp = t;
                t = b;
                b = temp;
        }
        term.top = t;
        term.bot = b;
}

tsetmode

  void
  tsetmode(int priv, int set, const int *args, int narg)
  {
          int alt; const int *lim;

          for (lim = args + narg; args < lim; ++args) {
                  if (priv) {
                          switch (*args) {
                          case 1: /* DECCKM -- Cursor key */
                                  xsetmode(set, MODE_APPCURSOR);
                                  break;
                          case 5: /* DECSCNM -- Reverse video */
                                  xsetmode(set, MODE_REVERSE);
                                  break;
                          case 6: /* DECOM -- Origin */
                                  MODBIT(term.c.state, set, CURSOR_ORIGIN);
                                  tmoveato(0, 0);
                                  break;
                          case 7: /* DECAWM -- Auto wrap */
                                  MODBIT(term.mode, set, MODE_WRAP);
                                  break;
                          case 0:  /* Error (IGNORED) */
                          case 2:  /* DECANM -- ANSI/VT52 (IGNORED) */
                          case 3:  /* DECCOLM -- Column  (IGNORED) */
                          case 4:  /* DECSCLM -- Scroll (IGNORED) */
                          case 8:  /* DECARM -- Auto repeat (IGNORED) */
                          case 18: /* DECPFF -- Printer feed (IGNORED) */
                          case 19: /* DECPEX -- Printer extent (IGNORED) */
                          case 42: /* DECNRCM -- National characters (IGNORED) */
                          case 12: /* att610 -- Start blinking cursor (IGNORED) */
                                  break;
                          case 25: /* DECTCEM -- Text Cursor Enable Mode */
                                  xsetmode(!set, MODE_HIDE);
                                  break;
                          case 9:    /* X10 mouse compatibility mode */
                                  xsetpointermotion(0);
                                  xsetmode(0, MODE_MOUSE);
                                  xsetmode(set, MODE_MOUSEX10);
                                  break;
                          case 1000: /* 1000: report button press */
                                  xsetpointermotion(0);
                                  xsetmode(0, MODE_MOUSE);
                                  xsetmode(set, MODE_MOUSEBTN);
                                  break;
                          case 1002: /* 1002: report motion on button press */
                                  xsetpointermotion(0);
                                  xsetmode(0, MODE_MOUSE);
                                  xsetmode(set, MODE_MOUSEMOTION);
                                  break;
                          case 1003: /* 1003: enable all mouse motions */
                                  xsetpointermotion(set);
                                  xsetmode(0, MODE_MOUSE);
                                  xsetmode(set, MODE_MOUSEMANY);
                                  break;
                          case 1004: /* 1004: send focus events to tty */
                                  xsetmode(set, MODE_FOCUS);
                                  break;
                          case 1006: /* 1006: extended reporting mode */
                                  xsetmode(set, MODE_MOUSESGR);
                                  break;
                          case 1034:
                                  xsetmode(set, MODE_8BIT);
                                  break;
                          case 1049: /* swap screen & set/restore cursor as xterm */
                                  if (!allowaltscreen)
                                          break;
                                  tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
                                  /* FALLTHROUGH */
                          case 47: /* swap screen */
                          case 1047:
                                  if (!allowaltscreen)
                                          break;
                                  alt = IS_SET(MODE_ALTSCREEN);
                                  if (alt) {
                                          tclearregion(0, 0, term.col-1,
                                                          term.row-1);
                                  }
                                  if (set ^ alt) /* set is always 1 or 0 */
                                          tswapscreen();
                                  if (*args != 1049)
                                          break;
                                  /* FALLTHROUGH */
                          case 1048:
                                  tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
                                  break;
                          case 2004: /* 2004: bracketed paste mode */
                                  xsetmode(set, MODE_BRCKTPASTE);
                                  break;
                          /* Not implemented mouse modes. See comments there. */
                          case 1001: /* mouse highlight mode; can hang the
                                        terminal by design when implemented. */
                          case 1005: /* UTF-8 mouse mode; will confuse
                                        applications not supporting UTF-8
                                        and luit. */
                          case 1015: /* urxvt mangled mouse mode; incompatible
                                        and can be mistaken for other control
                                        codes. */
                                  break;
                          default:
                                  fprintf(stderr,
                                          "erresc: unknown private set/reset mode %d\n",
*args);
                                  break;
                          }
                  } else {
                          switch (*args) {
                          case 0:  /* Error (IGNORED) */
                                  break;
                          case 2:
                                  xsetmode(set, MODE_KBDLOCK);
                                  break;
                          case 4:  /* IRM -- Insertion-replacement */
                                  MODBIT(term.mode, set, MODE_INSERT);
                                  break;
                          case 12: /* SRM -- Send/Receive */
                                  MODBIT(term.mode, !set, MODE_ECHO);
                                  break;
                          case 20: /* LNM -- Linefeed/new line */
                                  MODBIT(term.mode, set, MODE_CRLF);
                                  break;
                          default:
                                  fprintf(stderr,
                                          "erresc: unknown set/reset mode %d\n",
*args);
                                  break;
                          }
                  }
          }
  }

