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-rw-r--r--lib/mangle.c169
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 */