Added implementations from pdcore

[pdutils] / utils / cksum / cksum.c

diff --git a/utils/cksum/cksum.c b/utils/cksum/cksum.c
new file mode 100644 (file)
index 0000000..daba540
--- /dev/null
+++ b/utils/cksum/cksum.c
@@ -0,0 +1,115 @@
+/*
+ * cksum - report checksum and octet count of file(s)
+ *
+ * Version: 2008-1.01
+ * Build:   c89 -o cksum cksum.c
+ * Source:  <http://pdcore.sourceforge.net/>
+ * Spec:    <http://www.opengroup.org/onlinepubs/9699919799/utilities/cksum.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 <inttypes.h>
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define BUFSIZE 4096
+
+static void cksumfile(int fd, char *fn);
+static void error(char *s);
+
+static int exitstatus;
+
+
+int main(int argc, char **argv)
+{
+    int i, fd, hasrun = 0;
+    char *fn;
+
+    setlocale(LC_ALL, "");
+
+    for (i = 1; i < argc; i++)
+    {
+        fn = argv[i];
+
+        if (strcmp(fn, "--") == 0)
+            continue;
+        else
+        {
+            hasrun = 1;
+
+            if (strcmp(fn, "-") == 0)
+                cksumfile(STDIN_FILENO, "stdin");
+            else
+                if ((fd = open(fn, O_RDONLY)) == -1)
+                    error(fn);
+                else
+                {
+                    cksumfile(fd, fn);
+                    if (close(fd) == -1)
+                        error(fn);
+                }
+        }
+    }
+
+    if (! hasrun)
+        cksumfile(STDIN_FILENO, "stdin");
+
+    return(exitstatus);
+}
+
+
+void cksumfile(int fd, char *fn)
+{
+    unsigned char buf[BUFSIZE];
+    ssize_t cnt, n;
+    uint32_t crctab[256], crc, i;
+    int j;
+
+    for (i = 0; i < 256; ++i)
+    {
+        for (crc = i << 24, j = 0; j < 8; j++)
+            crc = (crc << 1) ^ (crc & 0x80000000 ? 0x04c11db7 : 0);
+        crctab[i] = crc;
+    }
+
+    cnt = crc = 0;
+
+    while ((n = read(fd, buf, BUFSIZE)) > 0)
+    {
+        cnt += n;
+
+        for (i = 0; i < (size_t)n; i++)
+            crc = crctab[((crc >> 24) ^ buf[i]) & 0xFF] ^ (crc << 8);
+    }
+
+    if (n < 0)
+        error(fn);
+    else
+    {
+        for (i = cnt; i != 0; i >>= 8)
+            crc = crctab[((crc >> 24) ^ i) & 0xFF] ^ (crc << 8);
+
+        printf("%lu %lu", (unsigned long)~crc, (unsigned long)cnt);
+        if (fd != STDIN_FILENO)
+            printf(" %s", fn);
+        printf("\n");
+    }
+}
+
+
+void error(char *s)
+{
+    fprintf(stderr, "cksum: %s: %s\n", s, strerror(errno));
+    exitstatus = 1;
+}