do not expand tabs here. instead, importers need to understand '\t'

and fill the canvas up to the tab stop with it. once that works,
support will be added here (treating it as space.) also, fewer columns
are now generated. apparently generating a minimal number of them
fixes a bunch of the table-layout bugs.

caca/codec/export.c

@@ -459,44 +459,40 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
 {
     char *data, *cur;
     int x, y, len;
-    int maxcols;
     int has_multi_cell_row = 0;
+    unsigned char *cell_boundary_bitmap;
 
     /* Table */
-    maxcols = 0;
+    cell_boundary_bitmap = (unsigned char *) malloc((cv->width + 7) / 8);
+    if(cell_boundary_bitmap)
+        memset((void *) cell_boundary_bitmap, 0, (cv->width + 7) / 8);
     for(y = 0; y < cv->height; y++)
     {
         uint32_t *lineattr = cv->attrs + y * cv->width;
-        uint32_t *linechar = cv->chars + y * cv->width;
-        int cols = 0;
 
-        for(x = 0; x < cv->width; x++)
-        {
-            if((! has_multi_cell_row)
-               &&
-               (x > 1)
-               &&
-               (caca_attr_to_ansi_bg(lineattr[x - 1])
-                !=
-                caca_attr_to_ansi_bg(lineattr[x]))
+        for(x = 1; x < cv->width; x++)
+            if((! (cell_boundary_bitmap
+                   ?
+                   (cell_boundary_bitmap[x / 8] & (1 << (x % 8)))
+                   :
+                   has_multi_cell_row))
                &&
-               ((caca_attr_to_ansi_bg(lineattr[x]) < 0x10)
-                ?
-                (_caca_attr_to_rgb24bg(lineattr[x - 1])
+               ((caca_attr_to_ansi_bg(lineattr[x - 1])
                  !=
-                 _caca_attr_to_rgb24bg(lineattr[x]))
-                :
-                0))
+                 caca_attr_to_ansi_bg(lineattr[x]))
+                ||
+                ((caca_attr_to_ansi_bg(lineattr[x]) < 0x10)
+                 ?
+                 (_caca_attr_to_rgb24bg(lineattr[x - 1])
+                  !=
+                  _caca_attr_to_rgb24bg(lineattr[x]))
+                 :
+                 0)))
             {
                 has_multi_cell_row = 1;
+                if(cell_boundary_bitmap)
+                    cell_boundary_bitmap[x / 8] |= 1 << (x % 8);
             }
-            if(linechar[x] == 0x00000009)
-                while((cols + 1) % 8)
-                    cols ++;
-            cols ++;
-        }
-        if (cols > maxcols)
-            maxcols = cols;
     }
     
     /* The HTML table markup: less than 1000 bytes
@@ -505,30 +501,37 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
      *          up to 36 chars for "<b><i><u><blink></blink></u></i></b>"
      *          up to 10 chars for "&#xxxxxxx;" (far less for pure ASCII)
      *          17 chars for "</font></tt></td>" */
-    *bytes = 1000 + cv->height * (10 + maxcols * (48 + 36 + 10 + 17));
+    *bytes = 1000 + cv->height * (10 + cv->width * (48 + 36 + 10 + 17));
     cur = data = malloc(*bytes);
 
-    cur += sprintf(cur, "<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" summary=\"[libcaca canvas html3 export]\">\n");
+    cur += sprintf(cur, "<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" summary=\"[libcaca canvas export]\">\n");
 
     for(y = 0; y < cv->height; y++)
     {
         uint32_t *lineattr = cv->attrs + y * cv->width;
         uint32_t *linechar = cv->chars + y * cv->width;
-        int taboff = 0;
 
         cur += sprintf(cur, "<tr>");
 
         for(x = 0; x < cv->width; x += len)
         {
             int i, needfont = 0;
-            int thistab = 0;
+            int nonblank = 0;
 
