Kill unused getbit_context->size_in_bits and add some doku.
[paraslash.git] / bitstream.c
index 2522b6d4e0a2be6e738fe5f1632c9f788e98a978..dedcdead5bc77bb12880ec9342dc95a39e6cd615 100644 (file)
@@ -27,9 +27,9 @@
 #include "wma.h"
 #include "bitstream.h"
 
-#define GET_DATA(v, table, i, wrap, size) \
+#define GET_DATA(v, table, i, size) \
 {\
-       const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
+       const uint8_t *ptr = (const uint8_t *)table + i * size; \
        switch (size) { \
        case 1: \
                v = *(const uint8_t *)ptr; \
@@ -54,10 +54,10 @@ static void alloc_table(struct vlc *vlc, int size)
 }
 
 static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
-               const void *bits, const void *codes, int codes_wrap,
-               int codes_size, uint32_t code_prefix, int n_prefix)
+               const void *bits, const void *codes, int codes_size,
+               uint32_t code_prefix, int n_prefix)
 {
-       int ret, 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, code_prefix2,
                symbol;
        uint32_t code;
        VLC_TYPE(*table)[2];
@@ -72,10 +72,10 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
                table[i][0] = -1;       //codes
        }
 
-       /* first pass: map codes and compute auxillary table sizes */
+       /* map codes and compute auxillary table sizes */
        for (i = 0; i < nb_codes; i++) {
-               GET_DATA(n, bits, i, 1, 1);
-               GET_DATA(code, codes, i, codes_wrap, codes_size);
+               GET_DATA(n, bits, i, 1);
+               GET_DATA(code, codes, i, codes_size);
                /* we accept tables with holes */
                if (n <= 0)
                        continue;
@@ -83,31 +83,33 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
                /* 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 (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)
-                                               return -E_BAD_CODES;
-                                       table[j][1] = n;        //bits
-                                       table[j][0] = symbol;
-                                       j++;
+               if (n <= 0 || code_prefix2 != 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);
                                }
-                       } else {
-                               n -= table_nb_bits;
-                               j = (code >> n) & ((1 << table_nb_bits) - 1);
-                               /* compute table size */
-                               n1 = -table[j][1];      //bits
-                               if (n > n1)
-                                       n1 = n;
-                               table[j][1] = -n1;      //bits
+                               table[j][1] = n;        //bits
+                               table[j][0] = symbol;
+                               j++;
                        }
+               } else {
+                       n -= table_nb_bits;
+                       j = (code >> n) & ((1 << table_nb_bits) - 1);
+                       /* compute table size */
+                       n1 = -table[j][1];      //bits
+                       if (n > n1)
+                               n1 = n;
+                       table[j][1] = -n1;      //bits
                }
        }
 
-       /* second pass : fill auxillary tables recursively */
+       /* fill auxillary tables recursively */
        for (i = 0; i < table_size; i++) {
                n = table[i][1];        //bits
                if (n < 0) {
@@ -116,14 +118,10 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
                                n = table_nb_bits;
                                table[i][1] = -n;       //bits
                        }
-                       ret = build_table(vlc, n, nb_codes,
-                               bits, codes, codes_wrap, codes_size,
-                               (code_prefix << table_nb_bits) | i,
+                       idx = build_table(vlc, n, nb_codes, bits, codes,
+                               codes_size, (code_prefix << table_nb_bits) | i,
                                n_prefix + table_nb_bits);
-                       if (ret < 0)
-                               return ret;
-                       idx = ret;
-                       /* note: realloc has been done, so reload tables */
+                       /* vlc->table might have changed */
                        table = &vlc->table[table_index];
                        table[i][0] = idx;      //code
                }
@@ -141,37 +139,24 @@ static int build_table(struct vlc *vlc, int table_nb_bits, int nb_codes,
  *
  * \param nb_codes Number of vlcs 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 bits Table which gives the size (in bits) of each vlc code.
  *
- * \param codes_wrap The number of bytes between each entry of the
- * 'codes' tables.
+ * \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
- * 'codes' tables.
+ * \param codes_size The number of bytes of each entry of the \a codes tables.
  *
  * The wrap and size parameters allow to use any memory configuration and
  * types (byte/word/long) to store the bits and codes tables.
  */
-int init_vlc(struct vlc *vlc, int nb_bits, int nb_codes,
-               const void *bits, const void *codes, int codes_wrap,
-               int codes_size)
+void init_vlc(struct vlc *vlc, int nb_bits, int nb_codes, const void *bits,
+               const void *codes, int codes_size)
 {
-       int ret;
-
-       PARA_INFO_LOG("nb_codes=%d\n", nb_codes);
+       PARA_INFO_LOG("nb_codes: %d\n", nb_codes);
        vlc->bits = nb_bits;
        vlc->table = NULL;
        vlc->table_allocated = 0;
        vlc->table_size = 0;
-       ret = build_table(vlc, nb_bits, nb_codes, bits,
-               codes, codes_wrap, codes_size, 0, 0);
-       if (ret < 0)
-               freep(&vlc->table);
-       return ret;
+       build_table(vlc, nb_bits, nb_codes, bits, codes, codes_size, 0, 0);
 }
 
 void free_vlc(struct vlc *vlc)