src/core/SkBase64.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkBase64_DEFINED
#define SkBase64_DEFINED

#include <cstddef>

struct SkBase64 {
public:
    enum Error {
        kNoError,
        kPadError,
        kBadCharError
    };

    /**
       Base64 encodes src into dst.

       Normally this is called once with 'dst' nullptr to get the required size, then again with an
       allocated 'dst' pointer to do the actual encoding.

       @param dst nullptr or a pointer to a buffer large enough to receive the result

       @param encode nullptr for default encoding or a pointer to at least 65 chars.
                     encode[64] will be used as the pad character.
                     Encodings other than the default encoding cannot be decoded.

       @return the required length of dst for encoding.
    */
    static size_t Encode(const void* src, size_t length, void* dst, const char* encode = nullptr);

    /**
       Returns the length of the buffer that needs to be allocated to encode srcDataLength bytes.
    */
    static size_t EncodedSize(size_t srcDataLength) {
        // Take the floor of division by 3 to find the number of groups that need to be encoded.
        // Each group takes 4 bytes to be represented in base64.
        return ((srcDataLength + 2) / 3) * 4;
    }

    /**
       Base64 decodes src into dst.

       Normally this is called once with 'dst' nullptr to get the required size, then again with an
       allocated 'dst' pointer to do the actual encoding.

       @param dst nullptr or a pointer to a buffer large enough to receive the result

       @param dstLength assigned the length dst is required to be. Must not be nullptr.
    */
    [[nodiscard]] static Error Decode(const void* src, size_t  srcLength,
                                      void* dst, size_t* dstLength);
};

#endif // SkBase64_DEFINED