1 /*****************************************************************************
2 * vlc_bits.h : Bit handling helpers
3 *****************************************************************************
4 * Copyright (C) 2001, 2002, 2003, 2006, 2015 VLC authors and VideoLAN
7 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
8 * Gildas Bazin <gbazin at videolan dot org>
9 * Rafaël Carré <funman at videolan dot org>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU Lesser General Public License as published by
13 * the Free Software Foundation; either version 2.1 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public License
22 * along with this program; if not, write to the Free Software Foundation,
23 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
24 *****************************************************************************/
29 #include <vlc_block.h>
33 * This file defines functions, structures for handling streams of bits in vlc
49 ssize_t i_left; /* i_count number of available bits */
52 static inline void bs_init( bs_t *s, const void *p_data, size_t i_data )
54 s->p_start = (void *)p_data;
56 s->p_end = s->p_start + i_data;
60 static inline int bs_pos( const bs_t *s )
62 return( 8 * ( s->p - s->p_start ) + 8 - s->i_left );
65 static inline int bs_eof( const bs_t *s )
67 return( s->p >= s->p_end ? 1: 0 );
70 static inline uint32_t bs_read( bs_t *s, int i_count )
72 static const uint32_t i_mask[33] =
74 0x01, 0x03, 0x07, 0x0f,
75 0x1f, 0x3f, 0x7f, 0xff,
76 0x1ff, 0x3ff, 0x7ff, 0xfff,
77 0x1fff, 0x3fff, 0x7fff, 0xffff,
78 0x1ffff, 0x3ffff, 0x7ffff, 0xfffff,
79 0x1fffff, 0x3fffff, 0x7fffff, 0xffffff,
80 0x1ffffff, 0x3ffffff, 0x7ffffff, 0xfffffff,
81 0x1fffffff,0x3fffffff,0x7fffffff,0xffffffff};
83 uint32_t i_result = 0;
87 if( s->p >= s->p_end )
92 if( ( i_shr = s->i_left - i_count ) >= 0 )
94 /* more in the buffer than requested */
95 i_result |= ( *s->p >> i_shr )&i_mask[i_count];
106 /* less in the buffer than requested */
107 i_result |= (*s->p&i_mask[s->i_left]) << -i_shr;
108 i_count -= s->i_left;
117 static inline uint32_t bs_read1( bs_t *s )
119 if( s->p < s->p_end )
121 unsigned int i_result;
124 i_result = ( *s->p >> s->i_left )&0x01;
136 static inline uint32_t bs_show( bs_t *s, int i_count )
139 return bs_read( &s_tmp, i_count );
142 static inline void bs_skip( bs_t *s, ssize_t i_count )
144 s->i_left -= i_count;
148 const int i_bytes = ( -s->i_left + 8 ) / 8;
151 s->i_left += 8 * i_bytes;
155 static inline void bs_write( bs_t *s, int i_count, uint32_t i_bits )
159 if( s->p >= s->p_end )
166 if( ( i_bits >> i_count )&0x01 )
168 *s->p |= 1 << ( s->i_left - 1 );
172 *s->p &= ~( 1 << ( s->i_left - 1 ) );
183 static inline void bs_align( bs_t *s )
192 static inline void bs_align_0( bs_t *s )
196 bs_write( s, s->i_left, 0 );
200 static inline void bs_align_1( bs_t *s )
202 while( s->i_left != 8 )
208 static inline int bo_init(bo_t *p_bo, int i_size)
210 p_bo->b = block_Alloc(i_size);
214 p_bo->b->i_buffer = 0;
215 p_bo->len = p_bo->basesize = i_size;
220 static inline void bo_set_8(bo_t *p_bo, size_t i_offset, uint8_t i)
