moves fraps huffman decoder to its own file, making it more generic

Originally committed as revision 10736 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/Makefile

@@ -79,7 +79,7 @@ OBJS-$(CONFIG_FLIC_DECODER)            += flicvideo.o
 OBJS-$(CONFIG_FLV_DECODER)             += h263dec.o h263.o
 OBJS-$(CONFIG_FLV_ENCODER)             += mpegvideo_enc.o motion_est.o ratecontrol.o h263.o
 OBJS-$(CONFIG_FOURXM_DECODER)          += 4xm.o
-OBJS-$(CONFIG_FRAPS_DECODER)           += fraps.o
+OBJS-$(CONFIG_FRAPS_DECODER)           += fraps.o huffman.o
 OBJS-$(CONFIG_GIF_DECODER)             += gifdec.o lzw.o
 OBJS-$(CONFIG_GIF_ENCODER)             += gif.o
 OBJS-$(CONFIG_H261_DECODER)            += h261dec.o h261.o

libavcodec/fraps.c

@@ -33,30 +33,18 @@
 
 #include "avcodec.h"
 #include "bitstream.h"
+#include "huffman.h"
+#include "bytestream.h"
 #include "dsputil.h"
 
 #define FPS_TAG MKTAG('F', 'P', 'S', 'x')
 
-/* symbol for Huffman tree node */
-#define HNODE -1
-
-/**
- * Huffman node
- * FIXME one day this should belong to one general framework
- */
-typedef struct Node{
-    int16_t sym;
-    int16_t n0;
-    int count;
-}Node;
-
 /**
  * local variable storage
  */
 typedef struct FrapsContext{
     AVCodecContext *avctx;
     AVFrame frame;
-    Node nodes[512];
     uint8_t *tmpbuf;
     DSPContext dsp;
 } FrapsContext;
@@ -92,36 +80,6 @@ static int huff_cmp(const void *va, const void *vb){
     return (a->count - b->count)*256 + a->sym - b->sym;
 }
 
-static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, Node *nodes, int node, uint32_t pfx, int pl, int *pos)
-{
-    int s;
-
-    s = nodes[node].sym;
-    if(s != HNODE || !nodes[node].count){
-        bits[*pos] = pfx;
-        lens[*pos] = pl;
-        xlat[*pos] = s;
-        (*pos)++;
-    }else{
-        pfx <<= 1;
-        pl++;
-        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0, pfx, pl, pos);
-        pfx |= 1;
-        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0+1, pfx, pl, pos);
-    }
-}
-
-static int build_huff_tree(VLC *vlc, Node *nodes, uint8_t *xlat)
-{
-    uint32_t bits[256];
-    int16_t lens[256];
-    int pos = 0;
-
-    get_tree_codes(bits, lens, xlat, nodes, 510, 0, 0, &pos);
-    return init_vlc(vlc, 9, pos, lens, 2, 2, bits, 4, 4, 0);
-}
-
-
 /**
  * decode Fraps v2 packed plane
  */
@@ -129,45 +87,15 @@ static int fraps2_decode_plane(FrapsContext *s, uint8_t *dst, int stride, int w,
                                int h, uint8_t *src, int size, int Uoff)
 {
     int i, j;
-    int cur_node;
     GetBitContext gb;
     VLC vlc;
-    int64_t sum = 0;
-    uint8_t recode[256];
-
-    for(i = 0; i < 256; i++){
-        s->nodes[i].sym = i;
-        s->nodes[i].count = AV_RL32(src);
-        s->nodes[i].n0 = -2;
-        if(s->nodes[i].count < 0) {
-            av_log(s->avctx, AV_LOG_ERROR, "Symbol count < 0\n");
-            return -1;
-        }
-        src += 4;
-        sum += s->nodes[i].count;
-    }
-    size -= 1024;
+    Node nodes[512];
 
-    if(sum >> 31) {
-        av_log(s->avctx, AV_LOG_ERROR, "Too high symbol frequencies. Tree construction is not possible\n");
-        return -1;
-    }
-    qsort(s->nodes, 256, sizeof(Node), huff_cmp);
-    cur_node = 256;
-    for(i = 0; i < 511; i += 2){
-        s->nodes[cur_node].sym = HNODE;
-        s->nodes[cur_node].count = s->nodes[i].count + s->nodes[i+1].count;
-        s->nodes[cur_node].n0 = i;
-        for(j = cur_node; j > 0; j--){
-            if(s->nodes[j].count >= s->nodes[j - 1].count) break;
-            FFSWAP(Node, s->nodes[j], s->nodes[j - 1]);
-        }
-        cur_node++;
-    }
-    if(build_huff_tree(&vlc, s->nodes, recode) < 0){
-        av_log(s->avctx, AV_LOG_ERROR, "Error building tree\n");
+    for(i = 0; i < 256; i++)
+        nodes[i].count = bytestream_get_le32(&src);
+    size -= 1024;
+    if (ff_huff_build_tree(s->avctx, &vlc, 256, nodes, huff_cmp, 0) < 0)
         return -1;
-    }
     /* we have built Huffman table and are ready to decode plane */
 
