Add a helper macro to compute the length of a base64 string

Modern compilers should optimize these common subexpressions fairly well.
This commit is contained in:
Frank Denis 2017-09-19 13:08:14 +02:00
parent 9209e89d96
commit 70e5ff5e14

View File

@ -66,6 +66,15 @@ int sodium_hex2bin(unsigned char * const bin, const size_t bin_maxlen,
#define sodium_base64_VARIANT_URLSAFE 5 #define sodium_base64_VARIANT_URLSAFE 5
#define sodium_base64_VARIANT_URLSAFE_NO_PADDING 7 #define sodium_base64_VARIANT_URLSAFE_NO_PADDING 7
/*
* Computes the required length to encode BIN_LEN bytes as a base64 string
* using the given variant. The computed length includes a trailing \0.
*/
#define sodium_base64_ENCODED_LEN(BIN_LEN, VARIANT) \
(((BIN_LEN) / 3U) * 4U + \
((((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) | (((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) >> 1)) & 1U) * \
(4U - (~((((VARIANT) & 2U) >> 1) - 1U) & (3U - ((BIN_LEN) - ((BIN_LEN) / 3U) * 3U)))) + 1U)
SODIUM_EXPORT SODIUM_EXPORT
char *sodium_bin2base64(char * const b64, const size_t b64_maxlen, char *sodium_bin2base64(char * const b64, const size_t b64_maxlen,
const unsigned char * const bin, const size_t bin_len, const unsigned char * const bin, const size_t bin_len,