Sync libwebp with head#I6ecefe33

Also added ARM/NEON code for decoder/encoder modules.

Change-Id: Ic8028037c94c1191c193d881b799a961b476138e

1 files changed, 30 insertions, 8 deletions

diff --git a/src/utils/bit_reader.h b/src/utils/bit_reader.h
index 11a40a55..a9c32436 100644
--- a/src/utils/bit_reader.h
+++ b/src/utils/bit_reader.h
@@ -24,11 +24,28 @@
 extern "C" {
 #endif
 
-#define BITS 32     // can be 32, 16 or 8
+//------------------------------------------------------------------------------
+// BITS can be either 32, 24, 16 or 8.
+// Pick values that fit natural register size.
+
+#if defined(__i386__) || defined(_M_IX86)      // x86 32bit
+#define BITS 16
+#elif defined(__arm__) || defined(_M_ARM)     // ARM
+#define BITS 8
+#else                      // reasonable default
+#define BITS 32
+#endif
+
+//------------------------------------------------------------------------------
+// Derived types and constants
+
 #define MASK ((((bit_t)1) << (BITS)) - 1)
 #if (BITS == 32)
 typedef uint64_t bit_t;   // natural register type
 typedef uint32_t lbit_t;  // natural type for memory I/O
+#elif (BITS == 24)
+typedef uint32_t bit_t;
+typedef uint32_t lbit_t;
 #elif (BITS == 16)
 typedef uint32_t bit_t;
 typedef uint16_t lbit_t;
@@ -38,7 +55,7 @@ typedef uint8_t lbit_t;
 #endif
 
 //------------------------------------------------------------------------------
-// Bitreader and code-tree reader
+// Bitreader
 
 typedef struct VP8BitReader VP8BitReader;
 struct VP8BitReader {
@@ -80,21 +97,26 @@ static WEBP_INLINE void VP8LoadNewBytes(VP8BitReader* const br) {
     lbit_t in_bits = *(lbit_t*)br->buf_;
     br->buf_ += (BITS) >> 3;
 #if !defined(__BIG_ENDIAN__)
-#if (BITS == 32)
+#if (BITS == 32) || (BITS == 24)
 #if defined(__i386__) || defined(__x86_64__)
     __asm__ volatile("bswap %k0" : "=r"(in_bits) : "0"(in_bits));
-    bits = (bit_t)in_bits;   // 32b -> 64b zero-extension
+    bits = (bit_t)in_bits;   // 24b/32b -> 32b/64b zero-extension
 #elif defined(_MSC_VER)
     bits = _byteswap_ulong(in_bits);
 #else
     bits = (bit_t)(in_bits >> 24) | ((in_bits >> 8) & 0xff00)
          | ((in_bits << 8) & 0xff0000)  | (in_bits << 24);
 #endif  // x86
+#if (BITS == 24)
+    bits >>= 8;
+#endif
 #elif (BITS == 16)
     // gcc will recognize a 'rorw $8, ...' here:
     bits = (bit_t)(in_bits >> 8) | ((in_bits & 0xff) << 8);
+#else   // BITS == 8
+    bits = (bit_t)in_bits;
 #endif
-#else    // LITTLE_ENDIAN
+#else    // BIG_ENDIAN
     bits = (bit_t)in_bits;
 #endif
     br->value_ |= bits << br->missing_;
@@ -121,7 +143,7 @@ static WEBP_INLINE int VP8BitUpdate(VP8BitReader* const br, bit_t split) {
 
 static WEBP_INLINE void VP8Shift(VP8BitReader* const br) {
   // range_ is in [0..127] interval here.
-  const int idx = br->range_ >> (BITS);
+  const bit_t idx = br->range_ >> (BITS);
   const int shift = kVP8Log2Range[idx];
   br->range_ = kVP8NewRange[idx];
   br->value_ <<= shift;
@@ -149,7 +171,7 @@ static WEBP_INLINE int VP8GetSigned(VP8BitReader* const br, int v) {
 
 
 // -----------------------------------------------------------------------------
-// Bitreader
+// Bitreader for lossless format
 
 typedef struct {
   uint64_t       val_;
@@ -182,7 +204,7 @@ uint32_t VP8LReadOneBit(VP8LBitReader* const br);
 // 32 times after the last VP8LFillBitWindow. Any subsequent calls
 // (without VP8LFillBitWindow) will return invalid data.
 static WEBP_INLINE uint32_t VP8LReadOneBitUnsafe(VP8LBitReader* const br) {
-  const uint32_t val = (br->val_ >> br->bit_pos_) & 1;
+  const uint32_t val = (uint32_t)((br->val_ >> br->bit_pos_) & 1);
   ++br->bit_pos_;
   return val;
 }