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242 lines
8.4 KiB
C
242 lines
8.4 KiB
C
/* Licensed under BSD-MIT - see LICENSE file for details */
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#ifndef CCAN_BASE64_H
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#define CCAN_BASE64_H
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#include <stddef.h>
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#include <stdbool.h>
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#include <sys/types.h>
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/**
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* base64_maps_t - structure to hold maps for encode/decode
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*/
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typedef struct {
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char encode_map[64];
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signed char decode_map[256];
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} base64_maps_t;
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/**
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* base64_encoded_length - Calculate encode buffer length
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* @param srclen the size of the data to be encoded
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* @note add 1 to this to get null-termination
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* @return Buffer length required for encode
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*/
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size_t base64_encoded_length(size_t srclen);
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/**
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* base64_decoded_length - Calculate decode buffer length
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* @param srclen Length of the data to be decoded
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* @note This does not return the size of the decoded data! see base64_decode
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* @return Minimum buffer length for safe decode
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*/
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size_t base64_decoded_length(size_t srclen);
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/**
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* base64_init_maps - populate a base64_maps_t based on a supplied alphabet
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* @param dest A base64 maps object
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* @param src Alphabet to populate the maps from (e.g. base64_alphabet_rfc4648)
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*/
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void base64_init_maps(base64_maps_t *dest, const char src[64]);
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/**
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* base64_encode_triplet_using_maps - encode 3 bytes into base64 using a specific alphabet
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* @param maps Maps to use for encoding (see base64_init_maps)
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* @param dest Buffer containing 3 bytes
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* @param src Buffer containing 4 characters
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*/
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void base64_encode_triplet_using_maps(const base64_maps_t *maps,
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char dest[4], const char src[3]);
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/**
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* base64_encode_tail_using_maps - encode the final bytes of a source using a specific alphabet
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* @param maps Maps to use for encoding (see base64_init_maps)
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* @param dest Buffer containing 4 bytes
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* @param src Buffer containing srclen bytes
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* @param srclen Number of bytes (<= 3) to encode in src
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*/
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void base64_encode_tail_using_maps(const base64_maps_t *maps, char dest[4],
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const char *src, size_t srclen);
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/**
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* base64_encode_using_maps - encode a buffer into base64 using a specific alphabet
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* @param maps Maps to use for encoding (see base64_init_maps)
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* @param dest Buffer to encode into
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* @param destlen Length of dest
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* @param src Buffer to encode
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* @param srclen Length of the data to encode
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* @return Number of encoded bytes set in dest. -1 on error (and errno set)
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* @note dest will be nul-padded to destlen (past any required padding)
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* @note sets errno = EOVERFLOW if destlen is too small
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*/
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ssize_t base64_encode_using_maps(const base64_maps_t *maps,
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char *dest, size_t destlen,
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const char *src, size_t srclen);
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/*
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* base64_char_in_alphabet - returns true if character can be part of an encoded string
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* @param maps A base64 maps object (see base64_init_maps)
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* @param b64char Character to check
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*/
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bool base64_char_in_alphabet(const base64_maps_t *maps, char b64char);
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/**
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* base64_decode_using_maps - decode a base64-encoded string using a specific alphabet
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* @param maps A base64 maps object (see base64_init_maps)
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* @param dest Buffer to decode into
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* @param destlen length of dest
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* @param src the buffer to decode
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* @param srclen the length of the data to decode
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note dest will be nul-padded to destlen
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* @note sets errno = EOVERFLOW if destlen is too small
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* @note sets errno = EDOM if src contains invalid characters
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*/
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ssize_t base64_decode_using_maps(const base64_maps_t *maps,
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char *dest, size_t destlen,
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const char *src, size_t srclen);
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/**
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* base64_decode_quartet_using_maps - decode 4 bytes from base64 using a specific alphabet
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* @param maps A base64 maps object (see base64_init_maps)
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* @param dest Buffer containing 3 bytes
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* @param src Buffer containing 4 bytes
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note sets errno = EDOM if src contains invalid characters
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*/
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ssize_t base64_decode_quartet_using_maps(const base64_maps_t *maps,
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char dest[3], const char src[4]);
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/**
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* base64_decode_tail_using_maps - decode the final bytes of a base64 string using a specific alphabet
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* @param maps A base64 maps object (see base64_init_maps)
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* @param dest Buffer containing 3 bytes
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* @param src Buffer containing 4 bytes - padded with '=' as required
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* @param srclen Number of bytes to decode in src
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note sets errno = EDOM if src contains invalid characters
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* @note sets errno = EINVAL if src is an invalid base64 tail
