avcodec/aacdec_fixed: use 64bit to avoid overflow in rounding in apply_dependent_coup...
[ffmpeg.git] / libavcodec / bitstream.c
index d39980f..ed528fe 100644 (file)
@@ -1,7 +1,8 @@
 /*
  * Common bit i/o utils
- * Copyright (c) 2000, 2001 Fabrice Bellard.
+ * Copyright (c) 2000, 2001 Fabrice Bellard
  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2010 Loren Merritt
  *
  * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
  *
  */
 
 /**
- * @file bitstream.c
+ * @file
  * bitstream api.
  */
 
+#include "libavutil/avassert.h"
+#include "libavutil/qsort.h"
 #include "avcodec.h"
-#include "bitstream.h"
-
-/**
- * Same as av_mallocz_static(), but does a realloc.
- *
- * @param[in] ptr The block of memory to reallocate.
- * @param[in] size The requested size.
- * @return Block of memory of requested size.
- * @deprecated. Code which uses ff_realloc_static is broken/misdesigned
- * and should correctly use static arrays
- */
-attribute_deprecated av_alloc_size(2)
-static void *ff_realloc_static(void *ptr, unsigned int size);
-
-static void *av_mallocz_static(unsigned int size)
-{
-    return av_mallocz(size);
-}
-
-static void *ff_realloc_static(void *ptr, unsigned int size)
-{
-    return av_realloc(ptr, size);
-}
-
-void align_put_bits(PutBitContext *s)
+#include "internal.h"
+#include "mathops.h"
+#include "put_bits.h"
+#include "vlc.h"
+
+const uint8_t ff_log2_run[41]={
+ 0, 0, 0, 0, 1, 1, 1, 1,
+ 2, 2, 2, 2, 3, 3, 3, 3,
+ 4, 4, 5, 5, 6, 6, 7, 7,
+ 8, 9,10,11,12,13,14,15,
+16,17,18,19,20,21,22,23,
+24,
+};
+
+void avpriv_align_put_bits(PutBitContext *s)
 {
-#ifdef ALT_BITSTREAM_WRITER
-    put_bits(s,(  - s->index) & 7,0);
-#else
-    put_bits(s,s->bit_left & 7,0);
-#endif
+    put_bits(s, s->bit_left & 7, 0);
 }
 
-void ff_put_string(PutBitContext * pbc, const char *s, int put_zero)
+void avpriv_put_string(PutBitContext *pb, const char *string,
+                       int terminate_string)
 {
-    while(*s){
-        put_bits(pbc, 8, *s);
-        s++;
+    while (*string) {
+        put_bits(pb, 8, *string);
+        string++;
     }
-    if(put_zero)
-        put_bits(pbc, 8, 0);
+    if (terminate_string)
+        put_bits(pb, 8, 0);
 }
 
-void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
+void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
 {
-    const uint16_t *srcw= (const uint16_t*)src;
-    int words= length>>4;
-    int bits= length&15;
+    int words = length >> 4;
+    int bits  = length & 15;
     int i;
 
-    if(length==0) return;
+    if (length == 0)
+        return;
 
-    if(ENABLE_SMALL || words < 16 || put_bits_count(pb)&7){
-        for(i=0; i<words; i++) put_bits(pb, 16, be2me_16(srcw[i]));
-    }else{
-        for(i=0; put_bits_count(pb)&31; i++)
+    av_assert0(length <= put_bits_left(pb));
+
+    if (CONFIG_SMALL || words < 16 || put_bits_count(pb) & 7) {
+        for (i = 0; i < words; i++)
+            put_bits(pb, 16, AV_RB16(src + 2 * i));
+    } else {
+        for (i = 0; put_bits_count(pb) & 31; i++)
             put_bits(pb, 8, src[i]);
         flush_put_bits(pb);
-        memcpy(pbBufPtr(pb), src+i, 2*words-i);
-        skip_put_bytes(pb, 2*words-i);
+        memcpy(put_bits_ptr(pb), src + i, 2 * words - i);
+        skip_put_bytes(pb, 2 * words - i);
     }
 
-    put_bits(pb, bits, be2me_16(srcw[words])>>(16-bits));
+    put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits));
 }
 
