st

 /* 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
 #define HISTSIZE      2000
 
 /* 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))
 #define TLINE(y)        ((y) < term.scr ? term.hist[((y) + term.histi - \
                 term.scr + HISTSIZE + 1) % HISTSIZE] : \
                 term.line[(y) - term.scr])
 
 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 */
     Line hist[HISTSIZE]; /* history buffer */
     int histi;    /* history index */
     int scr;      /* scroll back */
     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, int);
 static void tscrolldown(int, 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};
 
 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;
 }
 
 void *
 xmalloc(size_t len)
 {
     void *p;
 
     if (!(p = malloc(len)))
         die("malloc: %s\n", strerror(errno));
 
     return p;
 }
 
 void *
 xrealloc(void *p, size_t len)
 {
     if ((p = realloc(p, len)) == NULL)
         die("realloc: %s\n", strerror(errno));
 
     return p;
 }
 
 char *
 xstrdup(const char *s)
 {
     char *p;
 
     if ((p = strdup(s)) == NULL)
         die("strdup: %s\n", strerror(errno));
 
     return p;
 }
 
 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;
 }
 
 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;
 }
 
 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;
 }
 
 char
 utf8encodebyte(Rune u, size_t i)
 {
     return utfbyte[i] | (u & ~utfmask[i]);
 }
 
 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;
 }
 
 char
 base64dec_getc(const char **src)
 {
     while (**src && !isprint((unsigned char)**src))
         (*src)++;
     return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
 }
 
 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;
 }
 
 void
 selinit(void)
 {
     sel.mode = SEL_IDLE;
     sel.snap = 0;
     sel.ob.x = -1;
 }
 
 int
 tlinelen(int y)
 {
     int i = term.col;
 
     if (TLINE(y)[i - 1].mode & ATTR_WRAP)
         return i;
 
     while (i > 0 && TLINE(y)[i - 1].u == ' ')
         --i;
 
     return i;
 }
 
 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);
 }
 
 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;
 }
 
 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;
 }
 
 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);
 }
 
 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 = &TLINE(*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 (!(TLINE(yt)[xt].mode & ATTR_WRAP))
                     break;
             }
 
             if (newx >= tlinelen(newy))
                 break;
 
             gp = &TLINE(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 (!(TLINE(*y-1)[term.col-1].mode
                         & ATTR_WRAP)) {
                     break;
                 }
             }
         } else if (direction > 0) {
             for (; *y < term.row-1; *y += direction) {
                 if (!(TLINE(*y)[term.col-1].mode
                         & ATTR_WRAP)) {
                     break;
                 }
             }
         }
         break;
     }
 }
 
 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 = &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;
 }
 
 void
 selclear(void)
 {
     if (sel.ob.x == -1)
         return;
     sel.mode = SEL_IDLE;
     sel.ob.x = -1;
     tsetdirt(sel.nb.y, sel.ne.y);
 }
 
 void
 die(const char *errstr, ...)
 {
     va_list ap;
 
     va_start(ap, errstr);
     vfprintf(stderr, errstr, ap);
     va_end(ap);
     exit(1);
 }
 
 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);
 }
 
 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);
 }
 
 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");
 }
 
 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;
 }
 
 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;
     }
 }
 
 void
 ttywrite(const char *s, size_t n, int may_echo)
 {
     const char *next;
     Arg arg = (Arg) { .i = term.scr };
 
     kscrolldown(&arg);
 
     if (may_echo && IS_SET(MODE_ECHO))
         twrite(s, n, 1);
 
     if (!IS_SET(MODE_CRLF)) {
         ttywriteraw(s, n);
         return;
     }
 
     /* This is similar to how the kernel handles ONLCR for ttys */
     while (n > 0) {
         if (*s == '\r') {
             next = s + 1;
             ttywriteraw("\r\n", 2);
         } else {
             next = memchr(s, '\r', n);
             DEFAULT(next, s + n);
             ttywriteraw(s, next - s);
         }
         n -= next - s;
         s = next;
     }
 }
 
 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));
 }
 
 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));
 }
 
 void
 ttyhangup(void)
 {
     /* Send SIGHUP to shell */
     kill(pid, SIGHUP);
 }
 
 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;
 }
 
 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;
 }
 
 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;
             }
         }
     }
 }
 
 void
 tfulldirt(void)
 {
     tsetdirt(0, term.row-1);
 }
 
 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);
     }
 }
 
 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();
     }
 }
 
 void
 tnew(int col, int row)
 {
     term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
     tresize(col, row);
     treset();
 }
 
 int tisaltscr(void)
 {
     return IS_SET(MODE_ALTSCREEN);
 }
 
 void
 tswapscreen(void)
 {
     Line *tmp = term.line;
 
     term.line = term.alt;
     term.alt = tmp;
     term.mode ^= MODE_ALTSCREEN;
     tfulldirt();
 }
 
 void
 kscrolldown(const Arg* a)
 {
     int n = a->i;
 
     if (n < 0)
         n = term.row + n;
 
     if (n > term.scr)
         n = term.scr;
 
     if (term.scr > 0) {
         term.scr -= n;
         selscroll(0, -n);
         tfulldirt();
     }
 }
 
 void
 kscrollup(const Arg* a)
 {
     int n = a->i;
 
     if (n < 0)
         n = term.row + n;
 
     if (term.scr <= HISTSIZE-n) {
         term.scr += n;
         selscroll(0, n);
         tfulldirt();
     }
 }
 
 void
 tscrolldown(int orig, int n, int copyhist)
 {
     int i;
     Line temp;
 
