Leaked source code of windows server 2003
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292 lines
7.0 KiB

#include <windows.h>
#include <windowsx.h>
#include <win32.h>
#include <mmsystem.h>
#include "debug.h"
#include "aviidx.h"
#include "buffer.h"
#include "avifile.h"
#ifndef WIN32
LONG glDosBufUsage;
LPVOID glpDosBuf;
LONG glDosBufSize;
#endif
// Idea: keep a bunch (five, maybe) of buffers.
PBUFSYSTEM PASCAL InitBuffered(int nBuffers,
LONG lBufSize,
HSHFILE hshfile,
PAVIINDEX px)
{
PBUFSYSTEM pb = (PBUFSYSTEM)LocalAlloc(LPTR,
sizeof(BUFSYSTEM) + sizeof(BUFFER) * nBuffers);
int i;
LONG l;
if (!pb)
return NULL;
DPF("InitBuffered (%04x): %dx%ldK, pIndex = %08lx\n", pb, nBuffers, lBufSize / 1024, (DWORD) (LPVOID) px);
pb->nBuffers = nBuffers;
pb->lBufSize = lBufSize;
pb->px = px;
pb->lx = 0;
pb->lpBufMem = GlobalAllocPtr(GMEM_MOVEABLE | GMEM_SHARE, lBufSize * nBuffers);
if (!pb->lpBufMem) {
DPF("Couldn't allocate buffer memory!\n");
EndBuffered(pb);
return NULL;
}
pb->hshfile = hshfile;
l = shfileSeek(hshfile, 0, SEEK_CUR);
pb->lFileLength = shfileSeek(hshfile, 0, SEEK_END);
shfileSeek(hshfile, l, SEEK_SET);
for (i = 0; i < nBuffers; i++) {
pb->aBuf[i].lpBuffer = (BYTE _huge *) pb->lpBufMem + i * lBufSize;
pb->aBuf[i].lOffset = -1;
}
return pb;
}
LONG FAR PASCAL BufferedRead(PBUFSYSTEM pb, LONG lPos, LONG cb, LPVOID lp)
{
int i;
LPVOID lpCopy;
LONG cbCopy;
LONG cbRead = cb;
LONG l;
#if 0
if (cb > pb->lBufSize) {
if (shfileSeek(pb->hshfile, lPos, SEEK_SET) == -1)
return 0;
if (shfileRead(pb->hshfile, lp, cb) != cb)
return 0;
return cb;
}
#endif
while (cb > 0) {
if (lPos >= pb->lFileLength)
break;
// Find a buffer.
for (i = 0; i < pb->nBuffers; i++) {
if (pb->aBuf[i].lOffset < 0)
continue;
if (pb->aBuf[i].lOffset <= lPos &&
pb->aBuf[i].lOffset + pb->aBuf[i].lLength > lPos)
break;
}
// If we didn't find a buffer with valid data, read more.
if (i >= pb->nBuffers) {
i = pb->iNextBuf;
if (pb->px) {
LONG off,len;
for (l = pb->lx; l>=0 && l<pb->px->nIndex; ) {
off = IndexOffset(pb->px, l);
len = IndexLength(pb->px, l) + 2*sizeof(DWORD);
if (off <= lPos && lPos < off + len)
break;
if (lPos < off)
l--;
else
l++;
}
if (l == pb->px->nIndex || l < 0) {
DPF("Ran out of index!\n");
goto ack;
}
if (len > pb->lBufSize) {
DPF("Chunk is bigger than buffer.\n");
goto ack;
}
pb->aBuf[i].lOffset = off;
pb->aBuf[i].lLength = len;
DPF2("Buffer: Reading %lx bytes at %lx\n", pb->aBuf[i].lLength, pb->aBuf[i].lOffset);
//
// read as many records that will fit in our buffer
//
// we should scan backward!
//
for (l++; l<pb->px->nIndex; l++) {
off = IndexOffset(pb->px, l);
len = IndexLength(pb->px, l) + 2*sizeof(DWORD);
if (off < pb->aBuf[i].lOffset + pb->aBuf[i].lLength)
continue;
if (off != pb->aBuf[i].lOffset + pb->aBuf[i].lLength)
break;
if (pb->aBuf[i].lLength + len > pb->lBufSize)
break;
pb->aBuf[i].lLength += len;
DPF2(" Reading %lx bytes at %lx\n", pb->aBuf[i].lLength, pb->aBuf[i].lOffset);
}
if (l < pb->px->nIndex)
pb->lx = l; // save this for next time.
