From 679c2dabda094491599ce770ddba11611d08efc8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?S=C3=B8ren=20Sandmann=20Pedersen?= <sandmann@redhat.com>
Date: Fri, 18 Sep 2009 08:13:46 -0400
Subject: [PATCH] Fix four bit formats.

The original Render code used to index pixels with their position in
bits in the image. When the scanline code was introduced pixels were
indexed in bytes, but the FETCH/STORE_4/8 macros still assumed bits.

This commit fixes that by making the FETCH/STORE_4 macros first
convert the index to bit position.
---
 pixman/pixman-access.c | 68 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 27 deletions(-)

diff --git a/pixman/pixman-access.c b/pixman/pixman-access.c
index d9fd38c..41cd1b6 100644
--- a/pixman/pixman-access.c
+++ b/pixman/pixman-access.c
@@ -180,11 +180,11 @@ fetch_scanline_b8g8r8a8 (pixman_image_t *image,
     const uint32_t *bits = image->bits.bits + y * image->bits.rowstride;
     const uint32_t *pixel = (uint32_t *)bits + x;
     const uint32_t *end = pixel + width;
-    
+
     while (pixel < end)
     {
 	uint32_t p = READ (image, pixel++);
-	
+
 	*buffer++ = (((p & 0xff000000) >> 24)	|
 	             ((p & 0x00ff0000) >> 8)	|
 	             ((p & 0x0000ff00) << 8)	|
@@ -840,20 +840,22 @@ fetch_scanline_x4a4 (pixman_image_t *image,
     const uint32_t *bits = image->bits.bits + y * image->bits.rowstride;
     const uint8_t *pixel = (const uint8_t *)bits + x;
     const uint8_t *end = pixel + width;
-    
+   
     while (pixel < end)
     {
 	uint8_t p = READ (image, pixel++) & 0xf;
-	
+
 	*buffer++ = (p | (p << 4)) << 24;
     }
 }
 
-#define FETCH_8(img,l,o)    (READ (img, (uint8_t *)(l) + ((o) >> 2)))
+#define FETCH_8(img,l,o)    (READ (img, (((uint8_t *)(l)) + ((o) >> 3))))
 #ifdef WORDS_BIGENDIAN
-#define FETCH_4(img,l,o)    ((o) & 2 ? FETCH_8 (img,l,o) & 0xf : FETCH_8 (img,l,o) >> 4)
+#define FETCH_4(img,l,o)						\
+    (((4 * (o)) & 4) ? (FETCH_8 (img,l, 4 * (o)) & 0xf) : (FETCH_8 (img,l,(4 * (o))) >> 4))
 #else
-#define FETCH_4(img,l,o)    ((o) & 2 ? FETCH_8 (img,l,o) >> 4 : FETCH_8 (img,l,o) & 0xf)
+#define FETCH_4(img,l,o)						\
+    (((4 * (o)) & 4) ? (FETCH_8 (img, l, 4 * (o)) >> 4) : (FETCH_8 (img, l, (4 * (o))) & 0xf))
 #endif
 
 static void
@@ -867,13 +869,13 @@ fetch_scanline_a4 (pixman_image_t *image,
 {
     const uint32_t *bits = image->bits.bits + y * image->bits.rowstride;
     int i;
-    
+
     for (i = 0; i < width; ++i)
     {
 	uint32_t p = FETCH_4 (image, bits, i + x);
-	
+
 	p |= p << 4;
-	
+
 	*buffer++ = p << 24;
     }
 }
@@ -923,7 +925,7 @@ fetch_scanline_b1g2r1 (pixman_image_t *image,
 	b = ((p & 0x8) * 0xff) >> 3;
 	g = ((p & 0x6) * 0x55) << 7;
 	r = ((p & 0x1) * 0xff) << 16;
-	
+
 	*buffer++ = 0xff000000 | r | g | b;
     }
 }
@@ -2425,22 +2427,32 @@ store_scanline_x4a4 (bits_image_t *  image,
     uint32_t *bits = image->bits + image->rowstride * y;
     uint8_t   *pixel = ((uint8_t *) bits) + x;
     int i;
-    
+
     for (i = 0; i < width; ++i)
 	WRITE (image, pixel++, values[i] >> 28);
 }
 
