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/* audioopmodule - Module to detect peak values in arrays */
#define PY_SSIZE_T_CLEAN
#include "Python.h"
#if SIZEOF_INT == 4
typedef int Py_Int32;typedef unsigned int Py_UInt32;#else
#if SIZEOF_LONG == 4
typedef long Py_Int32;typedef unsigned long Py_UInt32;#else
#error "No 4-byte integral type"
#endif
#endif
typedef short PyInt16;
#if defined(__CHAR_UNSIGNED__)
#if defined(signed)
/* This module currently does not work on systems where only unsigned
characters are available. Take it out of Setup. Sorry. */#endif
#endif
static const int maxvals[] = {0, 0x7F, 0x7FFF, 0x7FFFFF, 0x7FFFFFFF};static const int minvals[] = {0, -0x80, -0x8000, -0x800000, -0x80000000};static const unsigned int masks[] = {0, 0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF};
static intfbound(double val, double minval, double maxval){ if (val > maxval) val = maxval; else if (val < minval + 1) val = minval; return (int)val;}
/* Code shamelessly stolen from sox, 12.17.7, g711.c
** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */
/* From g711.c:
* * December 30, 1994: * Functions linear2alaw, linear2ulaw have been updated to correctly * convert unquantized 16 bit values. * Tables for direct u- to A-law and A- to u-law conversions have been * corrected. * Borge Lindberg, Center for PersonKommunikation, Aalborg University. * bli@cpk.auc.dk * */#define BIAS 0x84 /* define the add-in bias for 16 bit samples */
#define CLIP 32635
#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
#define QUANT_MASK (0xf) /* Quantization field mask. */
#define SEG_SHIFT (4) /* Left shift for segment number. */
#define SEG_MASK (0x70) /* Segment field mask. */
static PyInt16 seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF};static PyInt16 seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF};
static PyInt16search(PyInt16 val, PyInt16 *table, int size){ int i;
for (i = 0; i < size; i++) { if (val <= *table++) return (i); } return (size);}#define st_ulaw2linear16(uc) (_st_ulaw2linear16[uc])
#define st_alaw2linear16(uc) (_st_alaw2linear16[uc])
static PyInt16 _st_ulaw2linear16[256] = { -32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956, -23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764, -15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412, -11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316, -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, -1372, -1308, -1244, -1180, -1116, -1052, -988, -924, -876, -844, -812, -780, -748, -716, -684, -652, -620, -588, -556, -524, -492, -460, -428, -396, -372, -356, -340, -324, -308, -292, -276, -260, -244, -228, -212, -196, -180, -164, -148, -132, -120, -112, -104, -96, -88, -80, -72, -64, -56, -48, -40, -32, -24, -16, -8, 0, 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, 1372, 1308, 1244, 1180, 1116, 1052, 988, 924, 876, 844, 812, 780, 748, 716, 684, 652, 620, 588, 556, 524, 492, 460, 428, 396, 372, 356, 340, 324, 308, 292, 276, 260, 244, 228, 212, 196, 180, 164, 148, 132, 120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0};
/*
* linear2ulaw() accepts a 14-bit signed integer and encodes it as u-law data * stored in a unsigned char. This function should only be called with * the data shifted such that it only contains information in the lower * 14-bits. * * In order to simplify the encoding process, the original linear magnitude * is biased by adding 33 which shifts the encoding range from (0 - 8158) to * (33 - 8191). The result can be seen in the following encoding table: * * Biased Linear Input Code Compressed Code * ------------------------ --------------- * 00000001wxyza 000wxyz * 0000001wxyzab 001wxyz * 000001wxyzabc 010wxyz * 00001wxyzabcd 011wxyz * 0001wxyzabcde 100wxyz * 001wxyzabcdef 101wxyz * 01wxyzabcdefg 110wxyz * 1wxyzabcdefgh 111wxyz * * Each biased linear code has a leading 1 which identifies the segment * number. The value of the segment number is equal to 7 minus the number * of leading 0's. The quantization interval is directly available as the * four bits wxyz. * The trailing bits (a - h) are ignored. * * Ordinarily the complement of the resulting code word is used for * transmission, and so the code word is complemented before it is returned. * * For further information see John C. Bellamy's Digital Telephony, 1982, * John Wiley & Sons, pps 98-111 and 472-476. */static unsigned charst_14linear2ulaw(PyInt16 pcm_val) /* 2's complement (14-bit range) */{ PyInt16 mask; PyInt16 seg; unsigned char uval;
/* The original sox code does this in the calling function, not here */ pcm_val = pcm_val >> 2;
/* u-law inverts all bits */ /* Get the sign and the magnitude of the value. */ if (pcm_val < 0) { pcm_val = -pcm_val; mask = 0x7F; } else { mask = 0xFF; } if ( pcm_val > CLIP ) pcm_val = CLIP; /* clip the magnitude */ pcm_val += (BIAS >> 2);
