ArrayBuffer.fromString & String.fromArrayBuffer handle nulls #1271

Moddable-OpenSource · Dec 19, 2023 · 9133fb3 · 9133fb3
1 parent d65b532
commit 9133fb3
Show file tree

Hide file tree

Showing 3 changed files with 49 additions and 11 deletions.
diff --git a/tests/xs/built-ins/String/fromArrayBuffer.js b/tests/xs/built-ins/String/fromArrayBuffer.js
@@ -29,4 +29,4 @@ assert.throws(TypeError, () => String.fromArrayBuffer("string"), "string");
 assert.throws(TypeError, () => String.fromArrayBuffer(), "no argument");
 assert.throws(TypeError, () => String.fromArrayBuffer(String.fromArrayBuffer), "host function");
 assert.throws(TypeError, () => String.fromArrayBuffer(new Uint8Array(12)), "Uint8Array");
-assert.sameValue("", String.fromArrayBuffer(new $TESTMC.HostBuffer(16)), "empty HostBuffer");
+assert.sameValue("\0\0\0\0", String.fromArrayBuffer(new $TESTMC.HostBuffer(4)), "HostBuffer with nulls");
diff --git a/xs/sources/xsDataView.c b/xs/sources/xsDataView.c
@@ -494,12 +494,36 @@ void fx_ArrayBuffer_fromBigInt(txMachine* the)
 #ifndef mxCESU8
 void fx_ArrayBuffer_fromString(txMachine* the)
 {
-	txSize length;
+	txSize length = 0;
 	if (mxArgc < 1)
 		mxTypeError("no argument");
-	length = mxStringLength(fxToString(the, mxArgv(0)));
-	fxConstructArrayBufferResult(the, mxThis, length);
-	c_memcpy(mxResult->value.reference->next->value.arrayBuffer.address, mxArgv(0)->value.string, length);
+
+	txString c = mxArgv(0)->value.string;
+	txInteger nulls = 0;
+	while (true) {
+		uint8_t b = (uint8_t)c_read8(c++);
+		if (!b) break;
+
+		length += 1;
+		if ((0xc0 == b) && (0x80 == (uint8_t)c_read8(c)))
+			nulls += 1;
+	} 
+
+	fxConstructArrayBufferResult(the, mxThis, length - nulls);
+	if (!nulls)
+		c_memcpy(mxResult->value.reference->next->value.arrayBuffer.address, mxArgv(0)->value.string, length);
+	else {
+		txString c = mxArgv(0)->value.string, end = c + length;
+		txByte *out = mxResult->value.reference->next->value.arrayBuffer.address;
+		while (c < end) {
+			uint8_t b = (uint8_t)c_read8(c++);
+			if ((0xc0 == (uint8_t)b) && (0x80 == (uint8_t)c_read8(c))) {
+				b = 0;
+				c += 1;
+			}
+			*out++ = b;
+		}
+	}
 }
 #endif
 
@@ -1365,7 +1389,7 @@ void fx_TypedArray(txMachine* the)
 			size = fxArgToByteLength(the, 2, -1);
 			info = fxGetBufferInfo(the, mxArgv(0));
 			if (size >= 0) {
-				txInteger delta = size << shift;
+				txInteger delta = size << shift;		//@@ overflow
 				txInteger end = fxAddChunkSizes(the, offset, delta);
 				if ((info->value.bufferInfo.length < end) || (end < offset))
 					mxRangeError("out of range length %ld", size);

diff --git a/xs/sources/xsString.c b/xs/sources/xsString.c
@@ -348,7 +348,7 @@ void fx_String_fromArrayBuffer(txMachine* the)
 	txSlot* arrayBuffer = C_NULL, *sharedArrayBuffer = C_NULL;
 	txSlot* bufferInfo;
 	txInteger limit, offset;
-	txInteger inLength, outLength = 0;
+	txInteger inLength, outLength = 0, nulls = 0;
 	unsigned char *in;
 	txString string;
 	if (mxArgc < 1)
@@ -381,7 +381,7 @@ void fx_String_fromArrayBuffer(txMachine* the)
 		unsigned char first = c_read8(in++), clen;
 		if (first < 0x80){
 			if (0 == first)
-				break;
+				nulls += 1;
 			inLength -= 1;
 			outLength += 1;
 			continue;
@@ -408,9 +408,23 @@ void fx_String_fromArrayBuffer(txMachine* the)
 		} while (--clen > 0);
 	}
 
-	string = fxNewChunk(the, outLength + 1);
-	c_memcpy(string, offset + (txString)(arrayBuffer ? arrayBuffer->value.arrayBuffer.address : sharedArrayBuffer->value.host.data), outLength);
-	string[outLength] = 0;
+	string = fxNewChunk(the, outLength + nulls + 1);
+	if (!nulls)
+		c_memcpy(string, offset + (txString)(arrayBuffer ? arrayBuffer->value.arrayBuffer.address : sharedArrayBuffer->value.host.data), outLength);
+	else {
+		txString c = string, end = c + outLength + nulls;
+		txString buf = offset + (txString)(arrayBuffer ? arrayBuffer->value.arrayBuffer.address : sharedArrayBuffer->value.host.data);
+		while (c < end) {
+			txByte b = c_read8(buf++);
+			if (b)
+				*c++ = b;
+			else {
+				*c++ = 0xC0;
+				*c++ = 0x80;
+			}
+		}
+	}
+	string[outLength + nulls] = 0;
 	mxResult->value.string = string;
 	mxResult->kind = XS_STRING_KIND;