222 if (i_offset >= p_bo->len)
224 int i_growth = p_bo->basesize;
225 while(i_offset >= p_bo->len + i_growth)
226 i_growth += p_bo->basesize;
228 int i = p_bo->b->i_buffer; /* Realloc would set payload size == buffer size */
229 p_bo->b = block_Realloc(p_bo->b, 0, p_bo->len + i_growth);
232 p_bo->b->i_buffer = i;
233 p_bo->len += i_growth;
235 p_bo->b->p_buffer[i_offset] = i;
238 static inline void bo_add_8(bo_t *p_bo, uint8_t i)
240 bo_set_8( p_bo, p_bo->b->i_buffer, i );
244 static inline void bo_add_16be(bo_t *p_bo, uint16_t i)
246 bo_add_8(p_bo, ((i >> 8) &0xff));
247 bo_add_8(p_bo, i &0xff);
250 static inline void bo_add_16le(bo_t *p_bo, uint16_t i)
252 bo_add_8(p_bo, i &0xff);
253 bo_add_8(p_bo, ((i >> 8) &0xff));
256 static inline void bo_set_16be(bo_t *p_bo, int i_offset, uint16_t i)
258 bo_set_8(p_bo, i_offset, ((i >> 8) &0xff));
259 bo_set_8(p_bo, i_offset + 1, i &0xff);
262 static inline void bo_set_16le(bo_t *p_bo, int i_offset, uint16_t i)
264 bo_set_8(p_bo, i_offset, i &0xff);
265 bo_set_8(p_bo, i_offset + 1, ((i >> 8) &0xff));
268 static inline void bo_add_24be(bo_t *p_bo, uint32_t i)
270 bo_add_8(p_bo, ((i >> 16) &0xff));
271 bo_add_8(p_bo, ((i >> 8) &0xff));
272 bo_add_8(p_bo, (i &0xff));
275 static inline void bo_add_32be(bo_t *p_bo, uint32_t i)
277 bo_add_16be(p_bo, ((i >> 16) &0xffff));
278 bo_add_16be(p_bo, i &0xffff);
281 static inline void bo_add_32le(bo_t *p_bo, uint32_t i)
283 bo_add_16le(p_bo, i &0xffff);
284 bo_add_16le(p_bo, ((i >> 16) &0xffff));
287 static inline void bo_set_32be(bo_t *p_bo, int i_offset, uint32_t i)
289 bo_set_16be(p_bo, i_offset, ((i >> 16) &0xffff));
290 bo_set_16be(p_bo, i_offset + 2, i &0xffff);
293 static inline void bo_set_32le(bo_t *p_bo, int i_offset, uint32_t i)
295 bo_set_16le(p_bo, i_offset, i &0xffff);
296 bo_set_16le(p_bo, i_offset + 2, ((i >> 16) &0xffff));
299 static inline void bo_swap_32be (bo_t *p_bo, int i_pos, uint32_t i)
301 p_bo->b->p_buffer[i_pos ] = (i >> 24)&0xff;
302 p_bo->b->p_buffer[i_pos + 1] = (i >> 16)&0xff;
303 p_bo->b->p_buffer[i_pos + 2] = (i >> 8)&0xff;
304 p_bo->b->p_buffer[i_pos + 3] = (i )&0xff;
307 static inline void bo_set_64be(bo_t *p_bo, int i_offset, uint64_t i)
309 bo_set_32be(p_bo, i_offset, ((i >> 32) &0xffffffff));
310 bo_set_32be(p_bo, i_offset + 4, i &0xffffffff);
313 static inline void bo_add_64be(bo_t *p_bo, uint64_t i)
315 bo_add_32be(p_bo, ((i >> 32) &0xffffffff));
316 bo_add_32be(p_bo, i &0xffffffff);
319 static inline void bo_add_64le(bo_t *p_bo, uint64_t i)
321 bo_add_32le(p_bo, i &0xffffffff);
322 bo_add_32le(p_bo, ((i >> 32) &0xffffffff));
325 static inline void bo_add_fourcc(bo_t *p_bo, const char *fcc)
327 bo_add_8(p_bo, fcc[0]);
328 bo_add_8(p_bo, fcc[1]);
329 bo_add_8(p_bo, fcc[2]);
330 bo_add_8(p_bo, fcc[3]);
333 static inline void bo_add_mem(bo_t *p_bo, int i_size, const uint8_t *p_mem)
335 for (int i = 0; i < i_size; i++)
336 bo_add_8(p_bo, p_mem[i]);
339 static inline void bo_add_mp4_tag_descr(bo_t *p_bo, uint8_t tag, uint32_t size)
342 for (int i = 3; i>0; i--)
343 bo_add_8(p_bo, (size>>(7*i)) | 0x80);
344 bo_add_8(p_bo, size & 0x7F);