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windows-nt/Source/XPSP1/NT/multimedia/media/avi/avifile/directio.cpp

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/****************************************************************************
*
* DIRECTIO.CPP
*
* routines for reading Standard AVI files
*
* Copyright (c) 1992 - 1995 Microsoft Corporation. All Rights Reserved.
*
*
* implementation of a disk i/o class designed to optimise
* sequential reading and writing to disk by using overlapped i/o (for read
* ahead and write behind) and using large buffers written with no buffering.
*
***************************************************************************/
#include <windows.h>
#include <win32.h>
#include "debug.h"
#include "directio.h"
#ifdef USE_DIRECTIO
//
// implementation of a disk i/o class designed to optimise
// sequential reading and writing to disk by using overlapped i/o (for read
// ahead and write behind) and using large buffers written with no buffering.
// -- CFileStream class methods ---------------------------------------
// initialise to known (invalid) state
CFileStream::CFileStream()
{
m_State = Invalid;
m_Position = 0;
m_hFile = INVALID_HANDLE_VALUE;
#ifdef CHICAGO
ZeroMemory(&m_qio, sizeof(m_qio));
#endif
}
BOOL
CFileStream::Open(LPTSTR file, BOOL bWrite, BOOL bTruncate)
{
if (m_State != Invalid) {
return FALSE;
}
// remember this for default streaming mode
m_bWrite = bWrite;
DWORD dwAccess = GENERIC_READ;
if (bWrite) {
dwAccess |= GENERIC_WRITE;
}
// open the file. Always get read access. exclusive open if we
// are writing the file, otherwise deny other write opens.
// never truncate the file, since the file may be de-fragmented.
#ifdef CHICAGO
DWORD dwFlags = FILE_FLAG_NO_BUFFERING;
#else
DWORD dwFlags = FILE_FLAG_OVERLAPPED | FILE_FLAG_NO_BUFFERING;
#endif
m_hFile = CreateFile(file,
dwAccess,
(bWrite ? 0 : FILE_SHARE_READ),
NULL,
OPEN_ALWAYS,
dwFlags,
0);
if (m_hFile == INVALID_HANDLE_VALUE) {
return FALSE;
}
#ifdef CHICAGO
if ( ! QioInitialize(&m_qio, m_hFile, THREAD_PRIORITY_HIGHEST)) {
CloseHandle (m_hFile);
return FALSE;
}
#endif
// find the bytes per sector that we have to round to for this file
// -requires finding the 'root path' for this file.
TCHAR ch[MAX_PATH];
LPTSTR ptmp; //required arg
GetFullPathName(file, sizeof(ch)/sizeof(ch[0]), ch, &ptmp);
// truncate this to the name of the root directory
if ((ch[0] == TEXT('\\')) && (ch[1] == TEXT('\\'))) {
// path begins with \\server\share\path so skip the first
// three backslashes
ptmp = &ch[2];
while (*ptmp && (*ptmp != TEXT('\\'))) {
ptmp++;
}
if (*ptmp) {
// advance past the third backslash
ptmp++;
}
} else {
// path must be drv:\path
ptmp = ch;
}
// find next backslash and put a null after it
while (*ptmp && (*ptmp != TEXT('\\'))) {
ptmp++;
}
// found a backslash ?
if (*ptmp) {
// skip it and insert null
ptmp++;
*ptmp = TEXT('\0');
}
DWORD dwtmp1, dwtmp2, dwtmp3;
if (!GetDiskFreeSpace(ch,
&dwtmp1,
&m_SectorSize,
&dwtmp2,
&dwtmp3))
m_SectorSize = 2048;
// sigh. now init the first buffer
// sets the right buffer count and size for current mode
m_State = Stopped;
if (!EnsureBuffersValid()) {
return FALSE;
}
m_Current = 0;
m_Position = 0;
// if asked to truncate the file, we will not actually do so, since this
// could throw away a de-fragged file. We will however, note that the file
// size is 0 and use this to affect reading and writing past 'eof' - eg
// if you write 8 bytes to the beginning of a truncated file, we do not
// need to read in the first sector beforehand.
