1 /*
2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3 ** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
4 **
5 ** This program is free software; you can redistribute it and/or modify
6 ** it under the terms of the GNU General Public License as published by
7 ** the Free Software Foundation; either version 2 of the License, or
8 ** (at your option) any later version.
9 **
10 ** This program is distributed in the hope that it will be useful,
11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 ** GNU General Public License for more details.
14 **
15 ** You should have received a copy of the GNU General Public License
16 ** along with this program; if not, write to the Free Software
17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 **
19 ** Any non-GPL usage of this software or parts of this software is strictly
20 ** forbidden.
21 **
22 ** The "appropriate copyright message" mentioned in section 2c of the GPLv2
23 ** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
24 **
25 ** Commercial non-GPL licensing of this software is possible.
26 ** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
27 **
28 ** $Id: bits.c,v 1.44 2007/11/01 12:33:29 menno Exp $
29 **/
30
31 #include "common.h"
32 #include "structs.h"
33
34 #include <stdlib.h>
35 #include "bits.h"
36
37 /* initialize buffer, call once before first getbits or showbits */
faad_initbits(bitfile * ld,const void * _buffer,const uint32_t buffer_size)38 void faad_initbits(bitfile *ld, const void *_buffer, const uint32_t buffer_size)
39 {
40 uint32_t tmp;
41
42 if (ld == NULL)
43 return;
44
45 // useless
46 //memset(ld, 0, sizeof(bitfile));
47
48 if (buffer_size == 0 || _buffer == NULL)
49 {
50 ld->error = 1;
51 return;
52 }
53
54 ld->buffer = _buffer;
55
56 ld->buffer_size = buffer_size;
57 ld->bytes_left = buffer_size;
58
59 if (ld->bytes_left >= 4)
60 {
61 tmp = getdword((uint32_t*)ld->buffer);
62 ld->bytes_left -= 4;
63 } else {
64 tmp = getdword_n((uint32_t*)ld->buffer, ld->bytes_left);
65 ld->bytes_left = 0;
66 }
67 ld->bufa = tmp;
68
69 if (ld->bytes_left >= 4)
70 {
71 tmp = getdword((uint32_t*)ld->buffer + 1);
72 ld->bytes_left -= 4;
73 } else {
74 tmp = getdword_n((uint32_t*)ld->buffer + 1, ld->bytes_left);
75 ld->bytes_left = 0;
76 }
77 ld->bufb = tmp;
78
79 ld->start = (uint32_t*)ld->buffer;
80 ld->tail = ((uint32_t*)ld->buffer + 2);
81
82 ld->bits_left = 32;
83
84 ld->error = 0;
85 }
86
faad_endbits(bitfile * ld)87 void faad_endbits(bitfile *ld)
88 {
89 // void
90 }
91
faad_get_processed_bits(bitfile * ld)92 uint32_t faad_get_processed_bits(bitfile *ld)
93 {
94 return (uint32_t)(8 * (4*(ld->tail - ld->start) - 4) - (ld->bits_left));
95 }
96
faad_byte_align(bitfile * ld)97 uint8_t faad_byte_align(bitfile *ld)
98 {
99 int remainder = (32 - ld->bits_left) & 0x7;
100
101 if (remainder)
102 {
103 faad_flushbits(ld, 8 - remainder);
104 return (uint8_t)(8 - remainder);
105 }
106 return 0;
107 }
108
faad_flushbits_ex(bitfile * ld,uint32_t bits)109 void faad_flushbits_ex(bitfile *ld, uint32_t bits)
110 {
111 uint32_t tmp;
112
113 ld->bufa = ld->bufb;
114 if (ld->bytes_left >= 4)
115 {
116 tmp = getdword(ld->tail);
117 ld->bytes_left -= 4;
118 } else {
119 tmp = getdword_n(ld->tail, ld->bytes_left);
120 ld->bytes_left = 0;
121 }
122 ld->bufb = tmp;
123 ld->tail++;
124 ld->bits_left += (32 - bits);
125 //ld->bytes_left -= 4;
126 // if (ld->bytes_left == 0)
127 // ld->no_more_reading = 1;
128 // if (ld->bytes_left < 0)