/* Convert the scaled magnitude to segment number. */ seg = search(pcm_val, seg_uend, 8);
/*
* Combine the sign, segment, quantization bits; * and complement the code word. */ if (seg >= 8) /* out of range, return maximum value. */ return (unsigned char) (0x7F ^ mask); else { uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF); return (uval ^ mask); }
}
static PyInt16 _st_alaw2linear16[256] = { -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736, -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944, -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136, -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472, -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568, -344, -328, -376, -360, -280, -264, -312, -296, -472, -456, -504, -488, -408, -392, -440, -424, -88, -72, -120, -104, -24, -8, -56, -40, -216, -200, -248, -232, -152, -136, -184, -168, -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, -688, -656, -752, -720, -560, -528, -624, -592, -944, -912, -1008, -976, -816, -784, -880, -848, 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736, 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784, 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368, 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392, 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944, 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136, 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472, 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568, 344, 328, 376, 360, 280, 264, 312, 296, 472, 456, 504, 488, 408, 392, 440, 424, 88, 72, 120, 104, 24, 8, 56, 40, 216, 200, 248, 232, 152, 136, 184, 168, 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184, 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696, 688, 656, 752, 720, 560, 528, 624, 592, 944, 912, 1008, 976, 816, 784, 880, 848};
/*
* linear2alaw() accepts an 13-bit signed integer and encodes it as A-law data * stored in a unsigned char. This function should only be called with * the data shifted such that it only contains information in the lower * 13-bits. * * Linear Input Code Compressed Code * ------------------------ --------------- * 0000000wxyza 000wxyz * 0000001wxyza 001wxyz * 000001wxyzab 010wxyz * 00001wxyzabc 011wxyz * 0001wxyzabcd 100wxyz * 001wxyzabcde 101wxyz * 01wxyzabcdef 110wxyz * 1wxyzabcdefg 111wxyz * * For further information see John C. Bellamy's Digital Telephony, 1982, * John Wiley & Sons, pps 98-111 and 472-476. */static unsigned charst_linear2alaw(PyInt16 pcm_val) /* 2's complement (13-bit range) */{ PyInt16 mask; short seg; unsigned char aval;
/* The original sox code does this in the calling function, not here */ pcm_val = pcm_val >> 3;
/* A-law using even bit inversion */ if (pcm_val >= 0) { mask = 0xD5; /* sign (7th) bit = 1 */ } else { mask = 0x55; /* sign bit = 0 */ pcm_val = -pcm_val - 1; }
/* Convert the scaled magnitude to segment number. */ seg = search(pcm_val, seg_aend, 8);
/* Combine the sign, segment, and quantization bits. */
if (seg >= 8) /* out of range, return maximum value. */ return (unsigned char) (0x7F ^ mask); else { aval = (unsigned char) seg << SEG_SHIFT; if (seg < 2) aval |= (pcm_val >> 1) & QUANT_MASK; else aval |= (pcm_val >> seg) & QUANT_MASK; return (aval ^ mask); }}/* End of code taken from sox */
/* Intel ADPCM step variation table */static int indexTable[16] = { -1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8,};
static int stepsizeTable[89] = { 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767};
#define CHARP(cp, i) ((signed char *)(cp+i))
#define SHORTP(cp, i) ((short *)(cp+i))
#define LONGP(cp, i) ((Py_Int32 *)(cp+i))
static PyObject *AudioopError;
static intaudioop_check_size(int size){ if (size != 1 && size != 2 && size != 4) { PyErr_SetString(AudioopError, "Size should be 1, 2 or 4"); return 0; } else return 1;}
static intaudioop_check_parameters(Py_ssize_t len, int size){ if (!audioop_check_size(size)) return 0; if (len % size != 0) { PyErr_SetString(AudioopError, "not a whole number of frames"); return 0; } return 1;}
static PyObject *audioop_getsample(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0;
if ( !PyArg_ParseTuple(args, "s#in:getsample", &cp, &len, &size, &i) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; if ( i < 0 || i >= len/size ) { PyErr_SetString(AudioopError, "Index out of range"); return 0; } if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i*2); else if ( size == 4 ) val = (int)*LONGP(cp, i*4); return PyLong_FromLong(val);}
static PyObject *audioop_max(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0; unsigned int absval, max = 0;
if ( !PyArg_ParseTuple(args, "s#i:max", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; for ( i=0; i<len; i+= size) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); if (val < 0) absval = (-val); else absval = val; if (absval > max) max = absval; } return PyLong_FromUnsignedLong(max);}