     LIMIT(n, 0, term.bot-orig+1);
 
     if (copyhist) {
         term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
         temp = term.hist[term.histi];
         term.hist[term.histi] = term.line[term.bot];
         term.line[term.bot] = temp;
     }
 
     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;
     }
 
     if (term.scr == 0)
         selscroll(orig, n);
 }
 
 void
 tscrollup(int orig, int n, int copyhist)
 {
     int i;
     Line temp;
 
     LIMIT(n, 0, term.bot-orig+1);
 
     if (copyhist) {
         term.histi = (term.histi + 1) % HISTSIZE;
         temp = term.hist[term.histi];
         term.hist[term.histi] = term.line[orig];
         term.line[orig] = temp;
     }
 
     if (term.scr > 0 && term.scr < HISTSIZE)
         term.scr = MIN(term.scr + n, HISTSIZE-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;
     }
 
     if (term.scr == 0)
         selscroll(orig, -n);
 }
 
 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();
         }
     }
 }
 
 void
 tnewline(int first_col)
 {
     int y = term.c.y;
 
     if (y == term.bot) {
         tscrollup(term.top, 1, 1);
     } else {
         y++;
     }
     tmoveto(first_col ? 0 : term.c.x, y);
 }
 
 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';
 }
 
 /* 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));
 }
 
 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);
 }
 
 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;
 }
 
 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 = ' ';
         }
     }
 }
 
 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);
 }
 
 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);
 }
 
 void
 tinsertblankline(int n)
 {
     if (BETWEEN(term.c.y, term.top, term.bot))
         tscrolldown(term.c.y, n, 0);
 }
 
 void
 tdeleteline(int n)
 {
     if (BETWEEN(term.c.y, term.top, term.bot))
         tscrollup(term.c.y, n, 0);
 }
 
 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;
 }
 
 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;
         }
     }
 }
 
 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;
 }
 
 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;
             }
         }
     }
 }
 
 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], 0);
         break;
     case 'T': /* SD -- Scroll <n> line down */
         DEFAULT(csiescseq.arg[0], 1);
         tscrolldown(term.top, csiescseq.arg[0], 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;
     }
 }
 
 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);
 }
 
 void
 csireset(void)
 {
     memset(&csiescseq, 0, sizeof(csiescseq));
 }
 
 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);
     }
 }
 
 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();
 }
 
 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';
     }
 }
 
 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");
 }
 
 void
 strreset(void)
 {
     strescseq = (STREscape){
         .buf = xrealloc(strescseq.buf, STR_BUF_SIZ),
         .siz = STR_BUF_SIZ,
     };
 }
 
 void
 sendbreak(const Arg *arg)
 {
     if (tcsendbreak(cmdfd, 0))
         perror("Error sending break");
 }
 
 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;
     }
 }
 
 void
 toggleprinter(const Arg *arg)
 {
     term.mode ^= MODE_PRINT;
 }
 
 void
 printscreen(const Arg *arg)
 {
     tdump();
 }
 
 void
 printsel(const Arg *arg)
 {
     tdumpsel();
 }
 
 void
 tdumpsel(void)
 {
     char *ptr;
 
     if ((ptr = getsel())) {
         tprinter(ptr, strlen(ptr));
         free(ptr);
     }
 }
 
 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);
 }
 
 void
 tdump(void)
 {
     int i;
 
     for (i = 0; i < term.row; ++i)
         tdumpline(i);
 }
 
 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);
 }
 
 void
 tdefutf8(char ascii)
 {
     if (ascii == 'G')
         term.mode |= MODE_UTF8;
     else if (ascii == '@')
         term.mode &= ~MODE_UTF8;
 }
 
 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];
     }
 }
 
 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);
         }
     }
 }
 
 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;
 }
 
 void
 tupdatebgcolor(int oldbg, int newbg)
 {
     for (int y = 0; y < term.row; y++) {
         for (int x = 0; x < term.col; x++) {
             if (term.line[y][x].bg == oldbg)
                 term.line[y][x].bg = newbg;
         }
     }
 }
 
 void
 tupdatefgcolor(int oldfg, int newfg)
 {
     for (int y = 0; y < term.row; y++) {
         for (int x = 0; x < term.col; x++) {
             if (term.line[y][x].fg == oldfg)
                 term.line[y][x].fg = newfg;
         }
     }
 }
 
 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);
 }
 
 /*
  * 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, 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, 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;
 }
 
 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;
     }
 }
 
 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;
 }
 
 void
 tresize(int col, int row)
 {
     int i, j;
     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));
 
     for (i = 0; i < HISTSIZE; i++) {
         term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
         for (j = mincol; j < col; j++) {
             term.hist[i][j] = term.c.attr;
             term.hist[i][j].u = ' ';
         }
     }
 
     /* 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;
 }
 
 void
 resettitle(void)
 {
     xsettitle(NULL);
 }
 
 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(TLINE(y), x1, y, x2);
     }
 }
 
 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);
     if (term.scr == 0)
         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);
 }
 
 void
 redraw(void)
 {
     tfulldirt();
     draw();
 }