diff options
Diffstat (limited to 'busybox/coreutils/cmp.c')
| -rw-r--r-- | busybox/coreutils/cmp.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/busybox/coreutils/cmp.c b/busybox/coreutils/cmp.c new file mode 100644 index 0000000..d0fc662 --- /dev/null +++ b/busybox/coreutils/cmp.c @@ -0,0 +1,152 @@ +/* vi: set sw=4 ts=4: */ +/* + * Mini cmp implementation for busybox + * + * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */ +/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */ + +/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) + * + * Original version majorly reworked for SUSv3 compliance, bug fixes, and + * size optimizations. Changes include: + * 1) Now correctly distinguishes between errors and actual file differences. + * 2) Proper handling of '-' args. + * 3) Actual error checking of i/o. + * 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format + * in the '-l' case. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include "busybox.h" + +static FILE *cmp_xfopen_input(const char *filename) +{ + FILE *fp; + + if ((fp = bb_wfopen_input(filename)) != NULL) { + return fp; + } + + exit(bb_default_error_retval); /* We already output an error message. */ +} + +static const char fmt_eof[] = "cmp: EOF on %s\n"; +static const char fmt_differ[] = "%s %s differ: char %d, line %d\n"; +#if 0 +static const char fmt_l_opt[] = "%.0s%.0s%d %o %o\n"; /* SUSv3 format */ +#else +static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n"; /* nicer gnu format */ +#endif + +static const char opt_chars[] = "sl"; + +enum { + OPT_s = 1, + OPT_l = 2 +}; + +int cmp_main(int argc, char **argv) +{ + FILE *fp1, *fp2, *outfile = stdout; + const char *filename1, *filename2; + const char *fmt; + int c1, c2, char_pos, line_pos; + int opt_flags; + int exit_val = 0; + + bb_default_error_retval = 2; /* 1 is returned if files are different. */ + + opt_flags = bb_getopt_ulflags(argc, argv, opt_chars); + + if ((opt_flags == 3) || (((unsigned int)(--argc - optind)) > 1)) { + bb_show_usage(); + } + + fp1 = cmp_xfopen_input(filename1 = *(argv += optind)); + + filename2 = "-"; + if (*++argv) { + filename2 = *argv; + } + fp2 = cmp_xfopen_input(filename2); + + if (fp1 == fp2) { /* Paranioa 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; + } + + fmt = fmt_differ; + if (opt_flags == OPT_l) { + fmt = fmt_l_opt; + } + + char_pos = 0; + line_pos = 1; + do { + c1 = getc(fp1); + c2 = getc(fp2); + ++char_pos; + if (c1 != c2) { /* Remember -- a read error may have occurred. */ + exit_val = 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) { + bb_xferror(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. */ + bb_xfflush_stdout(); + } + if (opt_flags != OPT_s) { + if (opt_flags == OPT_l) { + line_pos = c1; /* line_pos is unused in the -l case. */ + } + bb_fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); + if (opt_flags) { /* This must be -l since not -s. */ + /* If we encountered and EOF, the while check will catch it. */ + continue; + } + } + break; + } + if (c1 == '\n') { + ++line_pos; + } + } while (c1 != EOF); + + bb_xferror(fp1, filename1); + bb_xferror(fp2, filename2); + + bb_fflush_stdout_and_exit(exit_val); +} |