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add utility routines related to entropy coding

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This commit is contained in:
Josh Coalson
2002-08-17 15:21:29 +00:00
parent 48d87d0aeb
commit cda4c3c7b3
2 changed files with 108 additions and 0 deletions
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76
src/libFLAC/format.c
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@@ -21,6 +21,12 @@
#include <stdlib.h> /* for qsort() */
#include "FLAC/assert.h"
#include "FLAC/format.h"
#include "private/format.h"
#ifdef min
#undef min
#endif
#define min(a,b) ((a)<(b)?(a):(b))
const FLAC__byte FLAC__STREAM_SYNC_STRING[4] = { 'f','L','a','C' };
const unsigned FLAC__STREAM_SYNC = 0x664C6143;
@@ -195,3 +201,73 @@ unsigned FLAC__format_seektable_sort(FLAC__StreamMetadata_SeekTable *seek_table)
return j;
}
unsigned FLAC__format_get_max_rice_partition_order(unsigned blocksize, unsigned predictor_order)
{
return
FLAC__format_get_max_rice_partition_order_from_blocksize_limited_max_and_predictor_order(
FLAC__format_get_max_rice_partition_order_from_blocksize(blocksize),
blocksize,
predictor_order
);
}
unsigned FLAC__format_get_max_rice_partition_order_from_blocksize(unsigned blocksize)
{
unsigned max_rice_partition_order = 0;
while(!(blocksize & 1)) {
max_rice_partition_order++;
blocksize >>= 1;
}
return min(FLAC__MAX_RICE_PARTITION_ORDER, max_rice_partition_order);
}
unsigned FLAC__format_get_max_rice_partition_order_from_blocksize_limited_max_and_predictor_order(unsigned limit, unsigned blocksize, unsigned predictor_order)
{
unsigned max_rice_partition_order = limit;
while(max_rice_partition_order > 0 && (blocksize >> max_rice_partition_order) <= predictor_order)
max_rice_partition_order--;
FLAC__ASSERT(blocksize >> max_rice_partition_order > predictor_order);
return max_rice_partition_order;
}
void FLAC__format_entropy_coding_method_partitioned_rice_init(FLAC__EntropyCodingMethod_PartitionedRice *object)
{
FLAC__ASSERT(0 != object);
object->order = 0;
object->parameters = 0;
object->raw_bits = 0;
object->capacity_by_order = 0;
}
void FLAC__format_entropy_coding_method_partitioned_rice_clear(FLAC__EntropyCodingMethod_PartitionedRice *object)
{
FLAC__ASSERT(0 != object);
if(0 != object->parameters)
free(object->parameters);
if(0 != object->raw_bits)
free(object->raw_bits);
FLAC__format_entropy_coding_method_partitioned_rice_init(object);
}
FLAC__bool FLAC__format_entropy_coding_method_partitioned_rice_ensure_size(FLAC__EntropyCodingMethod_PartitionedRice *object, unsigned max_partition_order)
{
FLAC__ASSERT(0 != object);
FLAC__ASSERT(object->capacity_by_order > 0 || (0 == object->parameters && 0 == object->raw_bits));
if(object->capacity_by_order < max_partition_order) {
if(0 == (object->parameters = realloc(object->parameters, sizeof(unsigned)*(1 << max_partition_order))))
return false;
if(0 == (object->raw_bits = realloc(object->raw_bits, sizeof(unsigned)*(1 << max_partition_order))))
return false;
object->capacity_by_order = max_partition_order;
}
return true;
}