/* imageopmodule - Various operations on pictures */

#ifdef sun

#define signed

#endif

#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

#define CHARP(cp, xmax, x, y) ((char *)(cp+y*xmax+x))

#define SHORTP(cp, xmax, x, y) ((short *)(cp+2*(y*xmax+x)))

#define LONGP(cp, xmax, x, y) ((Py_Int32 *)(cp+4*(y*xmax+x)))

static PyObject *ImageopError;

static PyObject *ImageopDict;

/**

 * Check a coordonnate, make sure that (0 < value).

 * Return 0 on error.

 */

static int

check_coordonnate(int value, const char* name)

{

	if ( 0 < value)

		return 1;

	PyErr_Format(PyExc_ValueError, "%s value is negative or nul", name);

	return 0;

}

/**

 * Check integer overflow to make sure that product == x*y*size.

 * Return 0 on error.

 */

static int

check_multiply_size(int product, int x, const char* xname, int y, const char* yname, int size)

{

	if ( !check_coordonnate(x, xname) )

		return 0;

	if ( !check_coordonnate(y, yname) )

		return 0;

	if ( size == (product / y) / x )

		return 1;

	PyErr_SetString(ImageopError, "String has incorrect length");

	return 0;

}

/**

 * Check integer overflow to make sure that product == x*y.

 * Return 0 on error.

 */

static int

check_multiply(int product, int x, int y)

{

	return check_multiply_size(product, x, "x", y, "y", 1);

}

/* If this function returns true (the default if anything goes wrong), we're

   behaving in a backward-compatible way with respect to how multi-byte pixels

   are stored in the strings.  The code in this module was originally written

   for an SGI which is a big-endian system, and so the old code assumed that

   4-byte integers hold the R, G, and B values in a particular order.

   However, on little-endian systems the order is reversed, and so not

   actually compatible with what gl.lrectwrite and imgfile expect.

   (gl.lrectwrite and imgfile are also SGI-specific, however, it is

   conceivable that the data handled here comes from or goes to an SGI or that

   it is otherwise used in the expectation that the byte order in the strings

   is as specified.)

   The function returns the value of the module variable

   "backward_compatible", or 1 if the variable does not exist or is not an

   int.

 */

static int

imageop_backward_compatible(void)

{

	static PyObject *bcos;

	PyObject *bco;

	long rc;

	if (ImageopDict == NULL) /* "cannot happen" */

		return 1;

	if (bcos == NULL) {

		/* cache string object for future use */

		bcos = PyString_FromString("backward_compatible");

		if (bcos == NULL)

			return 1;

	}

	bco = PyDict_GetItem(ImageopDict, bcos);

	if (bco == NULL)

		return 1;

	if (!PyInt_Check(bco))

		return 1;

	rc = PyInt_AsLong(bco);

	if (PyErr_Occurred()) {

		/* not an integer, or too large, or something */

		PyErr_Clear();

		rc = 1;

	}

	return rc != 0;		/* convert to values 0, 1 */

}

static PyObject *

imageop_crop(PyObject *self, PyObject *args)

{

	char *cp, *ncp;

	short *nsp;

	Py_Int32 *nlp;

	int len, size, x, y, newx1, newx2, newy1, newy2, nlen;

	int ix, iy, xstep, ystep;

	PyObject *rv;

	if ( !PyArg_ParseTuple(args, "s#iiiiiii", &cp, &len, &size, &x, &y,

			  &newx1, &newy1, &newx2, &newy2) )

		return 0;

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

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

		return 0;

	}

	if ( !check_multiply_size(len, x, "x", y, "y", size) )

		return 0;

	xstep = (newx1 < newx2)? 1 : -1;

	ystep = (newy1 < newy2)? 1 : -1;

        nlen = (abs(newx2-newx1)+1)*(abs(newy2-newy1)+1)*size;

	if ( !check_multiply_size(nlen, abs(newx2-newx1)+1, "abs(newx2-newx1)+1", abs(newy2-newy1)+1, "abs(newy2-newy1)+1", size) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, nlen);

	if ( rv == 0 )

		return 0;

	ncp = (char *)PyString_AsString(rv);

	nsp = (short *)ncp;

	nlp = (Py_Int32 *)ncp;

	newy2 += ystep;

	newx2 += xstep;

	for( iy = newy1; iy != newy2; iy+=ystep ) {

		for ( ix = newx1; ix != newx2; ix+=xstep ) {

			if ( iy < 0 || iy >= y || ix < 0 || ix >= x ) {

				if ( size == 1 )

					*ncp++ = 0;

				else

					*nlp++ = 0;

