HEX: hexadecimal encode and decode

Functions
unsigned char *	n_hex_decode (const char *hex, size_t *out_len)
	decode a hex string (ASCII whitespace between digits is ignored) into a freshly allocated, NUL-terminated byte buffer; *out_len receives the decoded byte count.
int	n_hex_decode_to (unsigned char *out, size_t out_size, const char *hex, size_t nbytes)
	decode exactly nbytes bytes from the first 2*nbytes hex digits of hex (case-insensitive, no embedded whitespace) into the caller-provided buffer out (needs out_size >= nbytes).
N_STR *	n_hex_encode (const unsigned char *data, size_t len)
	encode len bytes of data as a lowercase hex N_STR (2*len characters); free with free_nstr.
size_t	n_hex_encode_to (char *out, size_t out_size, const unsigned char *data, size_t len)
	encode len bytes of data as lowercase hex into the caller-provided buffer out (needs out_size >= 2*len+1), NUL-terminating on success.

Detailed Description

Function Documentation

n_hex_decode()

unsigned char * n_hex_decode	(	const char *	hex,
		size_t *	out_len )

decode a hex string (ASCII whitespace between digits is ignored) into a freshly allocated, NUL-terminated byte buffer; *out_len receives the decoded byte count.

Free the buffer with Free()/free(). Returns NULL on an odd number of hex digits or an invalid character.

Definition at line 71 of file n_hex.c.

References __n_assert, LOG_ERR, Malloc, n_hex_value(), and n_log.

Referenced by test_decode_errors(), and test_decode_roundtrip().

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n_hex_decode_to()

int n_hex_decode_to	(	unsigned char *	out,
		size_t	out_size,
		const char *	hex,
		size_t	nbytes )

decode exactly nbytes bytes from the first 2*nbytes hex digits of hex (case-insensitive, no embedded whitespace) into the caller-provided buffer out (needs out_size >= nbytes).

Zero-allocation, fixed-length counterpart to n_hex_decode. Returns TRUE on success, FALSE on a too-small buffer, a hex string shorter than 2*nbytes, or an invalid hex digit.

Definition at line 141 of file n_hex.c.

References __n_assert, LOG_ERR, n_hex_value(), and n_log.

Referenced by test_bounded().

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n_hex_encode()

N_STR * n_hex_encode	(	const unsigned char *	data,
		size_t	len )

encode len bytes of data as a lowercase hex N_STR (2*len characters); free with free_nstr.

Returns NULL on a NULL/oversized input or on allocation failure.

Definition at line 48 of file n_hex.c.

References __n_assert, N_STR::data, LOG_ERR, n_hex_digits, n_log, new_nstr(), and N_STR::written.

Referenced by expect_encode(), expect_hex(), n_digest_sha256_hex(), n_random_hex_token(), and test_decode_roundtrip().

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n_hex_encode_to()

size_t n_hex_encode_to	(	char *	out,
		size_t	out_size,
		const unsigned char *	data,
		size_t	len )

encode len bytes of data as lowercase hex into the caller-provided buffer out (needs out_size >= 2*len+1), NUL-terminating on success.

Zero-allocation variant of n_hex_encode. Returns the number of hex characters written (2*len), or 0 on a NULL out, NULL/oversized data, or a too-small buffer (out left untouched).

Definition at line 117 of file n_hex.c.

References __n_assert, LOG_ERR, n_hex_digits, and n_log.

Referenced by test_bounded().

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