/* audioopmodule - Module to detect peak values in arrays */

#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

#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

/* Code shamelessly stolen from sox,

** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */

#define MINLIN -32768

#define MAXLIN 32767

#define LINCLIP(x) do { if ( x < MINLIN ) x = MINLIN ; \

else if ( x > MAXLIN ) x = MAXLIN; \

} while ( 0 )

static unsigned char st_linear_to_ulaw(int sample);

/*

** This macro converts from ulaw to 16 bit linear, faster.

**

** Jef Poskanzer

** 23 October 1989

**

** Input: 8 bit ulaw sample

** Output: signed 16 bit linear sample

*/

#define st_ulaw_to_linear(ulawbyte) ulaw_table[ulawbyte]

static int ulaw_table[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 };

/* #define ZEROTRAP */ /* turn on the trap as per the MIL-STD */

#define BIAS 0x84 /* define the add-in bias for 16 bit samples */

#define CLIP 32635

static unsigned char

st_linear_to_ulaw(int sample)

{

static int exp_lut[256] = {0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,

4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,

5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,

5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,

6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,

6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,

6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,

6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,

7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7};

int sign, exponent, mantissa;

unsigned char ulawbyte;

/* Get the sample into sign-magnitude. */

sign = (sample >> 8) & 0x80; /* set aside the sign */

if ( sign != 0 ) sample = -sample; /* get magnitude */

if ( sample > CLIP ) sample = CLIP; /* clip the magnitude */

/* Convert from 16 bit linear to ulaw. */

sample = sample + BIAS;

exponent = exp_lut[( sample >> 7 ) & 0xFF];

mantissa = ( sample >> ( exponent + 3 ) ) & 0x0F;

ulawbyte = ~ ( sign | ( exponent << 4 ) | mantissa );

#ifdef ZEROTRAP

if ( ulawbyte == 0 ) ulawbyte = 0x02; /* optional CCITT trap */

#endif

return ulawbyte;

}

/* 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 PyObject *

audioop_getsample(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0;

int i;

if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &size, &i) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

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 PyInt_FromLong(val);

}

static PyObject *

audioop_max(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0;

int i;

int max = 0;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

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 ) val = (-val);

if ( val > max ) max = val;

}

return PyInt_FromLong(max);

}

static PyObject *

audioop_minmax(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0;

int i;

int min = 0x7fffffff, max = -0x7fffffff;

if (!PyArg_Parse(args, "(s#i)", &cp, &len, &size))

return NULL;

if (size != 1 && size != 2 && size != 4) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

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;

int len, size, val = 0;

int i;

double avg = 0.0;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

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)(avg / (double)(len/size));

return PyInt_FromLong(val);

}

static PyObject *

audioop_rms(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0;

int i;

double sum_squares = 0.0;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

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 )

val = 0;

else

val = (int)sqrt(sum_squares / (double)(len/size));

return PyInt_FromLong(val);

}

static double _sum2(short *a, short *b, int len)

{

int 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;

int len1, len2;

int j, best_j;

double aj_m1, aj_lm1;

double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor;

if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &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;

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("(if)", 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;

int len1, len2;

double sum_ri_2, sum_aij_ri, result;

if ( !PyArg_Parse(args, "(s#s#)", &cp1, &len1, &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;

int len1, len2;

int j, best_j;

double aj_m1, aj_lm1;

double result, best_result;

if ( !PyArg_Parse(args, "(s#i)", &cp1, &len1, &len2) )

return 0;

if ( len1 & 1 ) {

PyErr_SetString(AudioopError, "Strings should be even-sized");

return 0;

}

len1 >>= 1;

if ( len1 < len2 ) {

PyErr_SetString(AudioopError, "Input sample should be longer");

return 0;

}

result = _sum2(cp1, cp1, len2);

best_result = result;

best_j = 0;

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 PyInt_FromLong(best_j);

}

static PyObject *

audioop_avgpp(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0, prevval = 0, prevextremevalid = 0,

prevextreme = 0;

int i;

double avg = 0.0;

int diff, prevdiff, extremediff, nextreme = 0;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

/* Compute first delta value ahead. Also automatically makes us

** skip the first extreme value

*/

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);

if ( size == 1 ) val = (int)*CHARP(cp, size);

else if ( size == 2 ) val = (int)*SHORTP(cp, size);

else if ( size == 4 ) val = (int)*LONGP(cp, size);

prevdiff = val - prevval;

