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Merge "inline vp9_reader_has_error()"

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James Zern 2015-07-07 00:48:57 +00:00 committed by Gerrit Code Review
commit 8c6d5a874d
2 changed files with 23 additions and 25 deletions
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23
vp9/decoder/vp9_reader.c
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@ -13,11 +13,6 @@
#include "vp9/decoder/vp9_reader.h"
// This is meant to be a large, positive constant that can still be efficiently
// loaded as an immediate (on platforms like ARM, for example).
// Even relatively modest values like 100 would work fine.
#define LOTS_OF_BITS 0x40000000
int vp9_reader_init(vp9_reader *r,
const uint8_t *buffer,
size_t size,
@ -86,21 +81,3 @@ const uint8_t *vp9_reader_find_end(vp9_reader *r) {
}
return r->buffer;
}
int vp9_reader_has_error(vp9_reader *r) {
// Check if we have reached the end of the buffer.
//
// Variable 'count' stores the number of bits in the 'value' buffer, minus
// 8. The top byte is part of the algorithm, and the remainder is buffered
// to be shifted into it. So if count == 8, the top 16 bits of 'value' are
// occupied, 8 for the algorithm and 8 in the buffer.
//
// When reading a byte from the user's buffer, count is filled with 8 and
// one byte is filled into the value buffer. When we reach the end of the
// data, count is additionally filled with LOTS_OF_BITS. So when
// count == LOTS_OF_BITS - 1, the user's data has been exhausted.
//
// 1 if we have tried to decode bits after the end of stream was encountered.
// 0 No error.
return r->count > BD_VALUE_SIZE && r->count < LOTS_OF_BITS;
}

25
vp9/decoder/vp9_reader.h
View File

@ -29,6 +29,11 @@ typedef size_t BD_VALUE;
#define BD_VALUE_SIZE ((int)sizeof(BD_VALUE) * CHAR_BIT)
// This is meant to be a large, positive constant that can still be efficiently
// loaded as an immediate (on platforms like ARM, for example).
// Even relatively modest values like 100 would work fine.
#define LOTS_OF_BITS 0x40000000
typedef struct {
// Be careful when reordering this struct, it may impact the cache negatively.
BD_VALUE value;
@ -49,10 +54,26 @@ int vp9_reader_init(vp9_reader *r,
void vp9_reader_fill(vp9_reader *r);
int vp9_reader_has_error(vp9_reader *r);
const uint8_t *vp9_reader_find_end(vp9_reader *r);
static INLINE int vp9_reader_has_error(vp9_reader *r) {
// Check if we have reached the end of the buffer.
//
// Variable 'count' stores the number of bits in the 'value' buffer, minus
// 8. The top byte is part of the algorithm, and the remainder is buffered
// to be shifted into it. So if count == 8, the top 16 bits of 'value' are
// occupied, 8 for the algorithm and 8 in the buffer.
//
// When reading a byte from the user's buffer, count is filled with 8 and
// one byte is filled into the value buffer. When we reach the end of the
// data, count is additionally filled with LOTS_OF_BITS. So when
// count == LOTS_OF_BITS - 1, the user's data has been exhausted.
//
// 1 if we have tried to decode bits after the end of stream was encountered.
// 0 No error.
return r->count > BD_VALUE_SIZE && r->count < LOTS_OF_BITS;
}
static INLINE int vp9_read(vp9_reader *r, int prob) {
unsigned int bit = 0;
BD_VALUE value;