1 /* libSoX file format: Grandstream ring tone (c) 2009 robs@users.sourceforge.net
2 *
3 * See https://web.archive.org/web/20101128121923/http://grandstream.com/ringtone.html
4 *
5 * This library is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU Lesser General Public License as published by
7 * the Free Software Foundation; either version 2.1 of the License, or (at
8 * your option) any later version.
9 *
10 * This library 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 Lesser
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this library; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 #include "sox_i.h"
21 #include <time.h>
22
23 #define VERSION_ 0x1000000
24 #define MAX_FILE_SIZE 0x10000
25 #define HEADER_SIZE (size_t)512
26 #define PADDING_SIZE (size_t)478
27
28 static char const id[16] = "ring.bin";
29
30 typedef struct {
31 char const * string;
32 int ft_encoding;
33 unsigned bits_per_sample;
34 sox_encoding_t sox_encoding;
35 } table_t;
36
37 static table_t const table[] = {
38 {NULL, 0, 8, SOX_ENCODING_ULAW},
39 {"G726", 2, 0, SOX_ENCODING_UNKNOWN},
40 {NULL, 3, 0, SOX_ENCODING_GSM},
41 {NULL, 4, 0, SOX_ENCODING_G723},
42 {NULL, 8, 8, SOX_ENCODING_ALAW},
43 {"G722", 9, 0, SOX_ENCODING_UNKNOWN},
44 {"G728", 15, 2, SOX_ENCODING_UNKNOWN},
45 {"iLBC", 98, 0, SOX_ENCODING_UNKNOWN},
46 };
47
ft_enc(unsigned bits_per_sample,sox_encoding_t encoding)48 static int ft_enc(unsigned bits_per_sample, sox_encoding_t encoding)
49 {
50 size_t i;
51 for (i = 0; i < array_length(table); ++i) {
52 table_t const * t = &table[i];
53 if (t->sox_encoding == encoding && t->bits_per_sample == bits_per_sample)
54 return t->ft_encoding;
55 }
56 return -1; /* Should never get here. */
57 }
58
sox_enc(int ft_encoding,unsigned * bits_per_sample)59 static sox_encoding_t sox_enc(int ft_encoding, unsigned * bits_per_sample)
60 {
61 size_t i;
62 for (i = 0; i < array_length(table); ++i) {
63 table_t const * t = &table[i];
64 if (t->ft_encoding == ft_encoding) {
65 *bits_per_sample = t->bits_per_sample;
66 if (t->sox_encoding == SOX_ENCODING_UNKNOWN)
67 lsx_report("unsupported encoding: %s", t->string);
68 return t->sox_encoding;
69 }
70 }
71 *bits_per_sample = 0;
72 return SOX_ENCODING_UNKNOWN;
73 }
74
start_read(sox_format_t * ft)75 static int start_read(sox_format_t * ft)
76 {
77 off_t num_samples;
78 char read_id[array_length(id)];
79 uint32_t file_size;
80 int16_t ft_encoding;
81 sox_encoding_t encoding;
82 unsigned bits_per_sample;
83
84 lsx_readdw(ft, &file_size);
85 num_samples = file_size? file_size * 2 - HEADER_SIZE : SOX_UNSPEC;
86
87 if (file_size >= 2 && ft->seekable) {
88 int i, checksum = (file_size >> 16) + file_size;
89 for (i = file_size - 2; i; --i) {
90 int16_t int16;
91 lsx_readsw(ft, &int16);
92 checksum += int16;
93 }
94 if (lsx_seeki(ft, (off_t)sizeof(file_size), SEEK_SET) != 0)
95 return SOX_EOF;
96 if (checksum & 0xffff)
97 lsx_warn("invalid checksum in input file %s", ft->filename);
98 }
99
100 lsx_skipbytes(ft, (size_t)(2 + 4 + 6)); /* Checksum, version, time stamp. */
101
102 lsx_readchars(ft, read_id, sizeof(read_id));
103 if (memcmp(read_id, id, strlen(id))) {
104 lsx_fail_errno(ft, SOX_EHDR, "gsrt: invalid file name in header");
105 return SOX_EOF;
106 }
107
108 lsx_readsw(ft, &ft_encoding);
