C++ (Cpp) IOBufferMemoryDescriptor::readBytes Exemples

Exemple #1

IOReturn
IOCDBlockStorageDriver::cacheTocInfo(void)
{
    IOBufferMemoryDescriptor *buffer;
    IOReturn result;
    CDTOC *toc;
    UInt16 tocSize;

    assert(sizeof(CDTOC) == 4);		/* (compiler/platform check) */
    assert(sizeof(CDTOCDescriptor) == 11);		/* (compiler/platform check) */

    assert(_toc == NULL);

    /* Read the TOC header: */

    buffer = IOBufferMemoryDescriptor::withCapacity(sizeof(CDTOC),kIODirectionIn);
    if (buffer == NULL) {
        return(kIOReturnNoMemory);
    }

    result = getProvider()->readTOC(buffer);
    if (result != kIOReturnSuccess) {
        buffer->release();
        return(result);
    }

    toc = (CDTOC *) buffer->getBytesNoCopy();
    tocSize = OSSwapBigToHostInt16(toc->length) + sizeof(toc->length);

    buffer->release();

    /* Reject the TOC if its size is too small: */

    if (tocSize <= sizeof(CDTOC)) {
        return(kIOReturnNotFound);
    }

    /* Read the TOC in full: */

    buffer = IOBufferMemoryDescriptor::withCapacity(tocSize,kIODirectionIn);
    if (buffer == NULL) {
        return(kIOReturnNoMemory);
    }

    result = getProvider()->readTOC(buffer);
    if (result != kIOReturnSuccess) {
        buffer->release();
        return(result);
    }

    toc = (CDTOC *) IOMalloc(tocSize);
    if (toc == NULL) {
        buffer->release();
        return(kIOReturnNoMemory);
    }

    if (buffer->readBytes(0,toc,tocSize) != tocSize) {
        buffer->release();
        IOFree(toc,tocSize);
        return(kIOReturnNoMemory);
    }

    _toc = toc;
    _tocSize = tocSize;

    buffer->release();

    return(result);
}