/*

     File: DataSource.cpp

 Abstract: DataSource.h

  Version: 1.1

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*/

#include "DataSource.h"

#if TARGET_OS_WIN32

    #include <io.h>

#else

    #include <unistd.h>

    #include <fcntl.h>

#endif

#include <sys/stat.h>

#include <algorithm>

#define VERBOSE 0

//////////////////////////////////////////////////////////////////////////////////////////

const UInt16 kPositionModeMask = 3;

DataSource::DataSource(Boolean inCloseOnDelete)

    : mCloseOnDelete(inCloseOnDelete)

{

}

DataSource::~DataSource()

{

}

SInt64 DataSource::CalcOffset(  UInt16 positionMode, 

                                SInt64 positionOffset,

                                SInt64 currentOffset,

                                SInt64 size)

{

    SInt64 newOffset = 0;

    switch (positionMode & kPositionModeMask) {

        //case fsAtMark : newOffset = currentOffset; break;

        case SEEK_SET : newOffset = positionOffset; break;

        case SEEK_END : newOffset = size + positionOffset; break;

        case SEEK_CUR : newOffset = positionOffset + currentOffset; break;

    }

    return newOffset;

}

//////////////////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////////////////

#if 0

MacFile_DataSource::MacFile_DataSource( FSIORefNum inForkRefNum, SInt8 inPermissions, Boolean inCloseOnDelete)

    : DataSource(inCloseOnDelete), mFileNum(inForkRefNum), mPermissions(inPermissions)

{

}

MacFile_DataSource::~MacFile_DataSource()

{

    if (mCloseOnDelete) FSCloseFork(mFileNum);

}

OSStatus MacFile_DataSource::GetSize(SInt64& outSize)

{

    outSize = -1; // in case of error

    OSStatus err = FSGetForkSize(mFileNum, &outSize);

    return err;

}

OSStatus MacFile_DataSource::GetPos(SInt64& outPos) const

{

    return FSGetForkPosition(mFileNum, &outPos);

}

OSStatus MacFile_DataSource::SetSize(SInt64 inSize)

{

    return FSSetForkSize(mFileNum, SEEK_SET, inSize);

}

OSStatus MacFile_DataSource::ReadBytes(

                    UInt16 positionMode, 

                    SInt64 positionOffset, 

                    UInt32 requestCount, 

                    void *buffer, 

                    UInt32* actualCount)

{

    if (actualCount) *actualCount = 0;

    if (!buffer) return kAudio_ParamError;

    ByteCount bc_actualCount = 0;

    OSStatus err = FSReadFork(mFileNum, positionMode, positionOffset, requestCount, buffer, &bc_actualCount);

    if (actualCount) *actualCount = (UInt32)bc_actualCount;

    return err;

}

OSStatus MacFile_DataSource::WriteBytes(

                    UInt16 positionMode, 

                    SInt64 positionOffset, 

                    UInt32 requestCount, 

                    const void *buffer, 

                    UInt32* actualCount)

{

    if (!buffer) return kAudio_ParamError;

    ByteCount bc_actualCount = 0;

    OSStatus err =  FSWriteFork(mFileNum, positionMode, positionOffset, requestCount, buffer, &bc_actualCount);

    if (actualCount) *actualCount = (UInt32)bc_actualCount;

    return err;

}

#endif

//////////////////////////////////////////////////////////////////////////////////////////

#define kAudioFileNoCacheMask       0x20

UnixFile_DataSource::UnixFile_DataSource( int inFD, SInt8 inPermissions, Boolean inCloseOnDelete)

    : DataSource(inCloseOnDelete), mFileD(inFD), mPermissions(inPermissions), mNoCache(0), mCachedSize(-1), mFilePointer(0)

{

}

UnixFile_DataSource::~UnixFile_DataSource()

{

    if (mCloseOnDelete) close(mFileD);

}

OSStatus    UnixFile_DataSource::GetSize(SInt64& outSize)

{

#if 0 // 6764274 using the cached file size causes a regression for apps that play a file while writing to it.

    if (mCachedSize >= 0) {

        outSize = mCachedSize;

        return noErr;

    }

#endif

    outSize = -1; // in case of error

    struct stat stbuf;

    if (fstat (mFileD, &stbuf) == -1) return kAudio_FileNotFoundError;

    outSize = mCachedSize = stbuf.st_size;

    return noErr;

}

OSStatus    UnixFile_DataSource::SetSize(SInt64 inSize)

