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A few more minor fixes in longobject.c
[python.git] / Modules / audioop.c
blob767cae64e9b56b2023e3a24a7cb5d0a1148cb6e7
1
2 /* audioopmodule - Module to detect peak values in arrays */
3
4 #include "Python.h"
5
6 #if SIZEOF_INT == 4
7 typedef int Py_Int32;
8 typedef unsigned int Py_UInt32;
9 #else
10 #if SIZEOF_LONG == 4
11 typedef long Py_Int32;
12 typedef unsigned long Py_UInt32;
13 #else
14 #error "No 4-byte integral type"
15 #endif
16 #endif
17
18 typedef short PyInt16;
19
20 #if defined(__CHAR_UNSIGNED__)
21 #if defined(signed)
22 /* This module currently does not work on systems where only unsigned
23 characters are available. Take it out of Setup. Sorry. */
24 #endif
25 #endif
26
27 /* Code shamelessly stolen from sox, 12.17.7, g711.c
28 ** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */
29
30 /* From g711.c:
31 *
32 * December 30, 1994:
33 * Functions linear2alaw, linear2ulaw have been updated to correctly
34 * convert unquantized 16 bit values.
35 * Tables for direct u- to A-law and A- to u-law conversions have been
36 * corrected.
37 * Borge Lindberg, Center for PersonKommunikation, Aalborg University.
38 * bli@cpk.auc.dk
39 *
40 */
41 #define BIAS 0x84 /* define the add-in bias for 16 bit samples */
42 #define CLIP 32635
43 #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
44 #define QUANT_MASK (0xf) /* Quantization field mask. */
45 #define SEG_SHIFT (4) /* Left shift for segment number. */
46 #define SEG_MASK (0x70) /* Segment field mask. */
47
48 static PyInt16 seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF,
49 0x1FF, 0x3FF, 0x7FF, 0xFFF};
50 static PyInt16 seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF,
51 0x3FF, 0x7FF, 0xFFF, 0x1FFF};
52
53 static PyInt16
54 search(PyInt16 val, PyInt16 *table, int size)
55 {
56 int i;
57
58 for (i = 0; i < size; i++) {
59 if (val <= *table++)
60 return (i);
61 }
62 return (size);
63 }
64 #define st_ulaw2linear16(uc) (_st_ulaw2linear16[uc])
65 #define st_alaw2linear16(uc) (_st_alaw2linear16[uc])
66
67 static PyInt16 _st_ulaw2linear16[256] = {
68 -32124, -31100, -30076, -29052, -28028, -27004, -25980,
69 -24956, -23932, -22908, -21884, -20860, -19836, -18812,
70 -17788, -16764, -15996, -15484, -14972, -14460, -13948,
71 -13436, -12924, -12412, -11900, -11388, -10876, -10364,
72 -9852, -9340, -8828, -8316, -7932, -7676, -7420,
73 -7164, -6908, -6652, -6396, -6140, -5884, -5628,
74 -5372, -5116, -4860, -4604, -4348, -4092, -3900,
75 -3772, -3644, -3516, -3388, -3260, -3132, -3004,
76 -2876, -2748, -2620, -2492, -2364, -2236, -2108,
77 -1980, -1884, -1820, -1756, -1692, -1628, -1564,
78 -1500, -1436, -1372, -1308, -1244, -1180, -1116,
79 -1052, -988, -924, -876, -844, -812, -780,
80 -748, -716, -684, -652, -620, -588, -556,
81 -524, -492, -460, -428, -396, -372, -356,
82 -340, -324, -308, -292, -276, -260, -244,
83 -228, -212, -196, -180, -164, -148, -132,
84 -120, -112, -104, -96, -88, -80, -72,
85 -64, -56, -48, -40, -32, -24, -16,
86 -8, 0, 32124, 31100, 30076, 29052, 28028,
87 27004, 25980, 24956, 23932, 22908, 21884, 20860,
88 19836, 18812, 17788, 16764, 15996, 15484, 14972,
89 14460, 13948, 13436, 12924, 12412, 11900, 11388,
90 10876, 10364, 9852, 9340, 8828, 8316, 7932,
91 7676, 7420, 7164, 6908, 6652, 6396, 6140,
92 5884, 5628, 5372, 5116, 4860, 4604, 4348,
93 4092, 3900, 3772, 3644, 3516, 3388, 3260,
94 3132, 3004, 2876, 2748, 2620, 2492, 2364,
95 2236, 2108, 1980, 1884, 1820, 1756, 1692,
96 1628, 1564, 1500, 1436, 1372, 1308, 1244,
97 1180, 1116, 1052, 988, 924, 876, 844,
98 812, 780, 748, 716, 684, 652, 620,
99 588, 556, 524, 492, 460, 428, 396,
100 372, 356, 340, 324, 308, 292, 276,
101 260, 244, 228, 212, 196, 180, 164,
102 148, 132, 120, 112, 104, 96, 88,
103 80, 72, 64, 56, 48, 40, 32,
104 24, 16, 8, 0
105 };
106
107 /*
108 * linear2ulaw() accepts a 14-bit signed integer and encodes it as u-law data
109 * stored in a unsigned char. This function should only be called with
110 * the data shifted such that it only contains information in the lower
111 * 14-bits.
112 *
113 * In order to simplify the encoding process, the original linear magnitude
114 * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
115 * (33 - 8191). The result can be seen in the following encoding table:
116 *
117 * Biased Linear Input Code Compressed Code
118 * ------------------------ ---------------
119 * 00000001wxyza 000wxyz
120 * 0000001wxyzab 001wxyz
121 * 000001wxyzabc 010wxyz
122 * 00001wxyzabcd 011wxyz
123 * 0001wxyzabcde 100wxyz
124 * 001wxyzabcdef 101wxyz
125 * 01wxyzabcdefg 110wxyz
126 * 1wxyzabcdefgh 111wxyz
127 *
128 * Each biased linear code has a leading 1 which identifies the segment
129 * number. The value of the segment number is equal to 7 minus the number
130 * of leading 0's. The quantization interval is directly available as the
131 * four bits wxyz. * The trailing bits (a - h) are ignored.
132 *
133 * Ordinarily the complement of the resulting code word is used for
134 * transmission, and so the code word is complemented before it is returned.
135 *
136 * For further information see John C. Bellamy's Digital Telephony, 1982,
137 * John Wiley & Sons, pps 98-111 and 472-476.
138 */
139 static unsigned char
140 st_14linear2ulaw(PyInt16 pcm_val) /* 2's complement (14-bit range) */
141 {
142 PyInt16 mask;
143 PyInt16 seg;
144 unsigned char uval;
145
146 /* The original sox code does this in the calling function, not here */
147 pcm_val = pcm_val >> 2;
148
149 /* u-law inverts all bits */
150 /* Get the sign and the magnitude of the value. */
151 if (pcm_val < 0) {
152 pcm_val = -pcm_val;
153 mask = 0x7F;
154 } else {
155 mask = 0xFF;
156 }
157 if ( pcm_val > CLIP ) pcm_val = CLIP; /* clip the magnitude */
158 pcm_val += (BIAS >> 2);
159
160 /* Convert the scaled magnitude to segment number. */
161 seg = search(pcm_val, seg_uend, 8);
162
163 /*
164 * Combine the sign, segment, quantization bits;
165 * and complement the code word.
