/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

MemoryBlock::MemoryBlock() noexcept
    : size (0)
{
}

MemoryBlock::MemoryBlock (const size_t initialSize, const bool initialiseToZero)
{
    if (initialSize > 0)
    {
        size = initialSize;
        data.allocate (initialSize, initialiseToZero);
    }
    else
    {
        size = 0;
    }
}

MemoryBlock::MemoryBlock (const MemoryBlock& other)
    : size (other.size)
{
    if (size > 0)
    {
        jassert (other.data != nullptr);
        data.malloc (size);
        memcpy (data, other.data, size);
    }
}

MemoryBlock::MemoryBlock (const void* const dataToInitialiseFrom, const size_t sizeInBytes)
    : size (sizeInBytes)
{
    jassert (((ssize_t) sizeInBytes) >= 0);

    if (size > 0)
    {
        jassert (dataToInitialiseFrom != nullptr); // non-zero size, but a zero pointer passed-in?

        data.malloc (size);

        if (dataToInitialiseFrom != nullptr)
            memcpy (data, dataToInitialiseFrom, size);
    }
}

MemoryBlock::~MemoryBlock() noexcept
{
}

MemoryBlock& MemoryBlock::operator= (const MemoryBlock& other)
{
    if (this != &other)
    {
        setSize (other.size, false);
        memcpy (data, other.data, size);
    }

    return *this;
}

MemoryBlock::MemoryBlock (MemoryBlock&& other) noexcept
    : data (static_cast<HeapBlockType&&> (other.data)),
      size (other.size)
{
}

MemoryBlock& MemoryBlock::operator= (MemoryBlock&& other) noexcept
{
    data = static_cast<HeapBlockType&&> (other.data);
    size = other.size;
    return *this;
}

//==============================================================================
bool MemoryBlock::operator== (const MemoryBlock& other) const noexcept
{
    return matches (other.data, other.size);
}

bool MemoryBlock::operator!= (const MemoryBlock& other) const noexcept
{
    return ! operator== (other);
}

bool MemoryBlock::matches (const void* dataToCompare, size_t dataSize) const noexcept
{
    return size == dataSize
            && memcmp (data, dataToCompare, size) == 0;
}

//==============================================================================
// this will resize the block to this size
void MemoryBlock::setSize (const size_t newSize, const bool initialiseToZero)
{
    if (size != newSize)
    {
        if (newSize <= 0)
        {
            reset();
        }
        else
        {
            if (data != nullptr)
            {
                data.realloc (newSize);

                if (initialiseToZero && (newSize > size))
                    zeromem (data + size, newSize - size);
            }
            else
            {
                data.allocate (newSize, initialiseToZero);
            }

            size = newSize;
        }
    }
}

void MemoryBlock::reset()
{
    data.free();
    size = 0;
}

void MemoryBlock::ensureSize (const size_t minimumSize, const bool initialiseToZero)
{
    if (size < minimumSize)
        setSize (minimumSize, initialiseToZero);
}

void MemoryBlock::swapWith (MemoryBlock& other) noexcept
{
    std::swap (size, other.size);
    data.swapWith (other.data);
}

//==============================================================================
void MemoryBlock::fillWith (const uint8 value) noexcept
{
    memset (data, (int) value, size);
}

void MemoryBlock::append (const void* const srcData, const size_t numBytes)
{
    if (numBytes > 0)
    {
        jassert (srcData != nullptr); // this must not be null!
        const size_t oldSize = size;
        setSize (size + numBytes);
        memcpy (data + oldSize, srcData, numBytes);
    }
}

void MemoryBlock::replaceWith (const void* const srcData, const size_t numBytes)
{
    if (numBytes > 0)
    {
        jassert (srcData != nullptr); // this must not be null!
        setSize (numBytes);
        memcpy (data, srcData, numBytes);
    }
}

void MemoryBlock::insert (const void* const srcData, const size_t numBytes, size_t insertPosition)
{
    if (numBytes > 0)
    {
        jassert (srcData != nullptr); // this must not be null!
        insertPosition = jmin (size, insertPosition);
        const size_t trailingDataSize = size - insertPosition;
        setSize (size + numBytes, false);

        if (trailingDataSize > 0)
            memmove (data + insertPosition + numBytes,
                     data + insertPosition,
                     trailingDataSize);

        memcpy (data + insertPosition, srcData, numBytes);
    }
}

void MemoryBlock::removeSection (const size_t startByte, const size_t numBytesToRemove)
{
    if (startByte + numBytesToRemove >= size)
    {
        setSize (startByte);
    }
    else if (numBytesToRemove > 0)
    {
        memmove (data + startByte,
                 data + startByte + numBytesToRemove,
                 size - (startByte + numBytesToRemove));

        setSize (size - numBytesToRemove);
    }
}

void MemoryBlock::copyFrom (const void* const src, int offset, size_t num) noexcept
{
    const char* d = static_cast<const char*> (src);

    if (offset < 0)
    {
        d -= offset;
        num += (size_t) -offset;
        offset = 0;
    }

    if ((size_t) offset + num > size)
        num = size - (size_t) offset;

    if (num > 0)
        memcpy (data + offset, d, num);
}

void MemoryBlock::copyTo (void* const dst, int offset, size_t num) const noexcept
{
    char* d = static_cast<char*> (dst);

    if (offset < 0)
    {
        zeromem (d, (size_t) -offset);
        d -= offset;
        num -= (size_t) -offset;
        offset = 0;
    }

    if ((size_t) offset + num > size)
    {
        const size_t newNum = (size_t) size - (size_t) offset;
        zeromem (d + newNum, num - newNum);
        num = newNum;
    }

    if (num > 0)
        memcpy (d, data + offset, num);
}

String MemoryBlock::toString() const
{
    return String::fromUTF8 (data, (int) size);
}

