binarybuffer.cpp

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// © Copyright 2010 - 2016 BlackTopp Studios Inc.
/* This file is part of The Mezzanine Engine.

    The Mezzanine Engine is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
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    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
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*/
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   'Docs' folder. See 'gpl.txt'
*/
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*/
#ifndef _binarytool_cpp
#define _binarytool_cpp

/// @file
/// @brief The implementation of some tools for making working with binary stuff easier.

#include "binarybuffer.h"
#include "exception.h"

#include <string.h>
#include <algorithm>

namespace Mezzanine
{
    namespace BinaryTools
    {
        /*
         * Some of the following functions and 1 variable were taken from http://www.adp-gmbh.ch/cpp/common/base64.html
         * for the functions IsBase64(unsigned char c),  Base64Encode(UInt8 const* BytesToEncode, unsigned int Length),
         *     Base64Decode(String const& EncodedString) and Base64Chars and maybe a few others in this file or the
         *     tests for this file
         * with written permission as follows.


           Copyright (C) 2004-2008 René Nyffenegger

           This source code is provided 'as-is', without any express or implied
           warranty. In no event will the author be held liable for any damages
           arising from the use of this software.

           Permission is granted to anyone to use this software for any purpose,
           including commercial applications, and to alter it and redistribute it
           freely, subject to the following restrictions:

           1. The origin of this source code must not be misrepresented; you must not
              claim that you wrote the original source code. If you use this source code
              in a product, an acknowledgment in the product documentation would be
              appreciated but is not required.

           2. Altered source versions must be plainly marked as such, and must not be
              misrepresented as being the original source code.

           3. This notice may not be removed or altered from any source distribution.

           René Nyffenegger rene.nyffenegger@adp-gmbh.ch

        */

        namespace
        {
            // Code change to Match BTS naming conventions and formatting
            static const String Base64Chars =
                         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                         "abcdefghijklmnopqrstuvwxyz"
                         "0123456789+/";

            /// @brief The actual implementation of the Base64 decoding
            /// @param EncodedString The String to decode
            /// @param Results A reference to a @ref BinaryBuffer with the Size set correctly and a Buffer Allocated, this will be the output.
            void Base64DecodeImpl(const String& EncodedString, BinaryBuffer& Results)
            {
                if(Results.Binary==0 || Results.Size==0)
                    { MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION, "Cannot encode an empty buffer."); }

                String::const_iterator Progress = EncodedString.begin();
                Whole Output = 0;

                //Initializing this RAM really slows it down like 30% to double onto execution time.
                //for(Whole c=0; c<Results.Size; c++)
                    //{ Results[c] = 0; }

                unsigned char First;
                unsigned char Second;
                unsigned char Third;
                unsigned char Fourth;

                while(Progress<EncodedString.end())
                {
                    // cout << *(Progress+0) << *(Progress+1) << *(Progress+2) << *(Progress+3) << endl;
                    // cout << !IsBase64(*Progress) << !IsBase64(*(Progress+1)) << !IsBase64(*(Progress+2)) << !IsBase64(*(Progress+3)) <<endl;
                    if(!IsBase64(*Progress) || !IsBase64(*(Progress+1)) || !IsBase64(*(Progress+2)) || !IsBase64(*(Progress+3)))
                        { MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION, "Base64 contains an invalid character and cannot be decoded."); }

                    First = Base64Chars.find(*(Progress+0));
                    Second = Base64Chars.find(*(Progress+1));
                    Third = *(Progress+2)=='=' ? 0 : Base64Chars.find(*(Progress+2));

                    #ifdef MEZZDEBUG
                    if(Output+1>Results.Size)
                        { MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Output of base64 Decoding is larger than it should be."); }
                    #endif

                    *(Results.Binary+Output+0) = (First << 2) + ((Second & 0x30) >> 4);
                    *(Results.Binary+Output+1) = ((Second & 0xf) << 4) + ((Third & 0x3c) >> 2);
                    if(*(Progress+3)!='=')
                    {
                        #ifdef MEZZDEBUG
                        if(Output+2>Results.Size)
                            { MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Output of base64 Decoding is larger than it should be."); }
                        #endif
                        Fourth = Base64Chars.find(*(Progress+3));
                        *(Results.Binary+Output+2) = ((Third & 0x3) << 6) + Fourth;
                    }