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*/
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ssize_t base64_decode_tail_using_maps(const base64_maps_t *maps, char *dest,
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const char *src, size_t srclen);
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/* the rfc4648 functions: */
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extern const base64_maps_t base64_maps_rfc4648;
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/**
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* base64_encode - Encode a buffer into base64 according to rfc4648
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* @param dest Buffer to encode into
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* @param destlen Length of the destination buffer
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* @param src Buffer to encode
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* @param srclen Length of the data to encode
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* @return Number of encoded bytes set in dest. -1 on error (and errno set)
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* @note dest will be nul-padded to destlen (past any required padding)
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* @note sets errno = EOVERFLOW if destlen is too small
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*
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* This function encodes src according to http://tools.ietf.org/html/rfc4648
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*
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* Example:
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* size_t encoded_length;
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* char dest[100];
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* const char *src = "This string gets encoded";
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* encoded_length = base64_encode(dest, sizeof(dest), src, strlen(src));
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* printf("Returned data of length %zd @%p\n", encoded_length, &dest);
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*/
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static inline
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ssize_t base64_encode(char *dest, size_t destlen,
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const char *src, size_t srclen)
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{
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return base64_encode_using_maps(&base64_maps_rfc4648,
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dest, destlen, src, srclen);
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}
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/**
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* base64_encode_triplet - encode 3 bytes into base64 according to rfc4648
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* @param dest Buffer containing 4 bytes
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* @param src Buffer containing 3 bytes
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*/
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static inline
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void base64_encode_triplet(char dest[4], const char src[3])
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{
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base64_encode_triplet_using_maps(&base64_maps_rfc4648, dest, src);
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}
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/**
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* base64_encode_tail - encode the final bytes of a source according to rfc4648
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* @param dest Buffer containing 4 bytes
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* @param src Buffer containing srclen bytes
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* @param srclen Number of bytes (<= 3) to encode in src
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*/
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static inline
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void base64_encode_tail(char dest[4], const char *src, size_t srclen)
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{
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base64_encode_tail_using_maps(&base64_maps_rfc4648, dest, src, srclen);
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}
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/**
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* base64_decode - decode An rfc4648 base64-encoded string
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* @param dest Buffer to decode into
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* @param destlen Length of the destination buffer
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* @param src Buffer to decode
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* @param srclen Length of the data to decode
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note dest will be nul-padded to destlen
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* @note sets errno = EOVERFLOW if destlen is too small
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* @note sets errno = EDOM if src contains invalid characters
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*
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* This function decodes the buffer according to
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* http://tools.ietf.org/html/rfc4648
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*
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* Example:
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* size_t decoded_length;
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* char ret[100];
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* const char *src = "Zm9vYmFyYmF6";
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* decoded_length = base64_decode(ret, sizeof(ret), src, strlen(src));
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* printf("Returned data of length %zd @%p\n", decoded_length, &ret);
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*/
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static inline
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ssize_t base64_decode(char *dest, size_t destlen,
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const char *src, size_t srclen)
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{
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return base64_decode_using_maps(&base64_maps_rfc4648,
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dest, destlen, src, srclen);
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}
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/**
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* base64_decode_quartet - decode the first 4 characters in src into dest
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* @param dest Buffer containing 3 bytes
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* @param src Buffer containing 4 characters
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note sets errno = EDOM if src contains invalid characters
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*/
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static inline
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ssize_t base64_decode_quartet(char dest[3], const char src[4])
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{
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return base64_decode_quartet_using_maps(&base64_maps_rfc4648,
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dest, src);
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}
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/**
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* @brief decode the final bytes of a base64 string from src into dest
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* @param dest Buffer containing 3 bytes
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* @param src Buffer containing 4 bytes - padded with '=' as required
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* @param srclen Number of bytes to decode in src
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* @return Number of decoded bytes set in dest. -1 on error (and errno set)
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* @note sets errno = EDOM if src contains invalid characters
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* @note sets errno = EINVAL if src is an invalid base64 tail
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*/
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static inline
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ssize_t base64_decode_tail(char dest[3], const char *src, size_t srclen)
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{
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return base64_decode_tail_using_maps(&base64_maps_rfc4648,
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dest, src, srclen);
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}
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/* end rfc4648 functions */
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#endif /* CCAN_BASE64_H */
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