Added implementations from pdcore

[pdutils] / utils / cat / cat.c

diff --git a/utils/cat/cat.c b/utils/cat/cat.c
new file mode 100644 (file)
index 0000000..c109550
--- /dev/null
+++ b/utils/cat/cat.c
@@ -0,0 +1,100 @@
+/*
+ * cat.c - concatenate file(s) to standard output
+ *
+ * Version: 2008-1.01
+ * Build:   c89 -o cat cat.c
+ * Source:  <http://pdcore.sourceforge.net/>
+ * Spec:    <http://www.opengroup.org/onlinepubs/9699919799/utilities/cat.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 <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define USAGE   "usage: cat [-u] [file ...]\n"
+#define BUFSIZE 4096
+
+static void catfile(int fd, char *fn);
+static void error(char *s);
+
+static int exitstatus;
+static int optu;
+
+
+int main(int argc, char **argv)
+{
+    extern int opterr, optind;
+    int c, fd;
+    char *fn;
+
+    setlocale(LC_ALL, "");
+    opterr = 0;
+
+    while ((c = getopt(argc, argv, "u")) != -1)
+        switch (c)
+        {
+        case 'u':
+            optu = 1;
+            break;
+        default:
+            fprintf(stderr, USAGE);
+            return(1);
+        }
+
+    if (optind >= argc)
+        catfile(STDIN_FILENO, "stdin");
+    else
+        while (optind < argc)
+        {
+            fn = argv[optind++];
+
+            if (strcmp(fn, "-") == 0)
+                catfile(STDIN_FILENO, "stdin");
+            else
+                if ((fd = open(fn, O_RDONLY)) == -1)
+                    error(fn);
+                else
+                {
+                    catfile(fd, fn);
+                    if (close(fd) == -1)
+                        error(fn);
+                }
+        }
+
+    return(exitstatus);
+}
+
+
+void catfile(int fd, char *fn)
+{
+    unsigned char buf[BUFSIZE];
+    ssize_t n;
+
+    while ((n = read(fd, buf, (optu ? 1 : BUFSIZE))) > 0)
+        if (write(STDOUT_FILENO, buf, (size_t)n) != n)
+        {
+            error("stdout");
+            break;
+        }
+
+    if (n < 0)
+        error(fn);
+}
+
+
+void error(char *s)
+{
+    fprintf(stderr, "cat: %s: %s\n", s, strerror(errno));
+    exitstatus = 1;
+}