static PyObject *audioop_minmax(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0; int min = 0x7fffffff, max = -0x80000000;
if (!PyArg_ParseTuple(args, "s#i:minmax", &cp, &len, &size)) return NULL; if (!audioop_check_parameters(len, size)) return NULL; for (i = 0; i < len; i += size) { if (size == 1) val = (int) *CHARP(cp, i); else if (size == 2) val = (int) *SHORTP(cp, i); else if (size == 4) val = (int) *LONGP(cp, i); if (val > max) max = val; if (val < min) min = val; } return Py_BuildValue("(ii)", min, max);}
static PyObject *audioop_avg(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0; double avg = 0.0;
if ( !PyArg_ParseTuple(args, "s#i:avg", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; for ( i=0; i<len; i+= size) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); avg += val; } if ( len == 0 ) val = 0; else val = (int)floor(avg / (double)(len/size)); return PyLong_FromLong(val);}
static PyObject *audioop_rms(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0; unsigned int res; double sum_squares = 0.0;
if ( !PyArg_ParseTuple(args, "s#i:rms", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; for ( i=0; i<len; i+= size) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); sum_squares += (double)val*(double)val; } if ( len == 0 ) res = 0; else res = (unsigned int)sqrt(sum_squares / (double)(len/size)); return PyLong_FromUnsignedLong(res);}
static double _sum2(short *a, short *b, Py_ssize_t len){ Py_ssize_t i; double sum = 0.0;
for( i=0; i<len; i++) { sum = sum + (double)a[i]*(double)b[i]; } return sum;}
/*
** Findfit tries to locate a sample within another sample. Its main use** is in echo-cancellation (to find the feedback of the output signal in** the input signal).** The method used is as follows:**** let R be the reference signal (length n) and A the input signal (length N)** with N > n, and let all sums be over i from 0 to n-1.**** Now, for each j in {0..N-n} we compute a factor fj so that -fj*R matches A** as good as possible, i.e. sum( (A[j+i]+fj*R[i])^2 ) is minimal. This** equation gives fj = sum( A[j+i]R[i] ) / sum(R[i]^2).**** Next, we compute the relative distance between the original signal and** the modified signal and minimize that over j:** vj = sum( (A[j+i]-fj*R[i])^2 ) / sum( A[j+i]^2 ) =>** vj = ( sum(A[j+i]^2)*sum(R[i]^2) - sum(A[j+i]R[i])^2 ) / sum( A[j+i]^2 )**** In the code variables correspond as follows:** cp1 A** cp2 R** len1 N** len2 n** aj_m1 A[j-1]** aj_lm1 A[j+n-1]** sum_ri_2 sum(R[i]^2)** sum_aij_2 sum(A[i+j]^2)** sum_aij_ri sum(A[i+j]R[i])**** sum_ri is calculated once, sum_aij_2 is updated each step and sum_aij_ri** is completely recalculated each step.*/static PyObject *audioop_findfit(PyObject *self, PyObject *args){ short *cp1, *cp2; Py_ssize_t len1, len2; Py_ssize_t j, best_j; double aj_m1, aj_lm1; double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor;
/* Passing a short** for an 's' argument is correct only
if the string contents is aligned for interpretation as short[]. Due to the definition of PyBytesObject, this is currently (Python 2.6) the case. */ if ( !PyArg_ParseTuple(args, "s#s#:findfit", (char**)&cp1, &len1, (char**)&cp2, &len2) ) return 0; if ( len1 & 1 || len2 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } len1 >>= 1; len2 >>= 1;
if ( len1 < len2 ) { PyErr_SetString(AudioopError, "First sample should be longer"); return 0; } sum_ri_2 = _sum2(cp2, cp2, len2); sum_aij_2 = _sum2(cp1, cp1, len2); sum_aij_ri = _sum2(cp1, cp2, len2);
result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2;
best_result = result; best_j = 0;
for ( j=1; j<=len1-len2; j++) { aj_m1 = (double)cp1[j-1]; aj_lm1 = (double)cp1[j+len2-1];
sum_aij_2 = sum_aij_2 + aj_lm1*aj_lm1 - aj_m1*aj_m1; sum_aij_ri = _sum2(cp1+j, cp2, len2);
result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2;
if ( result < best_result ) { best_result = result; best_j = j; }
}
factor = _sum2(cp1+best_j, cp2, len2) / sum_ri_2;
return Py_BuildValue("(nf)", best_j, factor);}
/*
** findfactor finds a factor f so that the energy in A-fB is minimal.** See the comment for findfit for details.*/static PyObject *audioop_findfactor(PyObject *self, PyObject *args){ short *cp1, *cp2; Py_ssize_t len1, len2; double sum_ri_2, sum_aij_ri, result;
if ( !PyArg_ParseTuple(args, "s#s#:findfactor", (char**)&cp1, &len1, (char**)&cp2, &len2) ) return 0; if ( len1 & 1 || len2 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } if ( len1 != len2 ) { PyErr_SetString(AudioopError, "Samples should be same size"); return 0; } len2 >>= 1; sum_ri_2 = _sum2(cp2, cp2, len2); sum_aij_ri = _sum2(cp1, cp2, len2);
result = sum_aij_ri / sum_ri_2;
return PyFloat_FromDouble(result);}
/*
