/**
* Read bytes from a file at a given offset into a S/G buffer.
* This function may modify the file position.
*
* @returns iprt status code.
* @param hFile Handle to the file.
* @param off Where to read.
* @param pSgBuf Pointer to the S/G buffer to read into.
* @param cbToRead How much to read.
* @param pcbRead How much we actually read.
* If NULL an error will be returned for a partial read.
*/
RTR3DECL(int) RTFileSgReadAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead)
{
int rc = VINF_SUCCESS;
size_t cbRead = 0;
while (cbToRead)
{
size_t cbThisRead = 0;
size_t cbBuf = cbToRead;
void *pvBuf = RTSgBufGetNextSegment(pSgBuf, &cbBuf);
rc = RTFileReadAt(hFile, off, pvBuf, cbBuf, pcbRead ? &cbThisRead : NULL);
if (RT_SUCCESS(rc))
cbRead += cbThisRead;
if ( RT_FAILURE(rc)
|| ( cbThisRead < cbBuf
&& pcbRead))
break;
cbToRead -= cbBuf;
off += cbBuf;
}
if (pcbRead)
*pcbRead = cbRead;
return rc;
}
/**
* Write bytes from a S/G buffer to a file at a given offset.
* This function may modify the file position.
*
* @returns iprt status code.
* @param hFile Handle to the file.
* @param off Where to write.
* @param pSgBuf What to write.
* @param cbToWrite How much to write.
* @param pcbWritten How much we actually wrote.
* If NULL an error will be returned for a partial write.
*/
RTR3DECL(int) RTFileSgWriteAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten)
{
int rc = VINF_SUCCESS;
size_t cbWritten = 0;
while (cbToWrite)
{
size_t cbThisWritten = 0;
size_t cbBuf = cbToWrite;
void *pvBuf = RTSgBufGetNextSegment(pSgBuf, &cbBuf);
rc = RTFileWriteAt(hFile, off, pvBuf, cbBuf, pcbWritten ? &cbThisWritten : NULL);
if (RT_SUCCESS(rc))
cbWritten += cbThisWritten;
if ( RT_FAILURE(rc)
|| ( cbThisWritten < cbBuf
&& pcbWritten))
break;
cbToWrite -= cbBuf;
off += cbBuf;
}
if (pcbWritten)
*pcbWritten = cbWritten;
return rc;
}
/**
* Writes data from the given S/G buffer into the I/O log.
*
* @returns VBox status code.
* @param pIoLogger The I/O logger to use.
* @param off The start offset in the log to write to.
* @param pSgBuf The S/G buffer to write.
* @param cbSgBuf How much data to write.
*/
static int vddbgIoLogWriteSgBuf(PVDIOLOGGERINT pIoLogger, uint64_t off, PCRTSGBUF pSgBuf, size_t cbSgBuf)
{
int rc = VINF_SUCCESS;
RTSGBUF SgBuf;
RTSgBufClone(&SgBuf, pSgBuf);
while (cbSgBuf)
{
void *pvSeg;
size_t cbSeg = cbSgBuf;
pvSeg = RTSgBufGetNextSegment(&SgBuf, &cbSeg);
AssertPtrBreakStmt(pvSeg, rc = VERR_INTERNAL_ERROR);
rc = RTFileWriteAt(pIoLogger->hFile, off, pvSeg, cbSeg, NULL);
if (RT_FAILURE(rc))
break;
cbSgBuf -= cbSeg;
off += cbSeg;
}
return rc;
}
