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/*
* Copyright (C) 1998, 1999, 2002 by Bernhard Herzog.
*
* All Rights Reserved
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of the author not be
* used in advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
*
* THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <ctype.h>
#include "hexfilter.h"
#define FBUFLEN 1024
/*
* Hex Encode
*/
typedef struct {
int column;
int maxcolumn;
} HexEncodeState;
static size_t
write_hex(void* clientdata, PyObject * target, const char * buf, size_t length)
{
static char * hexdigits = "0123456789abcdef";
HexEncodeState * state = (HexEncodeState*)clientdata;
int i, todo = length, chunk, maxbinary;
char encoded[FBUFLEN];
char * dest;
/* Estimate the number of unencoded bytes that fit into the buffer
* in encoded form. Each encoded line will have state->maxcolumn + 1
* characters which represent state->maxcolumn / 2 binary bytes.
*/
/* assume that state->maxcolumn is even */
maxbinary = (FBUFLEN / (state->maxcolumn + 1)) * (state->maxcolumn / 2);
if (maxbinary == 0)
/* for small FBUFLEN or large maxcolumn */
maxbinary = FBUFLEN / 3;
if (todo > maxbinary)
chunk = maxbinary;
else
chunk = todo;
for (i = 0, dest = encoded; i < chunk; i++, buf++)
{
*dest++ = hexdigits[(int)((*buf & 0xF0) >> 4)];
*dest++ = hexdigits[(int)(*buf & 0x0F)];
state->column += 2;
if (state->column >= state->maxcolumn)
{
*dest++ = '\n';
state->column = 0;
}
}
if (Filter_Write(target, encoded, dest - encoded) < 0)
return 0;
return chunk;
}
static int
close_hex(void * clientdata, PyObject * target)
{
if (((HexEncodeState*)clientdata)->column > 0)
{
if (Filter_Write(target, "\n", 1) == 0)
return EOF;
}
return 0;
}
PyObject *
Filter_HexEncode(PyObject * self, PyObject * args)
{
PyObject * target;
HexEncodeState * state;
int maxcolumn = 72;
if (!PyArg_ParseTuple(args, "O|i", &target, &maxcolumn))
return NULL;
state = malloc(sizeof(HexEncodeState));
if (!state)
return PyErr_NoMemory();
state->maxcolumn = maxcolumn - (maxcolumn & 1);
state->column = 0;
return Filter_NewEncoder(target, "HexEncode", 0, write_hex, close_hex,
free, state);
}
/*
* Hex Decode
*/
typedef struct {
int last_digit;
} HexDecodeState;
static size_t
read_hex(void * clientdata, PyObject * source, char * buf, size_t length)
{
size_t i, srclen, bytesread;
char encoded[FBUFLEN];
char *dest = buf;
HexDecodeState * state = (HexDecodeState*)clientdata;
int last_digit = state->last_digit;
if (2 * length > FBUFLEN)
srclen = FBUFLEN;
else
srclen = 2 * length;
bytesread = Filter_Read(source, encoded, srclen);
if (bytesread == 0)
{
/* end of file or data */
if (state->last_digit >= 0)
{
/* assume a trailing 0 (this is the PostScript filter behaviour */
*((unsigned char*)dest) = state->last_digit * 16;
return 1;
}
return 0;
}
for (i = 0; i < bytesread; i++)
{
if (isxdigit(encoded[i]))
{
int digit = ((unsigned char*)encoded)[i];
if ('0' <= digit && digit <= '9')
{
digit = digit - '0';
}
else if ('a' <= digit && digit <= 'f')
{
digit = digit - 'a' + 10;
}
else if ('A' <= digit && digit <= 'F')
{
digit = digit - 'A' + 10;
}
if (last_digit >= 0)
{
*((unsigned char*)dest) = last_digit * 16 + digit;
last_digit = -1;
dest += 1;
}
else
{
last_digit = digit;
}
}
/* else maybe raise error if not whitespace */
}
state->last_digit = last_digit;
return dest - buf;
}
PyObject *
Filter_HexDecode(PyObject * self, PyObject * args)
{
PyObject * source;
HexDecodeState * state;
if (!PyArg_ParseTuple(args, "O", &source))
return NULL;
state = malloc(sizeof(HexDecodeState));
if (!state)
return PyErr_NoMemory();
state->last_digit = -1;
return Filter_NewDecoder(source, "HexDecode", 0, read_hex, NULL, free,
state);
}
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