** findmax returns the index of the n-sized segment of the input sample** that contains the most energy.*/static PyObject *audioop_findmax(PyObject *self, PyObject *args){ short *cp1; Py_ssize_t len1, len2; Py_ssize_t j, best_j; double aj_m1, aj_lm1; double result, best_result;
if ( !PyArg_ParseTuple(args, "s#n:findmax", (char**)&cp1, &len1, &len2) ) return 0; if ( len1 & 1 ) { PyErr_SetString(AudioopError, "Strings should be even-sized"); return 0; } len1 >>= 1;
if ( len2 < 0 || len1 < len2 ) { PyErr_SetString(AudioopError, "Input sample should be longer"); return 0; }
result = _sum2(cp1, cp1, len2);
best_result = result; best_j = 0;
for ( j=1; j<=len1-len2; j++) { aj_m1 = (double)cp1[j-1]; aj_lm1 = (double)cp1[j+len2-1];
result = result + aj_lm1*aj_lm1 - aj_m1*aj_m1;
if ( result > best_result ) { best_result = result; best_j = j; }
}
return PyLong_FromSsize_t(best_j);}
static PyObject *audioop_avgpp(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0, prevval = 0, prevextremevalid = 0, prevextreme = 0; double sum = 0.0; unsigned int avg; int diff, prevdiff, nextreme = 0;
if ( !PyArg_ParseTuple(args, "s#i:avgpp", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; if (len <= size) return PyLong_FromLong(0); if ( size == 1 ) prevval = (int)*CHARP(cp, 0); else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0); else if ( size == 4 ) prevval = (int)*LONGP(cp, 0); prevdiff = 17; /* Anything != 0, 1 */ for ( i=size; i<len; i+= size) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); if (val != prevval) { diff = val < prevval; if (prevdiff == !diff) { /* Derivative changed sign. Compute difference to last
** extreme value and remember. */ if (prevextremevalid) { sum += fabs((double)prevval - (double)prevextreme); nextreme++; } prevextremevalid = 1; prevextreme = prevval; } prevval = val; prevdiff = diff; } } if ( nextreme == 0 ) avg = 0; else avg = (unsigned int)(sum / (double)nextreme); return PyLong_FromUnsignedLong(avg);}
static PyObject *audioop_maxpp(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0, prevval = 0, prevextremevalid = 0, prevextreme = 0; unsigned int max = 0, extremediff; int diff, prevdiff;
if ( !PyArg_ParseTuple(args, "s#i:maxpp", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; if (len <= size) return PyLong_FromLong(0); if ( size == 1 ) prevval = (int)*CHARP(cp, 0); else if ( size == 2 ) prevval = (int)*SHORTP(cp, 0); else if ( size == 4 ) prevval = (int)*LONGP(cp, 0); prevdiff = 17; /* Anything != 0, 1 */ for ( i=size; i<len; i+= size) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); if (val != prevval) { diff = val < prevval; if (prevdiff == !diff) { /* Derivative changed sign. Compute difference to
** last extreme value and remember. */ if (prevextremevalid) { if (prevval < prevextreme) extremediff = (unsigned int)prevextreme - (unsigned int)prevval; else extremediff = (unsigned int)prevval - (unsigned int)prevextreme; if ( extremediff > max ) max = extremediff; } prevextremevalid = 1; prevextreme = prevval; } prevval = val; prevdiff = diff; } } return PyLong_FromUnsignedLong(max);}
static PyObject *audioop_cross(PyObject *self, PyObject *args){ signed char *cp; Py_ssize_t len, i; int size, val = 0; int prevval; Py_ssize_t ncross;
if ( !PyArg_ParseTuple(args, "s#i:cross", &cp, &len, &size) ) return 0; if (!audioop_check_parameters(len, size)) return NULL; ncross = -1; prevval = 17; /* Anything <> 0,1 */ for ( i=0; i<len; i+= size) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) >> 7; else if ( size == 2 ) val = ((int)*SHORTP(cp, i)) >> 15; else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 31; val = val & 1; if ( val != prevval ) ncross++; prevval = val; } return PyLong_FromSsize_t(ncross);}
static PyObject *audioop_mul(PyObject *self, PyObject *args){ signed char *cp, *ncp; Py_ssize_t len, i; int size, val = 0; double factor, fval, maxval, minval; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#id:mul", &cp, &len, &size, &factor ) ) return 0; if (!audioop_check_parameters(len, size)) return NULL;
maxval = (double) maxvals[size]; minval = (double) minvals[size];
rv = PyBytes_FromStringAndSize(NULL, len); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i); fval = (double)val*factor; val = (int)floor(fbound(fval, minval, maxval)); if ( size == 1 ) *CHARP(ncp, i) = (signed char)val; else if ( size == 2 ) *SHORTP(ncp, i) = (short)val; else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)val; } return rv;}
static PyObject *audioop_tomono(PyObject *self, PyObject *args){ Py_buffer pcp; signed char *cp, *ncp; Py_ssize_t len, i; int size, val1 = 0, val2 = 0; double fac1, fac2, fval, maxval, minval; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s*idd:tomono", &pcp, &size, &fac1, &fac2 ) ) return 0; cp = pcp.buf; len = pcp.len; if (!audioop_check_parameters(len, size)) { PyBuffer_Release(&pcp); return NULL; } if (((len / size) & 1) != 0) { PyErr_SetString(AudioopError, "not a whole number of frames"); PyBuffer_Release(&pcp); return NULL; }
