#ifndef HEX_LL_H #define HEX_LL_H extern const signed char hexval_table[256]; static inline unsigned int hexval(unsigned char c) { … } /* * Convert two consecutive hexadecimal digits into a char. Return a * negative value on error. Don't run over the end of short strings. */ static inline int hex2chr(const char *s) { … } /* * Read `len` pairs of hexadecimal digits from `hex` and write the * values to `binary` as `len` bytes. Return 0 on success, or -1 if * the input does not consist of hex digits). */ int hex_to_bytes(unsigned char *binary, const char *hex, size_t len); #endif