166 */
167 if (seg >= 8) /* out of range, return maximum value. */
168 return (unsigned char) (0x7F ^ mask);
169 else {
170 uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);
171 return (uval ^ mask);
172 }
173
174 }
175
176 static PyInt16 _st_alaw2linear16[256] = {
177 -5504, -5248, -6016, -5760, -4480, -4224, -4992,
178 -4736, -7552, -7296, -8064, -7808, -6528, -6272,
179 -7040, -6784, -2752, -2624, -3008, -2880, -2240,
180 -2112, -2496, -2368, -3776, -3648, -4032, -3904,
181 -3264, -3136, -3520, -3392, -22016, -20992, -24064,
182 -23040, -17920, -16896, -19968, -18944, -30208, -29184,
183 -32256, -31232, -26112, -25088, -28160, -27136, -11008,
184 -10496, -12032, -11520, -8960, -8448, -9984, -9472,
185 -15104, -14592, -16128, -15616, -13056, -12544, -14080,
186 -13568, -344, -328, -376, -360, -280, -264,
187 -312, -296, -472, -456, -504, -488, -408,
188 -392, -440, -424, -88, -72, -120, -104,
189 -24, -8, -56, -40, -216, -200, -248,
190 -232, -152, -136, -184, -168, -1376, -1312,
191 -1504, -1440, -1120, -1056, -1248, -1184, -1888,
192 -1824, -2016, -1952, -1632, -1568, -1760, -1696,
193 -688, -656, -752, -720, -560, -528, -624,
194 -592, -944, -912, -1008, -976, -816, -784,
195 -880, -848, 5504, 5248, 6016, 5760, 4480,
196 4224, 4992, 4736, 7552, 7296, 8064, 7808,
197 6528, 6272, 7040, 6784, 2752, 2624, 3008,
198 2880, 2240, 2112, 2496, 2368, 3776, 3648,
199 4032, 3904, 3264, 3136, 3520, 3392, 22016,
200 20992, 24064, 23040, 17920, 16896, 19968, 18944,
201 30208, 29184, 32256, 31232, 26112, 25088, 28160,
202 27136, 11008, 10496, 12032, 11520, 8960, 8448,
203 9984, 9472, 15104, 14592, 16128, 15616, 13056,
204 12544, 14080, 13568, 344, 328, 376, 360,
205 280, 264, 312, 296, 472, 456, 504,
206 488, 408, 392, 440, 424, 88, 72,
207 120, 104, 24, 8, 56, 40, 216,
208 200, 248, 232, 152, 136, 184, 168,
209 1376, 1312, 1504, 1440, 1120, 1056, 1248,
210 1184, 1888, 1824, 2016, 1952, 1632, 1568,
211 1760, 1696, 688, 656, 752, 720, 560,
212 528, 624, 592, 944, 912, 1008, 976,
213 816, 784, 880, 848
214 };
215
216 /*
217 * linear2alaw() accepts an 13-bit signed integer and encodes it as A-law data
218 * stored in a unsigned char. This function should only be called with
219 * the data shifted such that it only contains information in the lower
220 * 13-bits.
221 *
222 * Linear Input Code Compressed Code
223 * ------------------------ ---------------
224 * 0000000wxyza 000wxyz
225 * 0000001wxyza 001wxyz
226 * 000001wxyzab 010wxyz
227 * 00001wxyzabc 011wxyz
228 * 0001wxyzabcd 100wxyz
229 * 001wxyzabcde 101wxyz
230 * 01wxyzabcdef 110wxyz
231 * 1wxyzabcdefg 111wxyz
232 *
233 * For further information see John C. Bellamy's Digital Telephony, 1982,
234 * John Wiley & Sons, pps 98-111 and 472-476.
235 */
236 static unsigned char
237 st_linear2alaw(PyInt16 pcm_val) /* 2's complement (13-bit range) */
238 {
239 PyInt16 mask;
240 short seg;
241 unsigned char aval;
242
243 /* The original sox code does this in the calling function, not here */
244 pcm_val = pcm_val >> 3;
245
246 /* A-law using even bit inversion */
247 if (pcm_val >= 0) {
248 mask = 0xD5; /* sign (7th) bit = 1 */
249 } else {
250 mask = 0x55; /* sign bit = 0 */
251 pcm_val = -pcm_val - 1;
252 }
253
254 /* Convert the scaled magnitude to segment number. */
255 seg = search(pcm_val, seg_aend, 8);
256
257 /* Combine the sign, segment, and quantization bits. */
258
259 if (seg >= 8) /* out of range, return maximum value. */
260 return (unsigned char) (0x7F ^ mask);
261 else {
262 aval = (unsigned char) seg << SEG_SHIFT;
263 if (seg < 2)
264 aval |= (pcm_val >> 1) & QUANT_MASK;
265 else
266 aval |= (pcm_val >> seg) & QUANT_MASK;
267 return (aval ^ mask);
268 }
269 }
270 /* End of code taken from sox */
271
272 /* Intel ADPCM step variation table */
273 static int indexTable[16] = {
274 -1, -1, -1, -1, 2, 4, 6, 8,
275 -1, -1, -1, -1, 2, 4, 6, 8,
276 };
277
278 static int stepsizeTable[89] = {
279 7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
280 19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
281 50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
282 130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
283 337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
284 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
285 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
286 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
287 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
288 };
289
290 #define CHARP(cp, i) ((signed char *)(cp+i))
291 #define SHORTP(cp, i) ((short *)(cp+i))
292 #define LONGP(cp, i) ((Py_Int32 *)(cp+i))
293
294
295
296 static PyObject *AudioopError;
297
298 static PyObject *
299 audioop_getsample(PyObject *self, PyObject *args)
300 {
301 signed char *cp;
302 int len, size, val = 0;
303 int i;
304
305 if ( !PyArg_ParseTuple(args, "s#ii:getsample", &cp, &len, &size, &i) )
306 return 0;
307 if ( size != 1 && size != 2 && size != 4 ) {
308 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
309 return 0;
310 }
311 if ( i < 0 || i >= len/size ) {
312 PyErr_SetString(AudioopError, "Index out of range");
313 return 0;
314 }
315 if ( size == 1 ) val = (int)*CHARP(cp, i);
316 else if ( size == 2 ) val = (int)*SHORTP(cp, i*2);
317 else if ( size == 4 ) val = (int)*LONGP(cp, i*4);
318 return PyInt_FromLong(val);
319 }
320
321 static PyObject *
322 audioop_max(PyObject *self, PyObject *args)
323 {
324 signed char *cp;
325 int len, size, val = 0;
326 int i;
327 int max = 0;
328
329 if ( !PyArg_ParseTuple(args, "s#i:max", &cp, &len, &size) )
330 return 0;
331 if ( size != 1 && size != 2 && size != 4 ) {
332 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
333 return 0;
334 }
335 for ( i=0; i<len; i+= size) {
336 if ( size == 1 ) val = (int)*CHARP(cp, i);
337 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
338 else if ( size == 4 ) val = (int)*LONGP(cp, i);
339 if ( val < 0 ) val = (-val);
340 if ( val > max ) max = val;
341 }
342 return PyInt_FromLong(max);
343 }
344
345 static PyObject *
346 audioop_minmax(PyObject *self, PyObject *args)
347 {
348 signed char *cp;
349 int len, size, val = 0;
350 int i;
351 int min = 0x7fffffff, max = -0x7fffffff;
352
353 if (!PyArg_ParseTuple(args, "s#i:minmax", &cp, &len, &size))
354 return NULL;
355 if (size != 1 && size != 2 && size != 4) {
356 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
357 return NULL;
358 }
359 for (i = 0; i < len; i += size) {
360 if (size == 1) val = (int) *CHARP(cp, i);
361 else if (size == 2) val = (int) *SHORTP(cp, i);
362 else if (size == 4) val = (int) *LONGP(cp, i);
363 if (val > max) max = val;
364 if (val < min) min = val;
365 }
366 return Py_BuildValue("(ii)", min, max);
367 }
368
369 static PyObject *
370 audioop_avg(PyObject *self, PyObject *args)
371 {
372 signed char *cp;
373 int len, size, val = 0;
374 int i;
375 double avg = 0.0;
376
377 if ( !PyArg_ParseTuple(args, "s#i:avg", &cp, &len, &size) )
378 return 0;
379 if ( size != 1 && size != 2 && size != 4 ) {
380 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
381 return 0;
382 }
383 for ( i=0; i<len; i+= size) {
384 if ( size == 1 ) val = (int)*CHARP(cp, i);
385 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
386 else if ( size == 4 ) val = (int)*LONGP(cp, i);
387 avg += val;
388 }
389 if ( len == 0 )
390 val = 0;
391 else
392 val = (int)(avg / (double)(len/size));
393 return PyInt_FromLong(val);
394 }
395
396 static PyObject *
397 audioop_rms(PyObject *self, PyObject *args)
398 {
399 signed char *cp;
400 int len, size, val = 0;
401 int i;
402 double sum_squares = 0.0;
403
404 if ( !PyArg_ParseTuple(args, "s#i:rms", &cp, &len, &size) )
405 return 0;
406 if ( size != 1 && size != 2 && size != 4 ) {
407 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
408 return 0;
409 }
410 for ( i=0; i<len; i+= size) {
411 if ( size == 1 ) val = (int)*CHARP(cp, i);
412 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
413 else if ( size == 4 ) val = (int)*LONGP(cp, i);
414 sum_squares += (double)val*(double)val;
415 }
416 if ( len == 0 )
417 val = 0;
418 else
419 val = (int)sqrt(sum_squares / (double)(len/size));
420 return PyInt_FromLong(val);
421 }
422
423 static double _sum2(short *a, short *b, int len)
424 {
425 int i;
426 double sum = 0.0;
427
428 for( i=0; i<len; i++) {
429 sum = sum + (double)a[i]*(double)b[i];
430 }
431 return sum;
432 }
433
434 /*
435 ** Findfit tries to locate a sample within another sample. Its main use
436 ** is in echo-cancellation (to find the feedback of the output signal in
437 ** the input signal).
