Added implementations from pdcore

[pdutils] / utils / cmp / cmp.c

diff --git a/utils/cmp/cmp.c b/utils/cmp/cmp.c
new file mode 100644 (file)
index 0000000..a1c0572
--- /dev/null
+++ b/utils/cmp/cmp.c
@@ -0,0 +1,163 @@
+/*
+ * cmp.c - compare two files
+ *
+ * Version: 2008-1.01
+ * Build:   c89 -o cmp cmp.c
+ * Source:  <http://pdcore.sourceforge.net/>
+ * Spec:    <http://www.opengroup.org/onlinepubs/9699919799/utilities/cmp.html>
+ *
+ * This is free and unencumbered software released into the public domain,
+ * provided "as is", without warranty of any kind, express or implied. See the
+ * file UNLICENSE and the website <http://unlicense.org> for further details.
+ */
+
+
+#define _POSIX_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define USAGE      "usage: cmp [-l|-s] file1 file2\n"
+#define ELSMUTEXCL "Options -l and -s are mutually exclusive"
+#define EBOTHSTDIN "Input files must be different"
+#define BUFSIZE    4096
+#define SYSERR     1
+#define APPERR     0
+
+static int cmpfiles(int fd1, char *fn1, int fd2, char *fn2);
+static void fatal(int errtype, char *s);
+
+static int optl, opts;
+
+
+int main(int argc, char **argv)
+{
+    extern int opterr, optind;
+    int c, exitstatus = 0;
+    int fd1, fd2;
+    char *fn1, *fn2;
+
+    setlocale(LC_ALL, "");
+    opterr = 0;
+
+    while ((c = getopt(argc, argv, "ls")) != -1)
+        switch (c)
+        {
+        case 'l':
+            optl = 1;
+            break;
+        case 's':
+            opts = 1;
+            break;
+        default:
+            fprintf(stderr, USAGE);
+            exit(2);
+        }
+
+    argc -= optind;
+    argv += optind;
+
+    if (optl && opts)
+        fatal(APPERR, ELSMUTEXCL);
+
+    if (argc != 2)
+        fatal(APPERR, USAGE);
+
+    fn1 = argv[0];
+    if (strcmp(fn1, "-") == 0)
+        fd1 = STDIN_FILENO;
+    else
+        if ((fd1 = open(fn1, O_RDONLY)) == -1)
+            fatal(SYSERR, fn1);
+
+    fn2 = argv[1];
+    if (strcmp(fn2, "-") == 0)
+        fd2 = STDIN_FILENO;
+    else
+        if ((fd2 = open(fn2, O_RDONLY)) == -1)
+            fatal(SYSERR, fn2);
+
+    if (fd1 == STDIN_FILENO && fd2 == STDIN_FILENO)
+        fatal(APPERR, EBOTHSTDIN);
+
+    exitstatus = cmpfiles(fd1, fn1, fd2, fn2);
+
+    if (fd1 != STDIN_FILENO && (close(fd1) == -1))
+        fatal(SYSERR, fn1);
+
+    if (fd2 != STDIN_FILENO && (close(fd2) == -1))
+        fatal(SYSERR, fn2);
+
+    return(exitstatus);
+}
+
+
+int cmpfiles(int fd1, char *fn1, int fd2, char *fn2)
+{
+    unsigned char buf1[BUFSIZE], buf2[BUFSIZE];
+    ssize_t n1, n2, byte = 1, line = 1;
+    int cnt, i, eof = 0, differ = 0, shorter = 0;
+
+    while (! eof)
+    {
+        if ((n1 = read(fd1, buf1, BUFSIZE)) == -1)
+            fatal(SYSERR, fn1);
+
+        if ((n2 = read(fd2, buf2, BUFSIZE)) == -1)
+            fatal(SYSERR, fn2);
+
+        if (n1 != BUFSIZE || n2 != BUFSIZE)
+        {
+            eof = 1;
+            if (n1 != n2)
+                shorter = (n1 < n2) ? 1 : 2;
+        }
+
+        cnt = (n1 < n2) ? n1 : n2;
+        for (i = 0; i < cnt; i++)
+        {
+            if (buf1[i] != buf2[i])
+            {
+                if (! differ && ! optl && ! opts)
+                {
+                    printf("%s %s differ: char %d, line %d\n", fn1, fn2, byte, line);
+                    return(1);  /* only need to report first mismatch */
+                }
+
+                differ = 1;
+
+                if (optl)
+                    printf("%d %o %o\n", byte, buf1[i], buf2[i]);
+            }
+
+            byte++;
+            if (buf1[i] == '\n')
+                line++;
+        }
+    }
+
+    if (shorter && (optl || (! opts && ! differ)))
+    {
+        differ = 1;
+        fprintf(stderr, "cmp: EOF on %s\n", (shorter == 1 ? fn1 : fn2));
+    }
+
+    return(differ || shorter);
+}
+
+
+void fatal(int errtype, char *s)
+{
+    if (errtype == SYSERR)
+        fprintf(stderr, "cmp: %s: %s\n", s, strerror(errno));
+    else
+        fprintf(stderr, "cmp: %s\n", s);
+
+    exit(2);
+}