Fix issues with RGB565 color conversion on big endian machines. The RGB565 routines are now abstracted in a separate file, with separate little-endian and big-endian versions defined at compile time through the use of macros (this is similar to how the colorspace extension routines work.) This allows big-endian machines to take advantage of the same performance optimizations as little-endian machines, and it retains the performance on little-endian machines, since the conditional branch for endianness is at a very coarse-grained level.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1399 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/wrbmp.c b/wrbmp.c
index 3a85441..e324260 100644
--- a/wrbmp.c
+++ b/wrbmp.c
@@ -5,6 +5,7 @@
* Copyright (C) 1994-1996, Thomas G. Lane.
* libjpeg-turbo Modifications:
* Copyright (C) 2013, Linaro Limited.
+ * Copyright (C) 2014, D. R. Commander.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains routines to write output images in Microsoft "BMP"
@@ -64,6 +65,15 @@
int map_entry_size);
+static inline boolean is_big_endian(void)
+{
+ int test_value = 1;
+ if(*(char *)&test_value != 1)
+ return TRUE;
+ return FALSE;
+}
+
+
/*
* Write some pixel data.
* In this module rows_supplied will always be 1.
@@ -93,18 +103,18 @@
outptr = image_ptr[0];
if(cinfo->out_color_space == JCS_RGB565) {
- #define red_mask 0xF800
- #define green_mask 0x7E0
- #define blue_mask 0x1F
- unsigned char r, g, b;
+ boolean big_endian = is_big_endian();
unsigned short *inptr2 = (unsigned short *)inptr;
for (col = cinfo->output_width; col > 0; col--) {
- r = (*inptr2 & red_mask) >> 11;
- g = (*inptr2 & green_mask) >> 5;
- b = (*inptr2 & blue_mask);
- outptr[0] = b << 3;
- outptr[1] = g << 2;
- outptr[2] = r << 3;
+ if (big_endian) {
+ outptr[0] = (*inptr2 >> 5) & 0xF8;
+ outptr[1] = ((*inptr2 << 5) & 0xE0) | ((*inptr2 >> 11) & 0x1C);
+ outptr[2] = *inptr2 & 0xF8;
+ } else {
+ outptr[0] = (*inptr2 << 3) & 0xF8;
+ outptr[1] = (*inptr2 >> 3) & 0xFC;
+ outptr[2] = (*inptr2 >> 8) & 0xF8;
+ }
outptr += 3;
inptr2++;
}