438 ** The method used is as follows:
439 **
440 ** let R be the reference signal (length n) and A the input signal (length N)
441 ** with N > n, and let all sums be over i from 0 to n-1.
442 **
443 ** Now, for each j in {0..N-n} we compute a factor fj so that -fj*R matches A
444 ** as good as possible, i.e. sum( (A[j+i]+fj*R[i])^2 ) is minimal. This
445 ** equation gives fj = sum( A[j+i]R[i] ) / sum(R[i]^2).
446 **
447 ** Next, we compute the relative distance between the original signal and
448 ** the modified signal and minimize that over j:
449 ** vj = sum( (A[j+i]-fj*R[i])^2 ) / sum( A[j+i]^2 ) =>
450 ** vj = ( sum(A[j+i]^2)*sum(R[i]^2) - sum(A[j+i]R[i])^2 ) / sum( A[j+i]^2 )
451 **
452 ** In the code variables correspond as follows:
453 ** cp1 A
454 ** cp2 R
455 ** len1 N
456 ** len2 n
457 ** aj_m1 A[j-1]
458 ** aj_lm1 A[j+n-1]
459 ** sum_ri_2 sum(R[i]^2)
460 ** sum_aij_2 sum(A[i+j]^2)
461 ** sum_aij_ri sum(A[i+j]R[i])
462 **
463 ** sum_ri is calculated once, sum_aij_2 is updated each step and sum_aij_ri
464 ** is completely recalculated each step.
465 */
466 static PyObject *
467 audioop_findfit(PyObject *self, PyObject *args)
468 {
469 short *cp1, *cp2;
470 int len1, len2;
471 int j, best_j;
472 double aj_m1, aj_lm1;
473 double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor;
474
475 /* Passing a short** for an 's' argument is correct only
476 if the string contents is aligned for interpretation
477 as short[]. Due to the definition of PyStringObject,
478 this is currently (Python 2.6) the case. */
479 if ( !PyArg_ParseTuple(args, "s#s#:findfit",
480 (char**)&cp1, &len1, (char**)&cp2, &len2) )
481 return 0;
482 if ( len1 & 1 || len2 & 1 ) {
483 PyErr_SetString(AudioopError, "Strings should be even-sized");
484 return 0;
485 }
486 len1 >>= 1;
487 len2 >>= 1;
488
489 if ( len1 < len2 ) {
490 PyErr_SetString(AudioopError, "First sample should be longer");
491 return 0;
492 }
493 sum_ri_2 = _sum2(cp2, cp2, len2);
494 sum_aij_2 = _sum2(cp1, cp1, len2);
495 sum_aij_ri = _sum2(cp1, cp2, len2);
496
497 result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2;
498
499 best_result = result;
500 best_j = 0;
501 j = 0;
502
503 for ( j=1; j<=len1-len2; j++) {
504 aj_m1 = (double)cp1[j-1];
505 aj_lm1 = (double)cp1[j+len2-1];
506
507 sum_aij_2 = sum_aij_2 + aj_lm1*aj_lm1 - aj_m1*aj_m1;
508 sum_aij_ri = _sum2(cp1+j, cp2, len2);
509
510 result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri)
511 / sum_aij_2;
512
513 if ( result < best_result ) {
514 best_result = result;
515 best_j = j;
516 }
517
518 }
519
520 factor = _sum2(cp1+best_j, cp2, len2) / sum_ri_2;
521
522 return Py_BuildValue("(if)", best_j, factor);
523 }
524
525 /*
526 ** findfactor finds a factor f so that the energy in A-fB is minimal.
527 ** See the comment for findfit for details.
528 */
529 static PyObject *
530 audioop_findfactor(PyObject *self, PyObject *args)
531 {
532 short *cp1, *cp2;
533 int len1, len2;
534 double sum_ri_2, sum_aij_ri, result;
535
536 if ( !PyArg_ParseTuple(args, "s#s#:findfactor",
537 (char**)&cp1, &len1, (char**)&cp2, &len2) )
538 return 0;
539 if ( len1 & 1 || len2 & 1 ) {
540 PyErr_SetString(AudioopError, "Strings should be even-sized");
541 return 0;
542 }
543 if ( len1 != len2 ) {
544 PyErr_SetString(AudioopError, "Samples should be same size");
545 return 0;
546 }
547 len2 >>= 1;
548 sum_ri_2 = _sum2(cp2, cp2, len2);
549 sum_aij_ri = _sum2(cp1, cp2, len2);
550
551 result = sum_aij_ri / sum_ri_2;
552
553 return PyFloat_FromDouble(result);
554 }
555
556 /*
557 ** findmax returns the index of the n-sized segment of the input sample
558 ** that contains the most energy.