if (bTruncate) {
m_Size = 0;
} else {
// get the current file size
m_Size = GetFileSize(m_hFile, NULL);
}
// all set
return TRUE;
}
BOOL
CFileStream::Seek(DWORD pos)
{
// we just record this and go away
//if (pos < m_Position) {
// DPF("seek back by 0x%x to 0x%x\n", m_Position - pos, pos);
//}
m_Position = pos;
return TRUE;
}
DWORD
CFileStream::GetCurrentPosition()
{
return m_Position;
}
BOOL
CFileStream::Write(LPBYTE pData, DWORD count, DWORD * pbyteswritten)
{
*pbyteswritten = 0;
// error if file not opened
if (m_State == Invalid) {
return FALSE;
}
DWORD nBytes;
while (count > 0) {
// is our current buffer ready to write this data ?
// (we need to tell it eof pos as well since if eof is
// in middle of buffer but beyond valid data, ok to write.)
if ((m_Current < 0) ||
(!m_Buffers[m_Current].QueryPosition(m_Position, m_Size))) {
// commit this buffer if we have changed position beyond it
if (m_Current >= 0) {
if (!m_Buffers[m_Current].Commit()) {
// file error - abort
return FALSE;
}
// if we are streaming, then advance to next buffer while
// current one is writing.
if (m_State != Stopped) {
m_Current = NextBuffer(m_Current);
}
} else {
m_Current = 0;
}
// make sure that previous operations on this buffer have completed
if (!m_Buffers[m_Current].WaitComplete()) {
// i/o error
return FALSE;
}
}
// we either have a buffer that has already pre-read the sector
// we start writing to, or we have an idle buffer that
// will do the pre-read for us
if (!m_Buffers[m_Current].Write(m_Position, pData, count, m_Size, &nBytes)) {
return FALSE;
}
count -= nBytes;
pData += nBytes;
m_Position += nBytes;
*pbyteswritten += nBytes;
}
if (m_Position > m_Size) {
m_Size = m_Position;
}
return TRUE;
}
BOOL
CFileStream::Read(LPBYTE pData, DWORD count, DWORD * pbytesread)
{
*pbytesread = 0;
// error if file not opened
if (m_State == Invalid) {
return FALSE;
}
// force the read to be within the file size limits
if (m_Position >= m_Size) {
// all done - nothing read
return TRUE;
} else {
count = min(count, (m_Size - m_Position));
}
BOOL bDoReadAhead = FALSE;
DWORD nBytes;
while (count > 0) {
// is data within current buffer
if ((m_Current < 0) ||
(!m_Buffers[m_Current].QueryPosition(m_Position, m_Size))) {
if (m_Current >= 0) {
// commit this buffer if we have changed position beyond it
if (!m_Buffers[m_Current].Commit()) {
// file error - abort
return FALSE;
}
// advance to next buffer (if streaming)
if (m_State == Writing) {
m_Current = NextBuffer(m_Current);
} else if (m_State == Reading) {
// smart read-ahead strategy: try to find in existing
// buffers, and only issue a read-ahead if we take the
// highest buffer
int n = NextBuffer(m_Current);
m_Current = -1;
for (int i = 0; i < m_NrValid; i++) {
if (m_Buffers[n].QueryPosition(m_Position, m_Size)) {
m_Current = n;
break;
}
n = NextBuffer(n);
}
if (m_Current < 0) {
// read-ahead is messed up because we have made too big
// a seek for the current buffer size
// Best thing is to use the lowest buffer (should be the
// one after the highest, and to restart readaheads with
// this position).
m_Current = NextBuffer(m_HighestBuffer);
m_HighestBuffer = m_Current;
DPF("using idle %d\n", m_Current);
}
if (m_Current == m_HighestBuffer) {
bDoReadAhead = TRUE;
}
}
} else {
m_Current = 0;
if (m_Current == m_HighestBuffer) {
bDoReadAhead = TRUE;
}
}
// make sure that previous operations on this buffer have completed
if (!m_Buffers[m_Current].WaitComplete()) {
// i/o error
return FALSE;
}
}
// now we have a buffer that either contains the data we want, or
// is idle and ready to fetch it.
if (!m_Buffers[m_Current].Read(m_Position, pData, count, m_Size, &nBytes)) {
return FALSE;
}
count -= nBytes;
pData += nBytes;
m_Position += nBytes;
*pbytesread += nBytes;
// do read ahead now if necessary (the Read() call may have required
// a seek and read if the data was not in the buffer, so delay the
// read-ahead until after it has completed).