csihandle

void
csihandle(void)
{
        char buf[40];
        int len;

        switch (csiescseq.mode[0]) {
        default:
        unknown:
                fprintf(stderr, "erresc: unknown csi ");
                csidump();
                /* die(""); */
                break;
        case '@': /* ICH -- Insert <n> blank char */
                DEFAULT(csiescseq.arg[0], 1);
                tinsertblank(csiescseq.arg[0]);
                break;
        case 'A': /* CUU -- Cursor <n> Up */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(term.c.x, term.c.y-csiescseq.arg[0]);
                break;
        case 'B': /* CUD -- Cursor <n> Down */
        case 'e': /* VPR --Cursor <n> Down */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(term.c.x, term.c.y+csiescseq.arg[0]);
                break;
        case 'i': /* MC -- Media Copy */
                switch (csiescseq.arg[0]) {
                case 0:
                        tdump();
                        break;
                case 1:
                        tdumpline(term.c.y);
                        break;
                case 2:
                        tdumpsel();
                        break;
                case 4:
                        term.mode &= ~MODE_PRINT;
                        break;
                case 5:
                        term.mode |= MODE_PRINT;
                        break;
                }
                break;
        case 'c': /* DA -- Device Attributes */
                if (csiescseq.arg[0] == 0)
                        ttywrite(vtiden, strlen(vtiden), 0);
                break;
        case 'b': /* REP -- if last char is printable print it <n> more times */
                DEFAULT(csiescseq.arg[0], 1);
                if (term.lastc)
                        while (csiescseq.arg[0]-- > 0)
                                tputc(term.lastc);
                break;
        case 'C': /* CUF -- Cursor <n> Forward */
        case 'a': /* HPR -- Cursor <n> Forward */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(term.c.x+csiescseq.arg[0], term.c.y);
                break;
        case 'D': /* CUB -- Cursor <n> Backward */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(term.c.x-csiescseq.arg[0], term.c.y);
                break;
        case 'E': /* CNL -- Cursor <n> Down and first col */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(0, term.c.y+csiescseq.arg[0]);
                break;
        case 'F': /* CPL -- Cursor <n> Up and first col */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(0, term.c.y-csiescseq.arg[0]);
                break;
        case 'g': /* TBC -- Tabulation clear */
                switch (csiescseq.arg[0]) {
                case 0: /* clear current tab stop */
                        term.tabs[term.c.x] = 0;
                        break;
                case 3: /* clear all the tabs */
                        memset(term.tabs, 0, term.col * sizeof(*term.tabs));
                        break;
                default:
                        goto unknown;
                }
                break;
        case 'G': /* CHA -- Move to <col> */
        case '`': /* HPA */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveto(csiescseq.arg[0]-1, term.c.y);
                break;
        case 'H': /* CUP -- Move to <row> <col> */
        case 'f': /* HVP */
                DEFAULT(csiescseq.arg[0], 1);
                DEFAULT(csiescseq.arg[1], 1);
                tmoveato(csiescseq.arg[1]-1, csiescseq.arg[0]-1);
                break;
        case 'I': /* CHT -- Cursor Forward Tabulation <n> tab stops */
                DEFAULT(csiescseq.arg[0], 1);
                tputtab(csiescseq.arg[0]);
                break;
        case 'J': /* ED -- Clear screen */
                switch (csiescseq.arg[0]) {
                case 0: /* below */
                        tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
                        if (term.c.y < term.row-1) {
                                tclearregion(0, term.c.y+1, term.col-1,
                                                term.row-1);
                        }
                        break;
                case 1: /* above */
                        if (term.c.y > 1)
                                tclearregion(0, 0, term.col-1, term.c.y-1);
                        tclearregion(0, term.c.y, term.c.x, term.c.y);
                        break;
                case 2: /* all */
                        tclearregion(0, 0, term.col-1, term.row-1);
                        break;
                default:
                        goto unknown;
                }
                break;
        case 'K': /* EL -- Clear line */
                switch (csiescseq.arg[0]) {
                case 0: /* right */
                        tclearregion(term.c.x, term.c.y, term.col-1,
                                        term.c.y);
                        break;
                case 1: /* left */
                        tclearregion(0, term.c.y, term.c.x, term.c.y);
                        break;
                case 2: /* all */
                        tclearregion(0, term.c.y, term.col-1, term.c.y);
                        break;
                }
                break;
        case 'S': /* SU -- Scroll <n> line up */
                DEFAULT(csiescseq.arg[0], 1);
                tscrollup(term.top, csiescseq.arg[0]);
                break;
        case 'T': /* SD -- Scroll <n> line down */
                DEFAULT(csiescseq.arg[0], 1);
                tscrolldown(term.top, csiescseq.arg[0]);
                break;
        case 'L': /* IL -- Insert <n> blank lines */
                DEFAULT(csiescseq.arg[0], 1);
                tinsertblankline(csiescseq.arg[0]);
                break;
        case 'l': /* RM -- Reset Mode */
                tsetmode(csiescseq.priv, 0, csiescseq.arg, csiescseq.narg);
                break;
        case 'M': /* DL -- Delete <n> lines */
                DEFAULT(csiescseq.arg[0], 1);
                tdeleteline(csiescseq.arg[0]);
                break;
        case 'X': /* ECH -- Erase <n> char */
                DEFAULT(csiescseq.arg[0], 1);
                tclearregion(term.c.x, term.c.y,
                                term.c.x + csiescseq.arg[0] - 1, term.c.y);
                break;
        case 'P': /* DCH -- Delete <n> char */
                DEFAULT(csiescseq.arg[0], 1);
                tdeletechar(csiescseq.arg[0]);
                break;
        case 'Z': /* CBT -- Cursor Backward Tabulation <n> tab stops */
                DEFAULT(csiescseq.arg[0], 1);
                tputtab(-csiescseq.arg[0]);
                break;
        case 'd': /* VPA -- Move to <row> */
                DEFAULT(csiescseq.arg[0], 1);
                tmoveato(term.c.x, csiescseq.arg[0]-1);
                break;
        case 'h': /* SM -- Set terminal mode */
                tsetmode(csiescseq.priv, 1, csiescseq.arg, csiescseq.narg);
                break;
        case 'm': /* SGR -- Terminal attribute (color) */
                tsetattr(csiescseq.arg, csiescseq.narg);
                break;
        case 'n': /* DSR – Device Status Report (cursor position) */
                if (csiescseq.arg[0] == 6) {
                        len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
                                        term.c.y+1, term.c.x+1);
                        ttywrite(buf, len, 0);
                }
                break;
        case 'r': /* DECSTBM -- Set Scrolling Region */
                if (csiescseq.priv) {
                        goto unknown;
                } else {
                        DEFAULT(csiescseq.arg[0], 1);
                        DEFAULT(csiescseq.arg[1], term.row);
                        tsetscroll(csiescseq.arg[0]-1, csiescseq.arg[1]-1);
                        tmoveato(0, 0);
                }
                break;
        case 's': /* DECSC -- Save cursor position (ANSI.SYS) */
                tcursor(CURSOR_SAVE);
                break;
        case 'u': /* DECRC -- Restore cursor position (ANSI.SYS) */
                tcursor(CURSOR_LOAD);
                break;
        case ' ':
                switch (csiescseq.mode[1]) {
                case 'q': /* DECSCUSR -- Set Cursor Style */
                        if (xsetcursor(csiescseq.arg[0]))
                                goto unknown;
                        break;
                default:
                        goto unknown;
                }
                break;
        }
}

