[cairo-commit] src/cairo-ps-surface.c

[Behdad Esfahbod]

 src/cairo-ps-surface.c |   28 +++++++++++++++-------------
 1 files changed, 15 insertions(+), 13 deletions(-)

New commits:
diff-tree 75eeb889767468b374df5f0aa6fb7ba1fe6addf9 (from 2dbb3dfd5f7e3d802f1c3c57b39f9d69b2b7ee1e)
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Tue Nov 21 12:10:36 2006 -0500

    [PS] Eliminate compiler warnings about unoptimizable loops
    
    An innocient-looking loop like this:
    
      for (j = 0; j <= last; j++)
        something();
    
    cannot be optimized, because it may loop forever!
    Imagine the case that last is MAXINT, the loop will never end.  The correct
    way to write it is:
    
      for (j = 0; j < last+1; j++)
        something();
    
    In this case, if last is MAXINT, the loop will never run.  Not correct, but
    better than looping forever.
    
    Still better would be to correctly handle the MAXINT case (even though it
    doesn't make any sense to show MAXINT number of glyphs in one operation!)  To
    do that, we can use the fact that the input num_glyphs is a signed.  If
    there is one good thing about using signed int as input length, it's that you
    can use an unsigned looping variable to avoid looping forever.  That is
    exactly what this patch does.

diff --git a/src/cairo-ps-surface.c b/src/cairo-ps-surface.c
index d02b251..f9ca3a1 100644
--- a/src/cairo-ps-surface.c
+++ b/src/cairo-ps-surface.c
@@ -2146,7 +2146,7 @@ _cairo_ps_surface_show_glyphs (void		   
     unsigned int font_id;
     cairo_ps_glyph_id_t *glyph_ids;
     cairo_status_t status;
-    int i, j, last, end;
+    unsigned int n_glyphs, i, j, last, end;
     cairo_bool_t vertical, horizontal;
     cairo_output_stream_t *word_wrap;
 
@@ -2158,15 +2158,17 @@ _cairo_ps_surface_show_glyphs (void		   
     _cairo_output_stream_printf (stream,
 				 "%% _cairo_ps_surface_show_glyphs\n");
 
-    if (num_glyphs == 0)
+    if (num_glyphs <= 0)
         return CAIRO_STATUS_SUCCESS;
 
+    n_glyphs = num_glyphs;
+
     emit_pattern (surface, source);
-    glyph_ids = malloc (num_glyphs*sizeof (cairo_ps_glyph_id_t));
+    glyph_ids = malloc (n_glyphs*sizeof (cairo_ps_glyph_id_t));
     if (glyph_ids == NULL)
         return CAIRO_STATUS_NO_MEMORY;
 
-    for (i = 0; i < num_glyphs; i++) {
+    for (i = 0; i < n_glyphs; i++) {
         status = _cairo_scaled_font_subsets_map_glyph (surface->font_subsets,
                                                        scaled_font, glyphs[i].index,
                                                        &font_id,
@@ -2177,7 +2179,7 @@ _cairo_ps_surface_show_glyphs (void		   
     }
 
     i = 0;
-    while (i < num_glyphs) {
+    while (i < n_glyphs) {
         if (glyph_ids[i].subset_id != current_subset_id) {
             _cairo_output_stream_printf (surface->stream,
                                          "/CairoFont-%d-%d findfont\n"
@@ -2200,7 +2202,7 @@ _cairo_ps_surface_show_glyphs (void		   
 
         horizontal = TRUE;
         vertical = TRUE;
-        end = num_glyphs;
+        end = n_glyphs;
         if (end - i > MAX_GLYPHS_PER_SHOW)
             end = i + MAX_GLYPHS_PER_SHOW;
         last = end - 1;
@@ -2220,13 +2222,13 @@ _cairo_ps_surface_show_glyphs (void		   
         } else {
             word_wrap = _word_wrap_stream_create (surface->stream, 79);
             _cairo_output_stream_printf (word_wrap, "<");
-            for (j = i; j <= last; j++)
+            for (j = i; j < last+1; j++)
                 _cairo_output_stream_printf (word_wrap, "%02x", glyph_ids[j].glyph_id);
             _cairo_output_stream_printf (word_wrap, ">\n[");
 
             if (horizontal) {
-                for (j = i; j <= last; j++) {
-                    if (j == num_glyphs - 1)
+                for (j = i; j < last+1; j++) {
+                    if (j == n_glyphs - 1)
                         _cairo_output_stream_printf (word_wrap, "0 ");
                     else
                         _cairo_output_stream_printf (word_wrap,
@@ -2234,8 +2236,8 @@ _cairo_ps_surface_show_glyphs (void		   
                 }
                 _cairo_output_stream_printf (word_wrap, "] xS\n");
             } else if (vertical) {
-                for (j = i; j <= last; j++) {
-                    if (j == num_glyphs - 1)
+                for (j = i; j < last+1; j++) {
+                    if (j == n_glyphs - 1)
                         _cairo_output_stream_printf (word_wrap, "0 ");
                     else
                         _cairo_output_stream_printf (word_wrap,
@@ -2243,8 +2245,8 @@ _cairo_ps_surface_show_glyphs (void		   
                 }
                 _cairo_output_stream_printf (word_wrap, "] yS\n");
             } else {
-                for (j = i; j <= last; j++) {
-                    if (j == num_glyphs - 1)
+                for (j = i; j < last+1; j++) {
+                    if (j == n_glyphs - 1)
                         _cairo_output_stream_printf (word_wrap, "0 ");
                     else
                         _cairo_output_stream_printf (word_wrap,