1 files changed, 127 insertions, 0 deletions

diff --git a/coreutils/cmp.c b/coreutils/cmp.c
new file mode 100644
index 000000000..71007eac1
--- /dev/null
+++ b/coreutils/cmp.c
@@ -0,0 +1,127 @@
+/* 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 "busybox.h"
+
+static FILE *cmp_xfopen_input(const char * const filename)
+{
+        FILE *fp;
+
+        fp = fopen_or_warn_stdin(filename);
+        if (fp)
+                return fp;
+        exit(xfunc_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";
+// This fmt_l_opt uses gnu-isms.  SUSv3 would be "%.0s%.0s%d %o %o\n"
+static const char fmt_l_opt[] = "%.0s%.0s%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)
+{
+        FILE *fp1, *fp2, *outfile = stdout;
+        const char *filename1, *filename2 = "-";
+        const char *fmt;
+        int c1, c2, char_pos = 0, line_pos = 1;
+        unsigned opt;
+        int retval = 0;
+
+        xfunc_error_retval = 2; /* 1 is returned if files are different. */
+
+        opt = getopt32(argc, argv, opt_chars);
+
+        if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
+                        || (((unsigned int)(--argc - optind)) > 1))
+                bb_show_usage();
+
+        fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
+
+        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;
+        }
+
+        if (opt & CMP_OPT_l)
+                fmt = fmt_l_opt;
+        else
+                fmt = fmt_differ;
+
+        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);
+}