559 */
560 static PyObject *
561 audioop_findmax(PyObject *self, PyObject *args)
562 {
563 short *cp1;
564 int len1, len2;
565 int j, best_j;
566 double aj_m1, aj_lm1;
567 double result, best_result;
568
569 if ( !PyArg_ParseTuple(args, "s#i:findmax",
570 (char**)&cp1, &len1, &len2) )
571 return 0;
572 if ( len1 & 1 ) {
573 PyErr_SetString(AudioopError, "Strings should be even-sized");
574 return 0;
575 }
576 len1 >>= 1;
577
578 if ( len2 < 0 || len1 < len2 ) {
579 PyErr_SetString(AudioopError, "Input sample should be longer");
580 return 0;
581 }
582
583 result = _sum2(cp1, cp1, len2);
584
585 best_result = result;
586 best_j = 0;
587 j = 0;
588
589 for ( j=1; j<=len1-len2; j++) {
590 aj_m1 = (double)cp1[j-1];
591 aj_lm1 = (double)cp1[j+len2-1];
592
593 result = result + aj_lm1*aj_lm1 - aj_m1*aj_m1;
594
595 if ( result > best_result ) {
596 best_result = result;
597 best_j = j;
598 }
599
600 }
601
602 return PyInt_FromLong(best_j);
603 }
604
605 static PyObject *
606 audioop_avgpp(PyObject *self, PyObject *args)
607 {
608 signed char *cp;
609 int len, size, val = 0, prevval = 0, prevextremevalid = 0,
610 prevextreme = 0;
611 int i;
612 double avg = 0.0;
613 int diff, prevdiff, extremediff, nextreme = 0;
614
615 if ( !PyArg_ParseTuple(args, "s#i:avgpp", &cp, &len, &size) )
616 return 0;
617 if ( size != 1 && size != 2 && size != 4 ) {
618 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
619 return 0;
620 }
621 /* Compute first delta value ahead. Also automatically makes us
622 ** skip the first extreme value
623 */
624 if ( size == 1 ) prevval = (int)*CHARP(cp, 0);
625 else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0);
626 else if ( size == 4 ) prevval = (int)*LONGP(cp, 0);
627 if ( size == 1 ) val = (int)*CHARP(cp, size);
628 else if ( size == 2 ) val = (int)*SHORTP(cp, size);
629 else if ( size == 4 ) val = (int)*LONGP(cp, size);
630 prevdiff = val - prevval;
631
632 for ( i=size; i<len; i+= size) {
633 if ( size == 1 ) val = (int)*CHARP(cp, i);
634 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
635 else if ( size == 4 ) val = (int)*LONGP(cp, i);
636 diff = val - prevval;
637 if ( diff*prevdiff < 0 ) {
638 /* Derivative changed sign. Compute difference to last
639 ** extreme value and remember.
640 */
641 if ( prevextremevalid ) {
642 extremediff = prevval - prevextreme;
643 if ( extremediff < 0 )
644 extremediff = -extremediff;
645 avg += extremediff;
646 nextreme++;
647 }
648 prevextremevalid = 1;
649 prevextreme = prevval;
650 }
651 prevval = val;
652 if ( diff != 0 )
653 prevdiff = diff;
654 }
655 if ( nextreme == 0 )
656 val = 0;
657 else
658 val = (int)(avg / (double)nextreme);
659 return PyInt_FromLong(val);
660 }
661
662 static PyObject *
663 audioop_maxpp(PyObject *self, PyObject *args)
664 {
665 signed char *cp;
666 int len, size, val = 0, prevval = 0, prevextremevalid = 0,
667 prevextreme = 0;
668 int i;
669 int max = 0;
670 int diff, prevdiff, extremediff;
671
672 if ( !PyArg_ParseTuple(args, "s#i:maxpp", &cp, &len, &size) )
673 return 0;
674 if ( size != 1 && size != 2 && size != 4 ) {
675 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
676 return 0;
677 }
678 /* Compute first delta value ahead. Also automatically makes us
679 ** skip the first extreme value
680 */
681 if ( size == 1 ) prevval = (int)*CHARP(cp, 0);
682 else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0);
683 else if ( size == 4 ) prevval = (int)*LONGP(cp, 0);
684 if ( size == 1 ) val = (int)*CHARP(cp, size);
685 else if ( size == 2 ) val = (int)*SHORTP(cp, size);
686 else if ( size == 4 ) val = (int)*LONGP(cp, size);
687 prevdiff = val - prevval;
688
689 for ( i=size; i<len; i+= size) {
690 if ( size == 1 ) val = (int)*CHARP(cp, i);
691 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
692 else if ( size == 4 ) val = (int)*LONGP(cp, i);
693 diff = val - prevval;
694 if ( diff*prevdiff < 0 ) {
695 /* Derivative changed sign. Compute difference to
696 ** last extreme value and remember.
697 */
698 if ( prevextremevalid ) {
699 extremediff = prevval - prevextreme;
700 if ( extremediff < 0 )
701 extremediff = -extremediff;
702 if ( extremediff > max )
703 max = extremediff;
704 }
705 prevextremevalid = 1;
706 prevextreme = prevval;
707 }
708 prevval = val;
709 if ( diff != 0 )
710 prevdiff = diff;
711 }
712 return PyInt_FromLong(max);
713 }
714
715 static PyObject *
716 audioop_cross(PyObject *self, PyObject *args)
717 {
718 signed char *cp;
719 int len, size, val = 0;
720 int i;
721 int prevval, ncross;
722
723 if ( !PyArg_ParseTuple(args, "s#i:cross", &cp, &len, &size) )
724 return 0;
725 if ( size != 1 && size != 2 && size != 4 ) {
726 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
727 return 0;
728 }
729 ncross = -1;
730 prevval = 17; /* Anything <> 0,1 */
731 for ( i=0; i<len; i+= size) {
732 if ( size == 1 ) val = ((int)*CHARP(cp, i)) >> 7;
733 else if ( size == 2 ) val = ((int)*SHORTP(cp, i)) >> 15;
734 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 31;
735 val = val & 1;
736 if ( val != prevval ) ncross++;
737 prevval = val;
738 }
739 return PyInt_FromLong(ncross);
740 }
741
742 static PyObject *
743 audioop_mul(PyObject *self, PyObject *args)
744 {
745 signed char *cp, *ncp;
746 int len, size, val = 0;
747 double factor, fval, maxval;
748 PyObject *rv;
749 int i;
750
751 if ( !PyArg_ParseTuple(args, "s#id:mul", &cp, &len, &size, &factor ) )
752 return 0;
753
754 if ( size == 1 ) maxval = (double) 0x7f;
755 else if ( size == 2 ) maxval = (double) 0x7fff;
756 else if ( size == 4 ) maxval = (double) 0x7fffffff;
757 else {
758 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
759 return 0;
760 }
761
762 rv = PyString_FromStringAndSize(NULL, len);
763 if ( rv == 0 )
764 return 0;
765 ncp = (signed char *)PyString_AsString(rv);
766
767
768 for ( i=0; i < len; i += size ) {
769 if ( size == 1 ) val = (int)*CHARP(cp, i);
770 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
771 else if ( size == 4 ) val = (int)*LONGP(cp, i);
772 fval = (double)val*factor;
