106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* make_t43_gray_code_tables.c - Generate the Gray code tables for T.43 image
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* compression.
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2012 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2, as
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* published by the Free Software Foundation.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <inttypes.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <memory.h>
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#include <math.h>
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int main(int argc, char *argv[])
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{
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int i;
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int j;
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int gray;
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int new_gray;
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int restore;
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printf("/* THIS FILE WAS AUTOMATICALLY GENERATED - ANY MODIFICATIONS MADE TO THIS");
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printf(" FILE MAY BE OVERWRITTEN DURING FUTURE BUILDS OF THE SOFTWARE */\n");
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printf("\n");
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printf("static const int16_t gray_code[4096] =\n{\n");
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for (i = 0; i < 4096; i++)
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{
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gray = i & 0x800;
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restore = i;
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for (j = 10; j >= 0; j--)
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{
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if (((i >> (j + 1)) & 1) ^ ((i >> j) & 1))
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gray |= (1 << j);
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}
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printf(" 0x%04x, /* 0x%04x */\n", gray, restore);
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/* Now reverse the process and check we get back where we start */
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restore = gray & 0x800;
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for (j = 10; j >= 0; j--)
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{
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if (((restore >> (j + 1)) & 1) ^ ((gray >> j) & 1))
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restore |= (1 << j);
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}
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if (i != restore)
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{
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printf("Ah\n");
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exit(2);
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}
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}
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printf("};\n\n");
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printf("static const int16_t anti_gray_code[4096] =\n{\n");
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for (i = 0; i < 4096; i++)
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{
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gray = i;
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restore = gray & 0x800;
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for (j = 10; j >= 0; j--)
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{
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if (((restore >> (j + 1)) & 1) ^ ((gray >> j) & 1))
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restore |= (1 << j);
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}
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printf(" 0x%04x, /* 0x%04x */\n", restore, gray);
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/* Now reverse the process and check we get back where we start */
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new_gray = restore & 0x800;
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for (j = 10; j >= 0; j--)
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{
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if (((restore >> (j + 1)) & 1) ^ ((restore >> j) & 1))
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new_gray |= (1 << j);
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}
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if (gray != new_gray)
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{
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printf("Ah\n");
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exit(2);
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}
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}
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printf("};\n");
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return 0;
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}
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/*- End of function --------------------------------------------------------*/
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/*- End of file ------------------------------------------------------------*/
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