libwebp: update to 0.4.1

third_party/libwebp/utils/bit_writer.c

Index: third_party/libwebp/utils/bit_writer.c
diff --git a/third_party/libwebp/utils/bit_writer.c b/third_party/libwebp/utils/bit_writer.c
index 29810a17492fa4a53a0809ae5959a207a6246747..23031f60ad5807b669a5def495b40a7814c93c9d 100644
--- a/third_party/libwebp/utils/bit_writer.c
+++ b/third_party/libwebp/utils/bit_writer.c
@@ -15,7 +15,10 @@
 #include <assert.h>
 #include <string.h>   // for memcpy()
 #include <stdlib.h>
+
 #include "./bit_writer.h"
+#include "./endian_inl.h"
+#include "./utils.h"
 
 //------------------------------------------------------------------------------
 // VP8BitWriter
@@ -34,7 +37,7 @@ static int BitWriterResize(VP8BitWriter* const bw, size_t extra_size) {
   new_size = 2 * bw->max_pos_;
   if (new_size < needed_size) new_size = needed_size;
   if (new_size < 1024) new_size = 1024;
-  new_buf = (uint8_t*)malloc(new_size);
+  new_buf = (uint8_t*)WebPSafeMalloc(1ULL, new_size);
   if (new_buf == NULL) {
     bw->error_ = 1;
     return 0;
@@ -43,7 +46,7 @@ static int BitWriterResize(VP8BitWriter* const bw, size_t extra_size) {
     assert(bw->buf_ != NULL);
     memcpy(new_buf, bw->buf_, bw->pos_);
   }
-  free(bw->buf_);
+  WebPSafeFree(bw->buf_);
   bw->buf_ = new_buf;
   bw->max_pos_ = new_size;
   return 1;
@@ -176,7 +179,7 @@ uint8_t* VP8BitWriterFinish(VP8BitWriter* const bw) {
 
 int VP8BitWriterAppend(VP8BitWriter* const bw,
                        const uint8_t* data, size_t size) {
-  assert(data);
+  assert(data != NULL);
   if (bw->nb_bits_ != -8) return 0;   // kFlush() must have been called
   if (!BitWriterResize(bw, size)) return 0;
   memcpy(bw->buf_ + bw->pos_, data, size);
@@ -185,8 +188,8 @@ int VP8BitWriterAppend(VP8BitWriter* const bw,
 }
 
 void VP8BitWriterWipeOut(VP8BitWriter* const bw) {
-  if (bw) {
-    free(bw->buf_);
+  if (bw != NULL) {
+    WebPSafeFree(bw->buf_);
     memset(bw, 0, sizeof(*bw));
   }
 }
@@ -194,32 +197,43 @@ void VP8BitWriterWipeOut(VP8BitWriter* const bw) {
 //------------------------------------------------------------------------------
 // VP8LBitWriter
 
+// This is the minimum amount of size the memory buffer is guaranteed to grow
+// when extra space is needed.
+#define MIN_EXTRA_SIZE  (32768ULL)
+
+#define VP8L_WRITER_BYTES ((int)sizeof(vp8l_wtype_t))
+#define VP8L_WRITER_BITS (VP8L_WRITER_BYTES * 8)
+#define VP8L_WRITER_MAX_BITS (8 * (int)sizeof(vp8l_atype_t))
+
 // Returns 1 on success.
 static int VP8LBitWriterResize(VP8LBitWriter* const bw, size_t extra_size) {
   uint8_t* allocated_buf;
   size_t allocated_size;
-  const size_t current_size = VP8LBitWriterNumBytes(bw);
+  const size_t max_bytes = bw->end_ - bw->buf_;
+  const size_t current_size = bw->cur_ - bw->buf_;
   const uint64_t size_required_64b = (uint64_t)current_size + extra_size;
   const size_t size_required = (size_t)size_required_64b;
   if (size_required != size_required_64b) {
     bw->error_ = 1;
     return 0;
   }
-  if (bw->max_bytes_ > 0 && size_required <= bw->max_bytes_) return 1;
-  allocated_size = (3 * bw->max_bytes_) >> 1;
+  if (max_bytes > 0 && size_required <= max_bytes) return 1;
+  allocated_size = (3 * max_bytes) >> 1;
   if (allocated_size < size_required) allocated_size = size_required;
   // make allocated size multiple of 1k
   allocated_size = (((allocated_size >> 10) + 1) << 10);
-  allocated_buf = (uint8_t*)malloc(allocated_size);
+  allocated_buf = (uint8_t*)WebPSafeMalloc(1ULL, allocated_size);
   if (allocated_buf == NULL) {
     bw->error_ = 1;
     return 0;
   }
-  memcpy(allocated_buf, bw->buf_, current_size);
-  free(bw->buf_);
+  if (current_size > 0) {
+    memcpy(allocated_buf, bw->buf_, current_size);
+  }
+  WebPSafeFree(bw->buf_);
   bw->buf_ = allocated_buf;
-  bw->max_bytes_ = allocated_size;
-  memset(allocated_buf + current_size, 0, allocated_size - current_size);
+  bw->cur_ = bw->buf_ + current_size;
+  bw->end_ = bw->buf_ + allocated_size;
   return 1;
 }
 