                    #ifdef MEZZDEBUG
                    if(Progress>EncodedString.end())
                        { MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Gone past the end of the input while decoding a base64 string."); }
                    #endif
                    Output+=3;
                    Progress+=4;
                }
            }
        }

        ///////////////////////////////////////////////////////////////////////////////
        // Binary Buffer Methods

        ///////////////////////////////////////////////////////////////////////////////
        // Construction and Destruction

        BinaryBuffer::BinaryBuffer() :
            Size(0),
            Binary(NULL)
            {  }

        BinaryBuffer::BinaryBuffer(const BinaryBuffer& Other)
        {
            this->Size = Other.Size;
            if( Other.Size && Other.Binary ) {
                this->Binary = new Byte[this->Size * sizeof(Byte)];
                memcpy(this->Binary,Other.Binary,this->Size);
            }else{
                this->Binary = 0;
            }
        }

        BinaryBuffer::BinaryBuffer(const Whole PredeterminedSize) :
            Size(PredeterminedSize),
            Binary(new Byte[PredeterminedSize])
            {  }

        BinaryBuffer::BinaryBuffer(Byte* BinaryPointer, const Whole PredeterminedSize) :
            Size(PredeterminedSize),
            Binary(BinaryPointer ? BinaryPointer : new Byte[PredeterminedSize])
            {  }

        BinaryBuffer::BinaryBuffer(const String& DataString, const Boole IsBase64)
        {
            if( IsBase64 ) {
                this->Binary = NULL;
                this->CreateFromBase64(DataString);
            }else{
                this->Size = DataString.size();
                this->CreateBuffer();
                memcpy(this->Binary, DataString.c_str(), this->Size);
            }
        }

        BinaryBuffer::~BinaryBuffer()
            { this->DeleteBuffer(); }

        ///////////////////////////////////////////////////////////////////////////////
        // Utility

        void BinaryBuffer::CreateBuffer()
        {
            if( this->Size ) {
                this->Binary = new Byte[this->Size * sizeof(Byte)];
            }else{
                MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Cannot create a 0 length Buffer.");
            }
        }

        void BinaryBuffer::DeleteBuffer(const Whole NewSize)
        {
            if( this->Binary )
                { delete[] this->Binary; }
            this->Binary = NULL;
            this->Size = NewSize;
        }

        void BinaryBuffer::CreateFromBase64(const String& EncodedBinaryData)
        {
            if( this->Binary )
                { delete[] Binary; }
            this->Size = PredictBinarySizeFromBase64String(EncodedBinaryData);
            this->Binary = new Byte[Size * sizeof(Byte)];
            Base64DecodeImpl(EncodedBinaryData,*this);
        }

        String BinaryBuffer::ToBase64String()
        {
            if( !this->Size || !this->Binary ) {
                MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Cannot encode 0 length or missing buffer.");
            }
            return Base64Encode((UInt8*)this->Binary,this->Size * sizeof(Byte));
        }

        void BinaryBuffer::Concatenate(const Byte* OtherBuffer, const Whole ByteSize)
        {
            Whole NewSize = (this->Size + ByteSize) * sizeof(Byte);
            Byte* TargetBuffer = new Byte[NewSize];

            memcpy(TargetBuffer, this->Binary, this->Size);
            memcpy(TargetBuffer+this->Size, OtherBuffer, ByteSize);

            this->DeleteBuffer(NewSize);
            this->Binary = TargetBuffer;
        }

        void BinaryBuffer::Concatenate(const BinaryBuffer BufferFromAnotherMother)
            { this->Concatenate(BufferFromAnotherMother.Binary, BufferFromAnotherMother.Size); }

        String BinaryBuffer::ToString()
        {
            if( !this->Size || !this->Binary ) {
                MEZZ_EXCEPTION(ExceptionBase::INVALID_STATE_EXCEPTION, "Cannot construct string from 0 length or missing buffer.");
            }
            return String((char*)(this->Binary),this->Size * sizeof(Byte));
        }

