summaryrefslogtreecommitdiff
path: root/libavcodec/common.c
diff options
context:
space:
mode:
Diffstat (limited to 'libavcodec/common.c')
-rw-r--r--libavcodec/common.c469
1 files changed, 469 insertions, 0 deletions
diff --git a/libavcodec/common.c b/libavcodec/common.c
new file mode 100644
index 0000000000..b9365c9d8d
--- /dev/null
+++ b/libavcodec/common.c
@@ -0,0 +1,469 @@
+/*
+ * Common bit i/o utils
+ * Copyright (c) 2000, 2001 Gerard Lantau.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#ifdef __FreeBSD__
+#include <sys/param.h>
+#endif
+#include <netinet/in.h>
+#include <math.h>
+#include "common.h"
+
+#define NDEBUG
+#include <assert.h>
+
+void init_put_bits(PutBitContext *s,
+ UINT8 *buffer, int buffer_size,
+ void *opaque,
+ void (*write_data)(void *, UINT8 *, int))
+{
+ s->buf = buffer;
+ s->buf_ptr = s->buf;
+ s->buf_end = s->buf + buffer_size;
+ s->bit_cnt=0;
+ s->bit_buf=0;
+ s->data_out_size = 0;
+ s->write_data = write_data;
+ s->opaque = opaque;
+}
+
+static void flush_buffer(PutBitContext *s)
+{
+ int size;
+ if (s->write_data) {
+ size = s->buf_ptr - s->buf;
+ if (size > 0)
+ s->write_data(s->opaque, s->buf, size);
+ s->buf_ptr = s->buf;
+ s->data_out_size += size;
+ }
+}
+
+void put_bits(PutBitContext *s, int n, unsigned int value)
+{
+ unsigned int bit_buf;
+ int bit_cnt;
+
+#ifdef STATS
+ st_out_bit_counts[st_current_index] += n;
+#endif
+ // printf("put_bits=%d %x\n", n, value);
+ assert(n == 32 || value < (1U << n));
+
+ bit_buf = s->bit_buf;
+ bit_cnt = s->bit_cnt;
+
+ // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
+ /* XXX: optimize */
+ if (n < (32-bit_cnt)) {
+ bit_buf |= value << (32 - n - bit_cnt);
+ bit_cnt+=n;
+ } else {
+ bit_buf |= value >> (n + bit_cnt - 32);
+ *(UINT32 *)s->buf_ptr = htonl(bit_buf);
+ //printf("bitbuf = %08x\n", bit_buf);
+ s->buf_ptr+=4;
+ if (s->buf_ptr >= s->buf_end)
+ flush_buffer(s);
+ bit_cnt=bit_cnt + n - 32;
+ if (bit_cnt == 0) {
+ bit_buf = 0;
+ } else {
+ bit_buf = value << (32 - bit_cnt);
+ }
+ }
+
+ s->bit_buf = bit_buf;
+ s->bit_cnt = bit_cnt;
+}
+
+/* return the number of bits output */
+long long get_bit_count(PutBitContext *s)
+{
+ return (s->buf_ptr - s->buf + s->data_out_size) * 8 + (long long)s->bit_cnt;
+}
+
+void align_put_bits(PutBitContext *s)
+{
+ put_bits(s,(8 - s->bit_cnt) & 7,0);
+}
+
+/* pad the end of the output stream with zeros */
+void flush_put_bits(PutBitContext *s)
+{
+ while (s->bit_cnt > 0) {
+ /* XXX: should test end of buffer */
+ *s->buf_ptr++=s->bit_buf >> 24;
+ s->bit_buf<<=8;
+ s->bit_cnt-=8;
+ }
+ flush_buffer(s);
+ s->bit_cnt=0;
+ s->bit_buf=0;
+}
+
+/* for jpeg : espace 0xff with 0x00 after it */
+void jput_bits(PutBitContext *s, int n, unsigned int value)
+{
+ unsigned int bit_buf, b;
+ int bit_cnt, i;
+
