libkern/c++/OSData.cpp

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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 */
/* IOData.m created by rsulack on Thu 25-Sep-1997 */

#include <string.h>

__BEGIN_DECLS
#include <vm/vm_kern.h>
__END_DECLS

#include <libkern/c++/OSData.h>
#include <libkern/c++/OSSerialize.h>
#include <libkern/c++/OSLib.h>
#include <libkern/c++/OSString.h>
#include <IOKit/IOLib.h>

#define super OSObject

OSDefineMetaClassAndStructors(OSData, OSObject)
OSMetaClassDefineReservedUsed(OSData, 0);    // setDeallocFunction
OSMetaClassDefineReservedUnused(OSData, 1);
OSMetaClassDefineReservedUnused(OSData, 2);
OSMetaClassDefineReservedUnused(OSData, 3);
OSMetaClassDefineReservedUnused(OSData, 4);
OSMetaClassDefineReservedUnused(OSData, 5);
OSMetaClassDefineReservedUnused(OSData, 6);
OSMetaClassDefineReservedUnused(OSData, 7);

#define EXTERNAL ((unsigned int) -1)

bool OSData::initWithCapacity(unsigned int inCapacity)
{
    if (data)
    {
        OSCONTAINER_ACCUMSIZE(-((size_t)capacity));
	if (!inCapacity || (capacity < inCapacity))
	{
	    // clean out old data's storage if it isn't big enough
	    if (capacity < page_size) kfree(data, capacity);
	    else                      kmem_free(kernel_map, (vm_offset_t)data, capacity);
	    data = 0;
	    capacity = 0;
	}
    }

    if (!super::init())
        return false;

    if (inCapacity && !data) {

	if (inCapacity < page_size) data = (void *) kalloc_container(inCapacity);
	else {
	    kern_return_t kr;
	    inCapacity = round_page_32(inCapacity);
	    kr = kmem_alloc(kernel_map, (vm_offset_t *)&data, inCapacity, IOMemoryTag(kernel_map));
	    if (KERN_SUCCESS != kr) data = NULL;
	}
        if (!data)
            return false;
        capacity = inCapacity;
    }
    OSCONTAINER_ACCUMSIZE(capacity);

    length = 0;
    if (inCapacity < 16)
        capacityIncrement = 16;
    else
        capacityIncrement = inCapacity;

    return true;
}

bool OSData::initWithBytes(const void *bytes, unsigned int inLength)
{
    if ((inLength && !bytes) || !initWithCapacity(inLength))
        return false;

    if (bytes != data)
	bcopy(bytes, data, inLength);
    length = inLength;

    return true;
}

bool OSData::initWithBytesNoCopy(void *bytes, unsigned int inLength)
{
    if (!super::init())
        return false;

    length = inLength;
    capacity = EXTERNAL;
    data = bytes;

    return true;
}

bool OSData::initWithData(const OSData *inData)
{
    return initWithBytes(inData->data, inData->length);
}

bool OSData::initWithData(const OSData *inData,
                          unsigned int start, unsigned int inLength)
{
    const void *localData = inData->getBytesNoCopy(start, inLength);

    if (localData)
        return initWithBytes(localData, inLength);
    else
        return false;
}

OSData *OSData::withCapacity(unsigned int inCapacity)
{
    OSData *me = new OSData;

    if (me && !me->initWithCapacity(inCapacity)) {
        me->release();
        return 0;
    }

    return me;
}

OSData *OSData::withBytes(const void *bytes, unsigned int inLength)
{
    OSData *me = new OSData;

    if (me && !me->initWithBytes(bytes, inLength)) {
        me->release();
        return 0;
    }
    return me;
}

