LibJS: Add a bunch of numeric conversions to Value

Namely:
- BigInt64
- BigUint64
- i16
- u16
- i8
- u8
- Clamped u8

These will be used in ArrayBuffer::numeric_to_raw_bytes later.

2 files changed, 120 insertions, 0 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/Value.cpp b/Userland/Libraries/LibJS/Runtime/Value.cpp
index bff74edc29..ab045e17a9 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Value.cpp
@@ -548,6 +548,24 @@ BigInt* Value::to_bigint(GlobalObject& global_object) const
     }
 }
 
+// 7.1.15 ToBigInt64 ( argument ), https://tc39.es/ecma262/multipage/abstract-operations.html#sec-tobigint64
+i64 Value::to_bigint_int64(GlobalObject& global_object) const
+{
+    auto* bigint = to_bigint(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    return static_cast<i64>(bigint->big_integer().to_u64());
+}
+
+// 7.1.16 ToBigUint64 ( argument ), https://tc39.es/ecma262/multipage/abstract-operations.html#sec-tobiguint64
+u64 Value::to_bigint_uint64(GlobalObject& global_object) const
+{
+    auto* bigint = to_bigint(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    return bigint->big_integer().to_u64();
+}
+
 // FIXME: These two conversions are wrong for JS, and seem likely to be footguns
 i32 Value::as_i32() const
 {
@@ -615,6 +633,101 @@ u32 Value::to_u32(GlobalObject& global_object) const
     return static_cast<u32>(int32bit);
 }
 
+// 7.1.8 ToInt16 ( argument ), https://tc39.es/ecma262/#sec-toint16
+i16 Value::to_i16(GlobalObject& global_object) const
+{
+    auto number = to_number(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    double value = number.as_double();
+    if (!isfinite(value) || value == 0)
+        return 0;
+    auto abs = fabs(value);
+    auto int_val = floor(abs);
+    if (signbit(value))
+        int_val = -int_val;
+    auto remainder = fmod(int_val, 65536.0);
+    auto int16bit = remainder >= 0.0 ? remainder : remainder + 65536.0; // The notation “x modulo y” computes a value k of the same sign as y
+    if (int16bit >= 32768.0)
+        int16bit -= 65536.0;
+    return static_cast<i16>(int16bit);
+}
+
+// 7.1.9 ToUint16 ( argument ), https://tc39.es/ecma262/#sec-touint16
+u16 Value::to_u16(GlobalObject& global_object) const
+{
+    auto number = to_number(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    double value = number.as_double();
+    if (!isfinite(value) || value == 0)
+        return 0;
+    auto int_val = floor(fabs(value));
+    if (signbit(value))
+        int_val = -int_val;
+    auto int16bit = fmod(int_val, NumericLimits<u16>::max() + 1.0);
+    return static_cast<u16>(int16bit);
+}
+
+// 7.1.10 ToInt8 ( argument ), https://tc39.es/ecma262/#sec-toint8
+i8 Value::to_i8(GlobalObject& global_object) const
+{
+    auto number = to_number(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    double value = number.as_double();
+    if (!isfinite(value) || value == 0)
+        return 0;
+    auto abs = fabs(value);
+    auto int_val = floor(abs);
+    if (signbit(value))
+        int_val = -int_val;
+    auto remainder = fmod(int_val, 256.0);
+    auto int8bit = remainder >= 0.0 ? remainder : remainder + 256.0; // The notation “x modulo y” computes a value k of the same sign as y
+    if (int8bit >= 128.0)
+        int8bit -= 256.0;
+    return static_cast<i8>(int8bit);
+}
+
+// 7.1.11 ToUint8 ( argument ), https://tc39.es/ecma262/#sec-touint8
+u8 Value::to_u8(GlobalObject& global_object) const
+{
+    auto number = to_number(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    double value = number.as_double();
+    if (!isfinite(value) || value == 0)
+        return 0;
+    auto int_val = floor(fabs(value));
+    if (signbit(value))
+        int_val = -int_val;
+    auto int8bit = fmod(int_val, NumericLimits<u8>::max() + 1.0);
+    return static_cast<u8>(int8bit);
+}
+
+// 7.1.12 ToUint8Clamp ( argument ), https://tc39.es/ecma262/#sec-touint8clamp
+u8 Value::to_u8_clamp(GlobalObject& global_object) const
+{
+    auto number = to_number(global_object);
+    if (global_object.vm().exception())
+        return INVALID;
+    if (number.is_nan())
+        return 0;
+    double value = number.as_double();
+    if (value <= 0.0)
+        return 0;
+    if (value >= 255.0)
+        return 255;
+    auto int_val = floor(value);
+    if (int_val + 0.5 < value)
+        return static_cast<u8>(int_val + 1.0);
+    if (value < int_val + 0.5)
+        return static_cast<u8>(int_val);
+    if (fmod(int_val, 2.0) == 1.0)
+        return static_cast<u8>(int_val + 1.0);
+    return static_cast<u8>(int_val);
+}
+
 // 7.1.20 ToLength ( argument ), https://tc39.es/ecma262/#sec-tolength
 size_t Value::to_length(GlobalObject& global_object) const
 {
diff --git a/Userland/Libraries/LibJS/Runtime/Value.h b/Userland/Libraries/LibJS/Runtime/Value.h
index 2e861feb99..09eca1530b 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.h
+++ b/Userland/Libraries/LibJS/Runtime/Value.h
@@ -265,6 +265,8 @@ public:
     Value to_numeric(GlobalObject&) const;
     Value to_number(GlobalObject&) const;
     BigInt* to_bigint(GlobalObject&) const;
+    i64 to_bigint_int64(GlobalObject&) const;
+    u64 to_bigint_uint64(GlobalObject&) const;
     double to_double(GlobalObject&) const;
     StringOrSymbol to_property_key(GlobalObject&) const;
     i32 to_i32(GlobalObject& global_object) const
@@ -274,6 +276,11 @@ public:
         return to_i32_slow_case(global_object);
     }
     u32 to_u32(GlobalObject&) const;
+    i16 to_i16(GlobalObject&) const;
+    u16 to_u16(GlobalObject&) const;
+    i8 to_i8(GlobalObject&) const;
+    u8 to_u8(GlobalObject&) const;
+    u8 to_u8_clamp(GlobalObject&) const;
     size_t to_length(GlobalObject&) const;
     size_t to_index(GlobalObject&) const;
     double to_integer_or_infinity(GlobalObject&) const;