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-rw-r--r--media/libwebp/utils/bit_writer_utils.h146
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diff --git a/media/libwebp/utils/bit_writer_utils.h b/media/libwebp/utils/bit_writer_utils.h
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+// 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 VP8PutBits(VP8BitWriter* const bw, uint32_t value, int nb_bits);
+void VP8PutSignedBits(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) {
+ const uint64_t nb_bits = 8 + bw->nb_bits_; // bw->nb_bits_ is <= 0, note
+ return (bw->pos_ + bw->run_) * 8 + 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
+#define VP8L_WRITER_BYTES 4 // sizeof(vp8l_wtype_t)
+#define VP8L_WRITER_BITS 32 // 8 * sizeof(vp8l_wtype_t)
+#define VP8L_WRITER_MAX_BITS 64 // 8 * sizeof(vp8l_atype_t)
+#else
+typedef uint32_t vp8l_atype_t;
+typedef uint16_t vp8l_wtype_t;
+#define WSWAP HToLE16
+#define VP8L_WRITER_BYTES 2
+#define VP8L_WRITER_BITS 16
+#define VP8L_WRITER_MAX_BITS 32
+#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);
+}
+
+// Returns false in case of memory allocation error.
+int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size);
+// Finalize the bitstream coding. Returns a pointer to the internal buffer.
+uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw);
+// Release any pending memory and zeroes the object.
+void VP8LBitWriterWipeOut(VP8LBitWriter* const bw);
+
+// Internal function for VP8LPutBits flushing 32 bits from the written state.
+void VP8LPutBitsFlushBits(VP8LBitWriter* const bw);
+
+// PutBits internal function used in the 16 bit vp8l_wtype_t case.
+void VP8LPutBitsInternal(VP8LBitWriter* const bw, uint32_t bits, int n_bits);
+
+// 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.
+static WEBP_INLINE void VP8LPutBits(VP8LBitWriter* const bw,
+ uint32_t bits, int n_bits) {
+ if (sizeof(vp8l_wtype_t) == 4) {
+ if (n_bits > 0) {
+ if (bw->used_ >= 32) {
+ VP8LPutBitsFlushBits(bw);
+ }
+ bw->bits_ |= (vp8l_atype_t)bits << bw->used_;
+ bw->used_ += n_bits;
+ }
+ } else {
+ VP8LPutBitsInternal(bw, bits, n_bits);
+ }
+}
+
+//------------------------------------------------------------------------------
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif /* WEBP_UTILS_BIT_WRITER_H_ */