Add parsing of DCS q sequences

These sequences are used to operate with sixels, but they are still
str sequences, so they are finished with \a, ST or with a C1 control
code. This patch also disables utf8 handling for the case of sixels.

diff --git a/st.c b/st.c
index ebbd7ca..6c16386 100644 (file)
--- a/st.c
+++ b/st.c
@@ -138,6 +138,7 @@ enum term_mode {
        MODE_BRCKTPASTE  = 1 << 19,
        MODE_PRINT       = 1 << 20,
        MODE_UTF8        = 1 << 21,
+       MODE_SIXEL       = 1 << 22,
        MODE_MOUSE       = MODE_MOUSEBTN|MODE_MOUSEMOTION|MODE_MOUSEX10\
                          |MODE_MOUSEMANY,
 };
@@ -155,11 +156,12 @@ enum charset {
 enum escape_state {
        ESC_START      = 1,
        ESC_CSI        = 2,
-       ESC_STR        = 4,  /* DCS, OSC, PM, APC */
+       ESC_STR        = 4,  /* 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,
+       ESC_DCS        =128,
 };
 
 enum window_state {
@@ -1485,7 +1487,7 @@ ttyread(void)
        ptr = buf;
 
        for (;;) {
-               if (IS_SET(MODE_UTF8)) {
+               if (IS_SET(MODE_UTF8) && !IS_SET(MODE_SIXEL)) {
                        /* process a complete utf8 char */
                        charsize = utf8decode(ptr, &unicodep, buflen);
                        if (charsize == 0)
@@ -1578,7 +1580,7 @@ ttysend(char *s, size_t n)
 
        lim = &s[n];
        for (t = s; t < lim; t += len) {
-               if (IS_SET(MODE_UTF8)) {
+               if (IS_SET(MODE_UTF8) && !IS_SET(MODE_SIXEL)) {
                        len = utf8decode(t, &u, n);
                } else {
                        u = *t & 0xFF;
@@ -2548,6 +2550,7 @@ strhandle(void)
                xsettitle(strescseq.args[0]);
                return;
        case 'P': /* DCS -- Device Control String */
+               term.mode |= ESC_DCS;
        case '_': /* APC -- Application Program Command */
        case '^': /* PM -- Privacy Message */
                return;
@@ -2754,9 +2757,12 @@ tdectest(char c)
 void
 tstrsequence(uchar c)
 {
+       strreset();
+
        switch (c) {
        case 0x90:   /* DCS -- Device Control String */
                c = 'P';
+               term.esc |= ESC_DCS;
                break;
        case 0x9f:   /* APC -- Application Program Command */
                c = '_';
@@ -2768,7 +2774,6 @@ tstrsequence(uchar c)
                c = ']';
                break;
        }
-       strreset();
        strescseq.type = c;
        term.esc |= ESC_STR;
 }
@@ -2968,7 +2973,7 @@ tputc(Rune u)
        Glyph *gp;
 
        control = ISCONTROL(u);
-       if (!IS_SET(MODE_UTF8)) {
+       if (!IS_SET(MODE_UTF8) && !IS_SET(MODE_SIXEL)) {
                c[0] = u;
                width = len = 1;
        } else {
@@ -2991,30 +2996,47 @@ tputc(Rune u)
        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_START|ESC_STR|ESC_DCS);
+                       if (IS_SET(MODE_SIXEL)) {
+                               /* TODO: render sixel */;
+                               term.mode &= ~MODE_SIXEL;
+                               return;
+                       }
                        term.esc |= ESC_STR_END;
-               } else if (strescseq.len + len < sizeof(strescseq.buf) - 1) {
-                       memmove(&strescseq.buf[strescseq.len], c, len);
-                       strescseq.len += len;
+                       goto check_control_code;
+               }
+
+
+               if (IS_SET(MODE_SIXEL)) {
+                       /* TODO: implement sixel mode */
                        return;
-               } else {
-               /*
-                * 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 (term.esc&ESC_DCS && strescseq.len == 0 && u == 'q')
+                       term.mode |= MODE_SIXEL;
+
+               if (strescseq.len+len >= sizeof(strescseq.buf)-1) {
+                       /*
+                        * 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();
+                        */
                        return;
                }
+
+               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