             /* Use colspan option to factor cells with same attributes
              * (see below) */
             len = 1;
-            while((y || (! has_multi_cell_row) || (cv->height == 1))
+            while((x + len < cv->width)
                   &&
-                  (x + len < cv->width)
+                  (y
+                   ||
+                   (! (cell_boundary_bitmap
+                       ?
+                       (cell_boundary_bitmap[(x + len) / 8] & (1 << ((x + len) % 8)))
+                       :
+                       has_multi_cell_row))
+                   ||
+                   (cv->height == 1))
                   &&
                   (caca_attr_to_ansi_bg(lineattr[x + len])
                    ==
@@ -544,9 +547,12 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
                 len++;
 
             for(i = 0; i < len; i++)
-                if(linechar[x + i] == 0x00000009)
-                    while((x + i + taboff + thistab + 1) % 8)
-                        thistab ++;
+                if(! ((linechar[x + i] <= 0x00000020)
+                      ||
+                      ((linechar[x + i] >= 0x0000007f)
+                       &&
+                       (linechar[x + i] <= 0x000000a0))))
+                    nonblank = 1;
 
             cur += sprintf(cur, "<td");
 
@@ -554,8 +560,22 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
                 cur += sprintf(cur, " bgcolor=\"#%.06lx\"", (unsigned long int)
                                _caca_attr_to_rgb24bg(lineattr[x]));
 
-            if((len + thistab) > 1)
-                cur += sprintf(cur, " colspan=\"%d\"", len + thistab);
+            if(has_multi_cell_row && (len > 1))
+            {
+                int colspan;
+
+                colspan = len;
+                if(cell_boundary_bitmap)
+                    for(i = 0; i < len; i ++)
+                        if(i
+                           &&
+                           ! (cell_boundary_bitmap[(x + i) / 8]
+                              &
+                              (1 << ((x + i) % 8))))
+                            colspan --;
+                if(colspan > 1)
+                    cur += sprintf(cur, " colspan=\"%d\"", colspan);
+            }
 
             cur += sprintf(cur, ">");
 
@@ -563,12 +583,19 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
 
             for(i = 0; i < len; i++)
             {
-                if((! i) || (lineattr[x + i] != lineattr[x + i - 1]))
+                if(nonblank
+                   &&
+                   ((! i)
+                    ||
+                    (lineattr[x + i] != lineattr[x + i - 1])))
                 {
-                    needfont = (caca_attr_to_ansi_fg(lineattr[x + i]) != CACA_DEFAULT);
+                    needfont = (caca_attr_to_ansi_fg(lineattr[x + i])
+                                !=
+                                CACA_DEFAULT);
 
                     if(needfont)
-                        cur += sprintf(cur, "<font color=\"#%.06lx\">", (unsigned long int)
+                        cur += sprintf(cur, "<font color=\"#%.06lx\">",
+                                       (unsigned long int)
                                        _caca_attr_to_rgb24fg(lineattr[x + i]));
 
                     if(lineattr[x + i] & CACA_BOLD)
@@ -587,22 +614,13 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
                         ||
                         ((linechar[x + i] >= 0x0000007f)
                          &&
-                         (linechar[x + i] <= 0x0000009f)))
+                         (linechar[x + i] <= 0x000000a0)))
                 {
                     /* Control characters and space converted to
                      * U+00A0 NO-BREAK SPACE, a.k.a. "&nbsp;" in HTML,
                      * but we use the equivalent numeric character
                      * reference &#160; so this will work in plain
-                     * XHTML with no DTD too. We also expand tabs
-                     * here, since they are not honored in HTML. */
-                    if(linechar[x + i] == 0x00000009)
-                    {
-                        while((x + i + taboff + 1) % 8)
-                        {
-                            cur += sprintf(cur, "&#160;");
-                            taboff ++;
-                        }
-                    }
+                     * XHTML with no DTD too. */
                     cur += sprintf(cur, "&#160;");
                 }
                 else if(linechar[x + i] == '&')
@@ -630,7 +648,11 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
                      * REPLACEMENT CHARACTER */
                     cur += sprintf(cur, "&#%i;", (unsigned int)0x0000fffd);
 
-                if (((i + 1) == len) || (lineattr[x + i + 1] != lineattr[x + i]))
+                if (nonblank
+                    &&
+                    (((i + 1) == len)
+                     ||
+                     (lineattr[x + i + 1] != lineattr[x + i])))
                 {
                     if(lineattr[x + i] & CACA_BLINK)
                         cur += sprintf(cur, "</blink>");
@@ -655,6 +677,10 @@ static void *export_html3(caca_canvas_t const *cv, size_t *bytes)
     /* Footer */
     cur += sprintf(cur, "</table>\n");
 
+    /* Free working memory */
+    if (cell_boundary_bitmap)
+        free((void *) cell_boundary_bitmap);
+
     /* Crop to really used size */
     debug("html3 export: alloc %lu bytes, realloc %lu",
           (unsigned long int)*bytes, (unsigned long int)(cur - data));