130 lines
2.3 KiB
C
130 lines
2.3 KiB
C
/* cmp - compare two files Author: Kees J. Bot. */
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#include <sys/types.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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void fatal(char *label);
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int cmp(int fd1, int fd2);
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void Usage(void);
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int main(int argc, char **argv);
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#define BLOCK 4096
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static int loud = 0, silent = 0;
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static char *name1, *name2;
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int main(argc, argv)
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int argc;
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char **argv;
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{
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int fd1, fd2;
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/* Process the '-l' or '-s' option. */
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while (argc > 1 && argv[1][0] == '-' && argv[1][1] != 0) {
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if (argv[1][2] != 0) Usage();
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switch (argv[1][1]) {
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case '-':
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/* '--': no-op option. */
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break;
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case 'l':
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loud = 1;
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break;
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case 's':
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silent = 1;
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break;
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default:
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Usage();
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}
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argc--;
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argv++;
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}
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if (argc != 3) Usage();
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/* Open the first file, '-' means standard input. */
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if (argv[1][0] == '-' && argv[1][1] == 0) {
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name1 = "stdin";
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fd1 = 0;
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} else {
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name1 = argv[1];
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if ((fd1 = open(name1, 0)) < 0) fatal(name1);
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}
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/* Second file likewise. */
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if (argv[2][0] == '-' && argv[2][1] == 0) {
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name2 = "stdin";
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fd2 = 0;
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} else {
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name2 = argv[2];
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if ((fd2 = open(name2, 0)) < 0) fatal(name2);
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}
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exit(cmp(fd1, fd2));
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}
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int cmp(fd1, fd2)
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int fd1, fd2;
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{
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static char buf1[BLOCK], buf2[BLOCK];
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int n1 = 0, n2 = 0, i1 = 0, i2 = 0, c1, c2;
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off_t pos = 0, line = 1;
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int eof = 0, differ = 0;
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for (;;) {
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if (i1 == n1) {
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pos += n1;
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if ((n1 = read(fd1, buf1, sizeof(buf1))) <= 0) {
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if (n1 < 0) fatal(name1);
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eof |= 1;
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}
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i1 = 0;
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}
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if (i2 == n2) {
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if ((n2 = read(fd2, buf2, sizeof(buf2))) <= 0) {
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if (n2 < 0) fatal(name2);
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eof |= 2;
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}
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i2 = 0;
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}
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if (eof != 0) break;
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c1 = buf1[i1++];
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c2 = buf2[i2++];
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if (c1 != c2) {
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if (!loud) {
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if (!silent) {
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printf("%s %s differ: char %d, line %d\n",
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name1, name2, pos + i1, line);
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}
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return(1);
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}
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printf("%10d %3o %3o\n", pos + i1, c1 & 0xFF, c2 & 0xFF);
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differ = 1;
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}
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if (c1 == '\n') line++;
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}
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if (eof == (1 | 2)) return(differ);
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if (!silent) fprintf(stderr, "cmp: EOF on %s\n", eof == 1 ? name1 : name2);
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return(1);
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}
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void fatal(label)
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char *label;
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{
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if (!silent) fprintf(stderr, "cmp: %s: %s\n", label, strerror(errno));
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exit(2);
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}
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void Usage()
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{
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fprintf(stderr, "Usage: cmp [-l | -s] file1 file2\n");
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exit(2);
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}
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