{

    mCachedSize = -1;

#if TARGET_OS_WIN32

    if (chsize (mFileD, inSize)) return kAudioFilePermissionsError;

#else

    if (ftruncate (mFileD, inSize) == -1) return kAudioFilePermissionsError;

#endif

    mCachedSize = inSize;

    return noErr;

}

OSStatus    UnixFile_DataSource::GetPos(SInt64& outPos) const

{

    outPos = mFilePointer;

    return noErr;

}

SInt64      UnixFile_DataSource::UFCurrentOffset (UInt16    positionMode, 

                                                SInt64      positionOffset)

{

    SInt64 offset = -1;

    switch (positionMode & kPositionModeMask) 

    {

        /*case fsAtMark : 

        {

            SInt64 pos;

            OSStatus result = GetPos (pos);

                if (result) return result;

            offset = pos; 

            break;

        }*/

        case SEEK_SET :

        {

            offset = positionOffset; 

            break;

        }

        case SEEK_END : 

        {

            SInt64 size;

            OSStatus result = GetSize (size);

                if (result) return result;

            offset = size + positionOffset; 

            break;

        }

        case SEEK_CUR :

        {

            SInt64 pos;

            OSStatus result = GetPos (pos);

                if (result) return result;

            offset = positionOffset + pos; 

            break;

        }

    }

    return offset;

}

OSStatus    UnixFile_DataSource::ReadBytes( UInt16 positionMode,

                                SInt64 positionOffset, 

                                UInt32 requestCount, 

                                void *buffer, 

                                UInt32* actualCount)

{

    if (actualCount) *actualCount = 0;

    if (!buffer) return kAudio_ParamError;

        // can't use current offset as we need to go to the disk too much       

    SInt64 offset = UFCurrentOffset (positionMode, positionOffset);

        if (offset < 0) return kAudioFilePositionError;

#if 0 // 6571050 fstat-ing the file every read causes a performance regression

    // 5931571 check that read may exceed eof and curtail it.

    do {

        SInt64 size;

        OSStatus serr = GetSize(size);

        if (serr) break;

        SInt64 remain = size - offset;

        if (remain < 0) requestCount = 0;

        else if (requestCount > remain) requestCount = remain;

    } while (false);

#endif

    if (requestCount <= 0) {

        if (actualCount) *actualCount = 0;

        return noErr;

    }

#if !TARGET_OS_WIN32

    UInt32 noCache = positionMode & kAudioFileNoCacheMask ? 1 : 0;

    if (noCache != mNoCache) {

        mNoCache = noCache;

        fcntl(mFileD, F_NOCACHE, mNoCache);

    }

#endif

    size_t readBytes = requestCount;

#if TARGET_OS_WIN32

    lseek(mFileD, offset, SEEK_SET);

    int numBytes = read (mFileD, buffer, readBytes);

#else

    ssize_t numBytes = pread (mFileD, buffer, readBytes, offset);

#endif

    if (numBytes == -1) return kAudioFilePositionError;

    mFilePointer = offset + numBytes;

    if (actualCount) *actualCount = (UInt32)numBytes;

    return noErr;

}

OSStatus    UnixFile_DataSource::WriteBytes(UInt16 positionMode, 

                                SInt64 positionOffset, 

                                UInt32 requestCount, 

                                const void *buffer, 

                                UInt32* actualCount)

{

    if (!buffer) return kAudio_ParamError;

        // can't use current offset as we need to go to the disk too much       

    SInt64 offset = UFCurrentOffset (positionMode, positionOffset);

        if (offset < 0) return kAudioFilePositionError;

    mCachedSize = -1;

    size_t writeBytes = requestCount;

#if !TARGET_OS_WIN32

    UInt32 noCache = positionMode & kAudioFileNoCacheMask ? 1 : 0;

    if (noCache != mNoCache) {

        mNoCache = noCache;

        fcntl(mFileD, F_NOCACHE, mNoCache);

    }

#endif

#if TARGET_OS_WIN32

    lseek(mFileD, offset, SEEK_SET);

    int numBytes = write (mFileD, buffer, writeBytes);

#else

    ssize_t numBytes = pwrite (mFileD, buffer, writeBytes, offset);

#endif

    if (numBytes == -1) return kAudioFilePositionError;

    mFilePointer = offset + numBytes;

    if (actualCount) *actualCount = (UInt32)numBytes;

    return noErr;

}

//////////////////////////////////////////////////////////////////////////////////////////

