这里是本地代码。
static void Dalvik_java_lang_System_arraycopy(const u4* args, JValue* pResult)
{
ArrayObject* srcArray = (ArrayObject*) args[0];
int srcPos = args[1];
ArrayObject* dstArray = (ArrayObject*) args[2];
int dstPos = args[3];
int length = args[4];
if (srcArray == NULL) {
dvmThrowNullPointerException("src == null");
RETURN_VOID();
}
if (dstArray == NULL) {
dvmThrowNullPointerException("dst == null");
RETURN_VOID();
}
if (!dvmIsArray(srcArray)) {
dvmThrowArrayStoreExceptionNotArray(((Object*)srcArray)->clazz, "source");
RETURN_VOID();
}
if (!dvmIsArray(dstArray)) {
dvmThrowArrayStoreExceptionNotArray(((Object*)dstArray)->clazz, "destination");
RETURN_VOID();
}
if (srcPos < 0 || dstPos < 0 || length < 0 ||
srcPos > (int) srcArray->length - length ||
dstPos > (int) dstArray->length - length)
{
dvmThrowExceptionFmt(gDvm.exArrayIndexOutOfBoundsException,
"src.length=%d srcPos=%d dst.length=%d dstPos=%d length=%d",
srcArray->length, srcPos, dstArray->length, dstPos, length);
RETURN_VOID();
}
ClassObject* srcClass = srcArray->clazz;
ClassObject* dstClass = dstArray->clazz;
char srcType = srcClass->descriptor[1];
char dstType = dstClass->descriptor[1];
bool srcPrim = (srcType != '[' && srcType != 'L');
bool dstPrim = (dstType != '[' && dstType != 'L');
if (srcPrim || dstPrim) {
if (srcPrim != dstPrim || srcType != dstType) {
dvmThrowArrayStoreExceptionIncompatibleArrays(srcClass, dstClass);
RETURN_VOID();
}
if (false) ALOGD("arraycopy prim[%c] dst=%p %d src=%p %d len=%d",
srcType, dstArray->contents, dstPos,
srcArray->contents, srcPos, length);
switch (srcType) {
case 'B':
case 'Z':
memmove((u1*) dstArray->contents + dstPos,
(const u1*) srcArray->contents + srcPos,
length);
break;
case 'C':
case 'S':
move16((u1*) dstArray->contents + dstPos * 2,
(const u1*) srcArray->contents + srcPos * 2,
length * 2);
break;
case 'F':
case 'I':
move32((u1*) dstArray->contents + dstPos * 4,
(const u1*) srcArray->contents + srcPos * 4,
length * 4);
break;
case 'D':
case 'J':
move32((u1*) dstArray->contents + dstPos * 8,
(const u1*) srcArray->contents + srcPos * 8,
length * 8);
break;
default:
ALOGE("Weird array type '%s'", srcClass->descriptor);
dvmAbort();
}
} else {
const int width = sizeof(Object*);
if (srcClass->arrayDim == dstClass->arrayDim &&
dvmInstanceof(srcClass, dstClass))
{
if (false) ALOGD("arraycopy ref dst=%p %d src=%p %d len=%d",
dstArray->contents, dstPos * width,
srcArray->contents, srcPos * width,
length * width);
move32((u1*)dstArray->contents + dstPos * width,
(const u1*)srcArray->contents + srcPos * width,
length * width);
dvmWriteBarrierArray(dstArray, dstPos, dstPos+length);
} else {
Object** srcObj;
int copyCount;
ClassObject* clazz = NULL;
srcObj = ((Object**)(void*)srcArray->contents) + srcPos;
if (length > 0 && srcObj[0] != NULL)
{
clazz = srcObj[0]->clazz;
if (!dvmCanPutArrayElement(clazz, dstClass))
clazz = NULL;
}
for (copyCount = 0; copyCount < length; copyCount++)
{
if (srcObj[copyCount] != NULL &&
srcObj[copyCount]->clazz != clazz &&
!dvmCanPutArrayElement(srcObj[copyCount]->clazz, dstClass))
{
break;
}
}
if (false) ALOGD("arraycopy iref dst=%p %d src=%p %d count=%d of %d",
dstArray->contents, dstPos * width,
srcArray->contents, srcPos * width,
copyCount, length);
move32((u1*)dstArray->contents + dstPos * width,
(const u1*)srcArray->contents + srcPos * width,
copyCount * width);
dvmWriteBarrierArray(dstArray, 0, copyCount);
if (copyCount != length) {
dvmThrowArrayStoreExceptionIncompatibleArrayElement(srcPos + copyCount,
srcObj[copyCount]->clazz, dstClass);
RETURN_VOID();
}
}
}
RETURN_VOID();
}