if (bDoReadAhead) {
// remember that this new buffer contains the highest position
// -- we should issue another readahead when we start using this
// buffer.
m_HighestBuffer = NextBuffer(m_Current);
DWORD p = m_Buffers[m_Current].GetNextPosition();
m_Buffers[m_HighestBuffer].ReadAhead(p, m_Size);
bDoReadAhead = FALSE;
}
}
return TRUE;
}
// set the right buffer size and count for current mode
BOOL
CFileStream::EnsureBuffersValid()
{
if (m_State == Invalid) {
// file not opened
return FALSE;
}
#ifdef CHICAGO
if (m_State == Writing) {
m_NrValid = 4; // total 256k
} else if (m_State == Reading) {
m_NrValid = 4; // total 256k
} else {
m_NrValid = 1; // total 64k
}
int size = (64 * 1024);
#else
if (m_State == Writing) {
m_NrValid = 2; // total 512k
} else if (m_State == Reading) {
m_NrValid = 4; // total 256k
} else {
m_NrValid = 1; // total 64k
}
int size = (64 * 1024);
if (m_State == Writing)
size = (256 * 1024);
#endif
int i =0;
Assert(m_NrValid <= NR_OF_BUFFERS);
// init valid buffers
for (; i < m_NrValid; i++) {
#ifdef CHICAGO
if (!m_Buffers[i].Init(m_SectorSize, size, &m_qio)) {
#else
if (!m_Buffers[i].Init(m_SectorSize, size, m_hFile)) {
#endif
return FALSE;
}
}
// discard others
for (; i < NR_OF_BUFFERS; i++) {
m_Buffers[i].FreeMemory();
}
return TRUE;
}
BOOL
CFileStream::StartStreaming()
{
if (m_bWrite) {
return StartWriteStreaming();
} else {
return StartReadStreaming();
}
}
BOOL
CFileStream::StartWriteStreaming()
{
m_State = Writing;
if (!EnsureBuffersValid()) {
return FALSE;
}
return TRUE;
}
BOOL
CFileStream::StartReadStreaming()
{
// commit the current buffer
if (!m_Buffers[m_Current].Commit()) {
return FALSE;
}
m_State = Reading;
if (!EnsureBuffersValid()) {
return FALSE;
}
// start read-ahead on buffer 0 - read from current position
// (tell buffer the eof point so it won't bother reading beyond it)
// remember that this is the highest current buffer - when we start using
// this buffer it is time to issue the next readahead (this allows for
// seeks backwards and forwards within the valid buffers without upsetting
// the read-aheads).
m_HighestBuffer = 0;
m_Buffers[0].ReadAhead(m_Position, m_Size);
// set m_Current invalid: this ensures that we will wait for read-ahead
// to complete before getting data, and that when we start using it, we
// will issue the next read-ahead.
m_Current = -1;
return TRUE;
}
BOOL
CFileStream::StopStreaming()
{
// complete all i/o
if (!CommitAndWait()) {
return FALSE;
}
m_Current = 0;
m_State = Stopped;
// recalc buffer size/count for new mode
if (!EnsureBuffersValid()) {
return FALSE;
}
return TRUE;
}
// wait for all transfers to complete.
BOOL CFileStream::CommitAndWait()
{
// write current buffer
//
if (!m_Buffers[m_Current].Commit())
return FALSE;
#ifdef CHICAGO
// flush all buffers that have been queued
//
//QioCommit (&m_qio);
#endif
// wait for all buffers to complete
for (int i = 0; i < m_NrValid; i++) {
if (!m_Buffers[i].WaitComplete()) {
return FALSE;
}
}
// no need to reset m_Current
return TRUE;
}
// destructor will call Commit()
CFileStream::~CFileStream()
{
if (m_hFile != INVALID_HANDLE_VALUE) {
CommitAndWait();
#ifdef CHICAGO
QioShutdown (&m_qio);
#endif
CloseHandle(m_hFile);
}
}
// --- CFileBuffer methods -----------------------------------------
// initiate to an invalid (no buffer ready) state
CFileBuffer::CFileBuffer()
{
m_pBuffer = NULL;
m_pAllocedMem = NULL;
m_State = Invalid;
#ifdef CHICAGO
m_pqio = NULL;
#endif
}
// allocate memory and become idle.