773 if ( fval > maxval ) fval = maxval;
774 else if ( fval < -maxval ) fval = -maxval;
775 val = (int)fval;
776 if ( size == 1 ) *CHARP(ncp, i) = (signed char)val;
777 else if ( size == 2 ) *SHORTP(ncp, i) = (short)val;
778 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)val;
779 }
780 return rv;
781 }
782
783 static PyObject *
784 audioop_tomono(PyObject *self, PyObject *args)
785 {
786 signed char *cp, *ncp;
787 int len, size, val1 = 0, val2 = 0;
788 double fac1, fac2, fval, maxval;
789 PyObject *rv;
790 int i;
791
792 if ( !PyArg_ParseTuple(args, "s#idd:tomono",
793 &cp, &len, &size, &fac1, &fac2 ) )
794 return 0;
795
796 if ( size == 1 ) maxval = (double) 0x7f;
797 else if ( size == 2 ) maxval = (double) 0x7fff;
798 else if ( size == 4 ) maxval = (double) 0x7fffffff;
799 else {
800 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
801 return 0;
802 }
803
804 rv = PyString_FromStringAndSize(NULL, len/2);
805 if ( rv == 0 )
806 return 0;
807 ncp = (signed char *)PyString_AsString(rv);
808
809
810 for ( i=0; i < len; i += size*2 ) {
811 if ( size == 1 ) val1 = (int)*CHARP(cp, i);
812 else if ( size == 2 ) val1 = (int)*SHORTP(cp, i);
813 else if ( size == 4 ) val1 = (int)*LONGP(cp, i);
814 if ( size == 1 ) val2 = (int)*CHARP(cp, i+1);
815 else if ( size == 2 ) val2 = (int)*SHORTP(cp, i+2);
816 else if ( size == 4 ) val2 = (int)*LONGP(cp, i+4);
817 fval = (double)val1*fac1 + (double)val2*fac2;
818 if ( fval > maxval ) fval = maxval;
819 else if ( fval < -maxval ) fval = -maxval;
820 val1 = (int)fval;
821 if ( size == 1 ) *CHARP(ncp, i/2) = (signed char)val1;
822 else if ( size == 2 ) *SHORTP(ncp, i/2) = (short)val1;
823 else if ( size == 4 ) *LONGP(ncp, i/2)= (Py_Int32)val1;
824 }
825 return rv;
826 }
827
828 static PyObject *
829 audioop_tostereo(PyObject *self, PyObject *args)
830 {
831 signed char *cp, *ncp;
832 int len, new_len, size, val1, val2, val = 0;
833 double fac1, fac2, fval, maxval;
834 PyObject *rv;
835 int i;
836
837 if ( !PyArg_ParseTuple(args, "s#idd:tostereo",
838 &cp, &len, &size, &fac1, &fac2 ) )
839 return 0;
840
841 if ( size == 1 ) maxval = (double) 0x7f;
842 else if ( size == 2 ) maxval = (double) 0x7fff;
843 else if ( size == 4 ) maxval = (double) 0x7fffffff;
844 else {
845 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
846 return 0;
847 }
848
849 new_len = len*2;
850 if (new_len < 0) {
851 PyErr_SetString(PyExc_MemoryError,
852 "not enough memory for output buffer");
853 return 0;
854 }
855
856 rv = PyString_FromStringAndSize(NULL, new_len);
857 if ( rv == 0 )
858 return 0;
859 ncp = (signed char *)PyString_AsString(rv);
860
861
862 for ( i=0; i < len; i += size ) {
863 if ( size == 1 ) val = (int)*CHARP(cp, i);
864 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
865 else if ( size == 4 ) val = (int)*LONGP(cp, i);
866
867 fval = (double)val*fac1;
868 if ( fval > maxval ) fval = maxval;
869 else if ( fval < -maxval ) fval = -maxval;
870 val1 = (int)fval;
871
872 fval = (double)val*fac2;
873 if ( fval > maxval ) fval = maxval;
874 else if ( fval < -maxval ) fval = -maxval;
875 val2 = (int)fval;
876
877 if ( size == 1 ) *CHARP(ncp, i*2) = (signed char)val1;
878 else if ( size == 2 ) *SHORTP(ncp, i*2) = (short)val1;
879 else if ( size == 4 ) *LONGP(ncp, i*2) = (Py_Int32)val1;
880
881 if ( size == 1 ) *CHARP(ncp, i*2+1) = (signed char)val2;
882 else if ( size == 2 ) *SHORTP(ncp, i*2+2) = (short)val2;
883 else if ( size == 4 ) *LONGP(ncp, i*2+4) = (Py_Int32)val2;
884 }
885 return rv;
886 }
887
888 static PyObject *
889 audioop_add(PyObject *self, PyObject *args)
890 {
891 signed char *cp1, *cp2, *ncp;
892 int len1, len2, size, val1 = 0, val2 = 0, maxval, newval;
893 PyObject *rv;
894 int i;
895
896 if ( !PyArg_ParseTuple(args, "s#s#i:add",
897 &cp1, &len1, &cp2, &len2, &size ) )
898 return 0;
899
900 if ( len1 != len2 ) {
901 PyErr_SetString(AudioopError, "Lengths should be the same");
902 return 0;
903 }
904
905 if ( size == 1 ) maxval = 0x7f;
906 else if ( size == 2 ) maxval = 0x7fff;
907 else if ( size == 4 ) maxval = 0x7fffffff;
908 else {
909 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
910 return 0;
911 }
912
913 rv = PyString_FromStringAndSize(NULL, len1);
914 if ( rv == 0 )
915 return 0;
916 ncp = (signed char *)PyString_AsString(rv);
917
918 for ( i=0; i < len1; i += size ) {
919 if ( size == 1 ) val1 = (int)*CHARP(cp1, i);
920 else if ( size == 2 ) val1 = (int)*SHORTP(cp1, i);
921 else if ( size == 4 ) val1 = (int)*LONGP(cp1, i);
922
923 if ( size == 1 ) val2 = (int)*CHARP(cp2, i);
924 else if ( size == 2 ) val2 = (int)*SHORTP(cp2, i);
925 else if ( size == 4 ) val2 = (int)*LONGP(cp2, i);
926
927 newval = val1 + val2;
928 /* truncate in case of overflow */
929 if (newval > maxval) newval = maxval;
930 else if (newval < -maxval) newval = -maxval;
931 else if (size == 4 && (newval^val1) < 0 && (newval^val2) < 0)
932 newval = val1 > 0 ? maxval : - maxval;
933
934 if ( size == 1 ) *CHARP(ncp, i) = (signed char)newval;
935 else if ( size == 2 ) *SHORTP(ncp, i) = (short)newval;
936 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)newval;
937 }
938 return rv;
939 }
940
941 static PyObject *
942 audioop_bias(PyObject *self, PyObject *args)
943 {
944 signed char *cp, *ncp;
945 int len, size, val = 0;
946 PyObject *rv;
947 int i;
948 int bias;
949
950 if ( !PyArg_ParseTuple(args, "s#ii:bias",
951 &cp, &len, &size , &bias) )
952 return 0;
953
954 if ( size != 1 && size != 2 && size != 4) {
955 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
956 return 0;
957 }
958
959 rv = PyString_FromStringAndSize(NULL, len);
960 if ( rv == 0 )
961 return 0;
962 ncp = (signed char *)PyString_AsString(rv);
963
964
965 for ( i=0; i < len; i += size ) {
966 if ( size == 1 ) val = (int)*CHARP(cp, i);
967 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
968 else if ( size == 4 ) val = (int)*LONGP(cp, i);
969
970 if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val+bias);
971 else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val+bias);
