From d3aadcff6ce412b17b3609d5ca2ed0e8ee4bfd2b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stephan=20A=C3=9Fmus?= <superstippi@gmx.de>
Date: Mon, 20 Sep 2010 18:24:31 +0000
Subject: [PATCH] =?UTF-8?q?In=20FFmpeg=20SVN=20r22715=20(I=20suppose),=20t?=
 =?UTF-8?q?here=20was=20an=20optimization=20done=20to=20speed=20up=20VLC?=
 =?UTF-8?q?=20table=20(whatever=20it=20is)=20initialization.=20Somehow=20t?=
 =?UTF-8?q?he=20code=20does=20not=20work=20on=20GCC2.=20Use=20the=20old=20?=
 =?UTF-8?q?code=20we=20had=20previously=20in=20SVN=20minus=20a=20flag=20(I?=
 =?UTF-8?q?NIT=5FVLC=5FUSE=5FSTATIC)=20which=20is=20no=20longer=20used=20i?=
 =?UTF-8?q?n=20FFmpeg.=20This=20fixes=20the=20GCC2=20build=20of=20FFmpeg?=
 =?UTF-8?q?=20and=20closes=20=C3=83#6643,=20#6582=20and=20#656.?=
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git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@38746 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../plugins/ffmpeg/libavcodec/bitstream.c     | 146 ++++++++++++++++++
 1 file changed, 146 insertions(+)

diff --git a/src/add-ons/media/plugins/ffmpeg/libavcodec/bitstream.c b/src/add-ons/media/plugins/ffmpeg/libavcodec/bitstream.c
index 0d7a2dbc85..25d8502526 100644
--- a/src/add-ons/media/plugins/ffmpeg/libavcodec/bitstream.c
+++ b/src/add-ons/media/plugins/ffmpeg/libavcodec/bitstream.c
@@ -138,6 +138,7 @@ static int compare_vlcspec(const void *a, const void *b)
     return (sa->code >> 1) - (sb->code >> 1);
 }
 
+#if __GNUC__ >= 3
 /**
  * Build VLC decoding tables suitable for use with get_vlc().
  *
@@ -327,6 +328,151 @@ int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
         av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
     return 0;
 }
+#else
+
+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)
+{
+    int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol;
+    uint32_t code;
+    VLC_TYPE (*table)[2];
+
+    table_size = 1 << table_nb_bits;
+    table_index = alloc_table(vlc, table_size, flags & 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_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++;
+                }
+            } 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
+            }
+        }
+    }
+
+    /* 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
+            }
+            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);
+            if (index < 0)
+                return -1;
+            /* note: realloc has been done, so reload tables */
+            table = &vlc->table[table_index];
+            table[i][0] = index; //code
+        }
+    }
+    return table_index;
+}
+
+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)
+{
+    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 {
+        vlc->table = NULL;
+        vlc->table_allocated = 0;
+        vlc->table_size = 0;
+    }
+
+#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;
+    }
+    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;
+}
+#endif // GCC2 version
 
 
 void free_vlc(VLC *vlc)