+ assert(n == 32 || value < (1U << n));
+
+ bit_buf = s->bit_buf;
+ bit_cnt = s->bit_cnt;
+
+ //printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
+ /* XXX: optimize */
+ if (n < (32-bit_cnt)) {
+ bit_buf |= value << (32 - n - bit_cnt);
+ bit_cnt+=n;
+ } else {
+ bit_buf |= value >> (n + bit_cnt - 32);
+ /* handle escape */
+ for(i=0;i<4;i++) {
+ b = (bit_buf >> 24);
+ *(s->buf_ptr++) = b;
+ if (b == 0xff)
+ *(s->buf_ptr++) = 0;
+ bit_buf <<= 8;
+ }
+ /* we flush the buffer sooner to handle worst case */
+ if (s->buf_ptr >= (s->buf_end - 8))
+ flush_buffer(s);
+
+ bit_cnt=bit_cnt + n - 32;
+ if (bit_cnt == 0) {
+ bit_buf = 0;
+ } else {
+ bit_buf = value << (32 - bit_cnt);
+ }
+ }
+
+ s->bit_buf = bit_buf;
+ s->bit_cnt = bit_cnt;
+}
+
+/* pad the end of the output stream with zeros */
+void jflush_put_bits(PutBitContext *s)
+{
+ unsigned int b;
+
+ while (s->bit_cnt > 0) {
+ b = s->bit_buf >> 24;
+ *s->buf_ptr++ = b;
+ if (b == 0xff)
+ *s->buf_ptr++ = 0;
+ s->bit_buf<<=8;
+ s->bit_cnt-=8;
+ }
+ flush_buffer(s);
+ s->bit_cnt=0;
+ s->bit_buf=0;
+}
+
+/* bit input functions */
+
+void init_get_bits(GetBitContext *s,
+ UINT8 *buffer, int buffer_size)
+{
+ s->buf = buffer;
+ s->buf_ptr = buffer;
+ s->buf_end = buffer + buffer_size;
+ s->bit_cnt = 0;
+ s->bit_buf = 0;
+ while (s->buf_ptr < s->buf_end &&
+ s->bit_cnt < 32) {
+ s->bit_buf |= (*s->buf_ptr++ << (24 - s->bit_cnt));
+ s->bit_cnt += 8;
+ }
+}
+
+/* n must be >= 1 and <= 32 */
+unsigned int get_bits(GetBitContext *s, int n)
+{
+ unsigned int val;
+ int bit_cnt;
+ unsigned int bit_buf;
+ UINT8 *buf_ptr;
+
+#ifdef STATS
+ st_bit_counts[st_current_index] += n;
+#endif
+
+ bit_cnt = s->bit_cnt;
+ bit_buf = s->bit_buf;
+
+ bit_cnt -= n;
+ if (bit_cnt >= 0) {
+ /* most common case here */
+ val = bit_buf >> (32 - n);
+ bit_buf <<= n;
+ } else {
+ val = bit_buf >> (32 - n);
+ buf_ptr = s->buf_ptr;
+ buf_ptr += 4;
+ /* handle common case: we can read everything */
+ if (buf_ptr <= s->buf_end) {
+ bit_buf = (buf_ptr[-4] << 24) |
+ (buf_ptr[-3] << 16) |
+ (buf_ptr[-2] << 8) |
+ (buf_ptr[-1]);
+ } else {
+ buf_ptr -= 4;
+ bit_buf = 0;
+ if (buf_ptr < s->buf_end)
+ bit_buf |= *buf_ptr++ << 24;
+ if (buf_ptr < s->buf_end)
+ bit_buf |= *buf_ptr++ << 16;
+ if (buf_ptr < s->buf_end)
+ bit_buf |= *buf_ptr++ << 8;
+ if (buf_ptr < s->buf_end)
+ bit_buf |= *buf_ptr++;
+ }
+ s->buf_ptr = buf_ptr;
+ val |= bit_buf >> (32 + bit_cnt);
+ bit_buf <<= - bit_cnt;
+ bit_cnt += 32;
+ }
+ s->bit_buf = bit_buf;
+ s->bit_cnt = bit_cnt;
+ return val;
+}
+
+void align_get_bits(GetBitContext *s)
+{
+ int n;
+ n = s->bit_cnt & 7;
+ if (n > 0) {
+ get_bits(s, n);
+ }
+}
+
+/* VLC decoding */
+
+//#define DEBUG_VLC
+
+#define GET_DATA(v, table, i, wrap, size) \
+{\
+ UINT8 *ptr = (UINT8 *)table + i * wrap;\
+ switch(size) {\