csidump

void
csidump(void)
{
        size_t i;
        uint c;

        fprintf(stderr, "ESC[");
        for (i = 0; i < csiescseq.len; i++) {
                c = csiescseq.buf[i] & 0xff;
                if (isprint(c)) {
                        putc(c, stderr);
                } else if (c == '\n') {
                        fprintf(stderr, "(\\n)");
                } else if (c == '\r') {
                        fprintf(stderr, "(\\r)");
                } else if (c == 0x1b) {
                        fprintf(stderr, "(\\e)");
                } else {
                        fprintf(stderr, "(%02x)", c);
                }
        }
        putc('\n', stderr);
}

csireset

void
csireset(void)
{
        memset(&csiescseq, 0, sizeof(csiescseq));
}

osc_color_response

void
osc_color_response(int num, int index, int is_osc4)
{
        int n;
        char buf[32];
        unsigned char r, g, b;

        if (xgetcolor(is_osc4 ? num : index, &r, &g, &b)) {
                fprintf(stderr, "erresc: failed to fetch %s color %d\n",
                        is_osc4 ? "osc4" : "osc",
                        is_osc4 ? num : index);
                return;
        }

        n = snprintf(buf, sizeof buf, "\033]%s%d;rgb:%02x%02x/%02x%02x/%02x%02x\007",
                     is_osc4 ? "4;" : "", num, r, r, g, g, b, b);
        if (n < 0 || n >= sizeof(buf)) {
                fprintf(stderr, "error: %s while printing %s response\n",
                        n < 0 ? "snprintf failed" : "truncation occurred",
                        is_osc4 ? "osc4" : "osc");
        } else {
                ttywrite(buf, n, 1);
        }
}

strhandle

  void
  strhandle(void)
  {
          char *p = NULL, *dec;
          int j, narg, par;
          const struct { int idx; char *str; } osc_table[] = {
                  { defaultfg, "foreground" },
                  { defaultbg, "background" },
                  { defaultcs, "cursor" }
          };

