| [9] | 1 | /* cmp - compare two files Author: Kees J. Bot. */
|
|---|
| 2 |
|
|---|
| 3 | #include <sys/types.h>
|
|---|
| 4 | #include <fcntl.h>
|
|---|
| 5 | #include <stdlib.h>
|
|---|
| 6 | #include <unistd.h>
|
|---|
| 7 | #include <stdio.h>
|
|---|
| 8 | #include <string.h>
|
|---|
| 9 | #include <errno.h>
|
|---|
| 10 |
|
|---|
| 11 | _PROTOTYPE(void fatal, (char *label));
|
|---|
| 12 | _PROTOTYPE(int cmp, (int fd1, int fd2));
|
|---|
| 13 | _PROTOTYPE(void Usage, (void));
|
|---|
| 14 | _PROTOTYPE(int main, (int argc, char **argv));
|
|---|
| 15 |
|
|---|
| 16 | #define BLOCK 4096
|
|---|
| 17 |
|
|---|
| 18 | static int loud = 0, silent = 0;
|
|---|
| 19 | static char *name1, *name2;
|
|---|
| 20 |
|
|---|
| 21 | int main(argc, argv)
|
|---|
| 22 | int argc;
|
|---|
| 23 | char **argv;
|
|---|
| 24 | {
|
|---|
| 25 | int fd1, fd2;
|
|---|
| 26 |
|
|---|
| 27 | /* Process the '-l' or '-s' option. */
|
|---|
| 28 | while (argc > 1 && argv[1][0] == '-' && argv[1][1] != 0) {
|
|---|
| 29 | if (argv[1][2] != 0) Usage();
|
|---|
| 30 |
|
|---|
| 31 | switch (argv[1][1]) {
|
|---|
| 32 | case '-':
|
|---|
| 33 | /* '--': no-op option. */
|
|---|
| 34 | break;
|
|---|
| 35 | case 'l':
|
|---|
| 36 | loud = 1;
|
|---|
| 37 | break;
|
|---|
| 38 | case 's':
|
|---|
| 39 | silent = 1;
|
|---|
| 40 | break;
|
|---|
| 41 | default:
|
|---|
| 42 | Usage();
|
|---|
| 43 | }
|
|---|
| 44 | argc--;
|
|---|
| 45 | argv++;
|
|---|
| 46 | }
|
|---|
| 47 | if (argc != 3) Usage();
|
|---|
| 48 |
|
|---|
| 49 | /* Open the first file, '-' means standard input. */
|
|---|
| 50 | if (argv[1][0] == '-' && argv[1][1] == 0) {
|
|---|
| 51 | name1 = "stdin";
|
|---|
| 52 | fd1 = 0;
|
|---|
| 53 | } else {
|
|---|
| 54 | name1 = argv[1];
|
|---|
| 55 | if ((fd1 = open(name1, 0)) < 0) fatal(name1);
|
|---|
| 56 | }
|
|---|
| 57 |
|
|---|
| 58 | /* Second file likewise. */
|
|---|
| 59 | if (argv[2][0] == '-' && argv[2][1] == 0) {
|
|---|
| 60 | name2 = "stdin";
|
|---|
| 61 | fd2 = 0;
|
|---|
| 62 | } else {
|
|---|
| 63 | name2 = argv[2];
|
|---|
| 64 | if ((fd2 = open(name2, 0)) < 0) fatal(name2);
|
|---|
| 65 | }
|
|---|
| 66 |
|
|---|
| 67 | exit(cmp(fd1, fd2));
|
|---|
| 68 | }
|
|---|
| 69 |
|
|---|
| 70 | int cmp(fd1, fd2)
|
|---|
| 71 | int fd1, fd2;
|
|---|
| 72 | {
|
|---|
| 73 | static char buf1[BLOCK], buf2[BLOCK];
|
|---|
| 74 | int n1 = 0, n2 = 0, i1 = 0, i2 = 0, c1, c2;
|
|---|
| 75 | off_t pos = 0, line = 1;
|
|---|
| 76 | int eof = 0, differ = 0;
|
|---|
| 77 |
|
|---|
| 78 | for (;;) {
|
|---|
| 79 | if (i1 == n1) {
|
|---|
| 80 | pos += n1;
|
|---|
| 81 |
|
|---|
| 82 | if ((n1 = read(fd1, buf1, sizeof(buf1))) <= 0) {
|
|---|
| 83 | if (n1 < 0) fatal(name1);
|
|---|
| 84 | eof |= 1;
|
|---|
| 85 | }
|
|---|
| 86 | i1 = 0;
|
|---|
| 87 | }
|
|---|
| 88 | if (i2 == n2) {
|
|---|
| 89 | if ((n2 = read(fd2, buf2, sizeof(buf2))) <= 0) {
|
|---|
| 90 | if (n2 < 0) fatal(name2);
|
|---|
| 91 | eof |= 2;
|
|---|
| 92 | }
|
|---|
| 93 | i2 = 0;
|
|---|
| 94 | }
|
|---|
| 95 | if (eof != 0) break;
|
|---|
| 96 |
|
|---|
| 97 | c1 = buf1[i1++];
|
|---|
| 98 | c2 = buf2[i2++];
|
|---|
| 99 |
|
|---|
| 100 | if (c1 != c2) {
|
|---|
| 101 | if (!loud) {
|
|---|
| 102 | if (!silent) {
|
|---|
| 103 | printf("%s %s differ: char %ld, line %ld\n",
|
|---|
| 104 | name1, name2, pos + i1, line);
|
|---|
| 105 | }
|
|---|
| 106 | return(1);
|
|---|
| 107 | }
|
|---|
| 108 | printf("%10ld %3o %3o\n", pos + i1, c1 & 0xFF, c2 & 0xFF);
|
|---|
| 109 | differ = 1;
|
|---|
| 110 | }
|
|---|
| 111 | if (c1 == '\n') line++;
|
|---|
| 112 | }
|
|---|
| 113 | if (eof == (1 | 2)) return(differ);
|
|---|
| 114 | if (!silent) fprintf(stderr, "cmp: EOF on %s\n", eof == 1 ? name1 : name2);
|
|---|
| 115 | return(1);
|
|---|
| 116 | }
|
|---|
| 117 |
|
|---|
| 118 | void fatal(label)
|
|---|
| 119 | char *label;
|
|---|
| 120 | {
|
|---|
| 121 | if (!silent) fprintf(stderr, "cmp: %s: %s\n", label, strerror(errno));
|
|---|
| 122 | exit(2);
|
|---|
| 123 | }
|
|---|
| 124 |
|
|---|
| 125 | void Usage()
|
|---|
| 126 | {
|
|---|
| 127 | fprintf(stderr, "Usage: cmp [-l | -s] file1 file2\n");
|
|---|
| 128 | exit(2);
|
|---|
| 129 | }
|
|---|