+ case 1:\
+ v = *(UINT8 *)ptr;\
+ break;\
+ case 2:\
+ v = *(UINT16 *)ptr;\
+ break;\
+ default:\
+ v = *(UINT32 *)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_bits = realloc(vlc->table_bits,
+ sizeof(INT8) * vlc->table_allocated);
+ vlc->table_codes = realloc(vlc->table_codes,
+ sizeof(INT16) * vlc->table_allocated);
+ if (!vlc->table_bits ||
+ !vlc->table_codes)
+ 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 code_prefix, int n_prefix)
+{
+ int i, j, k, n, table_size, table_index, nb, n1, index;
+ UINT32 code;
+ INT8 *table_bits;
+ INT16 *table_codes;
+
+ 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_bits = &vlc->table_bits[table_index];
+ table_codes = &vlc->table_codes[table_index];
+
+ for(i=0;i<table_size;i++) {
+ table_bits[i] = 0;
+ table_codes[i] = -1;
+ }
+
+ /* 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_bits[j] != 0) {
+ fprintf(stderr, "incorrect codes\n");
+ exit(1);
+ }
+ table_bits[j] = n;
+ table_codes[j] = i;
+ 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_bits[j];
+ if (n > n1)
+ n1 = n;
+ table_bits[j] = -n1;
+ }
+ }
+ }
+
+ /* second pass : fill auxillary tables recursively */
+ for(i=0;i<table_size;i++) {
+ n = table_bits[i];
+ if (n < 0) {
+ n = -n;
+ if (n > table_nb_bits) {
+ n = table_nb_bits;
+ table_bits[i] = -n;
+ }
+ 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_bits = &vlc->table_bits[table_index];
+ table_codes = &vlc->table_codes[table_index];
+ table_codes[i] = index;
+ }
+ }
+ return table_index;
+}
+
+
+/* wrap and size allow to handle most types of storage. */
+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_bits = NULL;
+ vlc->table_codes = 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) {
+ if (vlc->table_bits)
+ free(vlc->table_bits);
+ if (vlc->table_codes)
+ free(vlc->table_codes);
+ return -1;
+ }
+ return 0;
+}
+
+
+void free_vlc(VLC *vlc)
+{
+ free(vlc->table_bits);
+ free(vlc->table_codes);
+}
+
+int get_vlc(GetBitContext *s, VLC *vlc)
+{
+ int bit_cnt, code, n, nb_bits, index;
+ UINT32 bit_buf;
+ INT16 *table_codes;
+ INT8 *table_bits;
+ UINT8 *buf_ptr;
+
+ SAVE_BITS(s);
+ nb_bits = vlc->bits;
+ table_codes = vlc->table_codes;
+ table_bits = vlc->table_bits;
+ for(;;) {
+ SHOW_BITS(s, index, nb_bits);
+ code = table_codes[index];
+ n = table_bits[index];
+ if (n > 0) {
+ /* most common case */
+ FLUSH_BITS(n);
+#ifdef STATS
+ st_bit_counts[st_current_index] += n;
+#endif
+ break;
+ } else if (n == 0) {
+ return -1;
+ } else {
+ FLUSH_BITS(nb_bits);
+#ifdef STATS
+ st_bit_counts[st_current_index] += nb_bits;
+#endif
+ nb_bits = -n;
+ table_codes = vlc->table_codes + code;
+ table_bits = vlc->table_bits + code;
+ }
+ }
+ RESTORE_BITS(s);
+ return code;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-01 02:32:28 +0000