Move Hex from WinStd to stdex

Signed-off-by: Simon Rozman <simon@rozman.si>

include/stdex/hex

@@ -0,0 +1,159 @@
+/*
+    SPDX-License-Identifier: GPL-3.0-or-later
+    Copyright © 2016-2022 Amebis
+*/
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+
+namespace stdex
+{
+    ///
+    /// Hexadecimal encoding session
+    ///
+    class hex_enc
+    {
+    public:
+        ///
+        /// Constructs blank encoding session
+        ///
+        hex_enc() noexcept
+        {
+        }
+
+
+        ///
+        /// Encodes one block of information, and _appends_ it to the output
+        ///
+        /// \param[out] out   Output
+        /// \param[in ] data  Data to encode
+        /// \param[in ] size  Length of `data` in bytes
+        ///
+        template<class _Elem, class _Traits, class _Ax>
+        void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_bytecount_(size) const void *data, _In_ size_t size)
+        {
+            assert(data || !size);
+
+            // Preallocate output
+            out.reserve(out.size() + enc_size(size));
+
+            // Convert data character by character.
+            for (size_t i = 0; i < size; i++) {
+                unsigned char
+                    x   = reinterpret_cast<const unsigned char*>(data)[i],
+                    x_h = ((x & 0xf0) >> 4),
+                    x_l = ((x & 0x0f)     );
+
+                out += x_h < 10 ? '0' + x_h : 'A' - 10 + x_h;
+                out += x_l < 10 ? '0' + x_l : 'A' - 10 + x_l;
+            }
+        }
+
+
+        ///
+        /// Returns maximum encoded size
+        ///
+        /// \param size  Number of bytes to encode
+        ///
+        /// \returns Maximum number of bytes for the encoded data of `size` length
+        ///
+        size_t enc_size(size_t size) const noexcept
+        {
+            return size*2;
+        }
+    };
+
+
+    ///
+    /// Hexadecimal decoding session
+    ///
+    class hex_dec
+    {
+    public:
+        ///
+        /// Constructs blank decoding session
+        ///
+        hex_dec() noexcept :
+            buf(0),
+            num(0)
+        {
+        }
+
+
+        ///
+        /// Decodes one block of information, and _appends_ it to the output
+        ///
+        /// \param[inout] out      Output
+        /// \param[out  ] is_last  Was this the last block of data? Actually, is this block of data complete?
+        /// \param[in   ] data     Data to decode
+        /// \param[in   ] size     Length of `data` in bytes
+        ///
+        template<class _Ty, class _Ax, class _Tchr>
+        void decode(_Inout_ std::vector<_Ty, _Ax> &out, _Out_ bool &is_last, _In_z_count_(size) const _Tchr *data, _In_ size_t size)
+        {
+            is_last = false;
+
+            // Trim data size to first terminator.
+            for (size_t k = 0; k < size; k++)
+                if (!data[k]) { size = k; break; }
+
+            // Preallocate output
+            out.reserve(out.size() + dec_size(size));
+
+            for (size_t i = 0;; i++) {
+                if (num >= 2) {
+                    // Buffer full.
+                    out.push_back(buf);
+                    num = 0;
+                    is_last = true;
+                } else
+                    is_last = false;
+
+                if (i >= size)
+                    break;
+
+                int x = data[i];
+                if ('0' <= x && x <= '9') {
+                    buf = ((buf & 0xf) << 4) | (unsigned char)(x - '0');
+                    num++;
+                } else if ('A' <= x && x <= 'F') {
+                    buf = ((buf & 0xf) << 4) | (unsigned char)(x - ('A' - 10));
+                    num++;
+                } else if ('a' <= x && x <= 'f') {
+                    buf = ((buf & 0xf) << 4) | (unsigned char)(x - ('a' - 10));
+                    num++;
+                }
+            }
+        }
+
+
+        ///
+        /// Resets decoding session
+        ///
+        void clear() noexcept
+        {
+            num = 0;
+        }
+
+
+        ///
+        /// Returns maximum decoded size
+        ///
+        /// \param size  Number of bytes to decode
+        ///
+        /// \returns Maximum number of bytes for the decoded data of `size` length
+        ///
+        size_t dec_size(size_t size) const noexcept
+        {
+            return (size + 1)/2;
+        }
+
+
+    protected:
+        unsigned char buf;  ///< Internal buffer
+        size_t num;         ///< Number of nibbles used in `buf`
+    };
+}