130 lines
2.2 KiB
C
130 lines
2.2 KiB
C
#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#define BUFFER 4096
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static int do_open(const char *name)
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{
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int fd;
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fd = open(name, O_RDONLY);
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if (fd >= 0)
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return fd;
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perror(name);
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exit(1);
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}
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static void usage(const char *name)
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{
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fprintf(stderr,
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"usage: %s [-w|-l] [-B] file1 file2\n"
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" -w compare words (16 bits; default is bytes)\n"
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" -l compare long words (32 bits; default is bytes)\n"
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" -B use big-endian (default: little-endian)\n"
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, name);
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exit(1);
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}
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int main(int argc, char *const *argv)
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{
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int little = 1;
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int bytes = 1;
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int c;
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int fd1, fd2;
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const char *name1, *name2;
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uint8_t buf1[BUFFER], buf2[BUFFER];
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ssize_t got1, got2, len;
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uint32_t a, b;
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int i, j;
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static unsigned bin[32][2];
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while ((c = getopt(argc, argv, "Blw")) != EOF) {
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switch (c) {
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case 'B':
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little = 0;
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break;
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case 'l':
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bytes = 4;
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break;
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case 'w':
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bytes = 2;
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break;
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default:
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usage(*argv);
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}
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}
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if (argc-optind != 2)
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usage(*argv);
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name1 = argv[optind];
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name2 = argv[optind+1];
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fd1 = do_open(name1);
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fd2 = do_open(name2);
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while (1) {
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memset(buf1, 0, BUFFER);
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memset(buf2, 0, BUFFER);
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got1 = read(fd1, buf1, BUFFER);
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if (got1 < 0) {
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perror(name1);
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return 1;
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}
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got2 = read(fd2, buf2, BUFFER);
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if (got2 < 0) {
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perror(name2);
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return 1;
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}
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if (got1 != got2)
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fprintf(stderr, "%s < %s\n",
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got1 < got2 ? name1 : name2,
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got1 < got2 ? name2 : name1);
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len = got1 < got2 ? got1 : got2;
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if (!len)
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break;
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for (i = 0; i < len; i += bytes) {
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a = b = 0;
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switch (bytes) {
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case 4:
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a |= buf1[i+2] << 16;
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b |= buf2[i+2] << 16;
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a |= buf1[i+3] << 24;
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b |= buf2[i+3] << 24;
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/* fall through */
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case 2:
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a |= buf1[i+1] << 8;
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b |= buf2[i+1] << 8;
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/* fall through */
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case 1:
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a |= buf1[i];
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b |= buf2[i];
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break;
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default:
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abort();
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}
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for (j = 0; j != 32; j++)
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if ((a ^ b) & (1 << j))
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bin[j][(b >> j) & 1]++;
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}
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}
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for (j = 0; j != 8*bytes; j++) {
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if (little)
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i = j;
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else
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i = 8*(bytes-1-(j >> 3))+(j & 7);
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if (bin[i][0] || bin[i][1])
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printf("%2d: %u %u\n", j, bin[i][0], bin[i][1]);
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}
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return 0;
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}
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