/* * Copyright (c) 2010 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE 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. */#include <stdlib.h> #include "./vpx_config.h" #include "vpx_dsp/bitreader.h"#include "vpx_dsp/prob.h"#include "vpx_dsp/vpx_dsp_common.h"#include "vpx_ports/mem.h"#include "vpx_mem/vpx_mem.h"#include "vpx_util/endian_inl.h" int vpx_reader_init(vpx_reader *r, const uint8_t *buffer, size_t size, vpx_decrypt_cb decrypt_cb, void *decrypt_state) { if (size && !buffer) { return 1; } else { r->buffer_end = buffer + size; r->buffer = buffer; r->value = 0; r->count = -8; r->range = 255; r->decrypt_cb = decrypt_cb; r->decrypt_state = decrypt_state; vpx_reader_fill(r); return vpx_read_bit(r) != 0; // marker bit }} void vpx_reader_fill(vpx_reader *r) { const uint8_t *const buffer_end = r->buffer_end; const uint8_t *buffer = r->buffer; const uint8_t *buffer_start = buffer; BD_VALUE value = r->value; int count = r->count; const size_t bytes_left = buffer_end - buffer; const size_t bits_left = bytes_left * CHAR_BIT; int shift = BD_VALUE_SIZE - CHAR_BIT - (count + CHAR_BIT); if (r->decrypt_cb) { size_t n = VPXMIN(sizeof(r->clear_buffer), bytes_left); r->decrypt_cb(r->decrypt_state, buffer, r->clear_buffer, (int)n); buffer = r->clear_buffer; buffer_start = r->clear_buffer; } if (bits_left > BD_VALUE_SIZE) { const int bits = (shift & 0xfffffff8) + CHAR_BIT; BD_VALUE nv; BD_VALUE big_endian_values; memcpy(&big_endian_values, buffer, sizeof(BD_VALUE));#if SIZE_MAX == 0xffffffffffffffffULL big_endian_values = HToBE64(big_endian_values);#else big_endian_values = HToBE32(big_endian_values);#endif nv = big_endian_values >> (BD_VALUE_SIZE - bits); count += bits; buffer += (bits >> 3); value = r->value | (nv << (shift & 0x7)); } else { const int bits_over = (int)(shift + CHAR_BIT - (int)bits_left); int loop_end = 0; if (bits_over >= 0) { count += LOTS_OF_BITS; loop_end = bits_over; } if (bits_over < 0 || bits_left) { while (shift >= loop_end) { count += CHAR_BIT; value |= (BD_VALUE)*buffer++ << shift; shift -= CHAR_BIT; } } } // NOTE: Variable 'buffer' may not relate to 'r->buffer' after decryption, // so we increase 'r->buffer' by the amount that 'buffer' moved, rather than // assign 'buffer' to 'r->buffer'. r->buffer += buffer - buffer_start; r->value = value; r->count = count;} const uint8_t *vpx_reader_find_end(vpx_reader *r) { // Find the end of the coded buffer while (r->count > CHAR_BIT && r->count < BD_VALUE_SIZE) { r->count -= CHAR_BIT; r->buffer--; } return r->buffer;}
/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE 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.
*/
#include <stdlib.h>
#include "./vpx_config.h"
#include "vpx_dsp/bitreader.h"
#include "vpx_dsp/prob.h"
#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_ports/mem.h"
#include "vpx_mem/vpx_mem.h"
#include "vpx_util/endian_inl.h"
int vpx_reader_init(vpx_reader *r, const uint8_t *buffer, size_t size,
vpx_decrypt_cb decrypt_cb, void *decrypt_state) {
if (size && !buffer) {
return 1;
} else {
r->buffer_end = buffer + size;
r->buffer = buffer;
r->value = 0;
r->count = -8;
r->range = 255;
r->decrypt_cb = decrypt_cb;
r->decrypt_state = decrypt_state;
vpx_reader_fill(r);
return vpx_read_bit(r) != 0; // marker bit
}
}
void vpx_reader_fill(vpx_reader *r) {
const uint8_t *const buffer_end = r->buffer_end;
const uint8_t *buffer = r->buffer;
const uint8_t *buffer_start = buffer;
BD_VALUE value = r->value;
int count = r->count;
const size_t bytes_left = buffer_end - buffer;
const size_t bits_left = bytes_left * CHAR_BIT;
int shift = BD_VALUE_SIZE - CHAR_BIT - (count + CHAR_BIT);
if (r->decrypt_cb) {
size_t n = VPXMIN(sizeof(r->clear_buffer), bytes_left);
r->decrypt_cb(r->decrypt_state, buffer, r->clear_buffer, (int)n);
buffer = r->clear_buffer;
buffer_start = r->clear_buffer;
}
if (bits_left > BD_VALUE_SIZE) {
const int bits = (shift & 0xfffffff8) + CHAR_BIT;
BD_VALUE nv;
BD_VALUE big_endian_values;
memcpy(&big_endian_values, buffer, sizeof(BD_VALUE));
#if SIZE_MAX == 0xffffffffffffffffULL
big_endian_values = HToBE64(big_endian_values);
#else
big_endian_values = HToBE32(big_endian_values);
#endif
nv = big_endian_values >> (BD_VALUE_SIZE - bits);
count += bits;
buffer += (bits >> 3);
value = r->value | (nv << (shift & 0x7));
} else {
const int bits_over = (int)(shift + CHAR_BIT - (int)bits_left);
int loop_end = 0;
if (bits_over >= 0) {
count += LOTS_OF_BITS;
loop_end = bits_over;
}
if (bits_over < 0 || bits_left) {
while (shift >= loop_end) {
count += CHAR_BIT;
value |= (BD_VALUE)*buffer++ << shift;
shift -= CHAR_BIT;
}
}
}
// NOTE: Variable 'buffer' may not relate to 'r->buffer' after decryption,
// so we increase 'r->buffer' by the amount that 'buffer' moved, rather than
// assign 'buffer' to 'r->buffer'.
r->buffer += buffer - buffer_start;
r->value = value;
r->count = count;
}
const uint8_t *vpx_reader_find_end(vpx_reader *r) {
// Find the end of the coded buffer
while (r->count > CHAR_BIT && r->count < BD_VALUE_SIZE) {
r->count -= CHAR_BIT;
r->buffer--;
}
return r->buffer;
}