@@ -230,53 +244,64 @@ int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size) {
 
 void VP8LBitWriterDestroy(VP8LBitWriter* const bw) {
   if (bw != NULL) {
-    free(bw->buf_);
+    WebPSafeFree(bw->buf_);
     memset(bw, 0, sizeof(*bw));
   }
 }
 
 void VP8LWriteBits(VP8LBitWriter* const bw, int n_bits, uint32_t bits) {
-  if (n_bits < 1) return;
-#if !defined(__BIG_ENDIAN__)
-  // Technically, this branch of the code can write up to 25 bits at a time,
-  // but in prefix encoding, the maximum number of bits written is 18 at a time.
-  {
-    uint8_t* const p = &bw->buf_[bw->bit_pos_ >> 3];
-    uint32_t v = *(const uint32_t*)p;
-    v |= bits << (bw->bit_pos_ & 7);
-    *(uint32_t*)p = v;
-    bw->bit_pos_ += n_bits;
-  }
-#else  // BIG_ENDIAN
-  {
-    uint8_t* p = &bw->buf_[bw->bit_pos_ >> 3];
-    const int bits_reserved_in_first_byte = bw->bit_pos_ & 7;
-    const int bits_left_to_write = n_bits - 8 + bits_reserved_in_first_byte;
-    // implicit & 0xff is assumed for uint8_t arithmetic
-    *p++ |= bits << bits_reserved_in_first_byte;
-    bits >>= 8 - bits_reserved_in_first_byte;
-    if (bits_left_to_write >= 1) {
-      *p++ = bits;
-      bits >>= 8;
-      if (bits_left_to_write >= 9) {
-        *p++ = bits;
-        bits >>= 8;
+  assert(n_bits <= 32);
+  // That's the max we can handle:
+  assert(bw->used_ + n_bits <= 2 * VP8L_WRITER_MAX_BITS);
+  if (n_bits > 0) {
+    // Local field copy.
+    vp8l_atype_t lbits = bw->bits_;
+    int used = bw->used_;
+    // Special case of overflow handling for 32bit accumulator (2-steps flush).
+    if (VP8L_WRITER_BITS == 16) {
+      if (used + n_bits >= VP8L_WRITER_MAX_BITS) {
+        // Fill up all the VP8L_WRITER_MAX_BITS so it can be flushed out below.
+        const int shift = VP8L_WRITER_MAX_BITS - used;
+        lbits |= (vp8l_atype_t)bits << used;
+        used = VP8L_WRITER_MAX_BITS;
+        n_bits -= shift;
+        bits >>= shift;
+        assert(n_bits <= VP8L_WRITER_MAX_BITS);
       }
     }
-    assert(n_bits <= 25);
-    *p = bits;
-    bw->bit_pos_ += n_bits;
+    // If needed, make some room by flushing some bits out.
+    while (used >= VP8L_WRITER_BITS) {
+      if (bw->cur_ + VP8L_WRITER_BYTES > bw->end_) {
+        const uint64_t extra_size = (bw->end_ - bw->buf_) + MIN_EXTRA_SIZE;
+        if (extra_size != (size_t)extra_size ||
+            !VP8LBitWriterResize(bw, (size_t)extra_size)) {
+          bw->cur_ = bw->buf_;
+          bw->error_ = 1;
+          return;
+        }
+      }
+      *(vp8l_wtype_t*)bw->cur_ = (vp8l_wtype_t)WSWAP((vp8l_wtype_t)lbits);
+      bw->cur_ += VP8L_WRITER_BYTES;
+      lbits >>= VP8L_WRITER_BITS;
+      used -= VP8L_WRITER_BITS;
+    }
+    // Eventually, insert new bits.
+    bw->bits_ = lbits | ((vp8l_atype_t)bits << used);
+    bw->used_ = used + n_bits;
   }
-#endif
-  if ((bw->bit_pos_ >> 3) > (bw->max_bytes_ - 8)) {
-    const uint64_t extra_size = 32768ULL + bw->max_bytes_;
-    if (extra_size != (size_t)extra_size ||
-        !VP8LBitWriterResize(bw, (size_t)extra_size)) {
-      bw->bit_pos_ = 0;
-      bw->error_ = 1;
+}
+
+uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw) {
+  // flush leftover bits
+  if (VP8LBitWriterResize(bw, (bw->used_ + 7) >> 3)) {
+    while (bw->used_ > 0) {
+      *bw->cur_++ = (uint8_t)bw->bits_;
+      bw->bits_ >>= 8;
+      bw->used_ -= 8;
     }
+    bw->used_ = 0;
   }
+  return bw->buf_;
 }
 
 //------------------------------------------------------------------------------
-