			} else {

				if ( size == 1 )

					*ncp++ = *CHARP(cp, x, ix, iy);

				else if ( size == 2 )

					*nsp++ = *SHORTP(cp, x, ix, iy);

				else

					*nlp++ = *LONGP(cp, x, ix, iy);

			}

		}

	}

	return rv;

}

static PyObject *

imageop_scale(PyObject *self, PyObject *args)

{

	char *cp, *ncp;

	short *nsp;

	Py_Int32 *nlp;

	int len, size, x, y, newx, newy, nlen;

	int ix, iy;

	int oix, oiy;

	PyObject *rv;

	if ( !PyArg_ParseTuple(args, "s#iiiii",

			  &cp, &len, &size, &x, &y, &newx, &newy) )

		return 0;

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

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

		return 0;

	}

	if ( !check_multiply_size(len, x, "x", y, "y", size) )

		return 0;

        nlen = newx*newy*size;

	if ( !check_multiply_size(nlen, newx, "newx", newy, "newy", size) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, nlen);

	if ( rv == 0 )

		return 0;

	ncp = (char *)PyString_AsString(rv);

	nsp = (short *)ncp;

	nlp = (Py_Int32 *)ncp;

	for( iy = 0; iy < newy; iy++ ) {

		for ( ix = 0; ix < newx; ix++ ) {

			oix = ix * x / newx;

			oiy = iy * y / newy;

			if ( size == 1 )

				*ncp++ = *CHARP(cp, x, oix, oiy);

			else if ( size == 2 )

				*nsp++ = *SHORTP(cp, x, oix, oiy);

			else

				*nlp++ = *LONGP(cp, x, oix, oiy);

		}

	}

	return rv;

}

/* Note: this routine can use a bit of optimizing */

static PyObject *

imageop_tovideo(PyObject *self, PyObject *args)

{

	int maxx, maxy, x, y, len;

	int i;

	unsigned char *cp, *ncp;

	int width;

	PyObject *rv;

	if ( !PyArg_ParseTuple(args, "s#iii", &cp, &len, &width, &maxx, &maxy) )

		return 0;

	if ( width != 1 && width != 4 ) {

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

		return 0;

	}

	if ( !check_multiply_size(len, maxx, "max", maxy, "maxy", width) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, len);

	if ( rv == 0 )

		return 0;

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

	if ( width == 1 ) {

		memcpy(ncp, cp, maxx);		/* Copy first line */

		ncp += maxx;

		for (y=1; y<maxy; y++) {	/* Interpolate other lines */

			for(x=0; x<maxx; x++) {

				i = y*maxx + x;

				*ncp++ = ((int)cp[i] + (int)cp[i-maxx]) >> 1;

			}

		}

	} else {

		memcpy(ncp, cp, maxx*4);		/* Copy first line */

		ncp += maxx*4;

		for (y=1; y<maxy; y++) {	/* Interpolate other lines */

			for(x=0; x<maxx; x++) {

				i = (y*maxx + x)*4 + 1;

				*ncp++ = 0;	/* Skip alfa comp */

				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;

				i++;

				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;

				i++;

				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;

			}

		}

	}

	return rv;

}

static PyObject *

imageop_grey2mono(PyObject *self, PyObject *args)

{

	int tres, x, y, len;

	unsigned char *cp, *ncp;

	unsigned char ovalue;

	PyObject *rv;

	int i, bit;

	if ( !PyArg_ParseTuple(args, "s#iii", &cp, &len, &x, &y, &tres) )

		return 0;

	if ( !check_multiply(len, x, y) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, (len+7)/8);

	if ( rv == 0 )

		return 0;

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

	bit = 0x80;

	ovalue = 0;

	for ( i=0; i < len; i++ ) {

		if ( (int)cp[i] > tres )

			ovalue |= bit;

		bit >>= 1;

		if ( bit == 0 ) {

			*ncp++ = ovalue;

			bit = 0x80;

			ovalue = 0;

		}

	}

	if ( bit != 0x80 )

		*ncp++ = ovalue;

	return rv;

}

static PyObject *

imageop_grey2grey4(PyObject *self, PyObject *args)

{

	int x, y, len;

	unsigned char *cp, *ncp;

	unsigned char ovalue;

	PyObject *rv;

	int i;

	int pos;

	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )

		return 0;

	if ( !check_multiply(len, x, y) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, (len+1)/2);

	if ( rv == 0 )

		return 0;

