lib/string_helpers: introduce generic string_unescape

[mirror_ubuntu-artful-kernel.git] / include / linux / string_helpers.h

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index a3eb2f65b6561da94521d5c13bcd9ac4c051fd57..3eeee9672a4ac087fe57a691a1579637f810f5a1 100644 (file)
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -13,4 +13,62 @@ enum string_size_units {
 int string_get_size(u64 size, enum string_size_units units,
                    char *buf, int len);
 
+#define UNESCAPE_SPACE         0x01
+#define UNESCAPE_OCTAL         0x02
+#define UNESCAPE_HEX           0x04
+#define UNESCAPE_SPECIAL       0x08
+#define UNESCAPE_ANY           \
+       (UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL)
+
+/**
+ * string_unescape - unquote characters in the given string
+ * @src:       source buffer (escaped)
+ * @dst:       destination buffer (unescaped)
+ * @size:      size of the destination buffer (0 to unlimit)
+ * @flags:     combination of the flags (bitwise OR):
+ *     %UNESCAPE_SPACE:
+ *             '\f' - form feed
+ *             '\n' - new line
+ *             '\r' - carriage return
+ *             '\t' - horizontal tab
+ *             '\v' - vertical tab
+ *     %UNESCAPE_OCTAL:
+ *             '\NNN' - byte with octal value NNN (1 to 3 digits)
+ *     %UNESCAPE_HEX:
+ *             '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
+ *     %UNESCAPE_SPECIAL:
+ *             '\"' - double quote
+ *             '\\' - backslash
+ *             '\a' - alert (BEL)
+ *             '\e' - escape
+ *     %UNESCAPE_ANY:
+ *             all previous together
+ *
+ * Returns amount of characters processed to the destination buffer excluding
+ * trailing '\0'.
+ *
+ * Because the size of the output will be the same as or less than the size of
+ * the input, the transformation may be performed in place.
+ *
+ * Caller must provide valid source and destination pointers. Be aware that
+ * destination buffer will always be NULL-terminated. Source string must be
+ * NULL-terminated as well.
+ */
+int string_unescape(char *src, char *dst, size_t size, unsigned int flags);
+
+static inline int string_unescape_inplace(char *buf, unsigned int flags)
+{
+       return string_unescape(buf, buf, 0, flags);
+}
+
+static inline int string_unescape_any(char *src, char *dst, size_t size)
+{
+       return string_unescape(src, dst, size, UNESCAPE_ANY);
+}
+
+static inline int string_unescape_any_inplace(char *buf)
+{
+       return string_unescape_any(buf, buf, 0);
+}
+
 #endif