Add support for byte and octet Web IDL types to the bindings generator

Source/bindings/v8/V8Binding.cpp

Index: Source/bindings/v8/V8Binding.cpp
diff --git a/Source/bindings/v8/V8Binding.cpp b/Source/bindings/v8/V8Binding.cpp
index 9bd2b00b53eb63f053611e22034683d387649fd4..94400faf1aab3068d62a68b2121763275b1817b5 100644
--- a/Source/bindings/v8/V8Binding.cpp
+++ b/Source/bindings/v8/V8Binding.cpp
@@ -115,6 +115,9 @@ PassRefPtr<NodeFilter> toNodeFilter(v8::Handle<v8::Value> callback)
     return NodeFilter::create(V8NodeFilterCondition::create(callback));
 }
 
+static const int8_t kMaxInt8 = 127;
+static const int8_t kMinInt8 = -128;
+static const uint8_t kMaxUInt8 = 255;
 const int32_t kMaxInt32 = 0x7fffffff;
 const int32_t kMinInt32 = -kMaxInt32 - 1;
 const uint32_t kMaxUInt32 = 0xffffffff;
@@ -134,6 +137,78 @@ static double enforceRange(double x, double minimum, double maximum, bool& ok)
     return x;
 }
 
+int8_t toInt8(v8::Handle<v8::Value> value, IntegerConversionConfiguration configuration, bool& ok)
+{
+    ok = true;
+
+    // Fast case. The value is already a 32-bit integer in the right range.
+    if (value->IsInt32()) {
+        int32_t result = value->Int32Value();
+        if (result >= kMinInt8 && result <= kMaxInt8)
+            return static_cast<int8_t>(result);
+        if (configuration == EnforceRange) {
+            ok = false;
+            return 0;
+        }
+        result %= 256; // 2^8.
+        return static_cast<int8_t>(result > kMaxInt8 ? result - 256 : result);

[jsbell, 2013/06/13 16:51:31]

These two lines can be simplified to just: return static_cast<int8_t>(result); -
integral conversions have the modulus behavior built-in.
(http://en.cppreference.com/w/cpp/language/implicit_cast)

[do-not-use, 2013/06/13 19:11:20]

AFAIK, modulus behavior is only guaranteed for unsigned types. For signed types,
the behavior is implementation specific. From your link:
- If the destination type is unsigned, the resulting value is the value modulo
2n
- If the destination type is signed, the value does not change if the source
integer can be represented in the destination type. Otherwise the result is
implementation-defined. 

[jsbell, 2013/06/13 19:14:23]

Right, sorry. Carry on!

+    }
+
+    // Can the value be converted to a number?
+    v8::Local<v8::Number> numberObject = value->ToNumber();
+    if (numberObject.IsEmpty()) {
+        ok = false;
+        return 0;
+    }
+
+    if (configuration == EnforceRange)
+        return enforceRange(numberObject->Value(), kMinInt8, kMaxInt8, ok);
+
+    double numberValue = numberObject->Value();
+    if (std::isnan(numberValue) || std::isinf(numberValue) || !numberValue)
+        return 0;
+
+    numberValue = numberValue < 0 ? -floor(abs(numberValue)) : floor(abs(numberValue));
+    numberValue = fmod(numberValue, 256); // 2^8.
+
+    return static_cast<int8_t>(numberValue > kMaxInt8 ? numberValue - 256 : numberValue);

[jsbell, 2013/06/13 16:51:31]

Alternately, this line could be: return
static_cast<int8_t>(static_cast<uint8_t>(numberValue));

+}
+
+uint8_t toUInt8(v8::Handle<v8::Value> value, IntegerConversionConfiguration configuration, bool& ok)
+{
+    ok = true;
+
+    // Fast case. The value is a 32-bit signed integer - possibly positive?
+    if (value->IsInt32()) {
+        int32_t result = value->Int32Value();
+        if (result >= 0 && result <= kMaxUInt8)
+            return static_cast<uint8_t>(result);
+        if (configuration == EnforceRange) {
+            ok = false;
+            return 0;
+        }
+        return static_cast<uint8_t>(result % 256); // 2^8.

[jsbell, 2013/06/13 16:51:31]

The modulus should not be necessary here.

[do-not-use, 2013/06/13 19:11:20]

Yes, here it is not technically required since the type is unsigned.

+    }
+
+    // Can the value be converted to a number?
+    v8::Local<v8::Number> numberObject = value->ToNumber();
+    if (numberObject.IsEmpty()) {
+        ok = false;
+        return 0;
+    }
+
+    if (configuration == EnforceRange)
+        return enforceRange(numberObject->Value(), 0, kMaxUInt8, ok);
+
+    // Does the value convert to nan or to an infinity?
+    double numberValue = numberObject->Value();
+    if (std::isnan(numberValue) || std::isinf(numberValue) || !numberValue)
+        return 0;
+
+    numberValue = numberValue < 0 ? -floor(abs(numberValue)) : floor(abs(numberValue));
+    return static_cast<uint8_t>(fmod(numberValue, 256)); // 2^8.
+}
+
 int32_t toInt32(v8::Handle<v8::Value> value, IntegerConversionConfiguration configuration, bool& ok)
 {
     ok = true;