107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
/*
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* PostScript filter functions
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*
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* Copyright 2003 Huw D M Davies
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
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#include "psdrv.h"
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DWORD RLE_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
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{
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BYTE *next_in = in_buf, *next_out = out_buf;
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DWORD rl;
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while(next_in < in_buf + len) {
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if(next_in + 1 < in_buf + len) {
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if(*next_in == *(next_in + 1)) {
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next_in += 2;
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rl = 2;
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while(next_in < in_buf + len && *next_in == *(next_in - 1) && rl < 128) {
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next_in++;
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rl++;
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}
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*next_out++ = 257 - rl;
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*next_out++ = *(next_in - 1);
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} else {
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rl = 0;
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next_out++;
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while(next_in < in_buf + len && rl < 128) {
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if(next_in + 2 < in_buf + len && *next_in == *(next_in + 1)) {
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if(rl == 127 || *next_in == *(next_in + 2))
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break;
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}
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*next_out++ = *next_in++;
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rl++;
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}
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*(next_out - rl - 1) = rl - 1;
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}
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} else { /* special case: begin of run on last byte */
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*next_out++ = 0;
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*next_out++ = *next_in;
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break;
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}
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}
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*next_out++ = 128;
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return next_out - out_buf;
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}
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DWORD ASCII85_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
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{
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DWORD number;
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BYTE *next_in = in_buf, *next_out = out_buf;
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int i;
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while(next_in + 3 < in_buf + len) {
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number = (next_in[0] << 24) |
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(next_in[1] << 16) |
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(next_in[2] << 8) |
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(next_in[3] );
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next_in += 4;
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if(number == 0)
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*next_out++ = 'z';
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else {
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for(i = 4; i >= 0; i--) {
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next_out[i] = number % 85 + '!';
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number /= 85;
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}
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next_out += 5;
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}
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}
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if(next_in != in_buf + len) {
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number = (*next_in++ << 24) & 0xff000000;
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if(next_in < in_buf + len)
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number |= ((*next_in++ << 16) & 0x00ff0000);
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if(next_in < in_buf + len)
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number |= ((*next_in++ << 8) & 0x0000ff00);
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for(i = len % 4 + 1; i < 5; i++)
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number /= 85;
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for(i = len % 4; i >= 0; i--) {
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next_out[i] = number % 85 + '!';
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number /= 85;
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}
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next_out += len % 4 + 1;
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}
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return next_out - out_buf;
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}
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