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| -rw-r--r-- | src/main/jni/libwebp/utils/bit_reader.h | 169 |
1 files changed, 0 insertions, 169 deletions
diff --git a/src/main/jni/libwebp/utils/bit_reader.h b/src/main/jni/libwebp/utils/bit_reader.h deleted file mode 100644 index f569734f5..000000000 --- a/src/main/jni/libwebp/utils/bit_reader.h +++ /dev/null @@ -1,169 +0,0 @@ -// Copyright 2010 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. -// ----------------------------------------------------------------------------- -// -// Boolean decoder -// -// Author: Skal (pascal.massimino@gmail.com) -// Vikas Arora (vikaas.arora@gmail.com) - -#ifndef WEBP_UTILS_BIT_READER_H_ -#define WEBP_UTILS_BIT_READER_H_ - -#include <assert.h> -#ifdef _MSC_VER -#include <stdlib.h> // _byteswap_ulong -#endif -#include "../webp/types.h" - -#ifdef __cplusplus -extern "C" { -#endif - -// The Boolean decoder needs to maintain infinite precision on the value_ field. -// However, since range_ is only 8bit, we only need an active window of 8 bits -// for value_. Left bits (MSB) gets zeroed and shifted away when value_ falls -// below 128, range_ is updated, and fresh bits read from the bitstream are -// brought in as LSB. To avoid reading the fresh bits one by one (slow), we -// cache BITS of them ahead. The total of (BITS + 8) bits must fit into a -// natural register (with type bit_t). To fetch BITS bits from bitstream we -// use a type lbit_t. -// -// BITS can be any multiple of 8 from 8 to 56 (inclusive). -// Pick values that fit natural register size. - -#if defined(__i386__) || defined(_M_IX86) // x86 32bit -#define BITS 24 -#elif defined(__x86_64__) || defined(_M_X64) // x86 64bit -#define BITS 56 -#elif defined(__arm__) || defined(_M_ARM) // ARM -#define BITS 24 -#elif defined(__mips__) // MIPS -#define BITS 24 -#else // reasonable default -#define BITS 24 // TODO(skal): test aarch64 and find the proper BITS value. -#endif - -//------------------------------------------------------------------------------ -// Derived types and constants: -// bit_t = natural register type for storing 'value_' (which is BITS+8 bits) -// range_t = register for 'range_' (which is 8bits only) - -#if (BITS > 24) -typedef uint64_t bit_t; -#else -typedef uint32_t bit_t; -#endif - -typedef uint32_t range_t; - -//------------------------------------------------------------------------------ -// Bitreader - -typedef struct VP8BitReader VP8BitReader; -struct VP8BitReader { - // boolean decoder (keep the field ordering as is!) - bit_t value_; // current value - range_t range_; // current range minus 1. In [127, 254] interval. - int bits_; // number of valid bits left - // read buffer - const uint8_t* buf_; // next byte to be read - const uint8_t* buf_end_; // end of read buffer - int eof_; // true if input is exhausted -}; - -// Initialize the bit reader and the boolean decoder. -void VP8InitBitReader(VP8BitReader* const br, - const uint8_t* const start, const uint8_t* const end); - -// Update internal pointers to displace the byte buffer by the -// relative offset 'offset'. -void VP8RemapBitReader(VP8BitReader* const br, ptrdiff_t offset); - -// return the next value made of 'num_bits' bits -uint32_t VP8GetValue(VP8BitReader* const br, int num_bits); -static WEBP_INLINE uint32_t VP8Get(VP8BitReader* const br) { - return VP8GetValue(br, 1); -} - -// return the next value with sign-extension. -int32_t VP8GetSignedValue(VP8BitReader* const br, int num_bits); - -// bit_reader_inl.h will implement the following methods: -// static WEBP_INLINE int VP8GetBit(VP8BitReader* const br, int prob) -// static WEBP_INLINE int VP8GetSigned(VP8BitReader* const br, int v) -// and should be included by the .c files that actually need them. -// This is to avoid recompiling the whole library whenever this file is touched, -// and also allowing platform-specific ad-hoc hacks. - -// ----------------------------------------------------------------------------- -// Bitreader for lossless format - -// maximum number of bits (inclusive) the bit-reader can handle: -#define VP8L_MAX_NUM_BIT_READ 24 - -#define VP8L_LBITS 64 // Number of bits prefetched. -#define VP8L_WBITS 32 // Minimum number of bytes ready after VP8LFillBitWindow. - -typedef uint64_t vp8l_val_t; // right now, this bit-reader can only use 64bit. - -typedef struct { - vp8l_val_t val_; // pre-fetched bits - const uint8_t* buf_; // input byte buffer - size_t len_; // buffer length - size_t pos_; // byte position in buf_ - int bit_pos_; // current bit-reading position in val_ - int eos_; // bitstream is finished - int error_; // an error occurred (buffer overflow attempt...) -} VP8LBitReader; - -void VP8LInitBitReader(VP8LBitReader* const br, - const uint8_t* const start, - size_t length); - -// Sets a new data buffer. -void VP8LBitReaderSetBuffer(VP8LBitReader* const br, - const uint8_t* const buffer, size_t length); - -// Reads the specified number of bits from read buffer. -// Flags an error in case end_of_stream or n_bits is more than the allowed limit -// of VP8L_MAX_NUM_BIT_READ (inclusive). -// Flags eos_ if this read attempt is going to cross the read buffer. -uint32_t VP8LReadBits(VP8LBitReader* const br, int n_bits); - -// Return the prefetched bits, so they can be looked up. -static WEBP_INLINE uint32_t VP8LPrefetchBits(VP8LBitReader* const br) { - return (uint32_t)(br->val_ >> br->bit_pos_); -} - -// Returns true if there was an attempt at reading bit past the end of -// the buffer. Doesn't set br->eos_ flag. -static WEBP_INLINE int VP8LIsEndOfStream(const VP8LBitReader* const br) { - assert(br->pos_ <= br->len_); - return (br->pos_ == br->len_) && (br->bit_pos_ > VP8L_LBITS); -} - -// For jumping over a number of bits in the bit stream when accessed with -// VP8LPrefetchBits and VP8LFillBitWindow. -static WEBP_INLINE void VP8LSetBitPos(VP8LBitReader* const br, int val) { - br->bit_pos_ = val; - br->eos_ = VP8LIsEndOfStream(br); -} - -// Advances the read buffer by 4 bytes to make room for reading next 32 bits. -// Speed critical, but infrequent part of the code can be non-inlined. -extern void VP8LDoFillBitWindow(VP8LBitReader* const br); -static WEBP_INLINE void VP8LFillBitWindow(VP8LBitReader* const br) { - if (br->bit_pos_ >= VP8L_WBITS) VP8LDoFillBitWindow(br); -} - -#ifdef __cplusplus -} // extern "C" -#endif - -#endif /* WEBP_UTILS_BIT_READER_H_ */ |