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/* vi: set sw=4 ts=4: */
/*
* Mini cmp implementation for busybox
*
* Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config CMP
//config: bool "cmp (4.9 kb)"
//config: default y
//config: help
//config: cmp is used to compare two files and returns the result
//config: to standard output.
//applet:IF_CMP(APPLET(cmp, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_CMP) += cmp.o
//usage:#define cmp_trivial_usage
//usage: "[-ls] FILE1 [FILE2" IF_DESKTOP(" [SKIP1 [SKIP2]]") "]"
//usage:#define cmp_full_usage "\n\n"
//usage: "Compare FILE1 with FILE2 (or stdin)\n"
//usage: "\n -l Write the byte numbers (decimal) and values (octal)"
//usage: "\n for all differing bytes"
//usage: "\n -s Quiet"
/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
#include "libbb.h"
static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
#define OPT_STR "sl"
#define CMP_OPT_s (1<<0)
#define CMP_OPT_l (1<<1)
int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cmp_main(int argc UNUSED_PARAM, char **argv)
{
FILE *fp1, *fp2, *outfile = stdout;
const char *filename1, *filename2 = "-";
off_t skip1 = 0, skip2 = 0, char_pos = 0;
int line_pos = 1; /* Hopefully won't overflow... */
const char *fmt;
int c1, c2;
unsigned opt;
int retval = 0;
opt = getopt32(argv, "^"
OPT_STR
"\0" "-1"
IF_DESKTOP(":?4")
IF_NOT_DESKTOP(":?2")
":l--s:s--l"
);
argv += optind;
filename1 = *argv;
if (*++argv) {
filename2 = *argv;
if (ENABLE_DESKTOP && *++argv) {
skip1 = XATOOFF(*argv);
if (*++argv) {
skip2 = XATOOFF(*argv);
}
}
}
xfunc_error_retval = 2; /* missing file results in exitcode 2 */
if (opt & CMP_OPT_s)
logmode = 0; /* -s suppresses open error messages */
fp1 = xfopen_stdin(filename1);
fp2 = xfopen_stdin(filename2);
if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */
/* Note that we don't bother reading stdin. Neither does gnu wc.
* But perhaps we should, so that other apps down the chain don't
* get the input. Consider 'echo hello | (cmp - - && cat -)'.
*/
return 0;
}
logmode = LOGMODE_STDIO;
if (opt & CMP_OPT_l)
fmt = fmt_l_opt;
else
fmt = fmt_differ;
if (ENABLE_DESKTOP) {
while (skip1) { getc(fp1); skip1--; }
while (skip2) { getc(fp2); skip2--; }
}
do {
c1 = getc(fp1);
c2 = getc(fp2);
++char_pos;
if (c1 != c2) { /* Remember: a read error may have occurred. */
retval = 1; /* But assume the files are different for now. */
if (c2 == EOF) {
/* We know that fp1 isn't at EOF or in an error state. But to
* save space below, things are setup to expect an EOF in fp1
* if an EOF occurred. So, swap things around.
*/
fp1 = fp2;
filename1 = filename2;
c1 = c2;
}
if (c1 == EOF) {
die_if_ferror(fp1, filename1);
fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
outfile = stderr;
/* There may have been output to stdout (option -l), so
* make sure we fflush before writing to stderr. */
fflush_all();
}
if (!(opt & CMP_OPT_s)) {
if (opt & CMP_OPT_l) {
line_pos = c1; /* line_pos is unused in the -l case. */
}
fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
if (opt) { /* This must be -l since not -s. */
/* If we encountered an EOF,
* the while check will catch it. */
continue;
}
}
break;
}
if (c1 == '\n') {
++line_pos;
}
} while (c1 != EOF);
die_if_ferror(fp1, filename1);
die_if_ferror(fp2, filename2);
fflush_stdout_and_exit(retval);
}
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