Re: [AD] Endianness in file routines

[Eric Botcazou <ebotcazou@xxxxxxxxxx>]

> This reminds me, has anyone checked this?  It looks to me like the code
> assumes little endianness.

/* pack_igetw:
 *  Reads a 16 bit word from a file, using intel byte ordering.
 */
int pack_igetw(PACKFILE *f)
{
   int b1, b2;
   ASSERT(f);

   if ((b1 = pack_getc(f)) != EOF)
      if ((b2 = pack_getc(f)) != EOF)
	 return ((b2 << 8) | b1);

   return EOF;
}


/* pack_iputw:
 *  Writes a 16 bit int to a file, using intel byte ordering.
 */
int pack_iputw(int w, PACKFILE *f)
{
   int b1, b2;
   ASSERT(f);

   b1 = (w & 0xFF00) >> 8;
   b2 = w & 0x00FF;

   if (pack_putc(b2,f)==b2)
      if (pack_putc(b1,f)==b1)
	 return w;

   return EOF;
}


Both functions looks ok to me.


On the other hand, I've attached a patch that fixes an assumption of 
little-endianess in src/bmp.c:read_24bit_line(). Does it seem correct to 
you?

-- 
Eric Botcazou

--- /cvs/allegro/src/bmp.c	Wed Oct 16 14:02:38 2002
+++ allegro/src/bmp.c	Mon Oct 28 11:23:44 2002
@@ -262,9 +262,7 @@
       c.b = pack_getc(f);
       c.g = pack_getc(f);
       c.r = pack_getc(f);
-      bmp->line[line][i*3+_rgb_r_shift_24/8] = c.r;
-      bmp->line[line][i*3+_rgb_g_shift_24/8] = c.g;
-      bmp->line[line][i*3+_rgb_b_shift_24/8] = c.b;
+      bmp_write24((unsigned long)bmp->line[line]+i*3, makecol24(c.r, c.g, c.b));
       nbytes += 3;
    }