Merge branch 't/cpsi_improvement'

[paraslash.git] / bitstream.c

diff --git a/bitstream.c b/bitstream.c
index ee25fffaf2fed5853a3b4c38d8dddedb4dfb41d8..fb638d0a83317568c89e00a56d6bd375e6326a41 100644 (file)
--- a/bitstream.c
+++ b/bitstream.c
@@ -11,9 +11,7 @@
  * 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>
@@ -58,7 +56,7 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
                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];
 
@@ -75,24 +73,20 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
        /* map codes and compute auxiliary table sizes */
        for (i = 0; i < nb_codes; i++) {
                GET_DATA(n, bits, i, 1);
-               GET_DATA(code, codes, i, codes_size);
                /* we accept tables with holes */
+               n -= n_prefix;
                if (n <= 0)
                        continue;
+               GET_DATA(code, codes, i, codes_size);
                /* if code matches the prefix, it is in the table */
-               n -= n_prefix;
-               code_prefix2 = code >> n;
-               if (n <= 0 || 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++;
@@ -132,19 +126,15 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
  * 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.
  */
@@ -176,15 +166,14 @@ void free_vlc(struct vlc *vlc)
  * 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, must be
- * identical to nb_bits in init_vlc().
- *
- * \param max_depth The number of times bits bits must be read to completely
+ * \param bits The number of bits which will be read at once.
+ * \param max_depth The number of times \a 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,