1 files changed, 169 insertions, 0 deletions
diff --git a/lib/mangle.c b/lib/mangle.c
new file mode 100644
index 0000000..1a3b89a
--- /dev/null
+++ b/lib/mangle.c
@@ -0,0 +1,169 @@
+/*
+ * Functions for \oct encoding used in mtab/fstab/swaps/etc.
+ *
+ * No copyright is claimed.  This code is in the public domain; do with
+ * it what you wish.
+ *
+ * Copyright (C) 2010 Karel Zak <kzak@redhat.com>
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "mangle.h"
+#include "c.h"
+
+#define isoctal(a)		(((a) & ~7) == '0')
+
+#define from_hex(c)		(isdigit(c) ? c - '0' : tolower(c) - 'a' + 10)
+
+#define is_unwanted_char(x)	(strchr(" \t\n\\", (unsigned int) x) != NULL)
+
+
+char *mangle(const char *s)
+{
+	char *ss, *sp;
+
+	if (!s)
+		return NULL;
+
+	ss = sp = malloc(4 * strlen(s) + 1);
+	if (!sp)
+		return NULL;
+	while(1) {
+		if (!*s) {
+			*sp = '\0';
+			break;
+		}
+		if (is_unwanted_char(*s)) {
+			*sp++ = '\\';
+			*sp++ = '0' + ((*s & 0300) >> 6);
+			*sp++ = '0' + ((*s & 070) >> 3);
+			*sp++ = '0' + (*s & 07);
+		} else
+			*sp++ = *s;
+		s++;
+	}
+	return ss;
+}
+
+
+void unmangle_to_buffer(const char *s, char *buf, size_t len)
+{
+	size_t sz = 0;
+
+	if (!s)
+		return;
+
+	while(*s && sz < len - 1) {
+		if (*s == '\\' && sz + 3 < len - 1 && isoctal(s[1]) &&
+		    isoctal(s[2]) && isoctal(s[3])) {
+
+			*buf++ = 64*(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7);
+			s += 4;
+			sz += 4;
+		} else {
+			*buf++ = *s++;
+			sz++;
+		}
+	}
+	*buf = '\0';
+}
+
+size_t unhexmangle_to_buffer(const char *s, char *buf, size_t len)
+{
+	size_t sz = 0;
+	const char *buf0 = buf;
+
+	if (!s)
+		return 0;
+
+	while(*s && sz < len - 1) {
+		if (*s == '\\' && sz + 3 < len - 1 && s[1] == 'x' &&
+		    isxdigit(s[2]) && isxdigit(s[3])) {
+
+			*buf++ = from_hex(s[2]) << 4 | from_hex(s[3]);
+			s += 4;
+			sz += 4;
+		} else {
+			*buf++ = *s++;
+			sz++;
+		}
+	}
+	*buf = '\0';
+	return buf - buf0 + 1;
+}
+
+static inline const char *skip_nonspaces(const char *s)
+{
+	while (s && *s && !(*s == ' ' || *s == '\t'))
+		s++;
+	return s;
+}
+
+/*
+ * Returns mallocated buffer or NULL in case of error.
+ */
+char *unmangle(const char *s, const char **end)
+{
+	char *buf;
+	const char *e;
+	size_t sz;
+
+	if (!s)
+		return NULL;
+
+	e = skip_nonspaces(s);
+	sz = e - s + 1;
+
+	if (end)
+		*end = e;
+	if (e == s)
+		return NULL;	/* empty string */
+
+	buf = malloc(sz);
+	if (!buf)
+		return NULL;
+
+	unmangle_to_buffer(s, buf, sz);
+	return buf;
+}
+
+#ifdef TEST_PROGRAM_MANGLE
+#include <errno.h>
+int main(int argc, char *argv[])
+{
+	char *p = NULL;
+	if (argc < 3) {
+		fprintf(stderr, "usage: %s --mangle|unmangle <string>\n",
+						program_invocation_short_name);
+		return EXIT_FAILURE;
+	}
+
+	if (!strcmp(argv[1], "--mangle")) {
+		p = mangle(argv[2]);
+		printf("mangled: '%s'\n", p);
+		free(p);
+	}
+
+	else if (!strcmp(argv[1], "--unmangle")) {
+		char *x = unmangle(argv[2], NULL);
+
+		if (x) {
+			printf("unmangled: '%s'\n", x);
+			free(x);
+		}
+
+		x = strdup(argv[2]);
+		if (x) {
+			unmangle_to_buffer(x, x, strlen(x) + 1);
+
+			printf("self-unmangled: '%s'\n", x);
+			free(x);
+		}
+	}
+
+	return EXIT_SUCCESS;
+}
+#endif /* TEST_PROGRAM_MANGLE */