} else
{
ack:
// Always read aligned with the buffer size....
pb->aBuf[i].lOffset = lPos - (lPos % pb->lBufSize);
pb->aBuf[i].lLength =
min(pb->lFileLength - pb->aBuf[i].lOffset,
pb->lBufSize);
DPF("Buffer: Reading %lx bytes at %lx\n", pb->aBuf[i].lLength, pb->aBuf[i].lOffset);
}
shfileSeek(pb->hshfile, pb->aBuf[i].lOffset, SEEK_SET);
if (glpDosBuf) {
if (shfileRead(pb->hshfile,
glpDosBuf,
pb->aBuf[i].lLength) != pb->aBuf[i].lLength)
return 0;
hmemcpy(pb->aBuf[i].lpBuffer, glpDosBuf, pb->aBuf[i].lLength);
} else {
if (shfileRead(pb->hshfile,
pb->aBuf[i].lpBuffer,
pb->aBuf[i].lLength) != pb->aBuf[i].lLength)
return 0;
}
// !!! We should use an LRU algorithm or something here....
pb->iNextBuf = (i + 1) % pb->nBuffers;
}
lpCopy = (BYTE _huge *) pb->aBuf[i].lpBuffer + lPos - pb->aBuf[i].lOffset;
cbCopy = min(cb, pb->aBuf[i].lLength - (lPos - pb->aBuf[i].lOffset));
hmemcpy(lp, lpCopy, cbCopy);
lp = (BYTE _huge *) lp + cbCopy;
cb -= cbCopy;
lPos += cbCopy;
}
return cbRead;
}
LONG FAR PASCAL BeginBufferedStreaming(PBUFSYSTEM pb, BOOL fForward)
{
if (pb->fStreaming++)
return 0;
DPF("Streaming....\n");
#ifndef WIN32
if (pb->px) {
if (glDosBufSize < pb->lBufSize && GetProfileInt("avifile", "dosbuffer", 1)) {
LPVOID lpDosBuf;
lpDosBuf = (LPVOID)MAKELONG(0, LOWORD(GlobalDosAlloc(pb->lBufSize)));
if (!lpDosBuf) {
DPF("Couldn't get DOS buffer!\n");
} else {
GlobalReAlloc((HANDLE)HIWORD(lpDosBuf), 0, GMEM_MODIFY|GMEM_SHARE);
if (glpDosBuf)
GlobalDosFree(HIWORD(glpDosBuf));
glpDosBuf = lpDosBuf;
glDosBufSize = pb->lBufSize;
}
}
if (glpDosBuf && (glDosBufSize >= pb->lBufSize)) {
pb->fUseDOSBuf = TRUE;
glDosBufUsage++;
} else
pb->fUseDOSBuf = FALSE;
}
#endif
return 0;
}
LONG FAR PASCAL EndBufferedStreaming(PBUFSYSTEM pb)
{
if (!pb->fStreaming)
return AVIERR_INTERNAL;
if (--pb->fStreaming)
return 0;
DPF("No longer streaming....\n");
#ifndef WIN32
if (pb->fUseDOSBuf) {
if (--glDosBufUsage == 0) {
if (glpDosBuf)
GlobalDosFree(HIWORD(glpDosBuf));
glpDosBuf = NULL;
}
pb->fUseDOSBuf = FALSE;
}
#endif
return 0;
}
void FAR PASCAL EndBuffered(PBUFSYSTEM pb)
{
DPF("Freeing bufsystem %04x....\n", pb);
if (pb->lpBufMem)
GlobalFreePtr(pb->lpBufMem);
#ifndef WIN32
if (pb->fUseDOSBuf) {
if (--glDosBufUsage == 0) {
if (glpDosBuf)
GlobalDosFree(HIWORD(glpDosBuf));
glpDosBuf = NULL;
glDosBufSize = 0;
}
}
#endif
LocalFree((HLOCAL)pb);
}