338 lines
14 KiB
Java
338 lines
14 KiB
Java
package org.capnproto;
|
|
|
|
final class WireHelpers {
|
|
|
|
public static int roundBytesUpToWords(int bytes) {
|
|
return (bytes + 7) / 8;
|
|
}
|
|
|
|
public static int roundBitsUpToWords(long bits) {
|
|
//# This code assumes 64-bit words.
|
|
return (int)((bits + 63) / ((long) Constants.BITS_PER_WORD));
|
|
}
|
|
|
|
public static int allocate(int refOffset,
|
|
SegmentBuilder segment,
|
|
int amount, // in words
|
|
byte kind) {
|
|
|
|
// TODO check for nullness, amount == 0 case.
|
|
|
|
int allocation = segment.allocate(amount);
|
|
if (allocation == SegmentBuilder.FAILED_ALLOCATION) {
|
|
//# Need to allocate in a new segment. We'll need to
|
|
//# allocate an extra pointer worth of space to act as
|
|
//# the landing pad for a far pointer.
|
|
throw new Error("unimplemented");
|
|
} else {
|
|
WirePointer.setKindAndTarget(segment.buffer, refOffset, kind, allocation);
|
|
return allocation;
|
|
}
|
|
}
|
|
|
|
public static StructBuilder initStructPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
StructSize size) {
|
|
int ptrOffset = allocate(refOffset, segment, size.total(), WirePointer.STRUCT);
|
|
StructPointer.setFromStructSize(segment.buffer, refOffset, size);
|
|
return new StructBuilder(segment, ptrOffset * 8, ptrOffset + size.data,
|
|
size.data * 64, size.pointers, (byte)0);
|
|
}
|
|
|
|
public static StructBuilder getWritableStructPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
StructSize size) {
|
|
long ref = WirePointer.get(segment.buffer, refOffset);
|
|
int target = WirePointer.target(refOffset, ref);
|
|
if (WirePointer.isNull(ref)) {
|
|
return initStructPointer(refOffset, segment, size);
|
|
}
|
|
long oldRef = ref;
|
|
SegmentBuilder oldSegment = segment;
|
|
// TODO follow fars.
|
|
int oldPtrOffset = target;
|
|
|
|
short oldDataSize = StructPointer.dataSize(WirePointer.structPointer(oldRef));
|
|
short oldPointerCount = StructPointer.ptrCount(WirePointer.structPointer(oldRef));
|
|
int oldPointerSectionOffset = oldPtrOffset + oldDataSize;
|
|
|
|
if (oldDataSize < size.data || oldPointerCount < size.pointers) {
|
|
throw new Error("unimplemented");
|
|
} else {
|
|
return new StructBuilder(oldSegment, oldPtrOffset * 8,
|
|
oldPointerSectionOffset, oldDataSize * 64,
|
|
oldPointerCount, (byte)0);
|
|
}
|
|
|
|
}
|
|
|
|
public static ListBuilder initListPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
int elementCount,
|
|
byte elementSize) {
|
|
if (elementSize == FieldSize.INLINE_COMPOSITE) {
|
|
throw new InternalError("Should have called initStructListPointer instead");
|
|
}
|
|
|
|
int dataSize = FieldSize.dataBitsPerElement(elementSize);
|
|
int pointerCount = FieldSize.pointersPerElement(elementSize);
|
|
int step = dataSize + pointerCount * Constants.BITS_PER_POINTER;
|
|
int wordCount = roundBitsUpToWords((long)elementCount * (long)step);
|
|
int ptr = allocate(refOffset, segment, wordCount, WirePointer.LIST);
|
|
|
|
ListPointer.set(segment.buffer, refOffset, elementSize, elementCount);
|
|
|
|
return new ListBuilder(segment, ptr * Constants.BYTES_PER_WORD,
|
|
elementCount, step, dataSize, (short)pointerCount);
|
|
}
|
|
|
|
public static ListBuilder initStructListPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
int elementCount,
|
|
StructSize elementSize) {
|
|
if (elementSize.preferredListEncoding != FieldSize.INLINE_COMPOSITE) {
|
|
//# Small data-only struct. Allocate a list of primitives instead.
|
|
return initListPointer(refOffset, segment, elementCount,
|
|
elementSize.preferredListEncoding);
|
|
}
|
|
|
|
int wordsPerElement = elementSize.total();
|
|
|
|
//# Allocate the list, prefixed by a single WirePointer.
|
|
int wordCount = elementCount * wordsPerElement;
|
|
int ptrOffset = allocate(refOffset, segment, Constants.POINTER_SIZE_IN_WORDS + wordCount,
|
|
WirePointer.LIST);
|
|
|
|
//# Initialize the pointer.
