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Diffstat (limited to 'src/VBox/Runtime/common/misc/sg.cpp')
| -rw-r--r-- | src/VBox/Runtime/common/misc/sg.cpp | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/misc/sg.cpp b/src/VBox/Runtime/common/misc/sg.cpp new file mode 100644 index 00000000..34153f0a --- /dev/null +++ b/src/VBox/Runtime/common/misc/sg.cpp @@ -0,0 +1,447 @@ +/* $Id: sg.cpp $ */ +/** @file + * IPRT - S/G buffer handling. + */ + +/* + * Copyright (C) 2010-2020 Oracle Corporation + * + * This file is part of VirtualBox Open Source Edition (OSE), as + * available from http://www.virtualbox.org. This file is free software; + * you can redistribute it and/or modify it under the terms of the GNU + * General Public License (GPL) as published by the Free Software + * Foundation, in version 2 as it comes in the "COPYING" file of the + * VirtualBox OSE distribution. VirtualBox OSE is distributed in the + * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include <iprt/sg.h> +#include <iprt/string.h> +#include <iprt/assert.h> +#include <iprt/asm.h> + + +static void *rtSgBufGet(PRTSGBUF pSgBuf, size_t *pcbData) +{ + size_t cbData; + void *pvBuf; + + /* Check that the S/G buffer has memory left. */ + if (RT_UNLIKELY( pSgBuf->idxSeg == pSgBuf->cSegs + && !pSgBuf->cbSegLeft)) + { + *pcbData = 0; + return NULL; + } + +#ifndef RDESKTOP + AssertMsg( pSgBuf->cbSegLeft <= 128 * _1M + && (uintptr_t)pSgBuf->pvSegCur >= (uintptr_t)pSgBuf->paSegs[pSgBuf->idxSeg].pvSeg + && (uintptr_t)pSgBuf->pvSegCur + pSgBuf->cbSegLeft <= (uintptr_t)pSgBuf->paSegs[pSgBuf->idxSeg].pvSeg + pSgBuf->paSegs[pSgBuf->idxSeg].cbSeg, + ("pSgBuf->idxSeg=%d pSgBuf->cSegs=%d pSgBuf->pvSegCur=%p pSgBuf->cbSegLeft=%zd pSgBuf->paSegs[%d].pvSeg=%p pSgBuf->paSegs[%d].cbSeg=%zd\n", + pSgBuf->idxSeg, pSgBuf->cSegs, pSgBuf->pvSegCur, pSgBuf->cbSegLeft, pSgBuf->idxSeg, pSgBuf->paSegs[pSgBuf->idxSeg].pvSeg, pSgBuf->idxSeg, + pSgBuf->paSegs[pSgBuf->idxSeg].cbSeg)); +#endif + + cbData = RT_MIN(*pcbData, pSgBuf->cbSegLeft); + pvBuf = pSgBuf->pvSegCur; + pSgBuf->cbSegLeft -= cbData; + + /* Advance to the next segment if required. */ + if (!pSgBuf->cbSegLeft) + { + pSgBuf->idxSeg++; + + if (pSgBuf->idxSeg < pSgBuf->cSegs) + { + pSgBuf->pvSegCur = pSgBuf->paSegs[pSgBuf->idxSeg].pvSeg; + pSgBuf->cbSegLeft = pSgBuf->paSegs[pSgBuf->idxSeg].cbSeg; + } + + *pcbData = cbData; + } + else + pSgBuf->pvSegCur = (uint8_t *)pSgBuf->pvSegCur + cbData; + + return pvBuf; +} + + +RTDECL(void) RTSgBufInit(PRTSGBUF pSgBuf, PCRTSGSEG paSegs, size_t cSegs) +{ + AssertPtr(pSgBuf); + Assert( (cSegs > 0 && VALID_PTR(paSegs)) + || (!cSegs && !paSegs)); + Assert(cSegs < (~(unsigned)0 >> 1)); + + pSgBuf->paSegs = paSegs; + pSgBuf->cSegs = (unsigned)cSegs; + pSgBuf->idxSeg = 0; + if (cSegs && paSegs) + { + pSgBuf->pvSegCur = paSegs[0].pvSeg; + pSgBuf->cbSegLeft = paSegs[0].cbSeg; + } + else + { + pSgBuf->pvSegCur = NULL; + pSgBuf->cbSegLeft = 0; + } +} + + +RTDECL(void) RTSgBufReset(PRTSGBUF pSgBuf) +{ + AssertPtrReturnVoid(pSgBuf); + + pSgBuf->idxSeg = 0; + if (pSgBuf->cSegs) + { + pSgBuf->pvSegCur = pSgBuf->paSegs[0].pvSeg; + pSgBuf->cbSegLeft = pSgBuf->paSegs[0].cbSeg; + } + else + { + pSgBuf->pvSegCur = NULL; + pSgBuf->cbSegLeft = 0; + } +} + + +RTDECL(void) RTSgBufClone(PRTSGBUF pSgBufTo, PCRTSGBUF pSgBufFrom) +{ + AssertPtr(pSgBufTo); + AssertPtr(pSgBufFrom); + + pSgBufTo->paSegs = pSgBufFrom->paSegs; + pSgBufTo->cSegs = pSgBufFrom->cSegs; + pSgBufTo->idxSeg = pSgBufFrom->idxSeg; + pSgBufTo->pvSegCur = pSgBufFrom->pvSegCur; + pSgBufTo->cbSegLeft = pSgBufFrom->cbSegLeft; +} + + +RTDECL(void *) RTSgBufGetNextSegment(PRTSGBUF pSgBuf, size_t *pcbSeg) +{ + AssertPtrReturn(pSgBuf, NULL); + AssertPtrReturn(pcbSeg, NULL); + + if (!*pcbSeg) + *pcbSeg = pSgBuf->cbSegLeft; + + return rtSgBufGet(pSgBuf, pcbSeg); +} + + +RTDECL(size_t) RTSgBufCopy(PRTSGBUF pSgBufDst, PRTSGBUF pSgBufSrc, size_t cbCopy) +{ + AssertPtrReturn(pSgBufDst, 0); + AssertPtrReturn(pSgBufSrc, 0); + + size_t cbLeft = cbCopy; + while (cbLeft) + { + size_t cbThisCopy = RT_MIN(RT_MIN(pSgBufDst->cbSegLeft, cbLeft), pSgBufSrc->cbSegLeft); + if (!cbThisCopy) + break; + + size_t cbTmp = cbThisCopy; + void *pvBufDst = rtSgBufGet(pSgBufDst, &cbTmp); + Assert(cbTmp == cbThisCopy); + void *pvBufSrc = rtSgBufGet(pSgBufSrc, &cbTmp); + Assert(cbTmp == cbThisCopy); + + memcpy(pvBufDst, pvBufSrc, cbThisCopy); + + cbLeft -= cbThisCopy; + } + + return cbCopy - cbLeft; +} + + +RTDECL(int) RTSgBufCmp(PCRTSGBUF pSgBuf1, PCRTSGBUF pSgBuf2, size_t cbCmp) +{ + AssertPtrReturn(pSgBuf1, 0); + AssertPtrReturn(pSgBuf2, 0); + + /* Set up the temporary buffers */ + RTSGBUF SgBuf1; + RTSgBufClone(&SgBuf1, pSgBuf1); + RTSGBUF SgBuf2; + RTSgBufClone(&SgBuf2, pSgBuf2); + + size_t cbLeft = cbCmp; + while (cbLeft) + { + size_t cbThisCmp = RT_MIN(RT_MIN(SgBuf1.cbSegLeft, cbLeft), SgBuf2.cbSegLeft); + if (!cbThisCmp) + break; + + size_t cbTmp = cbThisCmp; + void *pvBuf1 = rtSgBufGet(&SgBuf1, &cbTmp); + Assert(cbTmp == cbThisCmp); + void *pvBuf2 = rtSgBufGet(&SgBuf2, &cbTmp); + Assert(cbTmp == cbThisCmp); + + int rc = memcmp(pvBuf1, pvBuf2, cbThisCmp); + if (rc) + return rc; + + cbLeft -= cbThisCmp; + } + + return 0; +} + + +RTDECL(int) RTSgBufCmpEx(PRTSGBUF pSgBuf1, PRTSGBUF pSgBuf2, size_t cbCmp, size_t *poffDiff, bool fAdvance) +{ + AssertPtrReturn(pSgBuf1, 0); + AssertPtrReturn(pSgBuf2, 0); + + RTSGBUF SgBuf1Tmp; + RTSGBUF SgBuf2Tmp; + PRTSGBUF pSgBuf1Tmp; + PRTSGBUF pSgBuf2Tmp; + + if (!fAdvance) + { + /* Set up the temporary buffers */ + RTSgBufClone(&SgBuf1Tmp, pSgBuf1); + RTSgBufClone(&SgBuf2Tmp, pSgBuf2); + pSgBuf1Tmp = &SgBuf1Tmp; + pSgBuf2Tmp = &SgBuf2Tmp; + } + else + { + pSgBuf1Tmp = pSgBuf1; + pSgBuf2Tmp = pSgBuf2; + } + + size_t cbLeft = cbCmp; + size_t off = 0; + while (cbLeft) + { + size_t cbThisCmp = RT_MIN(RT_MIN(pSgBuf1Tmp->cbSegLeft, cbLeft), pSgBuf2Tmp->cbSegLeft); + if (!cbThisCmp) + break; + + size_t cbTmp = cbThisCmp; + uint8_t *pbBuf1 = (uint8_t *)rtSgBufGet(pSgBuf1Tmp, &cbTmp); + Assert(cbTmp == cbThisCmp); + uint8_t *pbBuf2 = (uint8_t *)rtSgBufGet(pSgBuf2Tmp, &cbTmp); + Assert(cbTmp == cbThisCmp); + + int iDiff = memcmp(pbBuf1, pbBuf2, cbThisCmp); + if (iDiff) + { + /* Locate the first byte that differs if the caller requested this. */ + if (poffDiff) + { + while ( cbThisCmp-- > 0 + && *pbBuf1 == *pbBuf2) + { + pbBuf1++; + pbBuf2++; + off++; + } + + *poffDiff = off; + } + return iDiff; + } + + cbLeft -= cbThisCmp; + off += cbThisCmp; + } + + return 0; +} + + +RTDECL(size_t) RTSgBufSet(PRTSGBUF pSgBuf, uint8_t ubFill, size_t cbSet) +{ + AssertPtrReturn(pSgBuf, 0); + + size_t cbLeft = cbSet; + + while (cbLeft) + { + size_t cbThisSet = cbLeft; + void *pvBuf = rtSgBufGet(pSgBuf, &cbThisSet); + + if (!cbThisSet) + break; + + memset(pvBuf, ubFill, cbThisSet); + + cbLeft -= cbThisSet; + } + + return cbSet - cbLeft; +} + + +RTDECL(size_t) RTSgBufCopyToBuf(PRTSGBUF pSgBuf, void *pvBuf, size_t cbCopy) +{ + AssertPtrReturn(pSgBuf, 0); + AssertPtrReturn(pvBuf, 0); + + size_t cbLeft = cbCopy; + + while (cbLeft) + { + size_t cbThisCopy = cbLeft; + void *pvSrc = rtSgBufGet(pSgBuf, &cbThisCopy); + + if (!cbThisCopy) + break; + + memcpy(pvBuf, pvSrc, cbThisCopy); + + cbLeft -= cbThisCopy; + pvBuf = (void *)((uintptr_t)pvBuf + cbThisCopy); + } + + return cbCopy - cbLeft; +} + + +RTDECL(size_t) RTSgBufCopyFromBuf(PRTSGBUF pSgBuf, const void *pvBuf, size_t cbCopy) +{ + AssertPtrReturn(pSgBuf, 0); + AssertPtrReturn(pvBuf, 0); + + size_t cbLeft = cbCopy; + + while (cbLeft) + { + size_t cbThisCopy = cbLeft; + void *pvDst = rtSgBufGet(pSgBuf, &cbThisCopy); + + if (!cbThisCopy) + break; + + memcpy(pvDst, pvBuf, cbThisCopy); + + cbLeft -= cbThisCopy; + pvBuf = (const void *)((uintptr_t)pvBuf + cbThisCopy); + } + + return cbCopy - cbLeft; +} + + +RTDECL(size_t) RTSgBufAdvance(PRTSGBUF pSgBuf, size_t cbAdvance) +{ + AssertPtrReturn(pSgBuf, 0); + + size_t cbLeft = cbAdvance; + while (cbLeft) + { + size_t cbThisAdvance = cbLeft; + rtSgBufGet(pSgBuf, &cbThisAdvance); + if (!cbThisAdvance) + break; + + cbLeft -= cbThisAdvance; + } + + return cbAdvance - cbLeft; +} + + +RTDECL(size_t) RTSgBufSegArrayCreate(PRTSGBUF pSgBuf, PRTSGSEG paSeg, unsigned *pcSeg, size_t cbData) +{ + AssertPtrReturn(pSgBuf, 0); + AssertPtrReturn(pcSeg, 0); + + unsigned cSeg = 0; + size_t cb = 0; + + if (!paSeg) + { + if (pSgBuf->cbSegLeft > 0) + { + size_t idx = pSgBuf->idxSeg; + cSeg = 1; + + cb += RT_MIN(pSgBuf->cbSegLeft, cbData); + cbData -= RT_MIN(pSgBuf->cbSegLeft, cbData); + + while ( cbData + && idx < pSgBuf->cSegs - 1) + { + idx++; + cSeg++; + cb += RT_MIN(pSgBuf->paSegs[idx].cbSeg, cbData); + cbData -= RT_MIN(pSgBuf->paSegs[idx].cbSeg, cbData); + } + } + } + else + { + while ( cbData + && cSeg < *pcSeg) + { + size_t cbThisSeg = cbData; + void *pvSeg = rtSgBufGet(pSgBuf, &cbThisSeg); + + if (!cbThisSeg) + { + Assert(!pvSeg); + break; + } + + AssertMsg(cbThisSeg <= cbData, ("Impossible!\n")); + + paSeg[cSeg].cbSeg = cbThisSeg; + paSeg[cSeg].pvSeg = pvSeg; + cSeg++; + cbData -= cbThisSeg; + cb += cbThisSeg; + } + } + + *pcSeg = cSeg; + + return cb; +} + + +RTDECL(bool) RTSgBufIsZero(PRTSGBUF pSgBuf, size_t cbCheck) +{ + RTSGBUF SgBufTmp; + RTSgBufClone(&SgBufTmp, pSgBuf); + + bool fIsZero = true; + size_t cbLeft = cbCheck; + while (cbLeft) + { + size_t cbThisCheck = cbLeft; + void *pvBuf = rtSgBufGet(&SgBufTmp, &cbThisCheck); + if (!cbThisCheck) + break; + fIsZero = ASMMemIsZero(pvBuf, cbThisCheck); + if (!fIsZero) + break; + cbLeft -= cbThisCheck; + } + + return fIsZero; +} + |