AuroraRuntime/Source/Parse/Hex.cpp

/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Hex.cpp
    Date: 2021-8-28
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Hex.hpp"

namespace Aurora::Parse
{
    static bool HexToOctet(const char *hex, AuUInt8 &val)
    {
        val = 0;

        for (auto i = 0u; i < 2; i++)
        {
            AuUInt8 byte = *hex++;
            
            if (byte >= '0' && byte <= '9')
            {
                byte = byte - '0';
            }
            else if (byte >= 'A' && byte <= 'F')
            {
                byte = byte - 'A' + 10;
            }
            else if (byte >= 'a' && byte <= 'f')
            {
                byte = byte - 'a' + 10;
            }
            else
            {
                return false;
            }

            val = (val << 4) | (byte & 0xF);
        }

        return true;
    }

    AUKN_SYM bool HexToInt(const char *hex, AuUInt32 length, AuUInt64 &val)
    {
        val    = 0;
        length = AuMin(AuUInt32(sizeof(AuUInt64) * 2), length);
        
        for (auto i = 0u; i < length; i++)
        {
            AuUInt8 byte = *hex++;
            
            if (byte >= '0' && byte <= '9')
            {
                byte = byte - '0';
            }
            else if (byte >= 'A' && byte <= 'F')
            {
                byte = byte - 'A' + 10;
            }
            else if (byte >= 'a' && byte <= 'f')
            {
                byte = byte - 'a' + 10;
            }
            else
            {
                return false;
            }

            val = (val << 4) | (byte & 0xF);
        }

        return true;
    }
    
    AUKN_SYM bool HexToByte(const char (hex)[2], AuUInt8 &val)
    {
        return HexToOctet(hex, val);
    }

    static inline char NibbleToChar(AuUInt8 nib)
    {
        if (nib < 10)
            return '0' + nib;
        else
            return 'A' + (nib - 10);
    }
    
    AUKN_SYM void ByteToHex(AuUInt8 val, char (& hex)[2])
    {
        AuUInt8 lowNibble = val & 0xF;
        AuUInt8 hiNibble  = (val >> 4) & 0xF;
        
        hex[0] = NibbleToChar(hiNibble);
        hex[1] = NibbleToChar(lowNibble);
    }

    AUKN_SYM bool DecodeHex(const AuString &in, AuByteBuffer &out)
    {
    #define HEX_GRAMMAR_CONSUME_ALL(x) \
        for (; i < in.size(); i++)     \
        {                              \
            if (in[i] != x)            \
            {                          \
                break;                 \
            }                          \
        }
        
    #define HEX_GRAMMAR_CONSUME_ONE(x) \
        if (i < in.size())             \
        {                              \
            if (in[i] == x)            \
            {                          \
                i ++;                  \
            }                          \
        }

    #define HEX_GRAMMAR_CONSUME_EITHER(a, b) \
        if (i < in.size())                   \
        {                                    \
            if ((in[i] == a) ||              \
                (in[i] == b))                \
            {                                \
                i++;                         \
            }                                \
        }

    #define HEX_GRAMMAR_CONSUME_SPACE    \
        HEX_GRAMMAR_CONSUME_ALL(' ')

    #define HEX_GRAMMAR_CONSUME_NEW_LINE \
        HEX_GRAMMAR_CONSUME_ONE('\r')    \
        HEX_GRAMMAR_CONSUME_ALL('\n')

    #define HEX_GRAMMAR_CONSUME_END_OF_LINE \
        HEX_GRAMMAR_CONSUME_SPACE           \
        HEX_GRAMMAR_CONSUME_NEW_LINE        \
        HEX_GRAMMAR_CONSUME_SPACE

        AuUInt i = 0u;

        out.reserve(in.size() / 2);

        // Consume whitespace and/or literal start
        {
            HEX_GRAMMAR_CONSUME_SPACE;
            HEX_GRAMMAR_CONSUME_EITHER('{', '[');
            HEX_GRAMMAR_CONSUME_END_OF_LINE;
        }

        // Consume array
        for (; i < in.size(); )
        {
            // Consume prefix
            if ((i + 1) < in.size())
            {
                if ((in[i] == '0') && 
                    (in[i + 1] == 'x'))
                {
                    i += 2;
                }
            }
            
            // Consume octal
            if ((i + 1) < in.size())
            {
                AuUInt8 byte;

                if (!HexToOctet(&in[i], byte))
                {
                    out.clear();
                    return false;
                }

                out.Write(byte);
                i += 2;
            }

            HEX_GRAMMAR_CONSUME_ONE(',');
            HEX_GRAMMAR_CONSUME_END_OF_LINE;
            
            // Consume end literal hint
            if (i < in.size())
            {
                if ((in[i] == '}') ||
                    (in[i] == ']'))
                {
                    break;
                }
            }
        }

        return true;
    }

    AUKN_SYM void EncodeHex(const void *pBuf, AuUInt32 length, EHexDump formatting, AuString &in)
    {
        bool hexedit = formatting == EHexDump::eHexEditor;
        
        bool squareBracket = formatting == EHexDump::eJSLiteral;
        bool curlyBracket = formatting == EHexDump::eCLiteral;

        bool zeroX = formatting == EHexDump::eCLiteral || 
                     formatting == EHexDump::eJSLiteral ||
                     formatting == EHexDump::eZeroXSpace;
        
        bool space = formatting != EHexDump::eString;

        in.reserve(length * 4);

        auto &newLine = AuLocale::NewLine();

        if (hexedit)
        {
            in.insert(in.size(), "00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15");
            in.insert(in.size(), newLine);
            in.insert(in.size(), "00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F");
            in.insert(in.size(), newLine);
            in.insert(in.size(), "                                               ");
            in.insert(in.size(), newLine);
        }
        else if (squareBracket)
        {
            in.insert(in.end(), '[');
            in.insert(in.size(), newLine);
        }
        else if (curlyBracket)
        {
            in.insert(in.end(), '{');
            in.insert(in.size(), newLine);
        }

        for (int i = 0; i < length; )
        {
            AuUInt32 x, rowMax;
            
            if (i != 0)
            {
                if (hexedit || squareBracket || curlyBracket)
                {
                    in.insert(in.size(), newLine);
                }
            }

            if (squareBracket || curlyBracket)
            {
                in.insert(in.size(), "    ");
            }

            rowMax = AuMin(AuUInt32(i + 16), AuUInt32(length));
            
            for (x = i;
                 x < rowMax;
                 x ++)
            {
                if (space)
                {
                    if (x != i)
                    {
                        in.insert(in.end(), ' ');
                    }
                }

                if (zeroX)
                {
                    in.insert(in.size(), "0x");
                }

                {
                    char hex[2];
                    ByteToHex(reinterpret_cast<const AuUInt8*>(pBuf)[x], hex);
                    in.insert(in.size(), hex, 2);
                }
                
                if (x != (length - 1))
                {
                    if (squareBracket || curlyBracket)
                    {
                        in.insert(in.end(), ',');
                    }
                }
            }

            i = x;

            if (hexedit)
            {
                // TODO: print space + i * 16 padded + space hex(i * 16 padded)
            }
        }

        if (squareBracket)
        {
            in.insert(in.size(), newLine);
            in.insert(in.end(), ']');
        }
        else if (curlyBracket)
        {
            in.insert(in.size(), newLine);
            in.insert(in.end(), '}');
        }

        in.shrink_to_fit();
    }
}