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129 lines
3.5 KiB
C
129 lines
3.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini cmp implementation for busybox
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*
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* Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
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/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
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*
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* Original version majorly reworked for SUSv3 compliance, bug fixes, and
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* size optimizations. Changes include:
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* 1) Now correctly distinguishes between errors and actual file differences.
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* 2) Proper handling of '-' args.
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* 3) Actual error checking of i/o.
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* 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format
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* in the '-l' case.
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*/
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#include "busybox.h"
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static FILE *cmp_xfopen_input(const char * const filename)
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{
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FILE *fp;
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fp = fopen_or_warn_stdin(filename);
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if (fp)
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return fp;
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exit(xfunc_error_retval); /* We already output an error message. */
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}
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static const char fmt_eof[] = "cmp: EOF on %s\n";
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static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
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// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n"
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static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
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static const char opt_chars[] = "sl";
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#define CMP_OPT_s (1<<0)
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#define CMP_OPT_l (1<<1)
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int cmp_main(int argc, char **argv);
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int cmp_main(int argc, char **argv)
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{
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FILE *fp1, *fp2, *outfile = stdout;
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const char *filename1, *filename2 = "-";
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const char *fmt;
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int c1, c2, char_pos = 0, line_pos = 1;
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unsigned opt;
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int retval = 0;
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xfunc_error_retval = 2; /* 1 is returned if files are different. */
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opt = getopt32(argc, argv, opt_chars);
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if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
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|| (((unsigned int)(--argc - optind)) > 1))
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bb_show_usage();
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fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
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if (*++argv) {
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filename2 = *argv;
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}
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fp2 = cmp_xfopen_input(filename2);
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if (fp1 == fp2) { /* Paranioa check... stdin == stdin? */
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/* Note that we don't bother reading stdin. Neither does gnu wc.
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* But perhaps we should, so that other apps down the chain don't
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* get the input. Consider 'echo hello | (cmp - - && cat -)'.
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*/
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return 0;
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}
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if (opt & CMP_OPT_l)
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fmt = fmt_l_opt;
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else
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fmt = fmt_differ;
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do {
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c1 = getc(fp1);
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c2 = getc(fp2);
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++char_pos;
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if (c1 != c2) { /* Remember: a read error may have occurred. */
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retval = 1; /* But assume the files are different for now. */
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if (c2 == EOF) {
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/* We know that fp1 isn't at EOF or in an error state. But to
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* save space below, things are setup to expect an EOF in fp1
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* if an EOF occurred. So, swap things around.
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*/
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fp1 = fp2;
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filename1 = filename2;
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c1 = c2;
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}
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if (c1 == EOF) {
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die_if_ferror(fp1, filename1);
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fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
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outfile = stderr;
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/* There may have been output to stdout (option -l), so
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* make sure we fflush before writing to stderr. */
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xfflush_stdout();
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}
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if (!(opt & CMP_OPT_s)) {
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if (opt & CMP_OPT_l) {
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line_pos = c1; /* line_pos is unused in the -l case. */
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}
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fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
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if (opt) { /* This must be -l since not -s. */
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/* If we encountered an EOF,
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* the while check will catch it. */
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continue;
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}
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}
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break;
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}
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if (c1 == '\n') {
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++line_pos;
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}
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} while (c1 != EOF);
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die_if_ferror(fp1, filename1);
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die_if_ferror(fp2, filename2);
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fflush_stdout_and_exit(retval);
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}
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