maxval = (double) maxvals[size]; minval = (double) minvals[size];
rv = PyBytes_FromStringAndSize(NULL, len/2); if ( rv == 0 ) { PyBuffer_Release(&pcp); return 0; } ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size*2 ) { if ( size == 1 ) val1 = (int)*CHARP(cp, i); else if ( size == 2 ) val1 = (int)*SHORTP(cp, i); else if ( size == 4 ) val1 = (int)*LONGP(cp, i); if ( size == 1 ) val2 = (int)*CHARP(cp, i+1); else if ( size == 2 ) val2 = (int)*SHORTP(cp, i+2); else if ( size == 4 ) val2 = (int)*LONGP(cp, i+4); fval = (double)val1*fac1 + (double)val2*fac2; val1 = (int)floor(fbound(fval, minval, maxval)); if ( size == 1 ) *CHARP(ncp, i/2) = (signed char)val1; else if ( size == 2 ) *SHORTP(ncp, i/2) = (short)val1; else if ( size == 4 ) *LONGP(ncp, i/2)= (Py_Int32)val1; } PyBuffer_Release(&pcp); return rv;}
static PyObject *audioop_tostereo(PyObject *self, PyObject *args){ signed char *cp, *ncp; Py_ssize_t len, i; int size, val1, val2, val = 0; double fac1, fac2, fval, maxval, minval; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#idd:tostereo", &cp, &len, &size, &fac1, &fac2 ) ) return 0; if (!audioop_check_parameters(len, size)) return NULL;
maxval = (double) maxvals[size]; minval = (double) minvals[size];
if (len > PY_SSIZE_T_MAX/2) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; }
rv = PyBytes_FromStringAndSize(NULL, len*2); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = (int)*CHARP(cp, i); else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = (int)*LONGP(cp, i);
fval = (double)val*fac1; val1 = (int)floor(fbound(fval, minval, maxval));
fval = (double)val*fac2; val2 = (int)floor(fbound(fval, minval, maxval));
if ( size == 1 ) *CHARP(ncp, i*2) = (signed char)val1; else if ( size == 2 ) *SHORTP(ncp, i*2) = (short)val1; else if ( size == 4 ) *LONGP(ncp, i*2) = (Py_Int32)val1;
if ( size == 1 ) *CHARP(ncp, i*2+1) = (signed char)val2; else if ( size == 2 ) *SHORTP(ncp, i*2+2) = (short)val2; else if ( size == 4 ) *LONGP(ncp, i*2+4) = (Py_Int32)val2; } return rv;}
static PyObject *audioop_add(PyObject *self, PyObject *args){ signed char *cp1, *cp2, *ncp; Py_ssize_t len1, len2, i; int size, val1 = 0, val2 = 0, minval, maxval, newval; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#s#i:add", &cp1, &len1, &cp2, &len2, &size ) ) return 0; if (!audioop_check_parameters(len1, size)) return NULL; if ( len1 != len2 ) { PyErr_SetString(AudioopError, "Lengths should be the same"); return 0; }
maxval = maxvals[size]; minval = minvals[size];
rv = PyBytes_FromStringAndSize(NULL, len1); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len1; i += size ) { if ( size == 1 ) val1 = (int)*CHARP(cp1, i); else if ( size == 2 ) val1 = (int)*SHORTP(cp1, i); else if ( size == 4 ) val1 = (int)*LONGP(cp1, i);
if ( size == 1 ) val2 = (int)*CHARP(cp2, i); else if ( size == 2 ) val2 = (int)*SHORTP(cp2, i); else if ( size == 4 ) val2 = (int)*LONGP(cp2, i);
if (size < 4) { newval = val1 + val2; /* truncate in case of overflow */ if (newval > maxval) newval = maxval; else if (newval < minval) newval = minval; } else { double fval = (double)val1 + (double)val2; /* truncate in case of overflow */ newval = (int)floor(fbound(fval, minval, maxval)); }
if ( size == 1 ) *CHARP(ncp, i) = (signed char)newval; else if ( size == 2 ) *SHORTP(ncp, i) = (short)newval; else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)newval; } return rv;}
static PyObject *audioop_bias(PyObject *self, PyObject *args){ signed char *cp, *ncp; Py_ssize_t len, i; int size, bias; unsigned int val = 0, mask; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#ii:bias", &cp, &len, &size , &bias) ) return 0;
if (!audioop_check_parameters(len, size)) return NULL;
rv = PyBytes_FromStringAndSize(NULL, len); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
mask = masks[size];
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = (unsigned int)(unsigned char)*CHARP(cp, i); else if ( size == 2 ) val = (unsigned int)(unsigned short)*SHORTP(cp, i); else if ( size == 4 ) val = (unsigned int)(Py_UInt32)*LONGP(cp, i);
val += (unsigned int)bias; /* wrap around in case of overflow */ val &= mask;
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(unsigned char)val; else if ( size == 2 ) *SHORTP(ncp, i) = (short)(unsigned short)val; else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(Py_UInt32)val; } return rv;}
static PyObject *audioop_reverse(PyObject *self, PyObject *args){ signed char *cp; unsigned char *ncp; Py_ssize_t len, i, j; int size, val = 0; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#i:reverse", &cp, &len, &size) ) return 0;
if (!audioop_check_parameters(len, size)) return NULL;
rv = PyBytes_FromStringAndSize(NULL, len); if ( rv == 0 ) return 0; ncp = (unsigned char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 24; else if ( size == 2 ) val = ((int)*SHORTP(cp, i)) << 16; else if ( size == 4 ) val = (int)*LONGP(cp, i);