 /* VLC decoding */
 
-//#define DEBUG_VLC
-
-#define GET_DATA(v, table, i, wrap, size) \
-{\
-    const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
-    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;\
-    }\
+#define GET_DATA(v, table, i, wrap, size)                   \
+{                                                           \
+    const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
+    switch(size) {                                          \
+    case 1:                                                 \
+        v = *(const uint8_t *)ptr;                          \
+        break;                                              \
+    case 2:                                                 \
+        v = *(const uint16_t *)ptr;                         \
+        break;                                              \
+    case 4:                                                 \
+        v = *(const uint32_t *)ptr;                         \
+        break;                                              \
+    default:                                                \
+        av_assert1(0);                                      \
+    }                                                       \
 }
 
 
 static int alloc_table(VLC *vlc, int size, int use_static)
 {
-    int index;
-    index = vlc->table_size;
+    int index = vlc->table_size;
+
     vlc->table_size += size;
     if (vlc->table_size > vlc->table_allocated) {
-        if(use_static>1)
-            abort(); //cant do anything, init_vlc() is used with too little memory
+        if (use_static)
+            abort(); // cannot do anything, init_vlc() is used with too little memory
         vlc->table_allocated += (1 << vlc->bits);
-        if(use_static)
-            vlc->table = ff_realloc_static(vlc->table,
-                                           sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
-        else
-            vlc->table = av_realloc(vlc->table,
-                                    sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
-        if (!vlc->table)
-            return -1;
+        vlc->table = av_realloc_f(vlc->table, vlc->table_allocated, sizeof(VLC_TYPE) * 2);
+        if (!vlc->table) {
+            vlc->table_allocated = 0;
+            vlc->table_size = 0;
+            return AVERROR(ENOMEM);
+        }
+        memset(vlc->table + vlc->table_allocated - (1 << vlc->bits), 0, sizeof(VLC_TYPE) * 2 << vlc->bits);
     }
     return index;
 }
 
-static int build_table(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,
-                       const void *symbols, int symbols_wrap, int symbols_size,
-                       uint32_t code_prefix, int n_prefix, int flags)
+typedef struct VLCcode {
+    uint8_t bits;
+    uint16_t symbol;
+    /** codeword, with the first bit-to-be-read in the msb
+     * (even if intended for a little-endian bitstream reader) */
+    uint32_t code;
+} VLCcode;
+
+static int compare_vlcspec(const void *a, const void *b)
+{
+    const VLCcode *sa = a, *sb = b;
+    return (sa->code >> 1) - (sb->code >> 1);
+}
+/**
+ * Build VLC decoding tables suitable for use with get_vlc().
+ *
+ * @param vlc            the context to be initialized
+ *
+ * @param table_nb_bits  max length of vlc codes to store directly in this table
+ *                       (Longer codes are delegated to subtables.)
+ *
+ * @param nb_codes       number of elements in codes[]
+ *
+ * @param codes          descriptions of the vlc codes
+ *                       These must be ordered such that codes going into the same subtable are contiguous.
+ *                       Sorting by VLCcode.code is sufficient, though not necessary.
+ */
+static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
+                       VLCcode *codes, int flags)
 {
-    int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol;
+    int table_size, table_index, index, code_prefix, symbol, subtable_bits;
+    int i, j, k, n, nb, inc;
     uint32_t code;
-    VLC_TYPE (*table)[2];
+    volatile VLC_TYPE (* volatile table)[2]; // the double volatile is needed to prevent an internal compiler error in gcc 4.2
 