|
|
ListPointer.setInlineComposite(segment.buffer, refOffset, wordCount);
|
|
WirePointer.setKindAndInlineCompositeListElementCount(segment.buffer, ptrOffset,
|
|
WirePointer.STRUCT, elementCount);
|
|
StructPointer.setFromStructSize(segment.buffer, ptrOffset, elementSize);
|
|
|
|
ptrOffset += 1;
|
|
|
|
return new ListBuilder(segment, ptrOffset * 8, elementCount, wordsPerElement * 64,
|
|
elementSize.data * 64, elementSize.pointers);
|
|
}
|
|
|
|
public static ListBuilder getWritableListPointer(int origRefOffset,
|
|
SegmentBuilder origSegment,
|
|
byte elementSize) {
|
|
if (elementSize == FieldSize.INLINE_COMPOSITE) {
|
|
throw new InternalError("Use getStructList{Element,Field} for structs");
|
|
}
|
|
|
|
long origRef = WirePointer.get(origSegment.buffer, origRefOffset);
|
|
int origRefTarget = WirePointer.target(origRefOffset, origRef);
|
|
|
|
if (WirePointer.isNull(origRef)) {
|
|
throw new Error("unimplemented");
|
|
}
|
|
|
|
//# We must verify that the pointer has the right size. Unlike
|
|
//# in getWritableStructListReference(), we never need to
|
|
//# "upgrade" the data, because this method is called only for
|
|
//# non-struct lists, and there is no allowed upgrade path *to*
|
|
//# a non-struct list, only *from* them.
|
|
|
|
long ref = origRef;
|
|
SegmentBuilder segment = origSegment;
|
|
int ptr = origRefTarget; // TODO follow fars.
|
|
|
|
if (WirePointer.kind(ref) != WirePointer.LIST) {
|
|
throw new DecodeException("Called getList{Field,Element}() but existing pointer is not a list");
|
|
}
|
|
|
|
byte oldSize = ListPointer.elementSize(WirePointer.listPointer(ref));
|
|
|
|
if (oldSize == FieldSize.INLINE_COMPOSITE) {
|
|
//# The existing element size is InlineComposite, which
|
|
//# means that it is at least two words, which makes it
|
|
//# bigger than the expected element size. Since fields can
|
|
//# only grow when upgraded, the existing data must have
|
|
//# been written with a newer version of the protocol. We
|
|
//# therefore never need to upgrade the data in this case,
|
|
//# but we do need to validate that it is a valid upgrade
|
|
//# from what we expected.
|
|
throw new Error("unimplemented");
|
|
} else {
|
|
int dataSize = FieldSize.dataBitsPerElement(oldSize);
|
|
int pointerCount = FieldSize.pointersPerElement(oldSize);
|
|
|
|
if (dataSize < FieldSize.dataBitsPerElement(elementSize)) {
|
|
throw new DecodeException("Existing list value is incompatible with expected type.");
|
|
}
|
|
if (pointerCount < FieldSize.pointersPerElement(elementSize)) {
|
|
throw new DecodeException("Existing list value is incompatible with expected type.");
|
|
}
|
|
|
|
int step = dataSize + pointerCount * Constants.BITS_PER_POINTER;
|
|
|
|
return new ListBuilder(segment, ptr * Constants.BYTES_PER_WORD,
|
|
ListPointer.elementCount(WirePointer.listPointer(ref)),
|
|
step, dataSize, (short) pointerCount);
|
|
}
|
|
}
|
|
|
|
// size is in bytes
|
|
public static Text.Builder initTextPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
int size) {
|
|
//# The byte list must include a NUL terminator.
|
|
int byteSize = size + 1;
|
|
|
|
//# Allocate the space.
|
|
int ptrOffset = allocate(refOffset, segment, roundBytesUpToWords(byteSize), WirePointer.LIST);
|
|
|
|
//# Initialize the pointer.
|
|
ListPointer.set(segment.buffer, refOffset, FieldSize.BYTE, byteSize);
|
|
|
|
return new Text.Builder(segment.buffer, ptrOffset * 8, size);
|
|
}
|
|
|
|
public static Text.Builder setTextPointer(int refOffset,
|
|
SegmentBuilder segment,
|
|
Text.Reader value) {
|
|
Text.Builder builder = initTextPointer(refOffset, segment, value.size);
|
|
|
|
// TODO is there a way to do this with bulk methods?
|
|
for (int i = 0; i < builder.size; ++i) {
|
|
builder.buffer.put(builder.offset + i, value.buffer.get(value.offset + i));
|
|
}
|
|
return builder;
|
|
}
|
|
|
|
public static Text.Builder getWritableTextPointer(int refOffset,
|
|
SegmentBuilder segment) {
|
|
long ref = WirePointer.get(segment.buffer, refOffset);
|
|
|
|
if (WirePointer.isNull(ref)) {
|
|
// TODO default values
|
|
return new Text.Builder(null, 0, 0);
|
|
}
|
|
|
|
int refTarget = WirePointer.target(refOffset, ref);
|
|
int ptr = refTarget;
|
|
|
|
if (WirePointer.kind(ref) != WirePointer.LIST) {
|
|
throw new DecodeException("Called getText{Field,Element} but existing pointer is not a list.");
|
|
}
|
|
if (ListPointer.elementSize(WirePointer.listPointer(ref)) != FieldSize.BYTE) {
|
|
throw new DecodeException(
|
|
"Called getText{Field,Element} but existing list pointer is not byte-sized.");
|
|
}
|
|
|
|
|
|
//# Subtract 1 from the size for the NUL terminator.