109 encoding = sox_enc(ft_encoding, &bits_per_sample);
110 if (encoding != SOX_ENCODING_ALAW &&
111 encoding != SOX_ENCODING_ULAW)
112 ft->handler.read = NULL;
113
114 lsx_skipbytes(ft, PADDING_SIZE);
115
116 return lsx_check_read_params(ft, 1, 8000., encoding,
117 bits_per_sample, (uint64_t)num_samples, sox_true);
118 }
119
start_write(sox_format_t * ft)120 static int start_write(sox_format_t * ft)
121 {
122 int i, encoding = ft_enc(ft->encoding.bits_per_sample, ft->encoding.encoding);
123 time_t now = sox_globals.repeatable? 0 : time(NULL);
124 struct tm const * t = sox_globals.repeatable? gmtime(&now) : localtime(&now);
125
126 int checksum = (VERSION_ >> 16) + VERSION_;
127 checksum += t->tm_year + 1900;
128 checksum += ((t->tm_mon + 1) << 8) + t->tm_mday;
129 checksum += (t->tm_hour << 8) + t->tm_min;
130 for (i = sizeof(id) - 2; i >= 0; i -= 2)
131 checksum += (id[i] << 8) + id[i + 1];
132 checksum += encoding;
133
134 return lsx_writedw(ft, 0)
135 || lsx_writesw(ft, -checksum)
136 || lsx_writedw(ft, VERSION_)
137 || lsx_writesw(ft, t->tm_year + 1900)
138 || lsx_writesb(ft, t->tm_mon + 1)
139 || lsx_writesb(ft, t->tm_mday)
140 || lsx_writesb(ft, t->tm_hour)
141 || lsx_writesb(ft, t->tm_min)
142 || lsx_writechars(ft, id, sizeof(id))
143 || lsx_writesw(ft, encoding)
144 || lsx_padbytes(ft, PADDING_SIZE) ? SOX_EOF : SOX_SUCCESS;
145 }
146
write_samples(sox_format_t * ft,sox_sample_t const * buf,size_t nsamp)147 static size_t write_samples(
148 sox_format_t * ft, sox_sample_t const * buf, size_t nsamp)
149 {
150 size_t n = min(nsamp, MAX_FILE_SIZE - (size_t)ft->tell_off);
151 if (n != nsamp)
152 lsx_warn("audio truncated");
153 return lsx_rawwrite(ft, buf, n);
154 }
155
stop_write(sox_format_t * ft)156 static int stop_write(sox_format_t * ft)
157 {
158 long num_samples = ft->tell_off - HEADER_SIZE;
159
160 if (num_samples & 1) {
161 sox_sample_t pad = 0;
162 lsx_rawwrite(ft, &pad, 1);
163 }
164
165 if (ft->seekable) {
166 unsigned i, file_size = ft->tell_off >> 1;
167 int16_t int16;
168 int checksum;
169 if (!lsx_seeki(ft, (off_t)sizeof(uint32_t), SEEK_SET)) {
170 lsx_readsw(ft, &int16);
171 checksum = (file_size >> 16) + file_size - int16;
172 if (!lsx_seeki(ft, (off_t)HEADER_SIZE, SEEK_SET)) {
173 for (i = (num_samples + 1) >> 1; i; --i) {
174 lsx_readsw(ft, &int16);
175 checksum += int16;
176 }
177 if (!lsx_seeki(ft, (off_t)0, SEEK_SET)) {
178 lsx_writedw(ft, file_size);
179 lsx_writesw(ft, -checksum);
180 return SOX_SUCCESS;
181 }
182 }
183 }
184 }
185 lsx_warn("can't seek in output file `%s'; "
186 "length in file header will be unspecified", ft->filename);
187 return SOX_SUCCESS;
188 }
189
LSX_FORMAT_HANDLER(gsrt)190 LSX_FORMAT_HANDLER(gsrt)
191 {
192 static char const *const names[] = { "gsrt", NULL };
193 static sox_rate_t const write_rates[] = { 8000, 0 };
194 static unsigned const write_encodings[] = {
195 SOX_ENCODING_ALAW, 8, 0,
196 SOX_ENCODING_ULAW, 8, 0,
197 0
198 };
199 static sox_format_handler_t const handler = {
200 SOX_LIB_VERSION_CODE, "Grandstream ring tone",
201 names, SOX_FILE_BIG_END | SOX_FILE_MONO,
202 start_read, lsx_rawread, NULL,
203 start_write, write_samples, stop_write,
204 lsx_rawseek, write_encodings, write_rates, 0
205 };
206 return &handler;
207 }
208