j = len - i - size;
if ( size == 1 ) *CHARP(ncp, j) = (signed char)(val >> 24); else if ( size == 2 ) *SHORTP(ncp, j) = (short)(val >> 16); else if ( size == 4 ) *LONGP(ncp, j) = (Py_Int32)val; } return rv;}
static PyObject *audioop_lin2lin(PyObject *self, PyObject *args){ signed char *cp; unsigned char *ncp; Py_ssize_t len, i, j; int size, size2, val = 0; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#ii:lin2lin", &cp, &len, &size, &size2) ) return 0;
if (!audioop_check_parameters(len, size)) return NULL; if (!audioop_check_size(size2)) return NULL;
if (len/size > PY_SSIZE_T_MAX/size2) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; } rv = PyBytes_FromStringAndSize(NULL, (len/size)*size2); if ( rv == 0 ) return 0; ncp = (unsigned char *)PyBytes_AsString(rv);
for ( i=0, j=0; i < len; i += size, j += size2 ) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 24; else if ( size == 2 ) val = ((int)*SHORTP(cp, i)) << 16; else if ( size == 4 ) val = (int)*LONGP(cp, i);
if ( size2 == 1 ) *CHARP(ncp, j) = (signed char)(val >> 24); else if ( size2 == 2 ) *SHORTP(ncp, j) = (short)(val >> 16); else if ( size2 == 4 ) *LONGP(ncp, j) = (Py_Int32)val; } return rv;}
static intgcd(int a, int b){ while (b > 0) { int tmp = a % b; a = b; b = tmp; } return a;}
static PyObject *audioop_ratecv(PyObject *self, PyObject *args){ char *cp, *ncp; Py_ssize_t len; int size, nchannels, inrate, outrate, weightA, weightB; int chan, d, *prev_i, *cur_i, cur_o; PyObject *state, *samps, *str, *rv = NULL; int bytes_per_frame;
weightA = 1; weightB = 0; if (!PyArg_ParseTuple(args, "s#iiiiO|ii:ratecv", &cp, &len, &size, &nchannels, &inrate, &outrate, &state, &weightA, &weightB)) return NULL; if (!audioop_check_size(size)) return NULL; if (nchannels < 1) { PyErr_SetString(AudioopError, "# of channels should be >= 1"); return NULL; } if (size > INT_MAX / nchannels) { /* This overflow test is rigorously correct because
both multiplicands are >= 1. Use the argument names from the docs for the error msg. */ PyErr_SetString(PyExc_OverflowError, "width * nchannels too big for a C int"); return NULL; } bytes_per_frame = size * nchannels; if (weightA < 1 || weightB < 0) { PyErr_SetString(AudioopError, "weightA should be >= 1, weightB should be >= 0"); return NULL; } if (len % bytes_per_frame != 0) { PyErr_SetString(AudioopError, "not a whole number of frames"); return NULL; } if (inrate <= 0 || outrate <= 0) { PyErr_SetString(AudioopError, "sampling rate not > 0"); return NULL; } /* divide inrate and outrate by their greatest common divisor */ d = gcd(inrate, outrate); inrate /= d; outrate /= d; /* divide weightA and weightB by their greatest common divisor */ d = gcd(weightA, weightB); weightA /= d; weightA /= d;
if ((size_t)nchannels > PY_SIZE_MAX/sizeof(int)) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; } prev_i = (int *) PyMem_Malloc(nchannels * sizeof(int)); cur_i = (int *) PyMem_Malloc(nchannels * sizeof(int)); if (prev_i == NULL || cur_i == NULL) { (void) PyErr_NoMemory(); goto exit; }
len /= bytes_per_frame; /* # of frames */
if (state == Py_None) { d = -outrate; for (chan = 0; chan < nchannels; chan++) prev_i[chan] = cur_i[chan] = 0; } else { if (!PyArg_ParseTuple(state, "iO!;audioop.ratecv: illegal state argument", &d, &PyTuple_Type, &samps)) goto exit; if (PyTuple_Size(samps) != nchannels) { PyErr_SetString(AudioopError, "illegal state argument"); goto exit; } for (chan = 0; chan < nchannels; chan++) { if (!PyArg_ParseTuple(PyTuple_GetItem(samps, chan), "ii:ratecv", &prev_i[chan], &cur_i[chan])) goto exit; } }
/* str <- Space for the output buffer. */ if (len == 0) str = PyBytes_FromStringAndSize(NULL, 0); else { /* There are len input frames, so we need (mathematically)
ceiling(len*outrate/inrate) output frames, and each frame requires bytes_per_frame bytes. Computing this without spurious overflow is the challenge; we can settle for a reasonable upper bound, though, in this case ceiling(len/inrate) * outrate. */
/* compute ceiling(len/inrate) without overflow */ Py_ssize_t q = len > 0 ? 1 + (len - 1) / inrate : 0; if (outrate > PY_SSIZE_T_MAX / q / bytes_per_frame) str = NULL; else str = PyBytes_FromStringAndSize(NULL, q * outrate * bytes_per_frame); } if (str == NULL) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); goto exit; } ncp = PyBytes_AsString(str);
for (;;) { while (d < 0) { if (len == 0) { samps = PyTuple_New(nchannels); if (samps == NULL) goto exit; for (chan = 0; chan < nchannels; chan++) PyTuple_SetItem(samps, chan, Py_BuildValue("(ii)", prev_i[chan], cur_i[chan])); if (PyErr_Occurred()) goto exit; /* We have checked before that the length