972 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val+bias);
973 }
974 return rv;
975 }
976
977 static PyObject *
978 audioop_reverse(PyObject *self, PyObject *args)
979 {
980 signed char *cp;
981 unsigned char *ncp;
982 int len, size, val = 0;
983 PyObject *rv;
984 int i, j;
985
986 if ( !PyArg_ParseTuple(args, "s#i:reverse",
987 &cp, &len, &size) )
988 return 0;
989
990 if ( size != 1 && size != 2 && size != 4 ) {
991 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
992 return 0;
993 }
994
995 rv = PyString_FromStringAndSize(NULL, len);
996 if ( rv == 0 )
997 return 0;
998 ncp = (unsigned char *)PyString_AsString(rv);
999
1000 for ( i=0; i < len; i += size ) {
1001 if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
1002 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
1003 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
1004
1005 j = len - i - size;
1006
1007 if ( size == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8);
1008 else if ( size == 2 ) *SHORTP(ncp, j) = (short)(val);
1009 else if ( size == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16);
1010 }
1011 return rv;
1012 }
1013
1014 static PyObject *
1015 audioop_lin2lin(PyObject *self, PyObject *args)
1016 {
1017 signed char *cp;
1018 unsigned char *ncp;
1019 int len, new_len, size, size2, val = 0;
1020 PyObject *rv;
1021 int i, j;
1022
1023 if ( !PyArg_ParseTuple(args, "s#ii:lin2lin",
1024 &cp, &len, &size, &size2) )
1025 return 0;
1026
1027 if ( (size != 1 && size != 2 && size != 4) ||
1028 (size2 != 1 && size2 != 2 && size2 != 4)) {
1029 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1030 return 0;
1031 }
1032
1033 new_len = (len/size)*size2;
1034 if (new_len < 0) {
1035 PyErr_SetString(PyExc_MemoryError,
1036 "not enough memory for output buffer");
1037 return 0;
1038 }
1039 rv = PyString_FromStringAndSize(NULL, new_len);
1040 if ( rv == 0 )
1041 return 0;
1042 ncp = (unsigned char *)PyString_AsString(rv);
1043
1044 for ( i=0, j=0; i < len; i += size, j += size2 ) {
1045 if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
1046 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
1047 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
1048
1049 if ( size2 == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8);
1050 else if ( size2 == 2 ) *SHORTP(ncp, j) = (short)(val);
1051 else if ( size2 == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16);
1052 }
1053 return rv;
1054 }
1055
1056 static int
1057 gcd(int a, int b)
1058 {
1059 while (b > 0) {
1060 int tmp = a % b;
1061 a = b;
1062 b = tmp;
1063 }
1064 return a;
1065 }
1066
1067 static PyObject *
1068 audioop_ratecv(PyObject *self, PyObject *args)
1069 {
1070 char *cp, *ncp;
1071 int len, size, nchannels, inrate, outrate, weightA, weightB;
1072 int chan, d, *prev_i, *cur_i, cur_o;
1073 PyObject *state, *samps, *str, *rv = NULL;
1074 int bytes_per_frame;
1075 size_t alloc_size;
1076
1077 weightA = 1;
1078 weightB = 0;
1079 if (!PyArg_ParseTuple(args, "s#iiiiO|ii:ratecv", &cp, &len, &size,
1080 &nchannels, &inrate, &outrate, &state,
1081 &weightA, &weightB))
1082 return NULL;
1083 if (size != 1 && size != 2 && size != 4) {
1084 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1085 return NULL;
1086 }
1087 if (nchannels < 1) {
1088 PyErr_SetString(AudioopError, "# of channels should be >= 1");
1089 return NULL;
1090 }
1091 bytes_per_frame = size * nchannels;
1092 if (bytes_per_frame / nchannels != size) {
1093 /* This overflow test is rigorously correct because
1094 both multiplicands are >= 1. Use the argument names
1095 from the docs for the error msg. */
1096 PyErr_SetString(PyExc_OverflowError,
1097 "width * nchannels too big for a C int");
1098 return NULL;
1099 }
1100 if (weightA < 1 || weightB < 0) {
1101 PyErr_SetString(AudioopError,
1102 "weightA should be >= 1, weightB should be >= 0");
1103 return NULL;
1104 }
1105 if (len % bytes_per_frame != 0) {
1106 PyErr_SetString(AudioopError, "not a whole number of frames");
1107 return NULL;
1108 }
1109 if (inrate <= 0 || outrate <= 0) {
1110 PyErr_SetString(AudioopError, "sampling rate not > 0");
1111 return NULL;
1112 }
1113 /* divide inrate and outrate by their greatest common divisor */
1114 d = gcd(inrate, outrate);
1115 inrate /= d;
1116 outrate /= d;
1117
1118 alloc_size = sizeof(int) * (unsigned)nchannels;
1119 if (alloc_size < nchannels) {
1120 PyErr_SetString(PyExc_MemoryError,
1121 "not enough memory for output buffer");
1122 return 0;
1123 }
1124 prev_i = (int *) malloc(alloc_size);
1125 cur_i = (int *) malloc(alloc_size);
1126 if (prev_i == NULL || cur_i == NULL) {
1127 (void) PyErr_NoMemory();
1128 goto exit;
1129 }
1130
1131 len /= bytes_per_frame; /* # of frames */
1132
1133 if (state == Py_None) {
1134 d = -outrate;
1135 for (chan = 0; chan < nchannels; chan++)
1136 prev_i[chan] = cur_i[chan] = 0;
1137 }
1138 else {
1139 if (!PyArg_ParseTuple(state,
1140 "iO!;audioop.ratecv: illegal state argument",
1141 &d, &PyTuple_Type, &samps))
1142 goto exit;
1143 if (PyTuple_Size(samps) != nchannels) {
1144 PyErr_SetString(AudioopError,
1145 "illegal state argument");
1146 goto exit;
1147 }
1148 for (chan = 0; chan < nchannels; chan++) {
1149 if (!PyArg_ParseTuple(PyTuple_GetItem(samps, chan),
1150 "ii:ratecv", &prev_i[chan],
1151 &cur_i[chan]))
1152 goto exit;
1153 }
1154 }
1155
1156 /* str <- Space for the output buffer. */
1157 {
1158 /* There are len input frames, so we need (mathematically)
1159 ceiling(len*outrate/inrate) output frames, and each frame
1160 requires bytes_per_frame bytes. Computing this
1161 without spurious overflow is the challenge; we can
1162 settle for a reasonable upper bound, though. */
1163 int ceiling; /* the number of output frames */
1164 int nbytes; /* the number of output bytes needed */
1165 int q = len / inrate;
1166 /* Now len = q * inrate + r exactly (with r = len % inrate),
1167 and this is less than q * inrate + inrate = (q+1)*inrate.
1168 So a reasonable upper bound on len*outrate/inrate is
1169 ((q+1)*inrate)*outrate/inrate =
1170 (q+1)*outrate.
