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Diffstat (limited to 'editors/cmp.c')
| -rw-r--r-- | editors/cmp.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/editors/cmp.c b/editors/cmp.c new file mode 100644 index 000000000..e5dda80ff --- /dev/null +++ b/editors/cmp.c @@ -0,0 +1,145 @@ +/* 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 tarball for details. + */ + +/* 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 "libbb.h" + +static FILE *cmp_xfopen_input(const char *filename) +{ + FILE *fp; + + fp = fopen_or_warn_stdin(filename); + if (fp) + return fp; + xfunc_die(); /* 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 %"OFF_FMT"d, line %d\n"; +// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"d %o %o\n" +static const char fmt_l_opt[] = "%.0s%.0s%"OFF_FMT"d %3o %3o\n"; + +static const char opt_chars[] = "sl"; +#define CMP_OPT_s (1<<0) +#define CMP_OPT_l (1<<1) + +int cmp_main(int argc, char **argv); +int cmp_main(int argc, char **argv) +{ + FILE *fp1, *fp2, *outfile = stdout; + const char *filename1, *filename2 = "-"; + USE_DESKTOP(off_t skip1 = 0, skip2 = 0;) + off_t char_pos = 0; + int line_pos = 1; /* Hopefully won't overflow... */ + const char *fmt; + int c1, c2; + unsigned opt; + int retval = 0; + + xfunc_error_retval = 2; /* 1 is returned if files are different. */ + + opt_complementary = "?:-1" + USE_DESKTOP(":?4") + SKIP_DESKTOP(":?2") + ":l--s:s--l"; + opt = getopt32(argc, argv, opt_chars); + argv += optind; + + filename1 = *argv; + fp1 = cmp_xfopen_input(filename1); + + if (*++argv) { + filename2 = *argv; +#if ENABLE_DESKTOP + if (*++argv) { + skip1 = XATOOFF(*argv); + if (*++argv) { + skip2 = XATOOFF(*argv); + } + } +#endif + } + + fp2 = cmp_xfopen_input(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; + } + + 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--; } +#endif + 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. */ + xfflush_stdout(); + } + 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); +} |