--- /dev/null
+/*
+ * Common bit i/o utils
+ * Copyright (c) 2000, 2001 Fabrice Bellard.
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
+ */
+
+/**
+ * @file common.c
+ * common internal api.
+ */
+
+#include "avcodec.h"
+
+const uint8_t ff_sqrt_tab[128]={
+ 0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5,
+ 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
+ 9, 9, 9, 9,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,11
+};
+
+const uint8_t ff_log2_tab[256]={
+ 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+
+void init_put_bits(PutBitContext *s,
+ uint8_t *buffer, int buffer_size,
+ void *opaque,
+ void (*write_data)(void *, uint8_t *, int))
+{
+ s->buf = buffer;
+ s->buf_end = s->buf + buffer_size;
+ s->data_out_size = 0;
+ if(write_data!=NULL)
+ {
+ fprintf(stderr, "write Data callback is not supported\n");
+ }
+#ifdef ALT_BITSTREAM_WRITER
+ s->index=0;
+ ((uint32_t*)(s->buf))[0]=0;
+// memset(buffer, 0, buffer_size);
+#else
+ s->buf_ptr = s->buf;
+ s->bit_left=32;
+ s->bit_buf=0;
+#endif
+}
+
+#ifdef CONFIG_ENCODERS
+
+/* return the number of bits output */
+int64_t get_bit_count(PutBitContext *s)
+{
+#ifdef ALT_BITSTREAM_WRITER
+ return s->data_out_size * 8 + s->index;
+#else
+ return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (int64_t)s->bit_left;
+#endif
+}
+
+void 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
+}
+
+#endif //CONFIG_ENCODERS
+
+/* pad the end of the output stream with zeros */
+void flush_put_bits(PutBitContext *s)
+{
+#ifdef ALT_BITSTREAM_WRITER
+ align_put_bits(s);
+#else
+ s->bit_buf<<= s->bit_left;
+ while (s->bit_left < 32) {
+ /* XXX: should test end of buffer */
+ *s->buf_ptr++=s->bit_buf >> 24;
+ s->bit_buf<<=8;
+ s->bit_left+=8;
+ }
+ s->bit_left=32;
+ s->bit_buf=0;
+#endif
+}
+
+#ifdef CONFIG_ENCODERS
+
+void put_string(PutBitContext * pbc, char *s)
+{
+ while(*s){
+ put_bits(pbc, 8, *s);
+ s++;
+ }
+ put_bits(pbc, 8, 0);
+}
+
+/* bit input functions */
+
+#endif //CONFIG_ENCODERS
+
+/**
+ * init GetBitContext.
+ * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
+ * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
+ * @param bit_size the size of the buffer in bits
+ */
+void init_get_bits(GetBitContext *s,
+ const uint8_t *buffer, int bit_size)
+{
+ const int buffer_size= (bit_size+7)>>3;
+
+ s->buffer= buffer;
+ s->size_in_bits= bit_size;
+ s->buffer_end= buffer + buffer_size;
+#ifdef ALT_BITSTREAM_READER
+ s->index=0;
+#elif defined LIBMPEG2_BITSTREAM_READER
+#ifdef LIBMPEG2_BITSTREAM_READER_HACK
+ if ((int)buffer&1) {
+ /* word alignment */
+ s->cache = (*buffer++)<<24;
+ s->buffer_ptr = buffer;
+ s->bit_count = 16-8;
+ } else
+#endif
+ {
+ s->buffer_ptr = buffer;
+ s->bit_count = 16;
+ s->cache = 0;
+ }
+#elif defined A32_BITSTREAM_READER
+ s->buffer_ptr = (uint32_t*)buffer;
+ s->bit_count = 32;
+ s->cache0 = 0;
+ s->cache1 = 0;
+#endif
+ {
+ OPEN_READER(re, s)
+ UPDATE_CACHE(re, s)
+ UPDATE_CACHE(re, s)
+ CLOSE_READER(re, s)
+ }
+#ifdef A32_BITSTREAM_READER
+ s->cache1 = 0;
+#endif
+}
+
+/**
+ * reads 0-32 bits.
+ */
+unsigned int get_bits_long(GetBitContext *s, int n){
+ if(n<=17) return get_bits(s, n);
+ else{
+ int ret= get_bits(s, 16) << (n-16);
+ return ret | get_bits(s, n-16);
+ }
+}
+
+/**
+ * shows 0-32 bits.
