libwebp-0.6.0-rc1

third_party/libwebp/utils/utils.h

Index: third_party/libwebp/utils/utils.h
diff --git a/third_party/libwebp/utils/utils.h b/third_party/libwebp/utils/utils.h
index 3a5d4e6a7885283295e05325d841a176f825f643..3ab459050aaf0d4a49a38f3a3db53eaddfb70c49 100644
--- a/third_party/libwebp/utils/utils.h
+++ b/third_party/libwebp/utils/utils.h
@@ -62,7 +62,6 @@ WEBP_EXTERN(void) WebPSafeFree(void* const ptr);
 #define WEBP_ALIGN_CST 31
 #define WEBP_ALIGN(PTR) (((uintptr_t)(PTR) + WEBP_ALIGN_CST) & ~WEBP_ALIGN_CST)
 
-#if defined(WEBP_FORCE_ALIGNED)
 #include <string.h>
 // memcpy() is the safe way of moving potentially unaligned 32b memory.
 static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) {
@@ -73,16 +72,6 @@ static WEBP_INLINE uint32_t WebPMemToUint32(const uint8_t* const ptr) {
 static WEBP_INLINE void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) {
   memcpy(ptr, &val, sizeof(val));
 }
-#else
-static WEBP_UBSAN_IGNORE_UNDEF WEBP_INLINE
-uint32_t WebPMemToUint32(const uint8_t* const ptr) {
-  return *(const uint32_t*)ptr;
-}
-static WEBP_UBSAN_IGNORE_UNDEF WEBP_INLINE
-void WebPUint32ToMem(uint8_t* const ptr, uint32_t val) {
-  *(uint32_t*)ptr = val;
-}
-#endif
 
 //------------------------------------------------------------------------------
 // Reading/writing data.
@@ -118,6 +107,19 @@ static WEBP_INLINE void PutLE32(uint8_t* const data, uint32_t val) {
   PutLE16(data + 2, (int)(val >> 16));
 }
 
+// Returns 31 ^ clz(n) = log2(n). This is the default C-implementation, either
+// based on table or not. Can be used as fallback if clz() is not available.
+#define WEBP_NEED_LOG_TABLE_8BIT
+extern const uint8_t WebPLogTable8bit[256];
+static WEBP_INLINE int WebPLog2FloorC(uint32_t n) {
+  int log = 0;
+  while (n >= 256) {
+    log += 8;
+    n >>= 8;
+  }
+  return log + WebPLogTable8bit[n];
+}
+
 // Returns (int)floor(log2(n)). n must be > 0.
 // use GNU builtins where available.
 #if defined(__GNUC__) && \
@@ -135,22 +137,8 @@ static WEBP_INLINE int BitsLog2Floor(uint32_t n) {
   _BitScanReverse(&first_set_bit, n);
   return first_set_bit;
 }
-#else
-static WEBP_INLINE int BitsLog2Floor(uint32_t n) {
-  int log = 0;
-  uint32_t value = n;
-  int i;
-
-  for (i = 4; i >= 0; --i) {
-    const int shift = (1 << i);
-    const uint32_t x = value >> shift;
-    if (x != 0) {
-      value = x;
-      log += shift;
-    }
-  }
-  return log;
-}
+#else   // default: use the C-version.
+static WEBP_INLINE int BitsLog2Floor(uint32_t n) { return WebPLog2FloorC(n); }
 #endif
 
 //------------------------------------------------------------------------------
@@ -172,12 +160,12 @@ WEBP_EXTERN(void) WebPCopyPixels(const struct WebPPicture* const src,
 // Unique colors.
 
 // Returns count of unique colors in 'pic', assuming pic->use_argb is true.
-// If the unique color count is more than MAX_COLOR_COUNT, returns
-// MAX_COLOR_COUNT+1.
+// If the unique color count is more than MAX_PALETTE_SIZE, returns
+// MAX_PALETTE_SIZE+1.
 // If 'palette' is not NULL and number of unique colors is less than or equal to
-// MAX_COLOR_COUNT, also outputs the actual unique colors into 'palette'.
+// MAX_PALETTE_SIZE, also outputs the actual unique colors into 'palette'.
 // Note: 'palette' is assumed to be an array already allocated with at least
-// MAX_COLOR_COUNT elements.
+// MAX_PALETTE_SIZE elements.
 WEBP_EXTERN(int) WebPGetColorPalette(const struct WebPPicture* const pic,
                                      uint32_t* const palette);