#define NO_CACHE 0

OSStatus Cached_DataSource::ReadFromHeaderCache(

                    SInt64 offset, 

                    UInt32 requestCount,

                    void *buffer, 

                    UInt32* actualCount)

{

    if (actualCount) *actualCount = 0;

    OSStatus err = noErr;

    ByteCount theActualCount = 0;

#if VERBOSE 

    printf("read from header %lld %lu   %lld %lu\n", offset, requestCount, 0LL, mHeaderCacheSize);

#endif

    if (!mHeaderCache()) 

    {

        mHeaderCache.allocBytes(mHeaderCacheSize, true);

        err = mDataSource->ReadBytes(SEEK_SET, 0, mHeaderCacheSize, mHeaderCache(), &mHeaderCacheSize);

        if (err == kAudioFileEndOfFileError) err = noErr;

        if (err) return err;

    }

    ByteCount firstPart = std::min((ByteCount)requestCount, (ByteCount)(mHeaderCacheSize - offset));

    ByteCount secondPart = requestCount - firstPart;

    memcpy(buffer, mHeaderCache + (ByteCount)offset, firstPart);

    theActualCount = firstPart;

    if (secondPart) {

        UInt32 secondPartActualCount = 0;

        err = mDataSource->ReadBytes(SEEK_SET, mHeaderCacheSize, static_cast<UInt32>(secondPart), (char*)buffer + firstPart, &secondPartActualCount);

        theActualCount += secondPartActualCount;

    }

    if (actualCount) *actualCount = (UInt32)theActualCount;

    mOffset = offset + theActualCount;

    return err;

}

OSStatus Cached_DataSource::ReadBytes(

                    UInt16 positionMode, 

                    SInt64 positionOffset, 

                    UInt32 requestCount, 

                    void *buffer, 

                    UInt32* actualCount)

{

    if (actualCount) *actualCount = 0;

    OSStatus err = noErr;

    SInt64 size;

    UInt32 theActualCount = 0;

    if (!buffer) return kAudio_ParamError;

    if ((positionMode & kPositionModeMask) != SEEK_END) size = 0; // not used in this case

    else 

    {

        err = GetSize(size);

        if (err) return err;

    }

    SInt64 offset = CalcOffset(positionMode, positionOffset, mOffset, size);

    if (offset < 0) return kAudioFilePositionError;

    if (offset < mHeaderCacheSize) {

        return ReadFromHeaderCache(offset, requestCount, buffer, actualCount);

    }

#if NO_CACHE

    err = mDataSource->ReadBytes(positionMode, positionOffset, requestCount, buffer, &theActualCount);

    mOffset = offset + theActualCount;

#else

    SInt64 cacheEnd = mBodyCacheOffset + mBodyCacheCurSize;

    if (mBodyCache() && requestCount < mBodyCacheSize && offset >= mBodyCacheOffset && offset < cacheEnd)

    {

        if (offset + requestCount <= cacheEnd) 

        {

            // request is entirely within cache

#if VERBOSE 

            printf("request is entirely within cache %lld %lu   %lld %lu\n", offset, requestCount, mBodyCacheOffset, mBodyCacheCurSize);

#endif

            memcpy(buffer, mBodyCache + (size_t)(offset - mBodyCacheOffset), requestCount);

            theActualCount = requestCount;

        }

        else

        {

            // part of request is within cache. copy, read next cache block, copy.

#if VERBOSE 

            printf("part of request is within cache %lld %lu   %lld %lu\n", offset, requestCount, mBodyCacheOffset, mBodyCacheCurSize);

#endif

            // copy first part.

            ByteCount firstPart = (ByteCount)(cacheEnd - offset);

            ByteCount secondPart = requestCount - firstPart;

#if VERBOSE 

            printf("memcpy   offset %lld  mBodyCacheOffset %lld  offset - mBodyCacheOffset %lld  firstPart %lu   requestCount %lu\n", 

                        offset, mBodyCacheOffset, offset - mBodyCacheOffset, firstPart, requestCount);

#endif

            memcpy(buffer, mBodyCache + (size_t)(offset - mBodyCacheOffset), firstPart);

            theActualCount = static_cast<UInt32>(firstPart);

            // read new block

            SInt64 nextOffset = mBodyCacheOffset + mBodyCacheCurSize;

            err = mDataSource->ReadBytes(SEEK_SET, nextOffset, mBodyCacheSize, mBodyCache(), &mBodyCacheCurSize);

            if (err == kAudioFileEndOfFileError) err = noErr;

            if (err) goto leave;

            mBodyCacheOffset = nextOffset;