1171 */
1172 ceiling = (q+1) * outrate;
1173 nbytes = ceiling * bytes_per_frame;
1174 /* See whether anything overflowed; if not, get the space. */
1175 if (q+1 < 0 ||
1176 ceiling / outrate != q+1 ||
1177 nbytes / bytes_per_frame != ceiling)
1178 str = NULL;
1179 else
1180 str = PyString_FromStringAndSize(NULL, nbytes);
1181
1182 if (str == NULL) {
1183 PyErr_SetString(PyExc_MemoryError,
1184 "not enough memory for output buffer");
1185 goto exit;
1186 }
1187 }
1188 ncp = PyString_AsString(str);
1189
1190 for (;;) {
1191 while (d < 0) {
1192 if (len == 0) {
1193 samps = PyTuple_New(nchannels);
1194 if (samps == NULL)
1195 goto exit;
1196 for (chan = 0; chan < nchannels; chan++)
1197 PyTuple_SetItem(samps, chan,
1198 Py_BuildValue("(ii)",
1199 prev_i[chan],
1200 cur_i[chan]));
1201 if (PyErr_Occurred())
1202 goto exit;
1203 /* We have checked before that the length
1204 * of the string fits into int. */
1205 len = (int)(ncp - PyString_AsString(str));
1206 if (len == 0) {
1207 /*don't want to resize to zero length*/
1208 rv = PyString_FromStringAndSize("", 0);
1209 Py_DECREF(str);
1210 str = rv;
1211 } else if (_PyString_Resize(&str, len) < 0)
1212 goto exit;
1213 rv = Py_BuildValue("(O(iO))", str, d, samps);
1214 Py_DECREF(samps);
1215 Py_DECREF(str);
1216 goto exit; /* return rv */
1217 }
1218 for (chan = 0; chan < nchannels; chan++) {
1219 prev_i[chan] = cur_i[chan];
1220 if (size == 1)
1221 cur_i[chan] = ((int)*CHARP(cp, 0)) << 8;
1222 else if (size == 2)
1223 cur_i[chan] = (int)*SHORTP(cp, 0);
1224 else if (size == 4)
1225 cur_i[chan] = ((int)*LONGP(cp, 0)) >> 16;
1226 cp += size;
1227 /* implements a simple digital filter */
1228 cur_i[chan] =
1229 (weightA * cur_i[chan] +
1230 weightB * prev_i[chan]) /
1231 (weightA + weightB);
1232 }
1233 len--;
1234 d += outrate;
1235 }
1236 while (d >= 0) {
1237 for (chan = 0; chan < nchannels; chan++) {
1238 cur_o = (prev_i[chan] * d +
1239 cur_i[chan] * (outrate - d)) /
1240 outrate;
1241 if (size == 1)
1242 *CHARP(ncp, 0) = (signed char)(cur_o >> 8);
1243 else if (size == 2)
1244 *SHORTP(ncp, 0) = (short)(cur_o);
1245 else if (size == 4)
1246 *LONGP(ncp, 0) = (Py_Int32)(cur_o<<16);
1247 ncp += size;
1248 }
1249 d -= inrate;
1250 }
1251 }
1252 exit:
1253 if (prev_i != NULL)
1254 free(prev_i);
1255 if (cur_i != NULL)
1256 free(cur_i);
1257 return rv;
1258 }
1259
1260 static PyObject *
1261 audioop_lin2ulaw(PyObject *self, PyObject *args)
1262 {
1263 signed char *cp;
1264 unsigned char *ncp;
1265 int len, size, val = 0;
1266 PyObject *rv;
1267 int i;
1268
1269 if ( !PyArg_ParseTuple(args, "s#i:lin2ulaw",
1270 &cp, &len, &size) )
1271 return 0 ;
1272
1273 if ( size != 1 && size != 2 && size != 4) {
1274 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1275 return 0;
1276 }
1277
1278 rv = PyString_FromStringAndSize(NULL, len/size);
1279 if ( rv == 0 )
1280 return 0;
1281 ncp = (unsigned char *)PyString_AsString(rv);
1282
1283 for ( i=0; i < len; i += size ) {
1284 if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
1285 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
1286 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
1287
1288 *ncp++ = st_14linear2ulaw(val);
1289 }
1290 return rv;
1291 }
1292
1293 static PyObject *
1294 audioop_ulaw2lin(PyObject *self, PyObject *args)
1295 {
1296 unsigned char *cp;
1297 unsigned char cval;
1298 signed char *ncp;
1299 int len, new_len, size, val;
1300 PyObject *rv;
1301 int i;
1302
1303 if ( !PyArg_ParseTuple(args, "s#i:ulaw2lin",
1304 &cp, &len, &size) )
1305 return 0;
1306
1307 if ( size != 1 && size != 2 && size != 4) {
1308 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1309 return 0;
1310 }
1311
1312 new_len = len*size;
1313 if (new_len < 0) {
1314 PyErr_SetString(PyExc_MemoryError,
1315 "not enough memory for output buffer");
1316 return 0;
1317 }
1318 rv = PyString_FromStringAndSize(NULL, new_len);
1319 if ( rv == 0 )
1320 return 0;
1321 ncp = (signed char *)PyString_AsString(rv);
1322
1323 for ( i=0; i < new_len; i += size ) {
1324 cval = *cp++;
1325 val = st_ulaw2linear16(cval);
1326
1327 if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val >> 8);
1328 else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val);
1329 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val<<16);
1330 }
1331 return rv;
1332 }
1333
1334 static PyObject *
1335 audioop_lin2alaw(PyObject *self, PyObject *args)
1336 {
1337 signed char *cp;
1338 unsigned char *ncp;
1339 int len, size, val = 0;
1340 PyObject *rv;
1341 int i;
1342
1343 if ( !PyArg_ParseTuple(args, "s#i:lin2alaw",
1344 &cp, &len, &size) )
1345 return 0;
1346
1347 if ( size != 1 && size != 2 && size != 4) {
1348 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1349 return 0;
1350 }
1351
1352 rv = PyString_FromStringAndSize(NULL, len/size);
1353 if ( rv == 0 )
1354 return 0;
1355 ncp = (unsigned char *)PyString_AsString(rv);
1356
1357 for ( i=0; i < len; i += size ) {
1358 if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
1359 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
1360 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
1361
1362 *ncp++ = st_linear2alaw(val);
1363 }
1364 return rv;
1365 }
1366
1367 static PyObject *
1368 audioop_alaw2lin(PyObject *self, PyObject *args)
1369 {
1370 unsigned char *cp;
1371 unsigned char cval;
1372 signed char *ncp;
1373 int len, new_len, size, val;
1374 PyObject *rv;
1375 int i;
1376
1377 if ( !PyArg_ParseTuple(args, "s#i:alaw2lin",
1378 &cp, &len, &size) )
1379 return 0;
1380
1381 if ( size != 1 && size != 2 && size != 4) {
1382 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1383 return 0;
1384 }
1385
1386 new_len = len*size;
1387 if (new_len < 0) {
1388 PyErr_SetString(PyExc_MemoryError,
1389 "not enough memory for output buffer");
1390 return 0;
1391 }
1392 rv = PyString_FromStringAndSize(NULL, new_len);
1393 if ( rv == 0 )
1394 return 0;
1395 ncp = (signed char *)PyString_AsString(rv);
1396
1397 for ( i=0; i < new_len; i += size ) {
1398 cval = *cp++;
1399 val = st_alaw2linear16(cval);
1400
1401 if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val >> 8);
1402 else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val);
1403 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val<<16);
1404 }
1405 return rv;
1406 }
1407
1408 static PyObject *
1409 audioop_lin2adpcm(PyObject *self, PyObject *args)
1410 {
1411 signed char *cp;
1412 signed char *ncp;
1413 int len, size, val = 0, step, valpred, delta,
1414 index, sign, vpdiff, diff;
1415 PyObject *rv, *state, *str;
1416 int i, outputbuffer = 0, bufferstep;
1417
1418 if ( !PyArg_ParseTuple(args, "s#iO:lin2adpcm",
1419 &cp, &len, &size, &state) )
1420 return 0;
1421
1422
1423 if ( size != 1 && size != 2 && size != 4) {
1424 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1425 return 0;
1426 }
1427
1428 str = PyString_FromStringAndSize(NULL, len/(size*2));
1429 if ( str == 0 )
1430 return 0;
1431 ncp = (signed char *)PyString_AsString(str);
1432
1433 /* Decode state, should have (value, step) */
1434 if ( state == Py_None ) {
1435 /* First time, it seems. Set defaults */
1436 valpred = 0;
1437 step = 7;
1438 index = 0;
1439 } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) )
1440 return 0;
1441
1442 step = stepsizeTable[index];
1443 bufferstep = 1;
1444
1445 for ( i=0; i < len; i += size ) {
1446 if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8;
1447 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
1448 else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
1449
1450 /* Step 1 - compute difference with previous value */
1451 diff = val - valpred;
1452 sign = (diff < 0) ? 8 : 0;
1453 if ( sign ) diff = (-diff);
1454
1455 /* Step 2 - Divide and clamp */
1456 /* Note:
1457 ** This code *approximately* computes:
1458 ** delta = diff*4/step;
1459 ** vpdiff = (delta+0.5)*step/4;
1460 ** but in shift step bits are dropped. The net result of this
1461 ** is that even if you have fast mul/div hardware you cannot
1462 ** put it to good use since the fixup would be too expensive.