 #define STORE_8(img,l,o,v)  (WRITE (img, (uint8_t *)(l) + ((o) >> 3), (v)))
 #ifdef WORDS_BIGENDIAN
-#define STORE_4(img,l,o,v)					    \
-    STORE_8 (img,l,o,((o) & 4 ?					    \
-                      (FETCH_8 (img,l,o) & 0xf0) | (v) :            \
-                      (FETCH_8 (img,l,o) & 0x0f) | ((v) << 4)))
+
+#define STORE_4(img,l,o,v)						\
+    do									\
+    {									\
+	int bo = 4 * (o);						\
+	STORE_8 (img, l, bo, (bo & 4 ?					\
+			      (FETCH_8 (img, l, bo) & 0xf0) | (v) :	\
+			      (FETCH_8 (img, l, bo) & 0x0f) | ((v) << 4))); \
+    } while (0)
 #else
-#define STORE_4(img,l,o,v)					\
-    STORE_8 (img,l,o,((o) & 4 ?					\
-                      (FETCH_8 (img,l,o) & 0x0f) | ((v) << 4) : \
-                      (FETCH_8 (img,l,o) & 0xf0) | (v)))
+
+#define STORE_4(img,l,o,v)						\
+    do									\
+    {									\
+	int bo = 4 * (o);						\
+	STORE_8 (img, l, bo, (bo & 4 ?					\
+			      (FETCH_8 (img, l, bo) & 0x0f) | ((v) << 4) : \
+			      (FETCH_8 (img, l, bo) & 0xf0) | (v)));	\
+    } while (0)
 #endif
 
 static void
@@ -2452,7 +2464,7 @@ store_scanline_a4 (bits_image_t *  image,
 {
     uint32_t *bits = image->bits + image->rowstride * y;
     int i;
-    
+
     for (i = 0; i < width; ++i)
 	STORE_4 (image, bits, i + x, values[i] >> 28);
 }
@@ -2488,11 +2500,11 @@ store_scanline_b1g2r1 (bits_image_t *  image,
 {
     uint32_t *bits = image->bits + image->rowstride * y;
     int i;
-    
+
     for (i = 0; i < width; ++i)
     {
 	uint32_t pixel;
-	
+
 	SPLIT (values[i]);
 	pixel = (((b >> 4) & 0x8) |
 	         ((g >> 5) & 0x6) |
@@ -2510,16 +2522,17 @@ store_scanline_a1r1g1b1 (bits_image_t *  image,
 {
     uint32_t *bits = image->bits + image->rowstride * y;
     int i;
-    
+
     for (i = 0; i < width; ++i)
     {
 	uint32_t pixel;
-	
+
 	SPLIT_A (values[i]);
 	pixel = (((a >> 4) & 0x8) |
 	         ((r >> 5) & 0x4) |
 	         ((g >> 6) & 0x2) |
 	         ((b >> 7)      ));
+
 	STORE_4 (image, bits, i + x, pixel);
     }
 }
@@ -2533,16 +2546,17 @@ store_scanline_a1b1g1r1 (bits_image_t *  image,
 {
     uint32_t *bits = image->bits + image->rowstride * y;
     int i;
-    
+
     for (i = 0; i < width; ++i)
     {
 	uint32_t pixel;
-	
+
 	SPLIT_A (values[i]);
 	pixel = (((a >> 4) & 0x8) |
 	         ((b >> 5) & 0x4) |
 	         ((g >> 6) & 0x2) |
 	         ((r >> 7)      ));
+
 	STORE_4 (image, bits, i + x, pixel);
     }
 }
-- 
2.7.4