137 lines
3.0 KiB
C
137 lines
3.0 KiB
C
/*
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* Copyright (C) 2012 Alexey Galakhov
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as 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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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stddef.h>
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#include <errno.h>
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#define DEFAULT_BUF_SIZE 8192
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static int usage(const char* me)
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{
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printf("Usage: %s <input> <output> [<bufsize]\n", me);
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return 1;
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}
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static void put32(uint8_t *ptr, uint32_t value)
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{
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ptr[0] = value & 0xFF;
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ptr[1] = (value >> 8) & 0xFF;
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ptr[2] = (value >> 16) & 0xFF;
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ptr[3] = (value >> 24) & 0xFF;
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}
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static size_t safe_fread(void *buf, size_t len, FILE* file)
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{
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size_t rd = fread(buf, 1, len, file);
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if (! rd) {
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if (ferror(file))
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fprintf(stderr, "Error reading file: %s\n", strerror(errno));
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else
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fprintf(stderr, "Unexpected end of file\n");
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}
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return rd;
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}
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static size_t safe_fwrite(const void *buf, size_t len, FILE* file)
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{
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size_t wr = fwrite(buf, 1, len, file);
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if (wr != len) {
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fprintf(stderr, "Error writing file: %s\n", strerror(errno));
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return 0;
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}
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return wr;
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}
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static int process(FILE *input, FILE *output, uint8_t *buf, unsigned bufsize)
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{
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size_t rd;
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unsigned i;
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uint32_t cksum;
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/* Read first chunk */
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rd = safe_fread(buf + 16, bufsize - 16, input);
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if (! rd)
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return 4;
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/* Calculate header */
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put32(buf + 0, bufsize);
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cksum = 0;
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for (i = 16; i < bufsize; ++i)
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cksum += (uint32_t)buf[i];
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put32(buf + 8, cksum);
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if (! safe_fwrite(buf, bufsize, output))
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return 4;
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/* Copy the rest of file */
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while (! feof(input)) {
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rd = safe_fread(buf, bufsize, input);
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if (! rd)
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return 4;
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if (! safe_fwrite(buf, rd, output))
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return 4;
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}
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return 0;
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}
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static int work(const char* me, const char *infile, const char *outfile, unsigned bufsize)
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{
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uint8_t *buf;
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FILE *input;
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FILE *output;
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int ret;
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if (bufsize < 512 || bufsize > 65536)
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return usage(me);
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buf = calloc(1, bufsize);
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if (! buf) {
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fprintf(stderr, "Unable to allocate %u bytes of memory\n", bufsize);
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return 2;
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}
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input = fopen(infile, "r");
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if (! input) {
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fprintf(stderr, "Cannot open `%s' for reading\n", infile);
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free(buf);
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return 3;
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}
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output = fopen(outfile, "w");
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if (! output) {
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fprintf(stderr, "Cannot open `%s' for writing\n", outfile);
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fclose(input);
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free(buf);
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return 3;
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}
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ret = process(input, output, buf, bufsize);
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fclose(output);
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fclose(input);
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free(buf);
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return ret;
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}
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int main(int argc, char** argv)
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{
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switch (argc) {
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case 3:
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return work(argv[0], argv[1], argv[2], DEFAULT_BUF_SIZE);
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case 4:
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return work(argv[0], argv[1], argv[2], atoi(argv[3]));
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default:
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return usage(argv[0]);
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}
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}
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