BOOL
#ifdef CHICAGO
CFileBuffer::Init(DWORD nBytesPerSector, DWORD buffersize, LPQIO pqio)
#else
CFileBuffer::Init(DWORD nBytesPerSector, DWORD buffersize, HANDLE hfile)
#endif
{
if (m_State != Invalid) {
if ((nBytesPerSector == m_BytesPerSector) &&
(buffersize == RoundSizeToSector(m_TotalSize))) {
// we're there already
return TRUE;
}
// discard what we have
FreeMemory();
}
Assert(m_State == Invalid);
// round up RAWIO_SIZE to a multiple of sector size
m_BytesPerSector = nBytesPerSector;
m_TotalSize = (DWORD) RoundSizeToSector(buffersize);
m_DataLength = 0;
m_State = Idle;
m_bDirty = FALSE;
#ifdef CHICAGO
m_pqio = pqio;
m_pAllocedMem = (unsigned char *)VirtualAlloc (NULL, m_TotalSize,
MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE);
if (m_pAllocedMem == NULL)
return FALSE;
#else
m_hFile = hfile;
m_pAllocedMem = new BYTE[m_TotalSize];
if (m_pAllocedMem == NULL)
return FALSE;
m_Overlapped.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (!m_Overlapped.hEvent) {
delete[] m_pAllocedMem;
return FALSE;
}
#endif
// this is where my naming scheme falls down. RoundPos rounds down, and
// RoundSize rounds up. to correctly align the buffer and stay within it,
// we need to round the start address up and the size down.
// round start address up to sector size
m_pBuffer = (LPBYTE) RoundSizeToSector((LONG_PTR) m_pAllocedMem);
// remove rounding from size - and round it again!
m_TotalSize = (DWORD) RoundPosToSector(m_TotalSize - (m_pBuffer - m_pAllocedMem));
return TRUE;
}
// revert to invalid state (eg when streaming stops)
void
CFileBuffer::FreeMemory()
{
if (m_State == Idle) {
Commit();
}
if (m_State == Busy) {
WaitComplete();
}
if (m_State != Invalid) {
#ifdef CHICAGO
VirtualFree (m_pAllocedMem, 0, MEM_RELEASE);
m_pBuffer = NULL;
m_pAllocedMem = NULL;
#else
CloseHandle(m_Overlapped.hEvent);
delete[] m_pAllocedMem;
#endif
m_State = Invalid;
}
}
// calls commit if dirty before freeing everything.
CFileBuffer::~CFileBuffer()
{
FreeMemory();
}
// does this position occur anywhere within the current buffer ?
// needs to know current eof for some cases (writing beyond eof
// if eof is within this buffer is ok to this buffer).
//
// we can use this buffer if:
// 1. if the buffer is empty and the write is past eof (where eof is rounded
// to a sector boundary).
//
// 2. if the start position is within the current m_DataLength
//
// 3. if eof is within the buffer and the write is past eof
//
// all reads are limited by the caller to be within the file limits, so
// the reading case is covered by 2 above (1 and 3 will not occur).
//
// all other cases will require the read of data that is not in the buffer.
// or the (early) committing of data in the buffer
//
BOOL
CFileBuffer::QueryPosition(DWORD pos, DWORD filesize)
{
if (m_State == Invalid) {
return FALSE;
}
// round filesize to sector boundary
filesize = (DWORD) RoundSizeToSector(filesize);
if (pos >= filesize) {
// write is past eof. ok if buffer empty or if buffer contains
// eof (and has space in it)
if ((m_DataLength == 0) ||
((m_Position + m_DataLength == filesize) &&
(m_DataLength < m_TotalSize))) {
return TRUE;
}
// we have data that needs to be flushed before we can do this
return FALSE;
} else {
if ((pos >= m_Position) &&
(pos < m_Position + m_DataLength)) {
// we have this byte
return TRUE;
}
// we don't have this byte of valid data. we have some other.