            // copy second part

            secondPart = std::min(secondPart, (ByteCount)mBodyCacheCurSize);

            if (secondPart) memcpy((char*)buffer + firstPart, mBodyCache(), secondPart);

            theActualCount = static_cast<UInt32>(firstPart + secondPart);

        }

    }

    else 

    {

        if (requestCount > mBodyCacheSize)

        {

#if VERBOSE 

            printf("large request %lld %lu   %lld %lu\n", offset, requestCount, mBodyCacheOffset, mBodyCacheCurSize);

#endif

            // the request is larger than we normally cache, just do a read and don't cache.

            err = mDataSource->ReadBytes(positionMode, positionOffset, requestCount, buffer, &theActualCount);

            mOffset = offset + theActualCount;

        }

        else

        {

            // request is outside cache. read new block.

#if VERBOSE 

            printf("request is outside cache %lld %lu   %lld %lu\n", offset, requestCount, mBodyCacheOffset, mBodyCacheCurSize);

#endif

            if (!mBodyCache()) 

            {

                mBodyCache.allocBytes(mBodyCacheSize, true);

#if VERBOSE 

                printf("alloc mBodyCache %08X\n", mBodyCache());

#endif

            }

            mBodyCacheOffset = offset;

            err = mDataSource->ReadBytes(SEEK_SET, mBodyCacheOffset, mBodyCacheSize, mBodyCache(), &mBodyCacheCurSize);

#if VERBOSE 

            printf("read %08X %d    mBodyCacheOffset %lld   %lu %lu\n", err, err, mBodyCacheOffset, mBodyCacheSize, mBodyCacheCurSize);

#endif

            if (err == kAudioFileEndOfFileError) err = noErr;

            if (err) return err;

            theActualCount = std::min(requestCount, mBodyCacheCurSize);

            memcpy(buffer, mBodyCache(), theActualCount);

        }

    }

leave:

#endif

    if (actualCount) *actualCount = (UInt32)theActualCount;

#if VERBOSE 

    printf("<<read err %d  actualCount %lu\n", err, *actualCount);

#endif

    return err;

}

OSStatus Cached_DataSource::WriteBytes(

                    UInt16 positionMode, 

                    SInt64 positionOffset, 

                    UInt32 requestCount, 

                    const void *buffer, 

                    UInt32* actualCount)

{

    OSStatus err = noErr;

    SInt64 size;

    if (!buffer) return kAudio_ParamError;

    if ((positionMode & kPositionModeMask) != SEEK_END) size = 0; // not used in this case

    else 

    {

        err = GetSize(size);

        if (err) return err;

    }

    SInt64 offset = CalcOffset(positionMode, positionOffset, mOffset, size);

    if (offset < 0) return kAudioFilePositionError;

    if (mHeaderCache() && offset < mHeaderCacheSize) 

    {

        // header cache write through

        ByteCount firstPart = std::min((ByteCount)requestCount, (ByteCount)(mHeaderCacheSize - offset));

#if VERBOSE 

        printf("header cache write through %lu %lu\n", mHeaderCacheSize, firstPart);

#endif

        memcpy(mHeaderCache + (size_t)offset, buffer, firstPart);

    }

#if VERBOSE 

    printf("write %lld %lu    %lld %d %lld\n", offset, requestCount, mOffset, positionMode, positionOffset);

#endif

    SInt64 cacheEnd = mBodyCacheOffset + mBodyCacheCurSize;

    if (mBodyCache() && offset >= mBodyCacheOffset && offset < cacheEnd)

    {

        // body cache write through

        ByteCount firstPart = std::min((SInt64)requestCount, cacheEnd - offset);

#if VERBOSE 

        printf("body cache write through %lld %lu  %lld %lu\n", mBodyCacheOffset, mBodyCacheCurSize, offset, firstPart);

#endif

        memcpy(mBodyCache + (offset - mBodyCacheOffset), buffer, firstPart);

    }

    UInt32 theActualCount;

    err = mDataSource->WriteBytes(positionMode, positionOffset, requestCount, buffer, &theActualCount);

    mOffset = offset + theActualCount;

    if (actualCount) *actualCount = (UInt32)theActualCount;

    return err;

}

//////////////////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////////////////

