blend_bitmaps: cosmetic refactoring

All intptr_t would be gradually replaced with more logically correct
ptrdiff_t/size_t. It clearly signifies its intended use and should work
even for obscure architectures with sizeof(size_t) != sizeof(void *).
For generic architectures it's essentially the same and is a part of ABI.

3 files changed, 37 insertions, 38 deletions

diff --git a/libass/ass_bitmap_engine.h b/libass/ass_bitmap_engine.h
index 7175031..3682984 100644
--- a/libass/ass_bitmap_engine.h
+++ b/libass/ass_bitmap_engine.h
@@ -31,13 +31,13 @@ typedef void FillGenericTileFunc(uint8_t *buf, ptrdiff_t stride,
                                  int winding);
 typedef void MergeTileFunc(uint8_t *buf, ptrdiff_t stride, const uint8_t *tile);
 
-typedef void BitmapBlendFunc(uint8_t *dst, intptr_t dst_stride,
-                             uint8_t *src, intptr_t src_stride,
-                             intptr_t width, intptr_t height);
-typedef void BitmapMulFunc(uint8_t *dst, intptr_t dst_stride,
-                           uint8_t *src1, intptr_t src1_stride,
-                           uint8_t *src2, intptr_t src2_stride,
-                           intptr_t width, intptr_t height);
+typedef void BitmapBlendFunc(uint8_t *dst, ptrdiff_t dst_stride,
+                             const uint8_t *src, ptrdiff_t src_stride,
+                             size_t width, size_t height);
+typedef void BitmapMulFunc(uint8_t *dst, ptrdiff_t dst_stride,
+                           const uint8_t *src1, ptrdiff_t src1_stride,
+                           const uint8_t *src2, ptrdiff_t src2_stride,
+                           size_t width, size_t height);
 
 typedef void BeBlurFunc(uint8_t *buf, intptr_t stride,
                         intptr_t width, intptr_t height, uint16_t *tmp);
diff --git a/libass/c/c_blend_bitmaps.c b/libass/c/c_blend_bitmaps.c
index 9cebcc8..95d189e 100644
--- a/libass/c/c_blend_bitmaps.c
+++ b/libass/c/c_blend_bitmaps.c
@@ -29,44 +29,43 @@
  * \brief Add two bitmaps together at a given position
  * Uses additive blending, clipped to [0,255]. Pure C implementation.
  */
-void ass_add_bitmaps_c(uint8_t *dst, intptr_t dst_stride,
-                       uint8_t *src, intptr_t src_stride,
-                       intptr_t width, intptr_t height)
+void ass_add_bitmaps_c(uint8_t *dst, ptrdiff_t dst_stride,
+                       const uint8_t *src, ptrdiff_t src_stride,
+                       size_t width, size_t height)
 {
-    unsigned out;
-    uint8_t* end = dst + dst_stride * height;
+    uint8_t *end = dst + dst_stride * height;
     while (dst < end) {
-        for (unsigned j = 0; j < width; ++j) {
-            out = dst[j] + src[j];
-            dst[j] = FFMIN(out, 255);
+        for (size_t x = 0; x < width; x++) {
+            unsigned out = dst[x] + src[x];
+            dst[x] = FFMIN(out, 255);
         }
         dst += dst_stride;
         src += src_stride;
     }
 }
 
-void ass_imul_bitmaps_c(uint8_t *dst, intptr_t dst_stride,
-                        uint8_t *src, intptr_t src_stride,
-                        intptr_t width, intptr_t height)
+void ass_imul_bitmaps_c(uint8_t *dst, ptrdiff_t dst_stride,
+                        const uint8_t *src, ptrdiff_t src_stride,
+                        size_t width, size_t height)
 {
-    uint8_t* end = dst + dst_stride * height;
+    uint8_t *end = dst + dst_stride * height;
     while (dst < end) {
-        for (unsigned j = 0; j < width; ++j) {
-            dst[j] = (dst[j] * (255 - src[j]) + 255) >> 8;
+        for (size_t x = 0; x < width; x++) {
+            dst[x] = (dst[x] * (255 - src[x]) + 255) >> 8;
         }
         dst += dst_stride;
         src += src_stride;
     }
 }
 
-void ass_mul_bitmaps_c(uint8_t *dst, intptr_t dst_stride,
-                       uint8_t *src1, intptr_t src1_stride,
-                       uint8_t *src2, intptr_t src2_stride,
-                       intptr_t width, intptr_t height)
+void ass_mul_bitmaps_c(uint8_t *dst, ptrdiff_t dst_stride,
+                       const uint8_t *src1, ptrdiff_t src1_stride,
+                       const uint8_t *src2, ptrdiff_t src2_stride,
+                       size_t width, size_t height)
 {
-    uint8_t* end = src1 + src1_stride * height;
-    while (src1 < end) {
-        for (unsigned x = 0; x < width; ++x) {
+    uint8_t *end = dst + dst_stride * height;
+    while (dst < end) {
+        for (size_t x = 0; x < width; x++) {
             dst[x] = (src1[x] * src2[x] + 255) >> 8;
         }
         dst  += dst_stride;
diff --git a/libass/x86/blend_bitmaps.asm b/libass/x86/blend_bitmaps.asm
index e5b8760..cc4b81d 100644
--- a/libass/x86/blend_bitmaps.asm
+++ b/libass/x86/blend_bitmaps.asm
@@ -61,9 +61,9 @@ SECTION .text
 
 ;------------------------------------------------------------------------------
 ; ADD_BITMAPS
-; void add_bitmaps(uint8_t *dst, intptr_t dst_stride,
-;                  uint8_t *src, intptr_t src_stride,
-;                  intptr_t width, intptr_t height);
+; void add_bitmaps(uint8_t *dst, ptrdiff_t dst_stride,
+;                  const uint8_t *src, ptrdiff_t src_stride,
+;                  size_t width, size_t height);
 ;------------------------------------------------------------------------------
 
 %macro ADD_BITMAPS 0
@@ -114,9 +114,9 @@ ADD_BITMAPS
 
 ;------------------------------------------------------------------------------
 ; IMUL_BITMAPS
-; void imul_bitmaps(uint8_t *dst, intptr_t dst_stride,
-;                   uint8_t *src, intptr_t src_stride,
-;                   intptr_t width, intptr_t height);
+; void imul_bitmaps(uint8_t *dst, ptrdiff_t dst_stride,
+;                   const uint8_t *src, ptrdiff_t src_stride,
+;                   size_t width, size_t height);
 ;------------------------------------------------------------------------------
 
 %macro IMUL_BITMAPS 0
@@ -197,10 +197,10 @@ IMUL_BITMAPS
 
 ;------------------------------------------------------------------------------
 ; MUL_BITMAPS
-; void mul_bitmaps(uint8_t *dst, intptr_t dst_stride,
-;                  uint8_t *src1, intptr_t src1_stride,
-;                  uint8_t *src2, intptr_t src2_stride,
-;                  intptr_t width, intptr_t height);
+; void mul_bitmaps(uint8_t *dst, ptrdiff_t dst_stride,
+;                  const uint8_t *src1, ptrdiff_t src1_stride,
+;                  const uint8_t *src2, ptrdiff_t src2_stride,
+;                  size_t width, size_t height);
 ;------------------------------------------------------------------------------
 
 %macro MUL_BITMAPS 0