* For licencing details see COPYING.LIB.
*/
-/**
- * \file bitstream.c Bitstream API.
- */
+/** \file bitstream.c Bitstream API for the wma decoder. */
-#include <stdlib.h>
-#include <inttypes.h>
-#include <stdio.h>
-#include <string.h>
#include <regex.h>
#include "para.h"
#include "error.h"
#include "string.h"
#include "wma.h"
+#include "portable_io.h"
#include "bitstream.h"
-/** Read an 8, 16, or 32 bit entity from a VLC table. */
-#define GET_DATA(v, table, i, size) \
-{\
- const uint8_t *ptr = (const uint8_t *)table + i * size; \
- switch (size) { \
- case 1: \
- v = *(const uint8_t *)ptr; \
- break; \
- case 2: \
- v = *(const uint16_t *)ptr; \
- break; \
- default: \
- v = *(const uint32_t *)ptr; \
- break; \
- } \
+static inline uint32_t get_data(const void *table, int i, int size)
+{
+ const uint8_t *ptr = (const uint8_t *)table + i * size;
+ uint32_t v;
+
+ switch (size) {
+ case 1:
+ v = *(const uint8_t *)ptr;
+ break;
+ case 2:
+ v = *(const uint16_t *)ptr;
+ break;
+ default:
+ v = *(const uint32_t *)ptr;
+ break;
+ }
+ return v;
}
static void alloc_table(struct vlc *vlc, int size)
const void *bits, const void *codes, int codes_size,
uint32_t code_prefix, int n_prefix)
{
- int i, j, k, n, table_size, table_index, nb, n1, idx, code_prefix2;
+ int i, j, k, n, table_size, table_index, nb, n1, idx;
uint32_t code;
VLC_TYPE(*table)[2];
/* map codes and compute auxiliary table sizes */
for (i = 0; i < nb_codes; i++) {
- GET_DATA(n, bits, i, 1);
+ n = get_data(bits, i, 1);
/* we accept tables with holes */
n -= n_prefix;
if (n <= 0)
continue;
- GET_DATA(code, codes, i, codes_size);
+ code = get_data(codes, i, codes_size);
/* if code matches the prefix, it is in the table */
- code_prefix2 = code >> n;
- if (code_prefix2 != code_prefix)
+ if ((code >> n) != code_prefix)
continue;
if (n <= table_nb_bits) {
/* no need to add another table */
j = (code << (table_nb_bits - n)) & (table_size - 1);
nb = 1 << (table_nb_bits - n);
for (k = 0; k < nb; k++) {
- if (table[j][1] /* bits */ != 0) {
- PARA_EMERG_LOG("incorrect code\n");
- exit(EXIT_FAILURE);
- }
+ assert(table[j][1] == 0); /* incorrect code */
table[j][1] = n; /* bits */
table[j][0] = i;
j++;
* Build VLC decoding tables suitable for use with get_vlc().
*
* \param vlc The structure to be initialized.
- *
- * \param nb_bits Set the decoding table size (2^nb_bits) entries. The bigger
- * it is, the faster is the decoding. But it should not be too big to save
- * memory and L1 cache. '9' is a good compromise.
- *
- * \param nb_codes Number of vlcs codes.
- *
+ * \param nb_bits Set the decoding table size (2^nb_bits) entries.
+ * \param nb_codes Number of vlc codes.
* \param bits Table which gives the size (in bits) of each vlc code.
- *
* \param codes Table which gives the bit pattern of of each vlc code.
- *
* \param codes_size The number of bytes of each entry of the \a codes tables.
*
+ * The bigger \a nb_bits is, the faster is the decoding. But it should not be
+ * too big to save memory and L1 cache. '9' is a good compromise.
+ *
* The wrap and size parameters allow to use any memory configuration and
* types (byte/word/long) to store the bits and codes tables.
*/
* Parse a vlc code.
*
* \param gbc The getbit context structure.
- *
* \param table The vlc tables to use.
+ * \param bits The number of bits which will be read at once.
*
- * \param bits The number of bits which will be read at once, must be
- * identical to nb_bits in init_vlc().
- *
- * \param max_depth The number of times bits bits must be read to completely
- * read the longest vlc code = (max_vlc_length + bits - 1) / bits.
+ * The \a bits parameter must be identical to the \a nb_bits value supplied to
+ * \ref init_vlc().
*
* \return The vlc code.
*/
-int get_vlc(struct getbit_context *gbc, VLC_TYPE(*table)[2], int bits,
- int max_depth)
+int get_vlc(struct getbit_context *gbc, VLC_TYPE(*table)[2], int bits)
{
int n, idx, nb_bits, code;
idx = show_bits(gbc, bits);
code = table[idx][0];
n = table[idx][1];
- if (max_depth > 1 && n < 0) {
+ if (n < 0) {
skip_bits(gbc, bits);
nb_bits = -n;
idx = show_bits(gbc, nb_bits) + code;
code = table[idx][0];
n = table[idx][1];
- if (max_depth > 2 && n < 0) {
+ if (n < 0) {
skip_bits(gbc, nb_bits);
nb_bits = -n;
idx = show_bits(gbc, nb_bits) + code;
projects / paraslash.git / blobdiff