        Whole BinaryBuffer::GetSize() const
            { return this->Size; }

        ///////////////////////////////////////////////////////////////////////////////
        // Operators

        BinaryBuffer& BinaryBuffer::operator=(const BinaryBuffer& RH)
        {
            if( RH.Binary == this->Binary )
                { MEZZ_EXCEPTION(ExceptionBase::INVALID_ASSIGNMENT, "Attempted a self assignment of a BinaryBuffer"); }
            this->DeleteBuffer(RH.Size);
            if( RH.Size && RH.Binary ) {
                this->CreateBuffer();
                memcpy(this->Binary,RH.Binary,this->Size);
            }else{
                this->Binary = 0;
            }
            return *this;
        }

        BinaryBuffer& BinaryBuffer::operator+=(const BinaryBuffer& RH)
        {
            this->Concatenate(RH);
            return *this;
        }


        BinaryBuffer::Byte& BinaryBuffer::operator[](const Whole Index)
        {
            #ifdef MEZZDEBUG
            if( Index >= this->Size )
                { MEZZ_EXCEPTION(ExceptionBase::MM_OUT_OF_BOUNDS_EXCEPTION, "Attempted access beyond range of Binary Buffer"); }
            #endif
            return *(this->Binary + Index);
        }

        ///////////////////////////////////////////////////////////////////////////////
        // Base64 Helpers

        // Code change to Match BTS naming conventions and formatting
        Boole IsBase64(unsigned char Character)
            { return (isalnum(Character) || (Character == '+') || (Character == '/') || (Character == '=')); }

        String Base64Encode(String const& Unencoded)
            { return Base64Encode((UInt8 const*)Unencoded.c_str(), Unencoded.size()); }

        String Base64Encode(const BinaryBuffer &Buffer)
            { return Base64Encode((const UInt8*) Buffer.Binary,Buffer.Size); }

        // Code change to Match BTS naming conventions and formatting
        String Base64Encode(UInt8 const* BytesToEncode, unsigned int Length)
        {
            String Results;
            Results.reserve(PredictBase64StringSizeFromBinarySize(Length));

            int i = 0;
            int j = 0;
            unsigned char char_array_3[3];
            unsigned char char_array_4[4];

            while (Length--)
            {
                char_array_3[i++] = *(BytesToEncode++);
                if (i == 3)
                {
                    char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
                    char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
                    char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
                    char_array_4[3] = char_array_3[2] & 0x3f;

                    for(i = 0; (i <4) ; i++)
                        { Results += Base64Chars[char_array_4[i]]; }
                    i = 0;
                }
            }

            if (i)
            {
                for(j = i; j < 3; j++)
                    { char_array_3[j] = '\0'; }

                char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
                char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
                char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
                char_array_4[3] = char_array_3[2] & 0x3f;

                for (j = 0; (j < i + 1); j++)
                    { Results += Base64Chars[char_array_4[j]]; }

                while((i++ < 3))
                { Results += '='; }
            }

            return Results;
        }

        // Code change to Match BTS naming conventions and formatting, then eventually refactored algorithm to adjust return type and switch from Olog(n) to O(n).
        // This one is guaranteed exactly one memory allocation(+= on String likely only doubles allocation repeatidly), less copying, and in general is simpler
        BinaryBuffer Base64Decode(String const& EncodedString)
        {
            BinaryBuffer Results(PredictBinarySizeFromBase64String(EncodedString));

            Base64DecodeImpl(EncodedString, Results);

            return Results;
        }

        Whole PredictBinarySizeFromBase64String(String const& EncodedString)
        {
            if(EncodedString.size()<4)
                { MEZZ_EXCEPTION(ExceptionBase::PARAMETERS_EXCEPTION, "It is not possible to have a base64 string less than 4 bytes in length, but one was received.") }

            return EncodedString.size()/4*3 - ( EncodedString.at(EncodedString.size()-2)=='=' ?1:0) - ( EncodedString.at(EncodedString.size()-1)=='=' ?1:0);
        }

        Whole PredictBase64StringSizeFromBinarySize(Whole Length)
            { return (Length+2)/3*4; }
    }//BinaryTools
}//Mezzanine

#endif