152 lines
3.2 KiB
C++
152 lines
3.2 KiB
C++
/*
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SPDX-License-Identifier: MIT
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Copyright © 2016-2024 Amebis
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*/
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#pragma once
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#include "compat.hpp"
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#include <cstdint>
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#include <string>
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#include <vector>
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namespace stdex
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{
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///
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/// Hexadecimal encoding session
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///
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class hex_enc
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{
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public:
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///
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/// Constructs blank encoding session
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///
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hex_enc() noexcept
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{}
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///
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/// Encodes one block of information, and _appends_ it to the output
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///
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/// \param[in,out] out Output
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/// \param[in] data Data to encode
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/// \param[in] size Length of `data` in bytes
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///
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template<class T, class TR, class AX>
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void encode(_Inout_ std::basic_string<T, TR, AX> &out, _In_bytecount_(size) const void *data, _In_ size_t size)
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{
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_Assume_(data || !size);
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// Preallocate output
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out.reserve(out.size() + enc_size(size));
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// Convert data character by character.
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for (size_t i = 0; i < size; i++) {
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uint8_t
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x = reinterpret_cast<const uint8_t*>(data)[i],
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x_h = ((x & 0xf0) >> 4),
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x_l = ((x & 0x0f) );
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out += x_h < 10 ? '0' + x_h : 'A' - 10 + x_h;
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out += x_l < 10 ? '0' + x_l : 'A' - 10 + x_l;
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}
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}
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///
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/// Returns maximum encoded size
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///
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/// \param[in] size Number of bytes to encode
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///
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/// \returns Maximum number of bytes for the encoded data of `size` length
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///
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size_t enc_size(_In_ size_t size) const noexcept
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{
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return size*2;
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}
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};
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///
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/// Hexadecimal decoding session
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///
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class hex_dec
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{
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public:
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///
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/// Constructs blank decoding session
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///
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hex_dec() noexcept :
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buf(0),
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num(0)
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{}
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///
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/// Decodes one block of information, and _appends_ it to the output
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///
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/// \param[in,out] out Output
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/// \param[out] is_last Was this the last block of data? Actually, is this block of data complete?
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/// \param[in] data Data to decode
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/// \param[in] size Length of `data` in bytes
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///
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template<class T_to, class AX, class T_from>
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void decode(_Inout_ std::vector<T_to, AX> &out, _Out_ bool &is_last, _In_z_count_(size) const T_from *data, _In_ size_t size)
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{
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is_last = false;
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// Trim data size to first terminator.
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for (size_t k = 0; k < size; k++)
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if (!data[k]) { size = k; break; }
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// Preallocate output
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out.reserve(out.size() + dec_size(size));
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for (size_t i = 0;; i++) {
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if (num >= 2) {
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// Buffer full.
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out.push_back(buf);
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num = 0;
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is_last = true;
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} else
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is_last = false;
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if (i >= size)
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break;
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int x = data[i];
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if ('0' <= x && x <= '9') {
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buf = ((buf & 0xf) << 4) | (uint8_t)(x - '0');
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num++;
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} else if ('A' <= x && x <= 'F') {
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buf = ((buf & 0xf) << 4) | (uint8_t)(x - ('A' - 10));
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num++;
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} else if ('a' <= x && x <= 'f') {
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buf = ((buf & 0xf) << 4) | (uint8_t)(x - ('a' - 10));
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num++;
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}
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}
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}
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///
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/// Resets decoding session
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///
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void clear() noexcept
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{
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num = 0;
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}
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///
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/// Returns maximum decoded size
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///
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/// \param[in] size Number of bytes to decode
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///
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/// \returns Maximum number of bytes for the decoded data of `size` length
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///
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size_t dec_size(_In_ size_t size) const noexcept
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{
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return (size + 1)/2;
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}
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protected:
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uint8_t buf; ///< Internal buffer
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size_t num; ///< Number of nibbles used in `buf`
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};
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}
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