Use the upstream version of libwebp, v0.4.3.

third_party/libwebp/utils/bit_writer.h

+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Bit writing and boolean coder
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_UTILS_BIT_WRITER_H_
+#define WEBP_UTILS_BIT_WRITER_H_
+
+#include "../webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// Bit-writing
+
+typedef struct VP8BitWriter VP8BitWriter;
+struct VP8BitWriter {
+  int32_t  range_;      // range-1
+  int32_t  value_;
+  int      run_;        // number of outstanding bits
+  int      nb_bits_;    // number of pending bits
+  uint8_t* buf_;        // internal buffer. Re-allocated regularly. Not owned.
+  size_t   pos_;
+  size_t   max_pos_;
+  int      error_;      // true in case of error
+};
+
+// Initialize the object. Allocates some initial memory based on expected_size.
+int VP8BitWriterInit(VP8BitWriter* const bw, size_t expected_size);
+// Finalize the bitstream coding. Returns a pointer to the internal buffer.
+uint8_t* VP8BitWriterFinish(VP8BitWriter* const bw);
+// Release any pending memory and zeroes the object. Not a mandatory call.
+// Only useful in case of error, when the internal buffer hasn't been grabbed!
+void VP8BitWriterWipeOut(VP8BitWriter* const bw);
+
+int VP8PutBit(VP8BitWriter* const bw, int bit, int prob);
+int VP8PutBitUniform(VP8BitWriter* const bw, int bit);
+void VP8PutValue(VP8BitWriter* const bw, int value, int nb_bits);
+void VP8PutSignedValue(VP8BitWriter* const bw, int value, int nb_bits);
+
+// Appends some bytes to the internal buffer. Data is copied.
+int VP8BitWriterAppend(VP8BitWriter* const bw,
+                       const uint8_t* data, size_t size);
+
+// return approximate write position (in bits)
+static WEBP_INLINE uint64_t VP8BitWriterPos(const VP8BitWriter* const bw) {
+  return (uint64_t)(bw->pos_ + bw->run_) * 8 + 8 + bw->nb_bits_;
+}
+
+// Returns a pointer to the internal buffer.
+static WEBP_INLINE uint8_t* VP8BitWriterBuf(const VP8BitWriter* const bw) {
+  return bw->buf_;
+}
+// Returns the size of the internal buffer.
+static WEBP_INLINE size_t VP8BitWriterSize(const VP8BitWriter* const bw) {
+  return bw->pos_;
+}
+
+//------------------------------------------------------------------------------
+// VP8LBitWriter
+
+#if defined(__x86_64__) || defined(_M_X64)   // 64bit
+typedef uint64_t vp8l_atype_t;   // accumulator type
+typedef uint32_t vp8l_wtype_t;   // writing type
+#define WSWAP HToLE32
+#else
+typedef uint32_t vp8l_atype_t;
+typedef uint16_t vp8l_wtype_t;
+#define WSWAP HToLE16
+#endif
+
+typedef struct {
+  vp8l_atype_t bits_;   // bit accumulator
+  int          used_;   // number of bits used in accumulator
+  uint8_t*     buf_;    // start of buffer
+  uint8_t*     cur_;    // current write position
+  uint8_t*     end_;    // end of buffer
+
+  // After all bits are written (VP8LBitWriterFinish()), the caller must observe
+  // the state of error_. A value of 1 indicates that a memory allocation
+  // failure has happened during bit writing. A value of 0 indicates successful
+  // writing of bits.
+  int error_;
+} VP8LBitWriter;
+
+static WEBP_INLINE size_t VP8LBitWriterNumBytes(VP8LBitWriter* const bw) {
+  return (bw->cur_ - bw->buf_) + ((bw->used_ + 7) >> 3);
+}
+
+uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw);
+
+// Returns 0 in case of memory allocation error.
+int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size);
+
+void VP8LBitWriterDestroy(VP8LBitWriter* const bw);
+
+// This function writes bits into bytes in increasing addresses (little endian),
+// and within a byte least-significant-bit first.
+// This function can write up to 32 bits in one go, but VP8LBitReader can only
+// read 24 bits max (VP8L_MAX_NUM_BIT_READ).
+// VP8LBitWriter's error_ flag is set in case of  memory allocation error.
+void VP8LWriteBits(VP8LBitWriter* const bw, int n_bits, uint32_t bits);
+
+//------------------------------------------------------------------------------
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  /* WEBP_UTILS_BIT_WRITER_H_ */