streams.cpp   [plain text]

/*
 * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
 * 
 * The contents of this file constitute Original Code as defined in and are
 * subject to the Apple Public Source License Version 1.2 (the 'License').
 * You may not use this file except in compliance with the License. Please obtain
 * a copy of the License at http://www.apple.com/publicsource and read it before
 * using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
 * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
 * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
 * specific language governing rights and limitations under the License.
 */


//
// streams.h - lightweight source and sink objects
//
#include "streams.h"
#include <Security/memutils.h>


namespace Security {


//
// Source and Sink abstract superclasses
//
Source::State Source::state() const
{
    return mState;
}

size_t Source::getSize()
{
    return unknownSize;
}

void Sink::setSize(size_t)
{
    // ignored
}


//
// Null sources and sinks
//
void NullSource::produce(void *, size_t &length)
{
    length = 0;
}

Source::State NullSource::state() const
{
    return endOfData;
}

void NullSink::consume(const void *, size_t)
{
    // ignore the data
}


//
// File sources and sinks
//
void FileSource::produce(void *data, size_t &length)
{
    if ((length = read(data, length)) == 0)
        mState = endOfData;
}

size_t FileSource::getSize()
{
    return fileSize();
}


void FileSink::consume(const void *data, size_t length)
{
	write(data, length);
}


//
// Memory sources
//
void MemorySource::produce(void *data, size_t &length)
{
    if (mRemaining < length)
        length = mRemaining;
    memcpy(data, mData, length);
    mData = LowLevelMemoryUtilities::increment(mData, length);
    mRemaining -= length;
}

size_t MemorySource::getSize()
{
    return mRemaining;
}

Source::State MemorySource::state() const
{
    return mRemaining ? producing : endOfData;
}


//
// Memory sinks
//
void MemorySink::consume(const void *data, size_t length)
{
    if (mSize + length > mMax)
        grow(mSize * 3 / 2);
    assert(mSize + length <= mMax);
    memcpy(((char *)mBuffer) + mSize, data, length);
    mSize += length;
}

void MemorySink::setSize(size_t expectedSize)
{
    grow(expectedSize);
}

void MemorySink::grow(size_t newSize)
{
    if (void *p = realloc(mBuffer, newSize)) {
        mBuffer = p;
        mMax = newSize;
    } else
        UnixError::throwMe();
}


}	// end namespace Security