1463 */
1464 delta = 0;
1465 vpdiff = (step >> 3);
1466
1467 if ( diff >= step ) {
1468 delta = 4;
1469 diff -= step;
1470 vpdiff += step;
1471 }
1472 step >>= 1;
1473 if ( diff >= step ) {
1474 delta |= 2;
1475 diff -= step;
1476 vpdiff += step;
1477 }
1478 step >>= 1;
1479 if ( diff >= step ) {
1480 delta |= 1;
1481 vpdiff += step;
1482 }
1483
1484 /* Step 3 - Update previous value */
1485 if ( sign )
1486 valpred -= vpdiff;
1487 else
1488 valpred += vpdiff;
1489
1490 /* Step 4 - Clamp previous value to 16 bits */
1491 if ( valpred > 32767 )
1492 valpred = 32767;
1493 else if ( valpred < -32768 )
1494 valpred = -32768;
1495
1496 /* Step 5 - Assemble value, update index and step values */
1497 delta |= sign;
1498
1499 index += indexTable[delta];
1500 if ( index < 0 ) index = 0;
1501 if ( index > 88 ) index = 88;
1502 step = stepsizeTable[index];
1503
1504 /* Step 6 - Output value */
1505 if ( bufferstep ) {
1506 outputbuffer = (delta << 4) & 0xf0;
1507 } else {
1508 *ncp++ = (delta & 0x0f) | outputbuffer;
1509 }
1510 bufferstep = !bufferstep;
1511 }
1512 rv = Py_BuildValue("(O(ii))", str, valpred, index);
1513 Py_DECREF(str);
1514 return rv;
1515 }
1516
1517 static PyObject *
1518 audioop_adpcm2lin(PyObject *self, PyObject *args)
1519 {
1520 signed char *cp;
1521 signed char *ncp;
1522 int len, new_len, size, valpred, step, delta, index, sign, vpdiff;
1523 PyObject *rv, *str, *state;
1524 int i, inputbuffer = 0, bufferstep;
1525
1526 if ( !PyArg_ParseTuple(args, "s#iO:adpcm2lin",
1527 &cp, &len, &size, &state) )
1528 return 0;
1529
1530 if ( size != 1 && size != 2 && size != 4) {
1531 PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
1532 return 0;
1533 }
1534
1535 /* Decode state, should have (value, step) */
1536 if ( state == Py_None ) {
1537 /* First time, it seems. Set defaults */
1538 valpred = 0;
1539 step = 7;
1540 index = 0;
1541 } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) )
1542 return 0;
1543
1544 new_len = len*size*2;
1545 if (new_len < 0) {
1546 PyErr_SetString(PyExc_MemoryError,
1547 "not enough memory for output buffer");
1548 return 0;
1549 }
1550 str = PyString_FromStringAndSize(NULL, new_len);
1551 if ( str == 0 )
1552 return 0;
1553 ncp = (signed char *)PyString_AsString(str);
1554
1555 step = stepsizeTable[index];
1556 bufferstep = 0;
1557
1558 for ( i=0; i < new_len; i += size ) {
1559 /* Step 1 - get the delta value and compute next index */
1560 if ( bufferstep ) {
1561 delta = inputbuffer & 0xf;
1562 } else {
1563 inputbuffer = *cp++;
1564 delta = (inputbuffer >> 4) & 0xf;
1565 }
1566
1567 bufferstep = !bufferstep;
1568
1569 /* Step 2 - Find new index value (for later) */
1570 index += indexTable[delta];
1571 if ( index < 0 ) index = 0;
1572 if ( index > 88 ) index = 88;
1573
1574 /* Step 3 - Separate sign and magnitude */
1575 sign = delta & 8;
1576 delta = delta & 7;
1577
1578 /* Step 4 - Compute difference and new predicted value */
1579 /*
1580 ** Computes 'vpdiff = (delta+0.5)*step/4', but see comment
1581 ** in adpcm_coder.
1582 */
1583 vpdiff = step >> 3;
1584 if ( delta & 4 ) vpdiff += step;
1585 if ( delta & 2 ) vpdiff += step>>1;
1586 if ( delta & 1 ) vpdiff += step>>2;
1587
1588 if ( sign )
1589 valpred -= vpdiff;
1590 else
1591 valpred += vpdiff;
1592
1593 /* Step 5 - clamp output value */
1594 if ( valpred > 32767 )
1595 valpred = 32767;
1596 else if ( valpred < -32768 )
1597 valpred = -32768;
1598
1599 /* Step 6 - Update step value */
1600 step = stepsizeTable[index];
1601
1602 /* Step 6 - Output value */
1603 if ( size == 1 ) *CHARP(ncp, i) = (signed char)(valpred >> 8);
1604 else if ( size == 2 ) *SHORTP(ncp, i) = (short)(valpred);
1605 else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(valpred<<16);
1606 }
1607
1608 rv = Py_BuildValue("(O(ii))", str, valpred, index);
1609 Py_DECREF(str);
1610 return rv;
1611 }
1612
1613 static PyMethodDef audioop_methods[] = {
1614 { "max", audioop_max, METH_VARARGS },
1615 { "minmax", audioop_minmax, METH_VARARGS },
1616 { "avg", audioop_avg, METH_VARARGS },
1617 { "maxpp", audioop_maxpp, METH_VARARGS },
1618 { "avgpp", audioop_avgpp, METH_VARARGS },
1619 { "rms", audioop_rms, METH_VARARGS },
1620 { "findfit", audioop_findfit, METH_VARARGS },
1621 { "findmax", audioop_findmax, METH_VARARGS },
1622 { "findfactor", audioop_findfactor, METH_VARARGS },
1623 { "cross", audioop_cross, METH_VARARGS },
1624 { "mul", audioop_mul, METH_VARARGS },
1625 { "add", audioop_add, METH_VARARGS },
1626 { "bias", audioop_bias, METH_VARARGS },
1627 { "ulaw2lin", audioop_ulaw2lin, METH_VARARGS },
1628 { "lin2ulaw", audioop_lin2ulaw, METH_VARARGS },
1629 { "alaw2lin", audioop_alaw2lin, METH_VARARGS },
1630 { "lin2alaw", audioop_lin2alaw, METH_VARARGS },
1631 { "lin2lin", audioop_lin2lin, METH_VARARGS },
1632 { "adpcm2lin", audioop_adpcm2lin, METH_VARARGS },
1633 { "lin2adpcm", audioop_lin2adpcm, METH_VARARGS },
1634 { "tomono", audioop_tomono, METH_VARARGS },
1635 { "tostereo", audioop_tostereo, METH_VARARGS },
1636 { "getsample", audioop_getsample, METH_VARARGS },
1637 { "reverse", audioop_reverse, METH_VARARGS },
1638 { "ratecv", audioop_ratecv, METH_VARARGS },
1639 { 0, 0 }
1640 };
1641
1642 PyMODINIT_FUNC
1643 initaudioop(void)
1644 {
1645 PyObject *m, *d;
1646 m = Py_InitModule("audioop", audioop_methods);
1647 if (m == NULL)
1648 return;
1649 d = PyModule_GetDict(m);
1650 if (d == NULL)
1651 return;
1652 AudioopError = PyErr_NewException("audioop.error", NULL, NULL);
1653 if (AudioopError != NULL)
1654 PyDict_SetItemString(d,"error",AudioopError);
1655 }
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