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/**
* Copyright (C) 2021 Koichiro Iwao, all xrdp contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file common/base64.h
* @brief Base64 encoder / decoder
*
* Base-64 is described in RFC4648. The following notes apply to this
* implementation:-
* - The only supported characters are [A-Za-z0-9+/=]. At present,
* embedded linefeeds and URL encodings are not supported.
*
*/
#if !defined(BASE64_CALLS_H)
#define BASE64_CALLS_H
#include "arch.h"
/*
* Decodes a base64 string
*
* @param src Pointer to null-terminated source
* @param dst Pointer to output buffer
* @param dst_len Length of above. No more than this is written to the
* output buffer
* @param actual_len Pointer to value to receive actual length of decoded data
* @return 0 for success, 1 for an invalid input string
*
* The following notes apply to this implementation:-
* - Embedded padding is supported, provided it only occurs at the end
* of a quantum as described in RFC4648(4). This allows concatenated
* encodings to be fed into the decoder.
* - Padding of the last quantum is assumed if not provided.
* - Excess padding of the last quantum is ignored.
*
* Only dst_len bytes at most are written to the output. The length
* returned in actual_len however represents how much buffer is needed for
* a correct result. This may be more than dst_len, and enables the caller
* to detect a potential buffer overflow
*/
int
base64_decode(const char *src, char *dst, size_t dst_len, size_t *actual_len);
/*
* Encodes a buffer as base64
*
* @param src Pointer to source
* @param src_len Length of above.
* @param dst Pointer to output buffer for null-terminated string
* @param dst_len Length of above. No more than this is written to the
* output buffer
* @return Number of source characters processed
*
* The following notes apply to this implementation:-
* - Padding of the last quantum is always written if the number of
* source bytes is not divisible by 3.
*
* The number of source characters processed is always returned. If
* the destination buffer is too small for all the output plus a
* terminator, the returned value from this procedure will be less than
* src_len. In this case no padding characters will have been written,
* and the remaining characters can be converted with more calls to
* this procedure.
*/
size_t
base64_encode(const char *src, size_t src_len, char *dst, size_t dst_len);
#endif /* BASE64_CALLS_H */
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