source: vbox/trunk/src/VBox/Runtime/common/vfs/vfsprintf.cpp

/* $Id: vfsprintf.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
/** @file
 * IPRT - Virtual File System, File Printf.
 */

/*
 * Copyright (C) 2010-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox 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.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#include <iprt/vfs.h>

#include <iprt/errcore.h>
#include <iprt/string.h>


/** Writes the buffer to the VFS file. */
static void FlushPrintfBuffer(PVFSIOSTRMOUTBUF pBuf)
{
    if (pBuf->offBuf)
    {
        int rc = RTVfsIoStrmWrite(pBuf->hVfsIos, pBuf->szBuf, pBuf->offBuf, true /*fBlocking*/, NULL);
        if (RT_FAILURE(rc))
            pBuf->rc = rc;
        pBuf->offBuf   = 0;
        pBuf->szBuf[0] = '\0';
    }
}


/**
 * @callback_method_impl{FNRTSTROUTPUT,
 *      For use with VFSIOSTRMOUTBUF.}
 */
RTDECL(size_t) RTVfsIoStrmStrOutputCallback(void *pvArg, const char *pachChars, size_t cbChars)
{
    PVFSIOSTRMOUTBUF pBuf = (PVFSIOSTRMOUTBUF)pvArg;
    AssertReturn(pBuf->cbSelf == sizeof(*pBuf), 0);

    if (cbChars != 0)
    {
        if (cbChars <= sizeof(pBuf->szBuf) * 3 / 2)
        {
            /*
             * Small piece of output: Buffer it.
             */
            size_t offSrc = 0;
            while  (offSrc < cbChars)
            {
                size_t cbLeft = sizeof(pBuf->szBuf) - pBuf->offBuf - 1;
                if (cbLeft > 0)
                {
                    size_t cbToCopy = RT_MIN(cbChars - offSrc, cbLeft);
                    memcpy(&pBuf->szBuf[pBuf->offBuf], &pachChars[offSrc], cbToCopy);
                    pBuf->offBuf += cbToCopy;
                    pBuf->szBuf[pBuf->offBuf] = '\0';
                    if (cbLeft > cbToCopy)
                        break;
                    offSrc += cbToCopy;
                }
                FlushPrintfBuffer(pBuf);
            }
        }
        else
        {
            /*
             * Large chunk of output: Output it directly.
            */
            FlushPrintfBuffer(pBuf);

            int rc = RTVfsIoStrmWrite(pBuf->hVfsIos, pachChars, cbChars, true /*fBlocking*/, NULL);
            if (RT_FAILURE(rc))
                pBuf->rc = rc;
        }
    }
    else /* Special zero byte write at the end of the formatting. */
        FlushPrintfBuffer(pBuf);
    return cbChars;
}


RTDECL(ssize_t) RTVfsIoStrmPrintfV(RTVFSIOSTREAM hVfsIos, const char *pszFormat, va_list va)
{
    VFSIOSTRMOUTBUF Buf;
    VFSIOSTRMOUTBUF_INIT(&Buf, hVfsIos);

    size_t cchRet = RTStrFormatV(RTVfsIoStrmStrOutputCallback, &Buf, NULL, NULL, pszFormat, va);
    if (RT_SUCCESS(Buf.rc))
        return cchRet;
    return Buf.rc;
}


RTDECL(ssize_t) RTVfsIoStrmPrintf(RTVFSIOSTREAM hVfsIos, const char *pszFormat, ...)
{
    va_list va;
    va_start(va, pszFormat);
    ssize_t cchRet = RTVfsIoStrmPrintfV(hVfsIos, pszFormat, va);
    va_end(va);
    return cchRet;
}


RTDECL(ssize_t) RTVfsFilePrintfV(RTVFSFILE hVfsFile, const char *pszFormat, va_list va)
{
    ssize_t cchRet;
    RTVFSIOSTREAM hVfsIos = RTVfsFileToIoStream(hVfsFile);
    if (hVfsIos != NIL_RTVFSIOSTREAM)
    {
        cchRet = RTVfsIoStrmPrintfV(hVfsIos, pszFormat, va);
        RTVfsIoStrmRelease(hVfsIos);
    }
    else
        cchRet = VERR_INVALID_HANDLE;
    return cchRet;
}


RTDECL(ssize_t) RTVfsFilePrintf(RTVFSFILE hVfsFile, const char *pszFormat, ...)
{
    ssize_t cchRet;
    RTVFSIOSTREAM hVfsIos = RTVfsFileToIoStream(hVfsFile);
    if (hVfsIos != NIL_RTVFSIOSTREAM)
    {
        va_list va;
        va_start(va, pszFormat);
        cchRet = RTVfsIoStrmPrintfV(hVfsIos, pszFormat, va);
        va_end(va);
        RTVfsIoStrmRelease(hVfsIos);
    }
    else
        cchRet = VERR_INVALID_HANDLE;
    return cchRet;
}