          term.esc &= ~(ESC_STR_END|ESC_STR);
          strparse();
          par = (narg = strescseq.narg) ? atoi(strescseq.args[0]) : 0;

          switch (strescseq.type) {
          case ']': /* OSC -- Operating System Command */
                  switch (par) {
                  case 0:
                          if (narg > 1) {
                                  xsettitle(strescseq.args[1]);
                                  xseticontitle(strescseq.args[1]);
                          }
                          return;
                  case 1:
                          if (narg > 1)
                                  xseticontitle(strescseq.args[1]);
                          return;
                  case 2:
                          if (narg > 1)
                                  xsettitle(strescseq.args[1]);
                          return;
                  case 52:
                          if (narg > 2 && allowwindowops) {
                                  dec = base64dec(strescseq.args[2]);
                                  if (dec) {
                                          xsetsel(dec);
                                          xclipcopy();
                                  } else {
                                          fprintf(stderr, "erresc: invalid base64\n");
                                  }
                          }
                          return;
                  case 10:
                  case 11:
                  case 12:
                          if (narg < 2)
                                  break;
                          p = strescseq.args[1];
                          if ((j = par - 10) < 0 || j >= LEN(osc_table))
                                  break; /* shouldn't be possible */

                          if (!strcmp(p, "?")) {
                                  osc_color_response(par, osc_table[j].idx, 0);
                          } else if (xsetcolorname(osc_table[j].idx, p)) {
                                  fprintf(stderr, "erresc: invalid %s color: %s\n",
                                          osc_table[j].str, p);
                          } else {
                                  tfulldirt();
                          }
                          return;
                  case 4: /* color set */
                          if (narg < 3)
                                  break;
                          p = strescseq.args[2];
                          /* FALLTHROUGH */
                  case 104: /* color reset */
                          j = (narg > 1) ? atoi(strescseq.args[1]) : -1;

                          if (p && !strcmp(p, "?")) {
                                  osc_color_response(j, 0, 1);
                          } else if (xsetcolorname(j, p)) {
                                  if (par == 104 && narg <= 1)
                                          return; /* color reset without parameter */
                                  fprintf(stderr, "erresc: invalid color j=%d, p=%s\n",
                                          j, p ? p : "(null)");
                          } else {
                                  /*
* TODO if defaultbg color is changed, borders
* are dirty
*/
                                  tfulldirt();
                          }
                          return;
                  }
                  break;
          case 'k': /* old title set compatibility */
                  xsettitle(strescseq.args[0]);
                  return;
          case 'P': /* DCS -- Device Control String */
          case '_': /* APC -- Application Program Command */
          case '^': /* PM -- Privacy Message */
                  return;
          }

          fprintf(stderr, "erresc: unknown str ");
          strdump();
  }

strparse

  void
  strparse(void)
  {
          int c;
          char *p = strescseq.buf;

          strescseq.narg = 0;
          strescseq.buf[strescseq.len] = '\0';

          if (*p == '\0')
                  return;

          while (strescseq.narg < STR_ARG_SIZ) {
                  strescseq.args[strescseq.narg++] = p;
                  while ((c = *p) != ';' && c != '\0')
                          ++p;
                  if (c == '\0')
                          return;
*p++ = '\0';
          }
  }

strdump

void
strdump(void)
{
        size_t i;
        uint c;

        fprintf(stderr, "ESC%c", strescseq.type);
        for (i = 0; i < strescseq.len; i++) {
                c = strescseq.buf[i] & 0xff;
                if (c == '\0') {
                        putc('\n', stderr);
                        return;
                } else if (isprint(c)) {
                        putc(c, stderr);
                } else if (c == '\n') {
                        fprintf(stderr, "(\\n)");
                } else if (c == '\r') {
                        fprintf(stderr, "(\\r)");
                } else if (c == 0x1b) {
                        fprintf(stderr, "(\\e)");
                } else {
                        fprintf(stderr, "(%02x)", c);
                }
        }
        fprintf(stderr, "ESC\\\n");
}

strreset

void
strreset(void)
{
        strescseq = (STREscape){
                .buf = xrealloc(strescseq.buf, STR_BUF_SIZ),
                .siz = STR_BUF_SIZ,
        };
}

sendbreak

void
sendbreak(const Arg *arg)
{
        if (tcsendbreak(cmdfd, 0))
                perror("Error sending break");
}

tprinter

void
tprinter(char *s, size_t len)
{
        if (iofd != -1 && xwrite(iofd, s, len) < 0) {
                perror("Error writing to output file");
                close(iofd);
                iofd = -1;
        }
}