* of the string fits into int. */ len = (Py_ssize_t)(ncp - PyBytes_AsString(str)); rv = PyBytes_FromStringAndSize (PyBytes_AsString(str), len); Py_DECREF(str); str = rv; if (str == NULL) goto exit; rv = Py_BuildValue("(O(iO))", str, d, samps); Py_DECREF(samps); Py_DECREF(str); goto exit; /* return rv */ } for (chan = 0; chan < nchannels; chan++) { prev_i[chan] = cur_i[chan]; if (size == 1) cur_i[chan] = ((int)*CHARP(cp, 0)) << 24; else if (size == 2) cur_i[chan] = ((int)*SHORTP(cp, 0)) << 16; else if (size == 4) cur_i[chan] = (int)*LONGP(cp, 0); cp += size; /* implements a simple digital filter */ cur_i[chan] = (int)( ((double)weightA * (double)cur_i[chan] + (double)weightB * (double)prev_i[chan]) / ((double)weightA + (double)weightB)); } len--; d += outrate; } while (d >= 0) { for (chan = 0; chan < nchannels; chan++) { cur_o = (int)(((double)prev_i[chan] * (double)d + (double)cur_i[chan] * (double)(outrate - d)) / (double)outrate); if (size == 1) *CHARP(ncp, 0) = (signed char)(cur_o >> 24); else if (size == 2) *SHORTP(ncp, 0) = (short)(cur_o >> 16); else if (size == 4) *LONGP(ncp, 0) = (Py_Int32)(cur_o); ncp += size; } d -= inrate; } } exit: PyMem_Free(prev_i); PyMem_Free(cur_i); return rv;}
static PyObject *audioop_lin2ulaw(PyObject *self, PyObject *args){ signed char *cp; unsigned char *ncp; Py_ssize_t len, i; int size, val = 0; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#i:lin2ulaw", &cp, &len, &size) ) return 0 ;
if (!audioop_check_parameters(len, size)) return NULL;
rv = PyBytes_FromStringAndSize(NULL, len/size); if ( rv == 0 ) return 0; ncp = (unsigned char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
*ncp++ = st_14linear2ulaw(val); } return rv;}
static PyObject *audioop_ulaw2lin(PyObject *self, PyObject *args){ unsigned char *cp; unsigned char cval; signed char *ncp; Py_ssize_t len, i; int size, val; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#i:ulaw2lin", &cp, &len, &size) ) return 0;
if (!audioop_check_size(size)) return NULL;
if (len > PY_SSIZE_T_MAX/size) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; } rv = PyBytes_FromStringAndSize(NULL, len*size); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len*size; i += size ) { cval = *cp++; val = st_ulaw2linear16(cval);
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val >> 8); else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val); else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val<<16); } return rv;}
static PyObject *audioop_lin2alaw(PyObject *self, PyObject *args){ signed char *cp; unsigned char *ncp; Py_ssize_t len, i; int size, val = 0; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#i:lin2alaw", &cp, &len, &size) ) return 0;
if (!audioop_check_parameters(len, size)) return NULL;
rv = PyBytes_FromStringAndSize(NULL, len/size); if ( rv == 0 ) return 0; ncp = (unsigned char *)PyBytes_AsString(rv);
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
*ncp++ = st_linear2alaw(val); } return rv;}
static PyObject *audioop_alaw2lin(PyObject *self, PyObject *args){ unsigned char *cp; unsigned char cval; signed char *ncp; Py_ssize_t len, i; int size, val; PyObject *rv;
if ( !PyArg_ParseTuple(args, "s#i:alaw2lin", &cp, &len, &size) ) return 0;
if (!audioop_check_size(size)) return NULL;
if (len > PY_SSIZE_T_MAX/size) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; } rv = PyBytes_FromStringAndSize(NULL, len*size); if ( rv == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(rv);
for ( i=0; i < len*size; i += size ) { cval = *cp++; val = st_alaw2linear16(cval);
if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val >> 8); else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val); else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val<<16); } return rv;}
static PyObject *audioop_lin2adpcm(PyObject *self, PyObject *args){ signed char *cp; signed char *ncp; Py_ssize_t len, i; int size, val = 0, step, valpred, delta, index, sign, vpdiff, diff; PyObject *rv, *state, *str; int outputbuffer = 0, bufferstep;
if ( !PyArg_ParseTuple(args, "s#iO:lin2adpcm", &cp, &len, &size, &state) ) return 0;
if (!audioop_check_parameters(len, size)) return NULL;
str = PyBytes_FromStringAndSize(NULL, len/(size*2)); if ( str == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(str);
/* Decode state, should have (value, step) */ if ( state == Py_None ) { /* First time, it seems. Set defaults */ valpred = 0; index = 0; } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) ) return 0;
step = stepsizeTable[index]; bufferstep = 1;
for ( i=0; i < len; i += size ) { if ( size == 1 ) val = ((int)*CHARP(cp, i)) << 8; else if ( size == 2 ) val = (int)*SHORTP(cp, i); else if ( size == 4 ) val = ((int)*LONGP(cp, i)) >> 16;
/* Step 1 - compute difference with previous value */ diff = val - valpred; sign = (diff < 0) ? 8 : 0; if ( sign ) diff = (-diff);
/* Step 2 - Divide and clamp */ /* Note:
