JUCE/modules/juce_core/streams/juce_InputStream.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   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.

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

namespace juce
{

int64 InputStream::getNumBytesRemaining()
{
    auto len = getTotalLength();

    if (len >= 0)
        len -= getPosition();

    return len;
}

ssize_t InputStream::read (void* destBuffer, size_t size)
{
    ssize_t totalRead = 0;

    while (size > 0)
    {
        auto numToRead = (int) std::min (size, (size_t) 0x70000000);
        auto numRead = read (juce::addBytesToPointer (destBuffer, totalRead), numToRead);
        jassert (numRead <= numToRead);

        if (numRead < 0) return (ssize_t) numRead;
        if (numRead == 0) break;

        size -= (size_t) numRead;
        totalRead += numRead;
    }

    return totalRead;
}

char InputStream::readByte()
{
    char temp = 0;
    read (&temp, 1);
    return temp;
}

bool InputStream::readBool()
{
    return readByte() != 0;
}

short InputStream::readShort()
{
    char temp[2];

    if (read (temp, 2) == 2)
        return (short) ByteOrder::littleEndianShort (temp);

    return 0;
}

short InputStream::readShortBigEndian()
{
    char temp[2];

    if (read (temp, 2) == 2)
        return (short) ByteOrder::bigEndianShort (temp);

    return 0;
}

int InputStream::readInt()
{
    char temp[4];

    if (read (temp, 4) == 4)
        return (int) ByteOrder::littleEndianInt (temp);

    return 0;
}

int InputStream::readIntBigEndian()
{
    char temp[4];

    if (read (temp, 4) == 4)
        return (int) ByteOrder::bigEndianInt (temp);

    return 0;
}

int InputStream::readCompressedInt()
{
    auto sizeByte = (uint8) readByte();

    if (sizeByte == 0)
        return 0;

    const int numBytes = (sizeByte & 0x7f);

    if (numBytes > 4)
    {
        jassertfalse;  // trying to read corrupt data - this method must only be used
                       // to read data that was written by OutputStream::writeCompressedInt()
        return 0;
    }

    char bytes[4] = {};

    if (read (bytes, numBytes) != numBytes)
        return 0;

    auto num = (int) ByteOrder::littleEndianInt (bytes);
    return (sizeByte >> 7) ? -num : num;
}

int64 InputStream::readInt64()
{
    union { uint8 asBytes[8]; uint64 asInt64; } n;

    if (read (n.asBytes, 8) == 8)
        return (int64) ByteOrder::swapIfBigEndian (n.asInt64);

    return 0;
}

int64 InputStream::readInt64BigEndian()
{
    union { uint8 asBytes[8]; uint64 asInt64; } n;

    if (read (n.asBytes, 8) == 8)
        return (int64) ByteOrder::swapIfLittleEndian (n.asInt64);

    return 0;
}

float InputStream::readFloat()
{
    static_assert (sizeof (int32) == sizeof (float), "Union assumes float has the same size as an int32");
    union { int32 asInt; float asFloat; } n;
    n.asInt = (int32) readInt();
    return n.asFloat;
}

float InputStream::readFloatBigEndian()
{
    union { int32 asInt; float asFloat; } n;
    n.asInt = (int32) readIntBigEndian();
    return n.asFloat;
}

double InputStream::readDouble()
{
    union { int64 asInt; double asDouble; } n;
    n.asInt = readInt64();
    return n.asDouble;
}

double InputStream::readDoubleBigEndian()
{
    union { int64 asInt; double asDouble; } n;
    n.asInt = readInt64BigEndian();
    return n.asDouble;
}

String InputStream::readString()
{
    MemoryOutputStream buffer;

    for (;;)
    {
        auto c = readByte();
        buffer.writeByte (c);

        if (c == 0)
            return buffer.toUTF8();
    }
}

String InputStream::readNextLine()
{
    MemoryOutputStream buffer;

    for (;;)
    {
        auto c = readByte();

        if (c == 0 || c == '\n')
            break;

        if (c == '\r')
        {
            auto lastPos = getPosition();

            if (readByte() != '\n')
                setPosition (lastPos);

            break;
        }

        buffer.writeByte (c);
    }

    return buffer.toUTF8();
}

size_t InputStream::readIntoMemoryBlock (MemoryBlock& block, ssize_t numBytes)
{
    MemoryOutputStream mo (block, true);
    return (size_t) mo.writeFromInputStream (*this, numBytes);
}

String InputStream::readEntireStreamAsString()
{
    MemoryOutputStream mo;
    mo << *this;
    return mo.toString();
}

//==============================================================================
void InputStream::skipNextBytes (int64 numBytesToSkip)
{
    if (numBytesToSkip > 0)
    {
        auto skipBufferSize = (int) jmin (numBytesToSkip, (int64) 16384);
        HeapBlock<char> temp (skipBufferSize);

        while (numBytesToSkip > 0 && ! isExhausted())
            numBytesToSkip -= read (temp, (int) jmin (numBytesToSkip, (int64) skipBufferSize));
    }
}

} // namespace juce