toggleprinter

void
toggleprinter(const Arg *arg)
{
        term.mode ^= MODE_PRINT;
}

printscreen

void
printscreen(const Arg *arg)
{
        tdump();
}

printsel

void
printsel(const Arg *arg)
{
        tdumpsel();
}

tdumpsel

void
tdumpsel(void)
{
        char *ptr;

        if ((ptr = getsel())) {
                tprinter(ptr, strlen(ptr));
                free(ptr);
        }
}

tdumpline

void
tdumpline(int n)
{
        char buf[UTF_SIZ];
        const Glyph *bp, *end;

        bp = &term.line[n][0];
        end = &bp[MIN(tlinelen(n), term.col) - 1];
        if (bp != end || bp->u != ' ') {
                for ( ; bp <= end; ++bp)
                        tprinter(buf, utf8encode(bp->u, buf));
        }
        tprinter("\n", 1);
}

tdump

void
tdump(void)
{
        int i;

        for (i = 0; i < term.row; ++i)
                tdumpline(i);
}

tputtab

void
tputtab(int n)
{
        uint x = term.c.x;

        if (n > 0) {
                while (x < term.col && n--)
                        for (++x; x < term.col && !term.tabs[x]; ++x)
                                /* nothing */ ;
        } else if (n < 0) {
                while (x > 0 && n++)
                        for (--x; x > 0 && !term.tabs[x]; --x)
                                /* nothing */ ;
        }
        term.c.x = LIMIT(x, 0, term.col-1);
}

tdefutf8

void
tdefutf8(char ascii)
{
        if (ascii == 'G')
                term.mode |= MODE_UTF8;
        else if (ascii == '@')
                term.mode &= ~MODE_UTF8;
}

tdeftran

void
tdeftran(char ascii)
{
        static char cs[] = "0B";
        static int vcs[] = {CS_GRAPHIC0, CS_USA};
        char *p;

        if ((p = strchr(cs, ascii)) == NULL) {
                fprintf(stderr, "esc unhandled charset: ESC ( %c\n", ascii);
        } else {
                term.trantbl[term.icharset] = vcs[p - cs];
        }
}

tdectest

void
tdectest(char c)
{
        int x, y;

        if (c == '8') { /* DEC screen alignment test. */
                for (x = 0; x < term.col; ++x) {
                        for (y = 0; y < term.row; ++y)
                                tsetchar('E', &term.c.attr, x, y);
                }
        }
}

tstrsequence

void
tstrsequence(uchar c)
{
        switch (c) {
        case 0x90:   /* DCS -- Device Control String */
                c = 'P';
                break;
        case 0x9f:   /* APC -- Application Program Command */
                c = '_';
                break;
        case 0x9e:   /* PM -- Privacy Message */
                c = '^';
                break;
        case 0x9d:   /* OSC -- Operating System Command */
                c = ']';
                break;
        }
        strreset();
        strescseq.type = c;
        term.esc |= ESC_STR;
}

tcontrolcode

void
tcontrolcode(uchar ascii)
{
        switch (ascii) {
        case '\t':   /* HT */
                tputtab(1);
                return;
        case '\b':   /* BS */
                tmoveto(term.c.x-1, term.c.y);
                return;
        case '\r':   /* CR */
                tmoveto(0, term.c.y);
                return;
        case '\f':   /* LF */
        case '\v':   /* VT */
        case '\n':   /* LF */
                /* go to first col if the mode is set */
                tnewline(IS_SET(MODE_CRLF));
                return;
        case '\a':   /* BEL */
                if (term.esc & ESC_STR_END) {
                        /* backwards compatibility to xterm */
                        strhandle();
                } else {
                        xbell();
                }
                break;
        case '\033': /* ESC */
                csireset();
                term.esc &= ~(ESC_CSI|ESC_ALTCHARSET|ESC_TEST);
                term.esc |= ESC_START;
                return;
        case '\016': /* SO (LS1 -- Locking shift 1) */
        case '\017': /* SI (LS0 -- Locking shift 0) */
                term.charset = 1 - (ascii - '\016');
                return;
        case '\032': /* SUB */
                tsetchar('?', &term.c.attr, term.c.x, term.c.y);
                /* FALLTHROUGH */
        case '\030': /* CAN */
                csireset();
                break;
        case '\005': /* ENQ (IGNORED) */
        case '\000': /* NUL (IGNORED) */
        case '\021': /* XON (IGNORED) */
        case '\023': /* XOFF (IGNORED) */
        case 0177:   /* DEL (IGNORED) */
                return;
        case 0x80:   /* TODO: PAD */
        case 0x81:   /* TODO: HOP */
        case 0x82:   /* TODO: BPH */
        case 0x83:   /* TODO: NBH */
        case 0x84:   /* TODO: IND */
                break;
        case 0x85:   /* NEL -- Next line */
                tnewline(1); /* always go to first col */
                break;
        case 0x86:   /* TODO: SSA */
        case 0x87:   /* TODO: ESA */
                break;
        case 0x88:   /* HTS -- Horizontal tab stop */
                term.tabs[term.c.x] = 1;
                break;
        case 0x89:   /* TODO: HTJ */
        case 0x8a:   /* TODO: VTS */
        case 0x8b:   /* TODO: PLD */
        case 0x8c:   /* TODO: PLU */
        case 0x8d:   /* TODO: RI */
        case 0x8e:   /* TODO: SS2 */
        case 0x8f:   /* TODO: SS3 */
        case 0x91:   /* TODO: PU1 */
        case 0x92:   /* TODO: PU2 */
        case 0x93:   /* TODO: STS */
        case 0x94:   /* TODO: CCH */
        case 0x95:   /* TODO: MW */
        case 0x96:   /* TODO: SPA */
        case 0x97:   /* TODO: EPA */
        case 0x98:   /* TODO: SOS */
        case 0x99:   /* TODO: SGCI */
                break;
        case 0x9a:   /* DECID -- Identify Terminal */
                ttywrite(vtiden, strlen(vtiden), 0);
                break;
        case 0x9b:   /* TODO: CSI */
        case 0x9c:   /* TODO: ST */
                break;
        case 0x90:   /* DCS -- Device Control String */
        case 0x9d:   /* OSC -- Operating System Command */
        case 0x9e:   /* PM -- Privacy Message */
        case 0x9f:   /* APC -- Application Program Command */
                tstrsequence(ascii);
                return;
        }
        /* only CAN, SUB, \a and C1 chars interrupt a sequence */
        term.esc &= ~(ESC_STR_END|ESC_STR);
}