** This code *approximately* computes: ** delta = diff*4/step; ** vpdiff = (delta+0.5)*step/4; ** but in shift step bits are dropped. The net result of this ** is that even if you have fast mul/div hardware you cannot ** put it to good use since the fixup would be too expensive. */ delta = 0; vpdiff = (step >> 3);
if ( diff >= step ) { delta = 4; diff -= step; vpdiff += step; } step >>= 1; if ( diff >= step ) { delta |= 2; diff -= step; vpdiff += step; } step >>= 1; if ( diff >= step ) { delta |= 1; vpdiff += step; }
/* Step 3 - Update previous value */ if ( sign ) valpred -= vpdiff; else valpred += vpdiff;
/* Step 4 - Clamp previous value to 16 bits */ if ( valpred > 32767 ) valpred = 32767; else if ( valpred < -32768 ) valpred = -32768;
/* Step 5 - Assemble value, update index and step values */ delta |= sign;
index += indexTable[delta]; if ( index < 0 ) index = 0; if ( index > 88 ) index = 88; step = stepsizeTable[index];
/* Step 6 - Output value */ if ( bufferstep ) { outputbuffer = (delta << 4) & 0xf0; } else { *ncp++ = (delta & 0x0f) | outputbuffer; } bufferstep = !bufferstep; } rv = Py_BuildValue("(O(ii))", str, valpred, index); Py_DECREF(str); return rv;}
static PyObject *audioop_adpcm2lin(PyObject *self, PyObject *args){ signed char *cp; signed char *ncp; Py_ssize_t len, i; int size, valpred, step, delta, index, sign, vpdiff; PyObject *rv, *str, *state; int inputbuffer = 0, bufferstep;
if ( !PyArg_ParseTuple(args, "s#iO:adpcm2lin", &cp, &len, &size, &state) ) return 0;
if (!audioop_check_size(size)) return NULL;
/* Decode state, should have (value, step) */ if ( state == Py_None ) { /* First time, it seems. Set defaults */ valpred = 0; index = 0; } else if ( !PyArg_ParseTuple(state, "ii", &valpred, &index) ) return 0;
if (len > (PY_SSIZE_T_MAX/2)/size) { PyErr_SetString(PyExc_MemoryError, "not enough memory for output buffer"); return 0; } str = PyBytes_FromStringAndSize(NULL, len*size*2); if ( str == 0 ) return 0; ncp = (signed char *)PyBytes_AsString(str);
step = stepsizeTable[index]; bufferstep = 0;
for ( i=0; i < len*size*2; i += size ) { /* Step 1 - get the delta value and compute next index */ if ( bufferstep ) { delta = inputbuffer & 0xf; } else { inputbuffer = *cp++; delta = (inputbuffer >> 4) & 0xf; }
bufferstep = !bufferstep;
/* Step 2 - Find new index value (for later) */ index += indexTable[delta]; if ( index < 0 ) index = 0; if ( index > 88 ) index = 88;
/* Step 3 - Separate sign and magnitude */ sign = delta & 8; delta = delta & 7;
/* Step 4 - Compute difference and new predicted value */ /*
** Computes 'vpdiff = (delta+0.5)*step/4', but see comment ** in adpcm_coder. */ vpdiff = step >> 3; if ( delta & 4 ) vpdiff += step; if ( delta & 2 ) vpdiff += step>>1; if ( delta & 1 ) vpdiff += step>>2;
if ( sign ) valpred -= vpdiff; else valpred += vpdiff;
/* Step 5 - clamp output value */ if ( valpred > 32767 ) valpred = 32767; else if ( valpred < -32768 ) valpred = -32768;
/* Step 6 - Update step value */ step = stepsizeTable[index];
/* Step 6 - Output value */ if ( size == 1 ) *CHARP(ncp, i) = (signed char)(valpred >> 8); else if ( size == 2 ) *SHORTP(ncp, i) = (short)(valpred); else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(valpred<<16); }
rv = Py_BuildValue("(O(ii))", str, valpred, index); Py_DECREF(str); return rv;}
static PyMethodDef audioop_methods[] = { { "max", audioop_max, METH_VARARGS }, { "minmax", audioop_minmax, METH_VARARGS }, { "avg", audioop_avg, METH_VARARGS }, { "maxpp", audioop_maxpp, METH_VARARGS }, { "avgpp", audioop_avgpp, METH_VARARGS }, { "rms", audioop_rms, METH_VARARGS }, { "findfit", audioop_findfit, METH_VARARGS }, { "findmax", audioop_findmax, METH_VARARGS }, { "findfactor", audioop_findfactor, METH_VARARGS }, { "cross", audioop_cross, METH_VARARGS }, { "mul", audioop_mul, METH_VARARGS }, { "add", audioop_add, METH_VARARGS }, { "bias", audioop_bias, METH_VARARGS }, { "ulaw2lin", audioop_ulaw2lin, METH_VARARGS }, { "lin2ulaw", audioop_lin2ulaw, METH_VARARGS }, { "alaw2lin", audioop_alaw2lin, METH_VARARGS }, { "lin2alaw", audioop_lin2alaw, METH_VARARGS }, { "lin2lin", audioop_lin2lin, METH_VARARGS }, { "adpcm2lin", audioop_adpcm2lin, METH_VARARGS }, { "lin2adpcm", audioop_lin2adpcm, METH_VARARGS }, { "tomono", audioop_tomono, METH_VARARGS }, { "tostereo", audioop_tostereo, METH_VARARGS }, { "getsample", audioop_getsample, METH_VARARGS }, { "reverse", audioop_reverse, METH_VARARGS }, { "ratecv", audioop_ratecv, METH_VARARGS }, { 0, 0 }};
static struct PyModuleDef audioopmodule = { PyModuleDef_HEAD_INIT, "audioop", NULL, -1, audioop_methods, NULL, NULL, NULL, NULL};
PyMODINIT_FUNCPyInit_audioop(void){ PyObject *m, *d; m = PyModule_Create(&audioopmodule); if (m == NULL) return NULL; d = PyModule_GetDict(m); if (d == NULL) return NULL; AudioopError = PyErr_NewException("audioop.error", NULL, NULL); if (AudioopError != NULL) PyDict_SetItemString(d,"error",AudioopError); return m;}
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