Seekable_DataSource::Seekable_DataSource(   void * inClientData,

                            AudioFile_ReadProc                  inReadFunc, 

                            AudioFile_WriteProc                 inWriteFunc, 

                            AudioFile_GetSizeProc               inGetSizeFunc,

                            AudioFile_SetSizeProc               inSetSizeFunc)

    : DataSource(false), mClientData(inClientData), mReadFunc(inReadFunc), mWriteFunc(inWriteFunc), 

        mSizeFunc(inGetSizeFunc), mSetSizeFunc(inSetSizeFunc)

{

}

Seekable_DataSource::~Seekable_DataSource()

{

}

OSStatus Seekable_DataSource::GetSize(SInt64& outSize)

{

    if (!mSizeFunc) {

        outSize = LLONG_MAX;

    } else {

        outSize = (*mSizeFunc)(mClientData);

    }

    return noErr;

}

OSStatus Seekable_DataSource::SetSize(SInt64 inSize)

{

    if (!mSetSizeFunc) return kAudioFileOperationNotSupportedError;

    return (*mSetSizeFunc)(mClientData, inSize);

}

OSStatus Seekable_DataSource::ReadBytes(    

                            UInt16 positionMode, 

                            SInt64 positionOffset, 

                            UInt32 requestCount, 

                            void *buffer, 

                            UInt32* actualCount)

{

    OSStatus err;

    if (actualCount) *actualCount = 0;

    if (!mReadFunc) return kAudioFileOperationNotSupportedError;

    if (!buffer) return kAudio_ParamError;

    positionMode &= kPositionModeMask;

    SInt64 size;

    err = GetSize(size);

    if (err) return err;

    SInt64 offset = CalcOffset(positionMode, positionOffset, mOffset, size);

    // request is outside bounds of file

    if (offset < 0) 

        return kAudioFilePositionError;

    if (offset >= size) 

        return kAudioFileEndOfFileError;

    // reduce request if it exceeds the amount available

    requestCount = static_cast<UInt32>(std::min((SInt64)requestCount, size - offset));

    UInt32 theActualCount = 0;

    err = (*mReadFunc)(mClientData, offset, requestCount, buffer, &theActualCount);

    if (actualCount) *actualCount = theActualCount;

    mOffset = offset + theActualCount;

    return err;

}

OSStatus Seekable_DataSource::WriteBytes(

                            UInt16 positionMode, 

                            SInt64 positionOffset, 

                            UInt32 requestCount, 

                            const void *buffer, 

                            UInt32* actualCount)

{

    OSStatus err;

    if (!mWriteFunc) return kAudioFileOperationNotSupportedError;

    if (!buffer) return kAudio_ParamError;

    SInt64 size;

    positionMode &= kPositionModeMask;

    if (positionMode != SEEK_END) size = 0; // not used in this case

    else 

    {

        err = GetSize(size);

        if (err) return err;

    }

    SInt64 offset = CalcOffset(positionMode, positionOffset, mOffset, size);

    if (offset < 0) return kAudioFilePositionError;

    UInt32 theActualCount;

    err = (*mWriteFunc)(mClientData, offset, requestCount, buffer, &theActualCount);

    if (err) return err;

    if (actualCount) *actualCount = theActualCount;

    mOffset = offset + theActualCount;

    return noErr;

}

//////////////////////////////////////////////////////////////////////////////////////////

OSStatus Buffer_DataSource::ReadBytes(

                                UInt16 positionMode, 

                                SInt64 positionOffset, 

                                UInt32 requestCount, 

                                void *buffer, 

                                UInt32* actualCount)

{

    if (actualCount) *actualCount = 0;

    SInt64 offsetWithinBuffer = CalcOffset(positionMode, positionOffset, mOffset, mDataByteSize + mStartOffset) - mStartOffset;     

    if (offsetWithinBuffer < 0 || offsetWithinBuffer >= mDataByteSize) return kAudioFilePositionError;

    SInt64 bytesAfterOffset = mDataByteSize - offsetWithinBuffer;

    SInt64 theActualCount = std::min(bytesAfterOffset, (SInt64)requestCount);

    if (theActualCount <= 0) {

        if (actualCount) *actualCount = 0;

        return kAudio_ParamError;

    }

    memcpy(buffer, mData + offsetWithinBuffer, theActualCount);

    if (actualCount) *actualCount = static_cast<UInt32>(theActualCount);

    mOffset = offsetWithinBuffer + theActualCount;

    return noErr;

}

//////////////////////////////////////////////////////////////////////////////////////////