//
// you might think that if the write begins on a sector boundary, and
// this buffer's data is not dirty you could permit this without a
// pre-read - but we don't know yet where the write will end, and if
// it ends mid-sector and not past current eof, we will need to
// read that sector in.
return FALSE;
}
}
// write some data to buffer (must be committed separately)
// filesize parameter is the file size before this write, and is used to
// control what we do with the partial sector at beginning and end
// -if not past current eof, we need to read the current sector before
// writing to it.
BOOL
CFileBuffer::Write(
DWORD pos,
LPBYTE pData,
DWORD count,
DWORD filesize,
DWORD * pbytesWritten)
{
// remember for later (during commit)
m_FileLength = filesize;
*pbytesWritten = 0;
if (m_State != Idle) {
if (!WaitComplete()) {
return FALSE;
}
}
if (m_State == Invalid) {
// naughty boy!
return FALSE;
}
// do we need to commit the current contents or read anything ?
// if there is data, and the start position is not within the valid data
// range, then flush this lot. note that we count the region from
// end of valid data to end of actual buffer as valid data if the eof
// is within this buffer.
if ((m_DataLength > 0) &&
((pos < m_Position) ||
(pos >= m_Position + m_TotalSize) ||
((pos >= m_Position + m_DataLength) &&
((m_Position + m_DataLength) < filesize)))) {
// we're not ok - need to flush current contents
if (!Commit() || !WaitComplete()) {
return FALSE;
}
m_DataLength = 0;
}
// if empty (or we just flushed it), we can start at the beginning
if (m_DataLength == 0) {
m_Position = (DWORD) RoundPosToSector(pos);
// do we need to read the partial sector?
if ((pos < RoundSizeToSector(filesize)) &&
(pos % m_BytesPerSector != 0)) {
// yes - write starts partway through a valid sector
m_DataLength = m_BytesPerSector;
if (!ReadIntoBuffer(0, m_Position, m_BytesPerSector) ||
!WaitComplete()) {
return FALSE;
}
}
}
// we can start the data. now what about the end?
// if it all fits within the buffer, and it ends mid-sector and the
// final sector is within the file length but not currently in the
// buffer, we will need to pre-read the final buffer
if ((pos + count) < (m_Position + m_TotalSize)) {
if ((pos + count) % m_BytesPerSector) {
// we have to write a partial sector - is it past eof or within
// valid region ?
if ((pos+count > m_Position + m_DataLength) &&
(pos+count < filesize)) {
// yes need to read partial sector
DWORD sec = (DWORD) RoundPosToSector(pos+count);
// need to temporarily set m_DataLength
// to the amount read so that WaitComplete can check
// its ok
m_DataLength = m_BytesPerSector;
if (!ReadIntoBuffer(
sec - m_Position, // index in buffer
sec, // position in file
m_BytesPerSector) ||
!WaitComplete()) {
return FALSE;
}
// set size correctly again
m_DataLength = (sec - m_Position) + m_BytesPerSector;
}
}
}
// now we can stuff the data in
int index = pos - m_Position;
*pbytesWritten = min(count, m_TotalSize - index);
CopyMemory(
&m_pBuffer[index],
pData,
*pbytesWritten);
// adjust data length
if ((index + *pbytesWritten) > m_DataLength) {
m_DataLength = (DWORD) RoundSizeToSector(index + *pbytesWritten);
}
m_bDirty = TRUE;
return TRUE;
}
// read data from buffer (will seek and read if necessary first)
BOOL
CFileBuffer::Read(
DWORD pos,
LPBYTE pData,
DWORD count,
DWORD filelength,
DWORD * pBytesRead)
{
Assert(m_State == Idle);
// remember this for read completion checking
m_FileLength = filelength;
*pBytesRead = 0;
if ((pos < m_Position) ||
(pos >= m_Position + m_DataLength)) {
// not in current buffer - flush current contents if dirty
if (!Commit() || !WaitComplete()) {
return FALSE;
}
m_Position = (DWORD) RoundPosToSector(pos);
// remember if we round the start down, we also need to increase
// the length (as well as rounding it up at the other end)
// force a minimum read size to avoid lots of single sectors
m_DataLength = count + (pos - m_Position);
m_DataLength = max(MIN_READ_SIZE, m_DataLength);
m_DataLength = (DWORD) RoundSizeToSector(m_DataLength);
m_DataLength = min(m_DataLength, m_TotalSize);
if (!ReadIntoBuffer(0, m_Position, m_DataLength) ||
!WaitComplete()) {
return FALSE;
}
}
// we have (at least the start part of) the data in the buffer
int offset = pos - m_Position;
count = min(count, m_DataLength - offset);
CopyMemory(pData, &m_pBuffer[offset], count);
*pBytesRead = count;
return TRUE;
}
// what is the first file position after this buffer's valid data
// ---return this even if still busy reading it
DWORD
CFileBuffer::GetNextPosition()
{
if ((m_State == Invalid) || (m_DataLength == 0)) {
return 0;
} else {
return m_Position + m_DataLength;
}
}
// initiate a read-ahead
void
CFileBuffer::ReadAhead(DWORD start, DWORD filelength)
{
if (m_State != Idle) {
if (!CheckComplete()) {
return;
}
}
// we may already hold this position
if (QueryPosition(start, filelength)) {
return;
}
m_FileLength = filelength;
if (m_bDirty) {
// current data needs to be flushed to disk.