eschandle

  /*
* returns 1 when the sequence is finished and it hasn't to read
* more characters for this sequence, otherwise 0
*/
  int
  eschandle(uchar ascii)
  {
          switch (ascii) {
          case '[':
                  term.esc |= ESC_CSI;
                  return 0;
          case '#':
                  term.esc |= ESC_TEST;
                  return 0;
          case '%':
                  term.esc |= ESC_UTF8;
                  return 0;
          case 'P': /* DCS -- Device Control String */
          case '_': /* APC -- Application Program Command */
          case '^': /* PM -- Privacy Message */
          case ']': /* OSC -- Operating System Command */
          case 'k': /* old title set compatibility */
                  tstrsequence(ascii);
                  return 0;
          case 'n': /* LS2 -- Locking shift 2 */
          case 'o': /* LS3 -- Locking shift 3 */
                  term.charset = 2 + (ascii - 'n');
                  break;
          case '(': /* GZD4 -- set primary charset G0 */
          case ')': /* G1D4 -- set secondary charset G1 */
          case '*': /* G2D4 -- set tertiary charset G2 */
          case '+': /* G3D4 -- set quaternary charset G3 */
                  term.icharset = ascii - '(';
                  term.esc |= ESC_ALTCHARSET;
                  return 0;
          case 'D': /* IND -- Linefeed */
                  if (term.c.y == term.bot) {
                          tscrollup(term.top, 1);
                  } else {
                          tmoveto(term.c.x, term.c.y+1);
                  }
                  break;
          case 'E': /* NEL -- Next line */
                  tnewline(1); /* always go to first col */
                  break;
          case 'H': /* HTS -- Horizontal tab stop */
                  term.tabs[term.c.x] = 1;
                  break;
          case 'M': /* RI -- Reverse index */
                  if (term.c.y == term.top) {
                          tscrolldown(term.top, 1);
                  } else {
                          tmoveto(term.c.x, term.c.y-1);
                  }
                  break;
          case 'Z': /* DECID -- Identify Terminal */
                  ttywrite(vtiden, strlen(vtiden), 0);
                  break;
          case 'c': /* RIS -- Reset to initial state */
                  treset();
                  resettitle();
                  xloadcols();
                  break;
          case '=': /* DECPAM -- Application keypad */
                  xsetmode(1, MODE_APPKEYPAD);
                  break;
          case '>': /* DECPNM -- Normal keypad */
                  xsetmode(0, MODE_APPKEYPAD);
                  break;
          case '7': /* DECSC -- Save Cursor */
                  tcursor(CURSOR_SAVE);
                  break;
          case '8': /* DECRC -- Restore Cursor */
                  tcursor(CURSOR_LOAD);
                  break;
          case '\\': /* ST -- String Terminator */
                  if (term.esc & ESC_STR_END)
                          strhandle();
                  break;
          default:
                  fprintf(stderr, "erresc: unknown sequence ESC 0x%02X '%c'\n",
                          (uchar) ascii, isprint(ascii)? ascii:'.');
                  break;
          }
          return 1;
  }

tputc

  void
  tputc(Rune u)
  {
          char c[UTF_SIZ];
          int control;
          int width, len;
          Glyph *gp;

          control = ISCONTROL(u);
          if (u < 127 || !IS_SET(MODE_UTF8)) {
                  c[0] = u;
                  width = len = 1;
          } else {
                  len = utf8encode(u, c);
                  if (!control && (width = wcwidth(u)) == -1)
                          width = 1;
          }

          if (IS_SET(MODE_PRINT))
                  tprinter(c, len);