     table_size = 1 << table_nb_bits;
-    table_index = alloc_table(vlc, table_size, flags & (INIT_VLC_USE_STATIC|INIT_VLC_USE_NEW_STATIC));
-#ifdef DEBUG_VLC
-    av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d code_prefix=%x n=%d\n",
-           table_index, table_size, code_prefix, n_prefix);
-#endif
+    if (table_nb_bits > 30)
+       return -1;
+    table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
+    ff_dlog(NULL, "new table index=%d size=%d\n", table_index, table_size);
     if (table_index < 0)
-        return -1;
-    table = &vlc->table[table_index];
-
-    for(i=0;i<table_size;i++) {
-        table[i][1] = 0; //bits
-        table[i][0] = -1; //codes
-    }
-
-    /* first pass: 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(code, codes, i, codes_wrap, codes_size);
-        /* we accept tables with holes */
-        if (n <= 0)
-            continue;
-        if (!symbols)
-            symbol = i;
-        else
-            GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size);
-#if defined(DEBUG_VLC) && 0
-        av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
-#endif
-        /* if code matches the prefix, it is in the table */
-        n -= n_prefix;
-        if(flags & INIT_VLC_LE)
-            code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1);
-        else
-            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(flags & INIT_VLC_LE)
-                        j = (code >> n_prefix) + (k<<n);
-#ifdef DEBUG_VLC
-                    av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
-                           j, i, n);
-#endif
-                    if (table[j][1] /*bits*/ != 0) {
-                        av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
-                        return -1;
-                    }
-                    table[j][1] = n; //bits
-                    table[j][0] = symbol;
-                    j++;
+        return table_index;
+    table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
+
+    /* first pass: map codes and compute auxiliary table sizes */
+    for (i = 0; i < nb_codes; i++) {
+        n      = codes[i].bits;
+        code   = codes[i].code;
+        symbol = codes[i].symbol;
+        ff_dlog(NULL, "i=%d n=%d code=0x%"PRIx32"\n", i, n, code);
+        if (n <= table_nb_bits) {
+            /* no need to add another table */
+            j = code >> (32 - table_nb_bits);
+            nb = 1 << (table_nb_bits - n);
+            inc = 1;
+            if (flags & INIT_VLC_LE) {
+                j = bitswap_32(code);
+                inc = 1 << n;
+            }
+            for (k = 0; k < nb; k++) {
+                int bits = table[j][1];
+                ff_dlog(NULL, "%4x: code=%d n=%d\n", j, i, n);
+                if (bits != 0 && bits != n) {
+                    av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
+                    return AVERROR_INVALIDDATA;
                 }
-            } else {
-                n -= table_nb_bits;
-                j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1);
-#ifdef DEBUG_VLC
-                av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
-                       j, n);
-#endif
-                /* 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 += inc;
             }
-        }
-    }
-
-    /* second pass : fill auxillary tables recursively */
-    for(i=0;i<table_size;i++) {
-        n = table[i][1]; //bits
-        if (n < 0) {
-            n = -n;
-            if (n > table_nb_bits) {
-                n = table_nb_bits;
-                table[i][1] = -n; //bits
+        } else {
+            /* fill auxiliary table recursively */
+            n -= table_nb_bits;
+            code_prefix = code >> (32 - table_nb_bits);
+            subtable_bits = n;
+            codes[i].bits = n;
+            codes[i].code = code << table_nb_bits;
+            for (k = i+1; k < nb_codes; k++) {
+                n = codes[k].bits - table_nb_bits;
+                if (n <= 0)
+                    break;
+                code = codes[k].code;
+                if (code >> (32 - table_nb_bits) != code_prefix)
+                    break;
+                codes[k].bits = n;
+                codes[k].code = code << table_nb_bits;
+                subtable_bits = FFMAX(subtable_bits, n);
             }
-            index = build_table(vlc, n, nb_codes,
-                                bits, bits_wrap, bits_size,
-                                codes, codes_wrap, codes_size,
-                                symbols, symbols_wrap, symbols_size,
-                                (flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i),
-                                n_prefix + table_nb_bits, flags);
+            subtable_bits = FFMIN(subtable_bits, table_nb_bits);
+            j = (flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : code_prefix;
+            table[j][1] = -subtable_bits;
+            ff_dlog(NULL, "%4x: n=%d (subtable)\n",
+                    j, codes[i].bits + table_nb_bits);
+            index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
             if (index < 0)
-                return -1;
+                return index;
             /* note: realloc has been done, so reload tables */
-            table = &vlc->table[table_index];
-            table[i][0] = index; //code
+            table = (volatile VLC_TYPE (*)[2])&vlc->table[table_index];
+            table[j][0] = index; //code
+            i = k-1;
         }
     }
+
+    for (i = 0; i < table_size; i++) {
+        if (table[i][1] == 0) //bits
+            table[i][0] = -1; //codes
+    }
+
     return table_index;
 }
 
 
 /* Build VLC decoding tables suitable for use with get_vlc().
 
-   'nb_bits' set thee decoding table size (2^nb_bits) entries. The
+   'nb_bits' sets 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.
 
@@ -261,58 +257,101 @@ static int build_table(VLC *vlc, int table_nb_bits,
    'bits' or 'codes' tables.
 
    'xxx_size' : gives the number of bytes of each entry of the 'bits'
-   or 'codes' tables.
+   or 'codes' tables. Currently 1,2 and 4 are supported.
 
