src/base64.h

#ifndef SRC_BASE64_H_
#define SRC_BASE64_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include "util.h"

#include <cmath>
#include <cstddef>
#include <cstdint>

namespace node {
//// Base 64 ////

enum class Base64Mode {
  NORMAL,
  URL
};

static constexpr char base64_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                       "abcdefghijklmnopqrstuvwxyz"
                                       "0123456789+/";

static constexpr char base64_table_url[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                           "abcdefghijklmnopqrstuvwxyz"
                                           "0123456789-_";

static inline const char* base64_select_table(Base64Mode mode) {
  switch (mode) {
    case Base64Mode::NORMAL: return base64_table;
    case Base64Mode::URL: return base64_table_url;
    default: UNREACHABLE();
  }
}

static inline constexpr size_t base64_encoded_size(
    size_t size,
    Base64Mode mode = Base64Mode::NORMAL) {
  return mode == Base64Mode::NORMAL ? ((size + 2) / 3 * 4)
                                    : static_cast<size_t>(std::ceil(
                                          static_cast<double>(size * 4) / 3));
}

// Doesn't check for padding at the end.  Can be 1-2 bytes over.
static inline constexpr size_t base64_decoded_size_fast(size_t size) {
  // 1-byte input cannot be decoded
  return size > 1 ? (size / 4) * 3 + (size % 4 + 1) / 2 : 0;
}

inline uint32_t ReadUint32BE(const unsigned char* p);

template <typename TypeName>
size_t base64_decoded_size(const TypeName* src, size_t size);

template <typename TypeName>
size_t base64_decode(char* const dst, const size_t dstlen,
                     const TypeName* const src, const size_t srclen);

inline size_t base64_encode(const char* src,
                            size_t slen,
                            char* dst,
                            size_t dlen,
                            Base64Mode mode = Base64Mode::NORMAL);
}  // namespace node


#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#endif  // SRC_BASE64_H_