129 // ld->error = 1;
130 }
131
132 /* rewind to beginning */
faad_rewindbits(bitfile * ld)133 void faad_rewindbits(bitfile *ld)
134 {
135 uint32_t tmp;
136
137 ld->bytes_left = ld->buffer_size;
138
139 if (ld->bytes_left >= 4)
140 {
141 tmp = getdword((uint32_t*)&ld->start[0]);
142 ld->bytes_left -= 4;
143 } else {
144 tmp = getdword_n((uint32_t*)&ld->start[0], ld->bytes_left);
145 ld->bytes_left = 0;
146 }
147 ld->bufa = tmp;
148
149 if (ld->bytes_left >= 4)
150 {
151 tmp = getdword((uint32_t*)&ld->start[1]);
152 ld->bytes_left -= 4;
153 } else {
154 tmp = getdword_n((uint32_t*)&ld->start[1], ld->bytes_left);
155 ld->bytes_left = 0;
156 }
157 ld->bufb = tmp;
158
159 ld->bits_left = 32;
160 ld->tail = &ld->start[2];
161 }
162
163 /* reset to a certain point */
faad_resetbits(bitfile * ld,int bits)164 void faad_resetbits(bitfile *ld, int bits)
165 {
166 uint32_t tmp;
167 int words = bits >> 5;
168 int remainder = bits & 0x1F;
169
170 ld->bytes_left = ld->buffer_size - words*4;
171
172 if (ld->bytes_left >= 4)
173 {
174 tmp = getdword(&ld->start[words]);
175 ld->bytes_left -= 4;
176 } else {
177 tmp = getdword_n(&ld->start[words], ld->bytes_left);
178 ld->bytes_left = 0;
179 }
180 ld->bufa = tmp;
181
182 if (ld->bytes_left >= 4)
183 {
184 tmp = getdword(&ld->start[words+1]);
185 ld->bytes_left -= 4;
186 } else {
187 tmp = getdword_n(&ld->start[words+1], ld->bytes_left);
188 ld->bytes_left = 0;
189 }
190 ld->bufb = tmp;
191
192 ld->bits_left = 32 - remainder;
193 ld->tail = &ld->start[words+2];
194
195 /* recheck for reading too many bytes */
196 ld->error = 0;
197 // if (ld->bytes_left == 0)
198 // ld->no_more_reading = 1;
199 // if (ld->bytes_left < 0)
200 // ld->error = 1;
201 }
202
faad_getbitbuffer(bitfile * ld,uint32_t bits DEBUGDEC)203 uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits
204 DEBUGDEC)
205 {
206 int i;
207 unsigned int temp;
208 int bytes = bits >> 3;
209 int remainder = bits & 0x7;
210
211 uint8_t *buffer = (uint8_t*)faad_malloc((bytes+1)*sizeof(uint8_t));
212
213 for (i = 0; i < bytes; i++)
214 {
215 buffer[i] = (uint8_t)faad_getbits(ld, 8 DEBUGVAR(print,var,dbg));
216 }
217
218 if (remainder)
219 {
220 temp = faad_getbits(ld, remainder DEBUGVAR(print,var,dbg)) << (8-remainder);
221
222 buffer[bytes] = (uint8_t)temp;
223 }
224
225 return buffer;
226 }
227
228 #ifdef DRM
229 /* return the original data buffer */
faad_origbitbuffer(bitfile * ld)230 void *faad_origbitbuffer(bitfile *ld)
231 {
232 return (void*)ld->start;
233 }
234
235 /* return the original data buffer size */
faad_origbitbuffer_size(bitfile * ld)236 uint32_t faad_origbitbuffer_size(bitfile *ld)
237 {
238 return ld->buffer_size;
239 }
240 #endif
241
242 /* reversed bit reading routines, used for RVLC and HCR */
faad_initbits_rev(bitfile * ld,void * buffer,uint32_t bits_in_buffer)243 void faad_initbits_rev(bitfile *ld, void *buffer,
244 uint32_t bits_in_buffer)
245 {
246 uint32_t tmp;
247 int32_t index;
248
249 ld->buffer_size = bit2byte(bits_in_buffer);
250
251 index = (bits_in_buffer+31)/32 - 1;
252
253 ld->start = (uint32_t*)buffer + index - 2;
254
255 tmp = getdword((uint32_t*)buffer + index);
256 ld->bufa = tmp;
257
258 tmp = getdword((uint32_t*)buffer + index - 1);
259 ld->bufb = tmp;
260
261 ld->tail = (uint32_t*)buffer + index;
262
263 ld->bits_left = bits_in_buffer % 32;
264 if (ld->bits_left == 0)
265 ld->bits_left = 32;
266
267 ld->bytes_left = ld->buffer_size;
268 ld->error = 0;
269 }
270
271 /* EOF */
272