str/hex: to-from hexstring conversion routines.

[ccan] / ccan / str / hex / hex.h

diff --git a/ccan/str/hex/hex.h b/ccan/str/hex/hex.h
new file mode 100644 (file)
index 0000000..0a0d5c5
--- /dev/null
+++ b/ccan/str/hex/hex.h
@@ -0,0 +1,73 @@
+/* CC0 (Public domain) - see LICENSE file for details */
+#ifndef CCAN_HEX_H
+#define CCAN_HEX_H
+#include "config.h"
+#include <stdbool.h>
+#include <stdlib.h>
+
+/**
+ * hex_decode - Unpack a hex string.
+ * @str: the hexidecimal string
+ * @slen: the length of @str
+ * @buf: the buffer to write the data into
+ * @bufsize: the length of @buf
+ *
+ * Returns false if there are any characters which aren't 0-9, a-f or A-F,
+ * of the string wasn't the right length for @bufsize.
+ *
+ * Example:
+ *     unsigned char data[20];
+ *
+ *     if (!hex_decode(argv[1], strlen(argv[1]), data, 20))
+ *             printf("String is malformed!\n");
+ */
+bool hex_decode(const char *str, size_t slen, void *buf, size_t bufsize);
+
+/**
+ * hex_encode - Create a nul-terminated hex string
+ * @buf: the buffer to read the data from
+ * @bufsize: the length of @buf
+ * @dest: the string to fill
+ * @destsize: the max size of the string
+ *
+ * Returns true if the string, including terminator, fit in @destsize;
+ *
+ * Example:
+ *     unsigned char buf[] = { 0x1F, 0x2F };
+ *     char str[5];
+ *
+ *     if (!hex_encode(buf, sizeof(buf), str, sizeof(str)))
+ *             abort();
+ */
+bool hex_encode(const void *buf, size_t bufsize, char *dest, size_t destsize);
+
+/**
+ * hex_str_size - Calculate how big a nul-terminated hex string is
+ * @bytes: bytes of data to represent
+ *
+ * Example:
+ *     unsigned char buf[] = { 0x1F, 0x2F };
+ *     char str[hex_str_size(sizeof(buf))];
+ *
+ *     hex_encode(buf, sizeof(buf), str, sizeof(str));
+ */
+static inline size_t hex_str_size(size_t bytes)
+{
+       return 2 * bytes + 1;
+}
+
+/**
+ * hex_data_size - Calculate how many bytes of data in a hex string
+ * @strlen: the length of the string (with or without NUL)
+ *
+ * Example:
+ *     const char str[] = "1F2F";
+ *     unsigned char buf[hex_data_size(sizeof(str))];
+ *
+ *     hex_decode(str, strlen(str), buf, sizeof(buf));
+ */
+static inline size_t hex_data_size(size_t strlen)
+{
+       return strlen / 2;
+}
+#endif /* PETTYCOIN_HEX_H */