|
|
return new Text.Builder(segment.buffer, ptr * 8,
|
|
ListPointer.elementCount(WirePointer.listPointer(ref)) - 1);
|
|
|
|
}
|
|
|
|
public static StructReader readStructPointer(SegmentReader segment,
|
|
int refOffset,
|
|
int nestingLimit) {
|
|
|
|
// TODO error handling
|
|
|
|
if (nestingLimit < 0) {
|
|
throw new DecodeException("Message is too deeply nested or contains cycles.");
|
|
}
|
|
|
|
long ref = WirePointer.get(segment.buffer, refOffset);
|
|
int ptrOffset = WirePointer.target(refOffset, ref);
|
|
int structPtr = WirePointer.structPointer(ref);
|
|
int dataSizeWords = StructPointer.dataSize(structPtr);
|
|
|
|
return new StructReader(segment,
|
|
ptrOffset * 8,
|
|
(ptrOffset + dataSizeWords),
|
|
dataSizeWords * 64,
|
|
StructPointer.ptrCount(structPtr),
|
|
(byte)0,
|
|
nestingLimit - 1);
|
|
|
|
}
|
|
|
|
|
|
public static ListReader readListPointer(SegmentReader segment,
|
|
int refOffset,
|
|
byte expectedElementSize,
|
|
int nestingLimit) {
|
|
|
|
long ref = WirePointer.get(segment.buffer, refOffset);
|
|
|
|
// TODO check for null, follow fars, nestingLimit
|
|
if (WirePointer.isNull(ref)) {
|
|
return new ListReader();
|
|
}
|
|
|
|
int listPtr = WirePointer.listPointer(ref);
|
|
|
|
int ptrOffset = WirePointer.target(refOffset, ref);
|
|
long ptr = WirePointer.get(segment.buffer, ptrOffset);
|
|
|
|
switch (ListPointer.elementSize(listPtr)) {
|
|
case FieldSize.INLINE_COMPOSITE : {
|
|
int wordCount = ListPointer.inlineCompositeWordCount(listPtr);
|
|
|
|
long tag = ptr;
|
|
ptrOffset += 1;
|
|
|
|
// TODO bounds check
|
|
|
|
int size = WirePointer.inlineCompositeListElementCount(tag);
|
|
|
|
int structPtr = WirePointer.structPointer(tag);
|
|
int wordsPerElement = StructPointer.wordSize(structPtr);
|
|
|
|
// TODO check that elemements do not overrun word count
|
|
|
|
// TODO check whether the size is compatible
|
|
|
|
return new ListReader(segment, // TODO follow fars
|
|
ptrOffset * 8, //
|
|
size,
|
|
wordsPerElement * 64,
|
|
StructPointer.dataSize(structPtr) * 64,
|
|
StructPointer.ptrCount(structPtr),
|
|
nestingLimit - 1);
|
|
}
|
|
case FieldSize.VOID : break;
|
|
default :
|
|
throw new Error("unrecognized element size");
|
|
}
|
|
|
|
throw new Error();
|
|
}
|
|
|
|
public static Text.Reader readTextPointer(SegmentReader segment,
|
|
int refOffset) {
|
|
long ref = WirePointer.get(segment.buffer, refOffset);
|
|
|
|
if (WirePointer.isNull(ref)) {
|
|
// XXX should use the default value
|
|
return new Text.Reader(java.nio.ByteBuffer.wrap(new byte[0]), 0, 0);
|
|
}
|
|
|
|
int ptrOffset = WirePointer.target(refOffset, ref);
|
|
int listPtr = WirePointer.listPointer(ref);
|
|
int size = ListPointer.elementCount(listPtr);
|
|
|
|
if (WirePointer.kind(ref) != WirePointer.LIST) {
|
|
throw new DecodeException("Message contains non-list pointer where text was expected.");
|
|
}
|
|
|
|
if (ListPointer.elementSize(listPtr) != FieldSize.BYTE) {
|
|
throw new DecodeException("Message contains list pointer of non-bytes where text was expected.");
|
|
}
|
|
|
|
// TODO bounds check?
|
|
|
|
if (size == 0 || segment.buffer.get(8 * ptrOffset + size - 1) != 0) {
|
|
throw new DecodeException("Message contains text that is not NUL-terminated.");
|
|
}
|
|
|
|
return new Text.Reader(segment.buffer, ptrOffset, size - 1);
|
|
}
|
|
}
|