          /*
* STR sequence must be checked before anything else
* because it uses all following characters until it
* receives a ESC, a SUB, a ST or any other C1 control
* character.
*/
          if (term.esc & ESC_STR) {
                  if (u == '\a' || u == 030 || u == 032 || u == 033 ||
                     ISCONTROLC1(u)) {
                          term.esc &= ~(ESC_START|ESC_STR);
                          term.esc |= ESC_STR_END;
                          goto check_control_code;
                  }

                  if (strescseq.len+len >= strescseq.siz) {
                          /*
* Here is a bug in terminals. If the user never sends
* some code to stop the str or esc command, then st
* will stop responding. But this is better than
* silently failing with unknown characters. At least
* then users will report back.
*
* In the case users ever get fixed, here is the code:
*/
                          /*
* term.esc = 0;
* strhandle();
*/
                          if (strescseq.siz > (SIZE_MAX - UTF_SIZ) / 2)
                                  return;
                          strescseq.siz *= 2;
                          strescseq.buf = xrealloc(strescseq.buf, strescseq.siz);
                  }

                  memmove(&strescseq.buf[strescseq.len], c, len);
                  strescseq.len += len;
                  return;
          }

  check_control_code:
          /*
* Actions of control codes must be performed as soon they arrive
* because they can be embedded inside a control sequence, and
* they must not cause conflicts with sequences.
*/
          if (control) {
                  tcontrolcode(u);
                  /*
* control codes are not shown ever
*/
                  if (!term.esc)
                          term.lastc = 0;
                  return;
          } else if (term.esc & ESC_START) {
                  if (term.esc & ESC_CSI) {
                          csiescseq.buf[csiescseq.len++] = u;
                          if (BETWEEN(u, 0x40, 0x7E)
                                          || csiescseq.len >= \
                                          sizeof(csiescseq.buf)-1) {
                                  term.esc = 0;
                                  csiparse();
                                  csihandle();
                          }
                          return;
                  } else if (term.esc & ESC_UTF8) {
                          tdefutf8(u);
                  } else if (term.esc & ESC_ALTCHARSET) {
                          tdeftran(u);
                  } else if (term.esc & ESC_TEST) {
                          tdectest(u);
                  } else {
                          if (!eschandle(u))
                                  return;
                          /* sequence already finished */
                  }
                  term.esc = 0;
                  /*
* All characters which form part of a sequence are not
* printed
*/
                  return;
          }
          if (selected(term.c.x, term.c.y))
                  selclear();

          gp = &term.line[term.c.y][term.c.x];
          if (IS_SET(MODE_WRAP) && (term.c.state & CURSOR_WRAPNEXT)) {
                  gp->mode |= ATTR_WRAP;
                  tnewline(1);
                  gp = &term.line[term.c.y][term.c.x];
          }

          if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
                  memmove(gp+width, gp, (term.col - term.c.x - width) * sizeof(Glyph));

          if (term.c.x+width > term.col) {
                  tnewline(1);
                  gp = &term.line[term.c.y][term.c.x];
          }

          tsetchar(u, &term.c.attr, term.c.x, term.c.y);
          term.lastc = u;

          if (width == 2) {
                  gp->mode |= ATTR_WIDE;
                  if (term.c.x+1 < term.col) {
                          if (gp[1].mode == ATTR_WIDE && term.c.x+2 < term.col) {
                                  gp[2].u = ' ';
                                  gp[2].mode &= ~ATTR_WDUMMY;
                          }
                          gp[1].u = '\0';
                          gp[1].mode = ATTR_WDUMMY;
                  }
          }
          if (term.c.x+width < term.col) {
                  tmoveto(term.c.x+width, term.c.y);
          } else {
                  term.c.state |= CURSOR_WRAPNEXT;
          }
  }

twrite

int
twrite(const char *buf, int buflen, int show_ctrl)
{
        int charsize;
        Rune u;
        int n;

        for (n = 0; n < buflen; n += charsize) {
                if (IS_SET(MODE_UTF8)) {
                        /* process a complete utf8 char */
                        charsize = utf8decode(buf + n, &u, buflen - n);
                        if (charsize == 0)
                                break;
                } else {
                        u = buf[n] & 0xFF;
                        charsize = 1;
                }
                if (show_ctrl && ISCONTROL(u)) {
                        if (u & 0x80) {
                                u &= 0x7f;
                                tputc('^');
                                tputc('[');
                        } else if (u != '\n' && u != '\r' && u != '\t') {
                                u ^= 0x40;
                                tputc('^');
                        }
                }
                tputc(u);
        }
        return n;
}

tresize

  void
  tresize(int col, int row)
  {
          int i;
          int minrow = MIN(row, term.row);
          int mincol = MIN(col, term.col);
          int *bp;
          TCursor c;

          if (col < 1 || row < 1) {
                  fprintf(stderr,
                          "tresize: error resizing to %dx%d\n", col, row);
                  return;
          }