// we should initiate this, but we can't wait for
// it to complete, so we won't do the read-ahead
Commit();
return;
}
m_Position = (DWORD) RoundPosToSector(start);
m_DataLength = min((DWORD) RoundSizeToSector(filelength - m_Position),
m_TotalSize);
ReadIntoBuffer(0, m_Position, m_DataLength);
// no wait - this is an async readahead.
}
// initiate the i/o from the buffer
BOOL
CFileBuffer::Commit()
{
if ((m_State != Idle) || (!m_bDirty)) {
return TRUE;
}
#ifndef CHICAGO
DWORD nrWritten;
#endif
#ifdef CHICAGO
m_State = Busy;
m_qiobuf.dwOffset = m_Position;
m_qiobuf.lpv = m_pBuffer;
m_qiobuf.cb = m_DataLength;
m_qiobuf.cbDone = 0;
m_qiobuf.bWrite = TRUE;
m_qiobuf.dwError = ERROR_IO_PENDING;
QioAdd (m_pqio, &m_qiobuf);
#else
ResetEvent(m_Overlapped.hEvent);
m_State = Busy;
//start from m_Position
m_Overlapped.Offset = m_Position;
m_Overlapped.OffsetHigh = 0;
if (WriteFile(m_hFile, m_pBuffer, m_DataLength,
&nrWritten, &m_Overlapped)) {
DPF(("instant completion"));
// if it completed already, then sort out the new position
if (nrWritten != m_DataLength) {
DPF("commit- bad length %d not %d", nrWritten, m_DataLength);
return FALSE;
}
m_bDirty = FALSE;
m_State = Idle;
} else {
// should be pending
if (GetLastError() != ERROR_IO_PENDING) {
// no longer busy
m_State = Idle;
DPF("commit error %d", GetLastError());
return FALSE;
}
}
#endif
// we must do this here, since WaitComplete could complete a
// partial read that would leave the buffer dirty.
// we are safe since the buffer will remain Busy until this is
// actually TRUE. (if we fail to write to the disk then the
// file state is guaranteed messed up).
m_bDirty = FALSE;
return TRUE;
}
// wait for any pending commit or read to complete and check for errors.
