1 /*
2 * Copyright 2008-2013 Various Authors
3 * Copyright 2004 Timo Hirvonen
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * 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, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include "pcm.h"
20 #include "utils.h"
21
22 #include <stdint.h>
23 #include <stdlib.h>
24
25 /*
26 * Functions to convert PCM to 16-bit signed little-endian stereo
27 *
28 * Conversion for 8-bit PCM):
29 * 1. phase
30 * unsigned -> signed
31 * mono -> stereo
32 * 8 -> 16
33 *
34 * Conversion for 16-bit PCM:
35 * 1. phase
36 * be -> le
37 * unsigned -> signed
38 *
39 * 2. phase
40 * mono -> stereo
41 *
42 * There's no reason to split 8-bit conversion to 2 phases because we need to
43 * use separate buffer for 8->16 conversion anyway.
44 *
45 * Conversions for 16-bit stereo can be done in place. 16-bit mono needs to be
46 * converted to stereo so it's worthwhile to split the conversion to 2 phases.
47 */
48
convert_u8_1ch_to_s16_2ch(void * dst,const void * src,int count)49 static void convert_u8_1ch_to_s16_2ch(void *dst, const void *src, int count)
50 {
51 int16_t *d = dst;
52 const uint8_t *s = src;
53 int i, j = 0;
54
55 for (i = 0; i < count; i++) {
56 int16_t sample = s[i] << 8;
57 sample -= 32768;
58 d[j++] = sample;
59 d[j++] = sample;
60 }
61 }
62
convert_s8_1ch_to_s16_2ch(void * dst,const void * src,int count)63 static void convert_s8_1ch_to_s16_2ch(void *dst, const void *src, int count)
64 {
65 int16_t *d = dst;
66 const int8_t *s = src;
67 int i, j = 0;
68
69 for (i = 0; i < count; i++) {
70 int16_t sample = s[i] << 8;
71 d[j++] = sample;
72 d[j++] = sample;
73 }
74 }
75
convert_u8_2ch_to_s16_2ch(void * dst,const void * src,int count)76 static void convert_u8_2ch_to_s16_2ch(void *dst, const void *src, int count)
77 {
78 int16_t *d = dst;
79 const int8_t *s = src;
80 int i;
81
82 for (i = 0; i < count; i++) {
83 int16_t sample = s[i] << 8;
84 sample -= 32768;
85 d[i] = sample;
86 }
87 }
88
convert_s8_2ch_to_s16_2ch(void * dst,const void * src,int count)89 static void convert_s8_2ch_to_s16_2ch(void *dst, const void *src, int count)
90 {
91 int16_t *d = dst;
92 const int8_t *s = src;
93 int i;
94
95 for (i = 0; i < count; i++) {
96 int16_t sample = s[i] << 8;
97 d[i] = sample;
98 }
99 }
100
convert_u16_le_to_s16_le(void * buf,int count)101 static void convert_u16_le_to_s16_le(void *buf, int count)
102 {
103 int16_t *b = buf;
104 int i;
105
106 for (i = 0; i < count; i++) {
107 int sample = (uint16_t)b[i];
108 sample -= 32768;
109 b[i] = sample;
110 }
111 }
112
convert_u16_be_to_s16_le(void * buf,int count)113 static void convert_u16_be_to_s16_le(void *buf, int count)
114 {
115 int16_t *b = buf;
116 int i;
117
118 for (i = 0; i < count; i++) {
119 uint16_t u = b[i];
120 int sample;
121
122 u = swap_uint16(u);
123 sample = (int)u - 32768;
124 b[i] = sample;
125 }
126 }
127
swap_s16_byte_order(void * buf,int count)128 static void swap_s16_byte_order(void *buf, int count)
129 {
130 int16_t *b = buf;
131 int i;
132
133 for (i = 0; i < count; i++)
134 b[i] = swap_uint16(b[i]);
135 }
136
convert_16_1ch_to_16_2ch(void * dst,const void * src,int count)137 static void convert_16_1ch_to_16_2ch(void *dst, const void *src, int count)
138 {
139 int16_t *d = dst;
140 const int16_t *s = src;
141 int i, j = 0;
142
143 for (i = 0; i < count; i++) {
144 d[j++] = s[i];
145 d[j++] = s[i];
146 }
147 }
148
149 /* index is ((bits >> 2) & 4) | (is_signed << 1) | (channels - 1) */
150 pcm_conv_func pcm_conv[8] = {
151 convert_u8_1ch_to_s16_2ch,
152 convert_u8_2ch_to_s16_2ch,
153 convert_s8_1ch_to_s16_2ch,
154 convert_s8_2ch_to_s16_2ch,
155
156 convert_16_1ch_to_16_2ch,
157 NULL,
158 convert_16_1ch_to_16_2ch,
159 NULL
160 };
161
162 /* index is ((bits >> 2) & 4) | (is_signed << 1) | bigendian */
163 pcm_conv_in_place_func pcm_conv_in_place[8] = {
164 NULL,
165 NULL,
166 NULL,
167 NULL,
168
169 convert_u16_le_to_s16_le,
170 convert_u16_be_to_s16_le,
171
172 #ifdef WORDS_BIGENDIAN
173 swap_s16_byte_order,
174 NULL,
175 #else
176 NULL,
177 swap_s16_byte_order,
178 #endif
179 };
180