72 строки
2.1 KiB
C
72 строки
2.1 KiB
C
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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const int MOD_ADLER = 65521;
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uint64_t adler32(unsigned char *data, int32_t len) /* where data is the location of the data in physical memory and
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len is the length of the data in bytes */
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{
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uint64_t a = 1, b = 0;
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int32_t index;
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/* Process each byte of the data in order */
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for (index = 0; index < len; ++index)
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{
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a = (a + data[index]) % MOD_ADLER;
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b = (b + a) % MOD_ADLER;
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}
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return (b << 16) | a;
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}
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int main(int argc, char* argv[]) {
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long bufsize;
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if (argc != 2) {
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fputs("Need 1 argument\n", stderr);
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return (EXIT_FAILURE);
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}
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unsigned char *source = NULL;
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FILE *fp = fopen(argv[1], "rb");
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if (fp != NULL) {
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/* Go to the end of the file. */
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if (fseek(fp, 0L, SEEK_END) == 0) {
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/* Get the size of the file. */
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bufsize = ftell(fp);
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if (bufsize == -1) { fputs("Couldn't get size\n", stderr); return (EXIT_FAILURE); }
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/* Allocate our buffer to that size. */
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source = malloc(sizeof(char) * (bufsize + 1));
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if (source == NULL) { fputs("Couldn't allocate\n", stderr); return (EXIT_FAILURE); }
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/* Go back to the start of the file. */
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if (fseek(fp, 0L, SEEK_SET) == -1) { fputs("Couldn't seek\n", stderr); return (EXIT_FAILURE); }
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/* Read the entire file into memory. */
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size_t newLen = fread(source, sizeof(char), bufsize, fp);
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if (newLen == 0) {
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fputs("Error reading file\n", stderr);
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//return (EXIT_FAILURE);
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} else {
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source[++newLen] = '\0'; /* Just to be safe. */
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}
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} else {
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fputs("Couldn't seek to end\n", stderr);
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return (EXIT_FAILURE);
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}
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fclose(fp);
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} else {
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fputs("Couldn't open\n", stderr);
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return (EXIT_FAILURE);
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}
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printf("%d\n", (uint32_t) adler32(source, bufsize));
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free(source); /* Don't forget to call free() later! */
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return (EXIT_SUCCESS);
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}
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