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);

diff = val - prevval;

if ( diff*prevdiff < 0 ) {

/* Derivative changed sign. Compute difference to last

** extreme value and remember.

*/

if ( prevextremevalid ) {

extremediff = prevval - prevextreme;

if ( extremediff < 0 )

extremediff = -extremediff;

avg += extremediff;

nextreme++;

}

prevextremevalid = 1;

prevextreme = prevval;

}

prevval = val;

if ( diff != 0 )

prevdiff = diff;

}

if ( nextreme == 0 )

val = 0;

else

val = (int)(avg / (double)nextreme);

return PyInt_FromLong(val);

}

static PyObject *

audioop_maxpp(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0, prevval = 0, prevextremevalid = 0,

prevextreme = 0;

int i;

int max = 0;

int diff, prevdiff, extremediff;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

/* Compute first delta value ahead. Also automatically makes us

** skip the first extreme value

*/

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);

if ( size == 1 ) val = (int)*CHARP(cp, size);

else if ( size == 2 ) val = (int)*SHORTP(cp, size);

else if ( size == 4 ) val = (int)*LONGP(cp, size);

prevdiff = val - prevval;

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);

diff = val - prevval;

if ( diff*prevdiff < 0 ) {

/* Derivative changed sign. Compute difference to

** last extreme value and remember.

*/

if ( prevextremevalid ) {

extremediff = prevval - prevextreme;

if ( extremediff < 0 )

extremediff = -extremediff;

if ( extremediff > max )

max = extremediff;

}

prevextremevalid = 1;

prevextreme = prevval;

}

prevval = val;

if ( diff != 0 )

prevdiff = diff;

}

return PyInt_FromLong(max);

}

static PyObject *

audioop_cross(PyObject *self, PyObject *args)

{

signed char *cp;

int len, size, val = 0;

int i;

int prevval, ncross;

if ( !PyArg_Parse(args, "(s#i)", &cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

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 PyInt_FromLong(ncross);

}

static PyObject *

audioop_mul(PyObject *self, PyObject *args)

{

signed char *cp, *ncp;

int len, size, val = 0;

double factor, fval, maxval;

PyObject *rv;

int i;

if ( !PyArg_Parse(args, "(s#id)", &cp, &len, &size, &factor ) )

return 0;

if ( size == 1 ) maxval = (double) 0x7f;

else if ( size == 2 ) maxval = (double) 0x7fff;

else if ( size == 4 ) maxval = (double) 0x7fffffff;

else {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len);

if ( rv == 0 )

return 0;

ncp = (signed char *)PyString_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;

if ( fval > maxval ) fval = maxval;

else if ( fval < -maxval ) fval = -maxval;

val = (int)fval;

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)

{

signed char *cp, *ncp;

int len, size, val1 = 0, val2 = 0;

double fac1, fac2, fval, maxval;

PyObject *rv;

int i;

if ( !PyArg_Parse(args, "(s#idd)", &cp, &len, &size, &fac1, &fac2 ) )

return 0;

if ( size == 1 ) maxval = (double) 0x7f;

else if ( size == 2 ) maxval = (double) 0x7fff;

else if ( size == 4 ) maxval = (double) 0x7fffffff;

else {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len/2);

if ( rv == 0 )

return 0;

ncp = (signed char *)PyString_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;

if ( fval > maxval ) fval = maxval;

else if ( fval < -maxval ) fval = -maxval;

val1 = (int)fval;

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;

}

return rv;

}

static PyObject *

audioop_tostereo(PyObject *self, PyObject *args)

{

signed char *cp, *ncp;

int len, size, val1, val2, val = 0;

double fac1, fac2, fval, maxval;

PyObject *rv;

int i;

if ( !PyArg_Parse(args, "(s#idd)", &cp, &len, &size, &fac1, &fac2 ) )

return 0;

if ( size == 1 ) maxval = (double) 0x7f;

else if ( size == 2 ) maxval = (double) 0x7fff;

else if ( size == 4 ) maxval = (double) 0x7fffffff;

else {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len*2);

if ( rv == 0 )

return 0;

ncp = (signed char *)PyString_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;

if ( fval > maxval ) fval = maxval;

else if ( fval < -maxval ) fval = -maxval;

val1 = (int)fval;

fval = (double)val*fac2;

if ( fval > maxval ) fval = maxval;

else if ( fval < -maxval ) fval = -maxval;

val2 = (int)fval;