-   'wrap' and 'size' allows to use any memory configuration and types
+   'wrap' and 'size' make it possible to use any memory configuration and types
    (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
 
    'use_static' should be set to 1 for tables, which should be freed
-   with av_free_static(), 0 if free_vlc() will be used.
+   with av_free_static(), 0 if ff_free_vlc() will be used.
 */
-int init_vlc_sparse(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 *symbols, int symbols_wrap, int symbols_size,
-             int flags)
+int ff_init_vlc_sparse(VLC *vlc_arg, 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 *symbols, int symbols_wrap, int symbols_size,
+                       int flags)
 {
+    VLCcode *buf;
+    int i, j, ret;
+    VLCcode localbuf[1500]; // the maximum currently needed is 1296 by rv34
+    VLC localvlc, *vlc;
+
+    vlc = vlc_arg;
     vlc->bits = nb_bits;
-    if(flags & INIT_VLC_USE_NEW_STATIC){
-        if(vlc->table_size && vlc->table_size == vlc->table_allocated){
-            return 0;
-        }else if(vlc->table_size){
-            abort(); // fatal error, we are called on a partially initialized table
-        }
-    }else if(!(flags & INIT_VLC_USE_STATIC)) {
-        vlc->table = NULL;
-        vlc->table_allocated = 0;
+    if (flags & INIT_VLC_USE_NEW_STATIC) {
+        av_assert0(nb_codes + 1 <= FF_ARRAY_ELEMS(localbuf));
+        buf = localbuf;
+        localvlc = *vlc_arg;
+        vlc = &localvlc;
         vlc->table_size = 0;
     } else {
-        /* Static tables are initially always NULL, return
-           if vlc->table != NULL to avoid double allocation */
-        if(vlc->table)
-            return 0;
+        vlc->table           = NULL;
+        vlc->table_allocated = 0;
+        vlc->table_size      = 0;
+
+        buf = av_malloc_array((nb_codes + 1), sizeof(VLCcode));
+        if (!buf)
+            return AVERROR(ENOMEM);
     }
 
-#ifdef DEBUG_VLC
-    av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
-#endif
-
-    if (build_table(vlc, nb_bits, nb_codes,
-                    bits, bits_wrap, bits_size,
-                    codes, codes_wrap, codes_size,
-                    symbols, symbols_wrap, symbols_size,
-                    0, 0, flags) < 0) {
-        av_freep(&vlc->table);
-        return -1;
+
+    av_assert0(symbols_size <= 2 || !symbols);
+    j = 0;
+#define COPY(condition)\
+    for (i = 0; i < nb_codes; i++) {                                        \
+        GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size);               \
+        if (!(condition))                                                   \
+            continue;                                                       \
+        if (buf[j].bits > 3*nb_bits || buf[j].bits>32) {                    \
+            av_log(NULL, AV_LOG_ERROR, "Too long VLC (%d) in init_vlc\n", buf[j].bits);\
+            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
+                av_free(buf);                                               \
+            return -1;                                                      \
+        }                                                                   \
+        GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size);            \
+        if (buf[j].code >= (1LL<<buf[j].bits)) {                            \
+            av_log(NULL, AV_LOG_ERROR, "Invalid code %"PRIx32" for %d in "  \
+                   "init_vlc\n", buf[j].code, i);                           \
+            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
+                av_free(buf);                                               \
+            return -1;                                                      \
+        }                                                                   \
+        if (flags & INIT_VLC_LE)                                            \
+            buf[j].code = bitswap_32(buf[j].code);                          \
+        else                                                                \
+            buf[j].code <<= 32 - buf[j].bits;                               \
+        if (symbols)                                                        \
+            GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size) \
+        else                                                                \
+            buf[j].symbol = i;                                              \
+        j++;                                                                \
+    }
+    COPY(buf[j].bits > nb_bits);
+    // qsort is the slowest part of init_vlc, and could probably be improved or avoided
+    AV_QSORT(buf, j, struct VLCcode, compare_vlcspec);
+    COPY(buf[j].bits && buf[j].bits <= nb_bits);
+    nb_codes = j;
+
+    ret = build_table(vlc, nb_bits, nb_codes, buf, flags);
+
+    if (flags & INIT_VLC_USE_NEW_STATIC) {
+        if(vlc->table_size != vlc->table_allocated)
+            av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
+
+        av_assert0(ret >= 0);
+        *vlc_arg = *vlc;
+    } else {
+        av_free(buf);
+        if (ret < 0) {
+            av_freep(&vlc->table);
+            return ret;
+        }
     }
-    if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated)
-        av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
     return 0;
 }
 
 
-void free_vlc(VLC *vlc)
+void ff_free_vlc(VLC *vlc)
 {
     av_freep(&vlc->table);
 }
-