//==============================================================================
int MemoryBlock::getBitRange (const size_t bitRangeStart, size_t numBits) const noexcept
{
    int res = 0;

    size_t byte = bitRangeStart >> 3;
    size_t offsetInByte = bitRangeStart & 7;
    size_t bitsSoFar = 0;

    while (numBits > 0 && (size_t) byte < size)
    {
        const size_t bitsThisTime = jmin (numBits, 8 - offsetInByte);
        const int mask = (0xff >> (8 - bitsThisTime)) << offsetInByte;

        res |= (((data[byte] & mask) >> offsetInByte) << bitsSoFar);

        bitsSoFar += bitsThisTime;
        numBits -= bitsThisTime;
        ++byte;
        offsetInByte = 0;
    }

    return res;
}

void MemoryBlock::setBitRange (const size_t bitRangeStart, size_t numBits, int bitsToSet) noexcept
{
    size_t byte = bitRangeStart >> 3;
    size_t offsetInByte = bitRangeStart & 7;
    uint32 mask = ~((((uint32) 0xffffffff) << (32 - numBits)) >> (32 - numBits));

    while (numBits > 0 && (size_t) byte < size)
    {
        const size_t bitsThisTime = jmin (numBits, 8 - offsetInByte);

        const uint32 tempMask = (mask << offsetInByte) | ~((((uint32) 0xffffffff) >> offsetInByte) << offsetInByte);
        const uint32 tempBits = (uint32) bitsToSet << offsetInByte;

        data[byte] = (char) (((uint32) data[byte] & tempMask) | tempBits);

        ++byte;
        numBits -= bitsThisTime;
        bitsToSet >>= bitsThisTime;
        mask >>= bitsThisTime;
        offsetInByte = 0;
    }
}

//==============================================================================
void MemoryBlock::loadFromHexString (StringRef hex)
{
    ensureSize ((size_t) hex.length() >> 1);
    char* dest = data;
    String::CharPointerType t (hex.text);

    for (;;)
    {
        int byte = 0;

        for (int loop = 2; --loop >= 0;)
        {
            byte <<= 4;

            for (;;)
            {
                const juce_wchar c = t.getAndAdvance();

                if (c >= '0' && c <= '9')    { byte |= c - '0';        break; }
                if (c >= 'a' && c <= 'z')    { byte |= c - ('a' - 10); break; }
                if (c >= 'A' && c <= 'Z')    { byte |= c - ('A' - 10); break; }

                if (c == 0)
                {
                    setSize (static_cast<size_t> (dest - data));
                    return;
                }
            }
        }

        *dest++ = (char) byte;
    }
}

//==============================================================================
static const char base64EncodingTable[] = ".ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+";

String MemoryBlock::toBase64Encoding() const
{
    const size_t numChars = ((size << 3) + 5) / 6;

    String destString ((unsigned int) size); // store the length, followed by a '.', and then the data.
    const int initialLen = destString.length();
    destString.preallocateBytes (sizeof (String::CharPointerType::CharType) * (size_t) initialLen + 2 + numChars);

    String::CharPointerType d (destString.getCharPointer());
    d += initialLen;
    d.write ('.');

    for (size_t i = 0; i < numChars; ++i)
        d.write ((juce_wchar) (uint8) base64EncodingTable [getBitRange (i * 6, 6)]);

    d.writeNull();
    return destString;
}

static const char base64DecodingTable[] =
{
    63, 0, 0, 0, 0, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 0, 0, 0, 0, 0, 0, 0,
    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
    0, 0, 0, 0, 0, 0, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52
};

bool MemoryBlock::fromBase64Encoding (StringRef s)
{
    String::CharPointerType dot (CharacterFunctions::find (s.text, (juce_wchar) '.'));

    if (dot.isEmpty())
        return false;

    const int numBytesNeeded = String (s.text, dot).getIntValue();

    setSize ((size_t) numBytesNeeded, true);

    String::CharPointerType srcChars (dot + 1);
    int pos = 0;

    for (;;)
    {
        int c = (int) srcChars.getAndAdvance();

        if (c == 0)
            return true;

        c -= 43;
        if (isPositiveAndBelow (c, numElementsInArray (base64DecodingTable)))
        {
            setBitRange ((size_t) pos, 6, base64DecodingTable [c]);
            pos += 6;
        }
    }
}