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;

int len1, len2, size, val1 = 0, val2 = 0, maxval, newval;

PyObject *rv;

int i;

if ( !PyArg_Parse(args, "(s#s#i)",

&cp1, &len1, &cp2, &len2, &size ) )

return 0;

if ( len1 != len2 ) {

PyErr_SetString(AudioopError, "Lengths should be the same");

return 0;

}

if ( size == 1 ) maxval = 0x7f;

else if ( size == 2 ) maxval = 0x7fff;

else if ( size == 4 ) maxval = 0x7fffffff;

else {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len1);

if ( rv == 0 )

return 0;

ncp = (signed char *)PyString_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);

newval = val1 + val2;

/* truncate in case of overflow */

if (newval > maxval) newval = maxval;

else if (newval < -maxval) newval = -maxval;

else if (size == 4 && (newval^val1) < 0 && (newval^val2) < 0)

newval = val1 > 0 ? maxval : - 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;

int len, size, val = 0;

PyObject *rv;

int i;

int bias;

if ( !PyArg_Parse(args, "(s#ii)",

&cp, &len, &size , &bias) )

return 0;

if ( size != 1 && size != 2 && size != 4) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len);

if ( rv == 0 )

return 0;

ncp = (signed char *)PyString_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);

if ( size == 1 ) *CHARP(ncp, i) = (signed char)(val+bias);

else if ( size == 2 ) *SHORTP(ncp, i) = (short)(val+bias);

else if ( size == 4 ) *LONGP(ncp, i) = (Py_Int32)(val+bias);

}

return rv;

}

static PyObject *

audioop_reverse(PyObject *self, PyObject *args)

{

signed char *cp;

unsigned char *ncp;

int len, size, val = 0;

PyObject *rv;

int i, j;

if ( !PyArg_Parse(args, "(s#i)",

&cp, &len, &size) )

return 0;

if ( size != 1 && size != 2 && size != 4 ) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, len);

if ( rv == 0 )

return 0;

ncp = (unsigned char *)PyString_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;

j = len - i - size;

if ( size == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8);

else if ( size == 2 ) *SHORTP(ncp, j) = (short)(val);

else if ( size == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16);

}

return rv;

}

static PyObject *

audioop_lin2lin(PyObject *self, PyObject *args)

{

signed char *cp;

unsigned char *ncp;

int len, size, size2, val = 0;

PyObject *rv;

int i, j;

if ( !PyArg_Parse(args, "(s#ii)",

&cp, &len, &size, &size2) )

return 0;

if ( (size != 1 && size != 2 && size != 4) ||

(size2 != 1 && size2 != 2 && size2 != 4)) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return 0;

}

rv = PyString_FromStringAndSize(NULL, (len/size)*size2);

if ( rv == 0 )

return 0;

ncp = (unsigned char *)PyString_AsString(rv);

for ( i=0, j=0; i < len; i += size, j += size2 ) {

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;

if ( size2 == 1 ) *CHARP(ncp, j) = (signed char)(val >> 8);

else if ( size2 == 2 ) *SHORTP(ncp, j) = (short)(val);

else if ( size2 == 4 ) *LONGP(ncp, j) = (Py_Int32)(val<<16);

}

return rv;

}

static int

gcd(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;

int len, 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 (size != 1 && size != 2 && size != 4) {

PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");

return NULL;

}

if (nchannels < 1) {

PyErr_SetString(AudioopError, "# of channels should be >= 1");

return NULL;

}

bytes_per_frame = size * nchannels;

if (bytes_per_frame / nchannels != size) {

/* 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;

}

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;

prev_i = (int *) malloc(nchannels * sizeof(int));

cur_i = (int *) 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. */

{

/* 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. */

int ceiling; /* the number of output frames */

int nbytes; /* the number of output bytes needed */

int q = len / inrate;

/* Now len = q * inrate + r exactly (with r = len % inrate),

and this is less than q * inrate + inrate = (q+1)*inrate.

So a reasonable upper bound on len*outrate/inrate is

((q+1)*inrate)*outrate/inrate =

(q+1)*outrate.

*/

ceiling = (q+1) * outrate;

nbytes = ceiling * bytes_per_frame;

/* See whether anything overflowed; if not, get the space. */

if (q+1 < 0 ||

ceiling / outrate != q+1 ||

nbytes / bytes_per_frame != ceiling)

str = NULL;