+ */
+unsigned int show_bits_long(GetBitContext *s, int n){
+ if(n<=17) return show_bits(s, n);
+ else{
+ GetBitContext gb= *s;
+ int ret= get_bits_long(s, n);
+ *s= gb;
+ return ret;
+ }
+}
+
+void align_get_bits(GetBitContext *s)
+{
+ int n= (-get_bits_count(s)) & 7;
+ if(n) skip_bits(s, n);
+}
+
+int check_marker(GetBitContext *s, const char *msg)
+{
+ int bit= get_bits1(s);
+ if(!bit) printf("Marker bit missing %s\n", msg);
+
+ return bit;
+}
+
+/* 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;\
+ }\
+}
+
+
+static int alloc_table(VLC *vlc, int size)
+{
+ int index;
+ index = vlc->table_size;
+ vlc->table_size += size;
+ if (vlc->table_size > vlc->table_allocated) {
+ vlc->table_allocated += (1 << vlc->bits);
+ vlc->table = av_realloc(vlc->table,
+ sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
+ if (!vlc->table)
+ return -1;
+ }
+ 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,
+ uint32_t code_prefix, int n_prefix)
+{
+ int i, j, k, n, table_size, table_index, nb, n1, index;
+ uint32_t code;
+ VLC_TYPE (*table)[2];
+
+ table_size = 1 << table_nb_bits;
+ table_index = alloc_table(vlc, table_size);
+#ifdef DEBUG_VLC
+ printf("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 defined(DEBUG_VLC) && 0
+ printf("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 (n > 0 && (code >> n) == 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++) {
+#ifdef DEBUG_VLC
+ printf("%4x: code=%d n=%d\n",
+ j, i, n);
+#endif
+ if (table[j][1] /*bits*/ != 0) {
+ fprintf(stderr, "incorrect codes\n");
+ av_abort();
+ }
+ table[j][1] = n; //bits
+ table[j][0] = i; //code
+ j++;
+ }
+ } else {
+ n -= table_nb_bits;
+ j = (code >> n) & ((1 << table_nb_bits) - 1);
+#ifdef DEBUG_VLC
+ printf("%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,
+ (code_prefix << table_nb_bits) | i,
+ n_prefix + table_nb_bits);
+ 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;
+}
+
+
+/* Build VLC decoding tables suitable for use with get_vlc().
+
+ 'nb_bits' set thee 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.
+
+ 'nb_codes' : number of vlcs codes
+
+ 'bits' : table which gives the size (in bits) of each vlc code.
+
+ 'codes' : table which gives the bit pattern of of each vlc code.
+
+ 'xxx_wrap' : give the number of bytes between each entry of the
+ 'bits' or 'codes' tables.
+
+ 'xxx_size' : gives the number of bytes of each entry of the 'bits'
+ or 'codes' tables.
+
+ 'wrap' and 'size' allows to use any memory configuration and types
+ (byte/word/long) to store the 'bits' and 'codes' tables.
+*/
+int init_vlc(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)
+{
+ vlc->bits = nb_bits;
+ vlc->table = NULL;
+ vlc->table_allocated = 0;
+ vlc->table_size = 0;
+#ifdef DEBUG_VLC
+ printf("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,
+ 0, 0) < 0) {
+ av_free(vlc->table);
+ return -1;
+ }
+ return 0;
+}
+
+
+void free_vlc(VLC *vlc)
+{
+ av_free(vlc->table);
+}
+
+int64_t ff_gcd(int64_t a, int64_t b){
+ if(b) return ff_gcd(b, a%b);
+ else return a;
+}
+
+void ff_float2fraction(int *nom_arg, int *denom_arg, double f, int max){
+ double best_diff=1E10, diff;
+ int best_denom=1, best_nom=1;
+ int nom, denom, gcd;
+
+ //brute force here, perhaps we should try continued fractions if we need large max ...
+ for(denom=1; denom<=max; denom++){
+ nom= (int)(f*denom + 0.5);
+ if(nom<=0 || nom>max) continue;
+
+ diff= ABS( f - (double)nom / (double)denom );
+ if(diff < best_diff){
+ best_diff= diff;
+ best_nom= nom;
+ best_denom= denom;
+ }
+ }
+
+ gcd= ff_gcd(best_nom, best_denom);
+ best_nom /= gcd;
+ best_denom /= gcd;
+
+ *nom_arg= best_nom;
+ *denom_arg= best_denom;
+}
projects / synfig.git / blobdiff