BOOL
CFileBuffer::WaitComplete()
{
if (m_State == ErrorOccurred) {
// the i/o has completed in error but we haven't been able to
// report the fact yet
m_State = Idle;
return FALSE;
}
if (m_State == Busy) {
DWORD actual;
// no longer busy
m_State = Idle;
#ifdef CHICAGO
if ( ! QioWait (m_pqio, &m_qiobuf, TRUE))
return FALSE;
actual = m_qiobuf.cbDone;
#else
if (!GetOverlappedResult(m_hFile, &m_Overlapped, &actual, TRUE)) {
DPF("WC: GetOverlapped failed %d", GetLastError());
return FALSE;
}
#endif
if (actual != m_DataLength) {
// rounding to sector size may have taken us past eof
if (m_Position + actual != m_FileLength) {
DPF("WC: actual wrong (%d not %d)", actual, m_DataLength);
return FALSE;
}
}
}
return TRUE;
}
// non-blocking check to see if async io is complete
BOOL
CFileBuffer::CheckComplete()
{
if (m_State == Idle) {
return TRUE;
}
if (m_State != Busy) {
return FALSE; // invalid or error
}
#ifdef CHICAGO
if (QioWait(m_pqio, &m_qiobuf, FALSE))
return FALSE;
else if (m_qiobuf.dwError == 0) {
m_State = Idle;
return TRUE;
}
m_State = ErrorOccurred;
return FALSE;
#else
DWORD actual;
if (GetOverlappedResult(m_hFile, &m_Overlapped, &actual, FALSE)) {
if ((actual == m_DataLength) ||
(actual + m_Position == m_FileLength)) {
m_State = Idle;
return TRUE;
}
} else if (GetLastError() == ERROR_IO_INCOMPLETE) {
// still busy
return FALSE;
}
// some error state occurred - this must be reported by WaitComplete()
m_State = ErrorOccurred;
DPF("CheckComplete error %d", GetLastError());
return FALSE;
#endif
}
// initiates an async read request into the buffer (can be an insertion into
// middle of buffer rather than a complete buffer fill - and so will not
// adjust m_Position or m_DataLength). reads count bytes
// offset bytes from the start of the buffer, pos bytes from the start of the
// file. Assumes necessary rounding of length and position has already happened.
BOOL
CFileBuffer::ReadIntoBuffer(int offset, DWORD pos, DWORD count)
{
Assert(m_State == Idle);
#ifndef CHICAGO
DWORD nrRead;
#endif
#ifdef CHICAGO
m_State = Busy;
m_qiobuf.dwOffset = pos;
m_qiobuf.lpv = (LPVOID)(m_pBuffer + offset);
m_qiobuf.cb = count;
m_qiobuf.cbDone = 0;
m_qiobuf.bWrite = FALSE;
m_qiobuf.dwError = ERROR_IO_PENDING;
// if this read is not sector aligned, we cannot do it
// in async in chicago, so do it right now!
//
if ((count & 511) || (pos & 511) || (offset & 511))
{
DWORD dwOff;
m_qiobuf.bPending = FALSE;
DPF("%s %X bytes (non-aligned) at %08X into %08X\r\n", m_qiobuf.bWrite ? "Writing" : "Reading", m_qiobuf.cb, m_qiobuf.dwOffset, m_qiobuf.lpv);
dwOff = SetFilePointer (m_pqio->hFile, m_qiobuf.dwOffset, NULL, FILE_BEGIN);
if (dwOff != m_qiobuf.dwOffset)
{
m_qiobuf.dwError = GetLastError();
DPF("avifile32 non-aligned seek error %d", m_qiobuf.dwError);
return FALSE;
}
else if ( ! ReadFile (m_pqio->hFile, m_qiobuf.lpv, m_qiobuf.cb,
&m_qiobuf.cbDone, NULL) ||
(m_qiobuf.cbDone != m_qiobuf.cb))
{
m_qiobuf.dwError = GetLastError ();
DPF("avifile32 non-aligned read error %d", m_qiobuf.dwError);
return FALSE;
}
m_State = Idle;
}
else
return QioAdd (m_pqio, &m_qiobuf);
#else
ResetEvent(m_Overlapped.hEvent);
m_State = Busy;
//start from pos
m_Overlapped.Offset = pos;
m_Overlapped.OffsetHigh = 0;
if (ReadFile(m_hFile, &m_pBuffer[offset], count,
&nrRead, &m_Overlapped)) {
m_State = Idle;
DPF(("instant completion"));
// if it completed already, then sort out the new position
if (nrRead != count) {
// rounding to sector size may have taken us past eof -
// in this case we must still ask for the full sector, but
// we will be told about the actual size
if (m_Position + nrRead != m_FileLength) {
DPF("ReadInto: actual wrong");
return FALSE;
}
}
} else {
// should be pending
if (GetLastError() != ERROR_IO_PENDING) {
DPF("read failed %d\n", GetLastError());
// no longer busy
m_State = Idle;
DPF("ReadInto failed %d", GetLastError());
return FALSE;
}
}
#endif
return TRUE;
}
#endif // USE_DIRECTIO
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