OSData *OSData::withBytesNoCopy(void *bytes, unsigned int inLength)
{
    OSData *me = new OSData;

    if (me && !me->initWithBytesNoCopy(bytes, inLength)) {
        me->release();
        return 0;
    }

    return me;
}

OSData *OSData::withData(const OSData *inData)
{
    OSData *me = new OSData;

    if (me && !me->initWithData(inData)) {
        me->release();
        return 0;
    }

    return me;
}

OSData *OSData::withData(const OSData *inData,
                         unsigned int start, unsigned int inLength)
{
    OSData *me = new OSData;

    if (me && !me->initWithData(inData, start, inLength)) {
        me->release();
        return 0;
    }

    return me;
}

void OSData::free()
{
    if ((capacity != EXTERNAL) && data && capacity) {
	if (capacity < page_size) kfree(data, capacity);
	else                      kmem_free(kernel_map, (vm_offset_t)data, capacity);
        OSCONTAINER_ACCUMSIZE( -((size_t)capacity) );
    } else if (capacity == EXTERNAL) {
	DeallocFunction freemem = reserved ? reserved->deallocFunction : NULL;
	if (freemem && data && length) {
		freemem(data, length);
	}
    }
    if (reserved) kfree(reserved, sizeof(ExpansionData));
    super::free();
}

unsigned int OSData::getLength() const { return length; }
unsigned int OSData::getCapacity() const { return capacity; }

unsigned int OSData::getCapacityIncrement() const
{
    return capacityIncrement;
}

unsigned int OSData::setCapacityIncrement(unsigned increment)
{
    return capacityIncrement = increment;
}

// xx-review: does not check for capacity == EXTERNAL

unsigned int OSData::ensureCapacity(unsigned int newCapacity)
{
    unsigned char * newData;
    unsigned int finalCapacity;
    void * copydata;
    kern_return_t kr;

    if (newCapacity <= capacity)
        return capacity;

    finalCapacity = (((newCapacity - 1) / capacityIncrement) + 1)
                * capacityIncrement;

    // integer overflow check
    if (finalCapacity < newCapacity) return capacity;

    copydata = data;

    if (finalCapacity >= page_size) {
	// round up
	finalCapacity = round_page_32(finalCapacity);
	// integer overflow check
	if (finalCapacity < newCapacity) return capacity;
	if (capacity >= page_size) {
	    copydata = NULL;
	    kr = kmem_realloc(kernel_map,
			      (vm_offset_t)data,
			      capacity,
			      (vm_offset_t *)&newData,
			      finalCapacity,
			      IOMemoryTag(kernel_map));
	} else {
	    kr = kmem_alloc(kernel_map, (vm_offset_t *)&newData, finalCapacity, IOMemoryTag(kernel_map));
	}
	if (KERN_SUCCESS != kr) newData = NULL;
    }
    else newData = (unsigned char *) kalloc_container(finalCapacity);

    if ( newData ) {
        bzero(newData + capacity, finalCapacity - capacity);
        if (copydata) bcopy(copydata, newData, capacity);
        if (data) {
	    if (capacity < page_size) kfree(data, capacity);
	    else                      kmem_free(kernel_map, (vm_offset_t)data, capacity);
        }
        OSCONTAINER_ACCUMSIZE( ((size_t)finalCapacity) - ((size_t)capacity) );
        data = (void *) newData;
        capacity = finalCapacity;
    }

    return capacity;
}

bool OSData::appendBytes(const void *bytes, unsigned int inLength)
{
    unsigned int newSize;

    if (!inLength)
        return true;

    if (capacity == EXTERNAL)
        return false;

    newSize = length + inLength;
    if ( (newSize > capacity) && newSize > ensureCapacity(newSize) )
        return false;

    if (bytes)
        bcopy(bytes, &((unsigned char *)data)[length], inLength);
    else
        bzero(&((unsigned char *)data)[length], inLength);

    length = newSize;

    return true;
}

bool OSData::appendByte(unsigned char byte, unsigned int inLength)
{
    unsigned int newSize;

    if (!inLength)
        return true;

    if (capacity == EXTERNAL)
        return false;

    newSize = length + inLength;
    if ( (newSize > capacity) && newSize > ensureCapacity(newSize) )
        return false;

    memset(&((unsigned char *)data)[length], byte, inLength);
    length = newSize;

    return true;
}

bool OSData::appendBytes(const OSData *other)
{
    return appendBytes(other->data, other->length);
}

const void *OSData::getBytesNoCopy() const
{
    if (!length)
        return 0;
    else
        return data;
}

const void *OSData::getBytesNoCopy(unsigned int start,
                                   unsigned int inLength) const
{
    const void *outData = 0;

    if (length
    &&  start < length
    && (start + inLength) >= inLength // overflow check
    && (start + inLength) <= length)
        outData = (const void *) ((char *) data + start);

