1 // Copyright (2013) Jann Horn <jann@thejh.net>
3 HEADER #include <sys/types.h>
6 static inline char hexchar(unsigned char c) {
7 if (c >= 10) return c+'a'-10;
11 // If `in_len` is -1, it means that `in` is a null-terminated string.
12 // `out` must have space for `in_len*2+1` bytes.
13 PUBLIC_FN void hex_encode(char *in, ssize_t in_len, char *out) {
14 if (in_len == -1) in_len = strlen(in);
16 char *in_end = in+in_len;
18 unsigned char c = *(unsigned char *)(in++);
19 *(out++) = hexchar(c>>4);
20 *(out++) = hexchar(c&0xf);
25 static inline unsigned char unhexchar(char c) {
26 if (c >= '0' && c <= '9') return c-'0';
27 if (c >= 'a' && c <= 'f') return c-'a'+10;
28 if (c >= 'A' && c <= 'F') return c-'A'+10;
32 // Returns number of decoded bytes or -1(error).
33 // Does not null-terminate output.
34 PUBLIC_FN ssize_t hex_decode(char *in, ssize_t in_len, char *out) {
36 if (in_len == -1) in_len = strlen(in);
38 if (in_len&1) return -1; /* n%2 must be 0 */
39 char *in_end = in + in_len;
41 unsigned char hi = unhexchar(*(in++));
42 unsigned char lo = unhexchar(*(in++));
43 if (hi == 255 || lo == 255) return -1;
44 *(out++) = (hi<<4) | lo;