          /*
* slide screen to keep cursor where we expect it -
* tscrollup would work here, but we can optimize to
* memmove because we're freeing the earlier lines
*/
          for (i = 0; i <= term.c.y - row; i++) {
                  free(term.line[i]);
                  free(term.alt[i]);
          }
          /* ensure that both src and dst are not NULL */
          if (i > 0) {
                  memmove(term.line, term.line + i, row * sizeof(Line));
                  memmove(term.alt, term.alt + i, row * sizeof(Line));
          }
          for (i += row; i < term.row; i++) {
                  free(term.line[i]);
                  free(term.alt[i]);
          }

          /* resize to new height */
          term.line = xrealloc(term.line, row * sizeof(Line));
          term.alt  = xrealloc(term.alt,  row * sizeof(Line));
          term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
          term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));

          /* resize each row to new width, zero-pad if needed */
          for (i = 0; i < minrow; i++) {
                  term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
                  term.alt[i]  = xrealloc(term.alt[i],  col * sizeof(Glyph));
          }

          /* allocate any new rows */
          for (/* i = minrow */; i < row; i++) {
                  term.line[i] = xmalloc(col * sizeof(Glyph));
                  term.alt[i] = xmalloc(col * sizeof(Glyph));
          }
          if (col > term.col) {
                  bp = term.tabs + term.col;

                  memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
                  while (--bp > term.tabs && !*bp)
                          /* nothing */ ;
                  for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
*bp = 1;
          }
          /* update terminal size */
          term.col = col;
          term.row = row;
          /* reset scrolling region */
          tsetscroll(0, row-1);
          /* make use of the LIMIT in tmoveto */
          tmoveto(term.c.x, term.c.y);
          /* Clearing both screens (it makes dirty all lines) */
          c = term.c;
          for (i = 0; i < 2; i++) {
                  if (mincol < col && 0 < minrow) {
                          tclearregion(mincol, 0, col - 1, minrow - 1);
                  }
                  if (0 < col && minrow < row) {
                          tclearregion(0, minrow, col - 1, row - 1);
                  }
                  tswapscreen();
                  tcursor(CURSOR_LOAD);
          }
          term.c = c;
  }

resettitle

void
resettitle(void)
{
        xsettitle(NULL);
}

drawregion

void
drawregion(int x1, int y1, int x2, int y2)
{
        int y;

        for (y = y1; y < y2; y++) {
                if (!term.dirty[y])
                        continue;

                term.dirty[y] = 0;
                xdrawline(term.line[y], x1, y, x2);
        }
}

draw

void
draw(void)
{
        int cx = term.c.x, ocx = term.ocx, ocy = term.ocy;

        if (!xstartdraw())
                return;

        /* adjust cursor position */
        LIMIT(term.ocx, 0, term.col-1);
        LIMIT(term.ocy, 0, term.row-1);
        if (term.line[term.ocy][term.ocx].mode & ATTR_WDUMMY)
                term.ocx--;
        if (term.line[term.c.y][cx].mode & ATTR_WDUMMY)
                cx--;

        drawregion(0, 0, term.col, term.row);
        xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
                        term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
        term.ocx = cx;
        term.ocy = term.c.y;
        xfinishdraw();
        if (ocx != term.ocx || ocy != term.ocy)
                xximspot(term.ocx, term.ocy);
}

redraw

void
redraw(void)
{
        tfulldirt();
        draw();
}

Stのソースコードのライセンス文

MIT/X Consortium License

© 2014-2022 Hiltjo Posthuma <hiltjo at codemadness dot org> © 2018 Devin J. Pohly <djpohly at gmail dot com> © 2014-2017 Quentin Rameau <quinq at fifth dot space> © 2009-2012 Aurélien APTEL <aurelien dot aptel at gmail dot com> © 2008-2017 Anselm R Garbe <garbeam at gmail dot com> © 2012-2017 Roberto E. Vargas Caballero <k0ga at shike2 dot com> © 2012-2016 Christoph Lohmann <20h at r-36 dot net> © 2013 Eon S. Jeon <esjeon at hyunmu dot am> © 2013 Alexander Sedov <alex0player at gmail dot com> © 2013 Mark Edgar <medgar123 at gmail dot com> © 2013-2014 Eric Pruitt <eric.pruitt at gmail dot com> © 2013 Michael Forney <mforney at mforney dot org> © 2013-2014 Markus Teich <markus dot teich at stusta dot mhn dot de> © 2014-2015 Laslo Hunhold <dev at frign dot de>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.