    return outData;
}

bool OSData::isEqualTo(const OSData *aData) const
{
    unsigned int len;

    len = aData->length;
    if ( length != len )
        return false;

    return isEqualTo(aData->data, len);
}

bool OSData::isEqualTo(const void *someData, unsigned int inLength) const
{
    return (length >= inLength) && (bcmp(data, someData, inLength) == 0);
}

bool OSData::isEqualTo(const OSMetaClassBase *obj) const
{
    OSData *	otherData;
    OSString *  str;

    if ((otherData = OSDynamicCast(OSData, obj)))
        return isEqualTo(otherData);
    else if ((str = OSDynamicCast (OSString, obj)))
        return isEqualTo(str);
    else
        return false;
}

bool OSData::isEqualTo(const OSString *obj) const
{
    const char * aCString;
    char * dataPtr;
    unsigned int checkLen = length;
    unsigned int stringLen;

    if (!obj)
      return false;

    stringLen = obj->getLength ();

    dataPtr = (char *)data;

    if (stringLen != checkLen) {

      // check for the fact that OSData may be a buffer that
      // that includes a termination byte and will thus have
      // a length of the actual string length PLUS 1. In this
      // case we verify that the additional byte is a terminator
      // and if so count the two lengths as being the same.

      if ( (checkLen - stringLen) == 1) {
	if (dataPtr[checkLen-1] != 0) // non-zero means not a terminator and thus not likely the same
	  return false;
        checkLen--;
      }
      else
	return false;
    }

    aCString = obj->getCStringNoCopy ();

    for ( unsigned int i=0; i < checkLen; i++ ) {
      if ( *dataPtr++ != aCString[i] )
        return false;
    }

   return true;
}

//this was taken from CFPropertyList.c
static const char __CFPLDataEncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

bool OSData::serialize(OSSerialize *s) const
{
    unsigned int i;
    const unsigned char *p;
    unsigned char c;
    unsigned int serializeLength;

    if (s->previouslySerialized(this)) return true;

    if (!s->addXMLStartTag(this, "data")) return false;

    serializeLength = length;
    if (reserved && reserved->disableSerialization) serializeLength = 0;

    for (i = 0, p = (unsigned char *)data; i < serializeLength; i++, p++) {
        /* 3 bytes are encoded as 4 */
        switch (i % 3) {
	case 0:
		c = __CFPLDataEncodeTable [ ((p[0] >> 2) & 0x3f)];
		if (!s->addChar(c)) return false;
		break;
	case 1:
		c = __CFPLDataEncodeTable [ ((((p[-1] << 8) | p[0]) >> 4) & 0x3f)];
		if (!s->addChar(c)) return false;
		break;
	case 2:
		c = __CFPLDataEncodeTable [ ((((p[-1] << 8) | p[0]) >> 6) & 0x3f)];
		if (!s->addChar(c)) return false;
		c = __CFPLDataEncodeTable [ (p[0] & 0x3f)];
		if (!s->addChar(c)) return false;
		break;
	}
    }
    switch (i % 3) {
    case 0:
	    break;
    case 1:
	    c = __CFPLDataEncodeTable [ ((p[-1] << 4) & 0x30)];
	    if (!s->addChar(c)) return false;
	    if (!s->addChar('=')) return false;
	    if (!s->addChar('=')) return false;
	    break;
    case 2:
	    c = __CFPLDataEncodeTable [ ((p[-1] << 2) & 0x3c)];
	    if (!s->addChar(c)) return false;
	    if (!s->addChar('=')) return false;
	    break;
    }

    return s->addXMLEndTag("data");
}

void OSData::setDeallocFunction(DeallocFunction func)
{
    if (!reserved)
    {
    	reserved = (typeof(reserved)) kalloc_container(sizeof(ExpansionData));
        if (!reserved) return;
        bzero(reserved, sizeof(ExpansionData));
    }
    reserved->deallocFunction = func;
}

void OSData::setSerializable(bool serializable)
{
    if (!reserved)
    {
    	reserved = (typeof(reserved)) kalloc_container(sizeof(ExpansionData));
	if (!reserved) return;
	bzero(reserved, sizeof(ExpansionData));
    }
    reserved->disableSerialization = (!serializable);
}