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

	pos = 0;

	ovalue = 0;

	for ( i=0; i < len; i++ ) {

		ovalue |= ((int)cp[i] & 0xf0) >> pos;

		pos += 4;

		if ( pos == 8 ) {

			*ncp++ = ovalue;

			ovalue = 0;

			pos = 0;

		}

	}

	if ( pos != 0 )

		*ncp++ = ovalue;

	return rv;

}

static PyObject *

imageop_grey2grey2(PyObject *self, PyObject *args)

{

	int x, y, len;

	unsigned char *cp, *ncp;

	unsigned char ovalue;

	PyObject *rv;

	int i;

	int pos;

	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )

		return 0;

	if ( !check_multiply(len, x, y) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, (len+3)/4);

	if ( rv == 0 )

		return 0;

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

	pos = 0;

	ovalue = 0;

	for ( i=0; i < len; i++ ) {

		ovalue |= ((int)cp[i] & 0xc0) >> pos;

		pos += 2;

		if ( pos == 8 ) {

			*ncp++ = ovalue;

			ovalue = 0;

			pos = 0;

		}

	}

	if ( pos != 0 )

		*ncp++ = ovalue;

	return rv;

}

static PyObject *

imageop_dither2mono(PyObject *self, PyObject *args)

{

	int sum, x, y, len;

	unsigned char *cp, *ncp;

	unsigned char ovalue;

	PyObject *rv;

	int i, bit;

	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )

		return 0;

	if ( !check_multiply(len, x, y) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, (len+7)/8);

	if ( rv == 0 )

		return 0;

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

	bit = 0x80;

	ovalue = 0;

	sum = 0;

	for ( i=0; i < len; i++ ) {

		sum += cp[i];

		if ( sum >= 256 ) {

			sum -= 256;

			ovalue |= bit;

		}

		bit >>= 1;

		if ( bit == 0 ) {

			*ncp++ = ovalue;

			bit = 0x80;

			ovalue = 0;

		}

	}

	if ( bit != 0x80 )

		*ncp++ = ovalue;

	return rv;

}

static PyObject *

imageop_dither2grey2(PyObject *self, PyObject *args)

{

	int x, y, len;

	unsigned char *cp, *ncp;

	unsigned char ovalue;

	PyObject *rv;

	int i;

	int pos;

	int sum = 0, nvalue;

	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )

		return 0;

	if ( !check_multiply(len, x, y) )

		return 0;

	rv = PyString_FromStringAndSize(NULL, (len+3)/4);

	if ( rv == 0 )

		return 0;

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

	pos = 1;

	ovalue = 0;

	for ( i=0; i < len; i++ ) {

		sum += cp[i];

		nvalue = sum & 0x180;

		sum -= nvalue;

		ovalue |= nvalue >> pos;

		pos += 2;

		if ( pos == 9 ) {

			*ncp++ = ovalue;

			ovalue = 0;

			pos = 1;

		}

	}

	if ( pos != 0 )

		*ncp++ = ovalue;

	return rv;

}

static PyObject *

imageop_mono2grey(PyObject *self, PyObject *args)

{

	int v0, v1, x, y, len, nlen;

	unsigned char *cp, *ncp;

	PyObject *rv;

	int i, bit;

	if ( !PyArg_ParseTuple(args, "s#iiii", &cp, &len, &x, &y, &v0, &v1) )

		return 0;

        nlen = x*y;

	if ( !check_multiply(nlen, x, y) )

		return 0;

	if ( (nlen+7)/8 != len ) {

		PyErr_SetString(ImageopError, "String has incorrect length");

		return 0;

	}

	rv = PyString_FromStringAndSize(NULL, nlen);

	if ( rv == 0 )

		return 0;

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

	bit = 0x80;

	for ( i=0; i < nlen; i++ ) {

		if ( *cp & bit )

			*ncp++ = v1;

		else

			*ncp++ = v0;

		bit >>= 1;

		if ( bit == 0 ) {

			bit = 0x80;

			cp++;

		}

	}

	return rv;

}

static PyObject *

imageop_grey22grey(PyObject *self, PyObject *args)

{

	int x, y, len, nlen;

	unsigned char *cp, *ncp;

	PyObject *rv;

	int i, pos, value = 0, nvalue;

	if ( !PyArg_ParseTuple(args, "s#ii", &cp, &len, &x, &y) )

		return 0;

	nlen = x*y;

	if ( !check_multiply(nlen, x, y) ) {

		return 0;

	}

	if ( (nlen+3)/4 != len ) {

		PyErr_SetString(ImageopError, "String has incorrect length");

		return 0;

	}

	rv = PyString_FromStringAndSize(NULL, nlen);

	if ( rv == 0 )

		return 0;

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