/*
* Common bit i/o utils
* Copyright (c) 2000, 2001 Fabrice Bellard.
+ * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
*
* 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]={
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
-}
-
-/* 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
#endif
}
-/* 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
-}
-
-void put_string(PutBitContext * pbc, char *s)
+void put_string(PutBitContext * pbc, char *s, int put_zero)
{
while(*s){
put_bits(pbc, 8, *s);
s++;
}
- put_bits(pbc, 8, 0);
+ if(put_zero)
+ put_bits(pbc, 8, 0);
}
/* bit input functions */
-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
- 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)
+/**
+ * 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;
}
-#ifdef A32_BITSTREAM_READER
- s->cache1 = 0;
-#endif
}
void align_get_bits(GetBitContext *s)
int check_marker(GetBitContext *s, const char *msg)
{
int bit= get_bits1(s);
- if(!bit) printf("Marker bit missing %s\n", msg);
+ if(!bit)
+ av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg);
return bit;
}
nb = 1 << (table_nb_bits - n);
for(k=0;k<nb;k++) {
#ifdef DEBUG_VLC
- printf("%4x: code=%d n=%d\n",
+ av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
j, i, n);
#endif
if (table[j][1] /*bits*/ != 0) {
- fprintf(stderr, "incorrect codes\n");
- exit(1);
+ av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
+ av_abort();
}
table[j][1] = n; //bits
table[j][0] = i; //code
av_free(vlc->table);
}
-int ff_gcd(int a, int b){
+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;
-}