bitstream: Abort on invalid codes

[paraslash.git] / bitstream.c

diff --git a/bitstream.c b/bitstream.c
index 23adb2bd28912bd3364234b2a367d562ced1740e..11429489ee2b2fb64fa1e9eac25aaf0148e35594 100644 (file)
--- a/bitstream.c
+++ b/bitstream.c
@@ -43,35 +43,28 @@
        } \
 }
 
-static int alloc_table(struct vlc *vlc, int size)
+static void alloc_table(struct vlc *vlc, int size)
 {
-       int idx;
-
-       idx = vlc->table_size;
        vlc->table_size += size;
        if (vlc->table_size > vlc->table_allocated) {
                vlc->table_allocated += (1 << vlc->bits);
                vlc->table = para_realloc(vlc->table,
                        sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
        }
-       return idx;
 }
 
-static int build_table(struct vlc *vlc, int table_nb_bits,
-               int nb_codes, const void *bits, int bits_wrap, int bits_size,
-               const void *codes, int codes_wrap, int codes_size,
-               uint32_t code_prefix, int n_prefix)
+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)
 {
-       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];
 
        table_size = 1 << table_nb_bits;
-       ret = alloc_table(vlc, table_size);
-       if (ret < 0)
-               return ret;
-       table_index = ret;
+       table_index = vlc->table_size;
+       alloc_table(vlc, table_size);
        table = &vlc->table[table_index];
 
        for (i = 0; i < table_size; i++) {
@@ -79,9 +72,9 @@ static int build_table(struct vlc *vlc, int table_nb_bits,
                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, bits_wrap, bits_size);
+               GET_DATA(n, bits, i, 1, 1);
                GET_DATA(code, codes, i, codes_wrap, codes_size);
                /* we accept tables with holes */
                if (n <= 0)
@@ -96,8 +89,10 @@ static int build_table(struct vlc *vlc, int table_nb_bits,
                                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;
+                                       if (table[j][1] /* bits */ != 0) {
+                                               PARA_EMERG_LOG("detected incorrect code\n");
+                                               exit(EXIT_FAILURE);
+                                       }
                                        table[j][1] = n;        //bits
                                        table[j][0] = symbol;
                                        j++;
@@ -114,7 +109,7 @@ static int build_table(struct vlc *vlc, int table_nb_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) {
@@ -123,15 +118,11 @@ static int build_table(struct vlc *vlc, int table_nb_bits,
                                n = table_nb_bits;
                                table[i][1] = -n;       //bits
                        }
-                       ret = build_table(vlc, n, nb_codes,
-                               bits, bits_wrap, bits_size,
-                               codes, codes_wrap, codes_size,
+                       idx = build_table(vlc, n, nb_codes,
+                               bits, codes, codes_wrap, 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
                }
@@ -155,22 +146,18 @@ static int build_table(struct vlc *vlc, int table_nb_bits,
  * \param codes Table which gives the bit pattern of of each
  * vlc code.
  *
- * \param bits_wrap The number of bytes between each entry of the
- * 'bits' or 'codes' tables.
- *
- * \param bits_size The number of bytes of each entry of the
- * 'bits' or 'codes' tables.
- *
- * \param codes_wrap Same as bits_wrap but uses the 'codes' table.
+ * \param codes_wrap The number of bytes between each entry of the
+ * 'codes' tables.
  *
- * \param codes_size Same as bits_size but for the 'codes' table.
+ * \param codes_size The number of bytes of each entry of the
+ * '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, int bits_wrap, int bits_size,
-               const void *codes, int codes_wrap, int codes_size)
+               const void *bits, const void *codes, int codes_wrap,
+               int codes_size)
 {
        int ret;
 
@@ -179,7 +166,7 @@ int init_vlc(struct vlc *vlc, int nb_bits, int nb_codes,
        vlc->table = NULL;
        vlc->table_allocated = 0;
        vlc->table_size = 0;
-       ret = build_table(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size,
+       ret = build_table(vlc, nb_bits, nb_codes, bits,
                codes, codes_wrap, codes_size, 0, 0);
        if (ret < 0)
                freep(&vlc->table);