     /* convert bits so they may be used by standard bitreader */
@@ -176,7 +104,7 @@ static int fraps2_decode_plane(FrapsContext *s, uint8_t *dst, int stride, int w,
     init_get_bits(&gb, s->tmpbuf, size * 8);
     for(j = 0; j < h; j++){
         for(i = 0; i < w; i++){
-            dst[i] = recode[get_vlc2(&gb, vlc.table, 9, 3)];
+            dst[i] = get_vlc2(&gb, vlc.table, 9, 3);
             /* lines are stored as deltas between previous lines
              * and we need to add 0x80 to the first lines of chroma planes
              */

libavcodec/huffman.c

@@ -0,0 +1,103 @@
+/**
+ * @file huffman.c
+ * huffman tree builder and VLC generator
+ * Copyright (c) 2006 Konstantin Shishkov
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "bitstream.h"
+#include "huffman.h"
+
+/* symbol for Huffman tree node */
+#define HNODE -1
+
+
+static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, Node *nodes, int node, uint32_t pfx, int pl, int *pos)
+{
+    int s;
+
+    s = nodes[node].sym;
+    if(s != HNODE || !nodes[node].count){
+        bits[*pos] = pfx;
+        lens[*pos] = pl;
+        xlat[*pos] = s;
+        (*pos)++;
+    }else{
+        pfx <<= 1;
+        pl++;
+        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0, pfx, pl, pos);
+        pfx |= 1;
+        get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0+1, pfx, pl, pos);
+    }
+}
+
+static int build_huff_tree(VLC *vlc, Node *nodes, int head)
+{
+    uint32_t bits[256];
+    int16_t lens[256];
+    uint8_t xlat[256];
+    int pos = 0;
+
+    get_tree_codes(bits, lens, xlat, nodes, head, 0, 0, &pos);
+    return init_vlc_sparse(vlc, 9, pos, lens, 2, 2, bits, 4, 4, xlat, 1, 1, 0);
+}
+
+
+/**
+ * first nb_codes nodes.count must be set
+ */
+int ff_huff_build_tree(AVCodecContext *avctx, VLC *vlc, int nb_codes,
+                       Node nodes[2*nb_codes], huff_cmp_t cmp, int hnode_first)
+{
+    int i, j;
+    int cur_node;
+    int64_t sum = 0;
+
+    for(i = 0; i < nb_codes; i++){
+        nodes[i].sym = i;
+        nodes[i].n0 = -2;
+        sum += nodes[i].count;
+    }
+
+    if(sum >> 31) {
+        av_log(avctx, AV_LOG_ERROR, "Too high symbol frequencies. Tree construction is not possible\n");
+        return -1;
+    }
+    qsort(nodes, nb_codes, sizeof(Node), cmp);
+    cur_node = nb_codes;
+    for(i = 0; i < nb_codes*2-1; i += 2){
+        nodes[cur_node].sym = HNODE;
+        nodes[cur_node].count = nodes[i].count + nodes[i+1].count;
+        nodes[cur_node].n0 = i;
+        for(j = cur_node; j > 0; j--){
+            if(nodes[j].count > nodes[j-1].count ||
+               (nodes[j].count == nodes[j-1].count &&
+                (!hnode_first || nodes[j].n0==j-1 || nodes[j].n0==j-2 ||
+                 (nodes[j].sym!=HNODE && nodes[j-1].sym!=HNODE))))
+                break;
+            FFSWAP(Node, nodes[j], nodes[j-1]);
+        }
+        cur_node++;
+    }
+    if(build_huff_tree(vlc, nodes, nb_codes*2-2) < 0){
+        av_log(avctx, AV_LOG_ERROR, "Error building tree\n");
+        return -1;
+    }
+    return 0;
+}

libavcodec/huffman.h

@@ -0,0 +1,38 @@
+/**
+ * @file huffman.h
+ * huffman tree builder and VLC generator
+ * Copyright (C) 2007  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_HUFFMAN_H
+#define AVCODEC_HUFFMAN_H
+
+#include "avcodec.h"
+
+typedef struct {
+    int16_t  sym;
+    int16_t  n0;
+    uint32_t count;
+} Node;
+
+typedef int (*huff_cmp_t)(const void *va, const void *vb);
+int ff_huff_build_tree(AVCodecContext *avctx, VLC *vlc, int nb_codes,
+                       Node nodes[2*nb_codes], huff_cmp_t cmp, int hnode_first);
+
+#endif /* AVCODEC_HUFFMAN_H */