internal static WebAssemblyType GetInitExprType(InitExpr init)
{
if (init.expr.Length < 1)
{
throw new Exception("Unexpected init expression.");
}
switch (init.expr[0])
{
case (byte)WebAssemblyOpcode.I32_CONST:
return(WebAssemblyType.i32);
case (byte)WebAssemblyOpcode.I64_CONST:
return(WebAssemblyType.i64);
case (byte)WebAssemblyOpcode.F32_CONST:
return(WebAssemblyType.f32);
case (byte)WebAssemblyOpcode.F64_CONST:
return(WebAssemblyType.f64);
default:
throw new Exception("Invalid init expression. Expected only simple constant load instruction.");
}
}
public GlobalVariable(BinaryReader reader)
{
type = new GlobalType(reader);
init = new InitExpr(reader);
if (type.content_type != WebAssemblyHelper.GetInitExprType(init))
{
throw new Exception("Global variable type and expression mismatch.");
}
}
public GlobalVariable(GlobalType type, InitExpr init)
{
this.type = type ?? throw new ArgumentException(nameof(type));
this.init = init ?? throw new ArgumentException(nameof(init));
if (type.content_type != WebAssemblyHelper.GetInitExprType(init))
{
throw new Exception("Global variable type and expression mismatch.");
}
}
public DataSegment(BinaryReader reader)
{
memory_index = LEB128.ReadUInt32(reader);
offset = new InitExpr(reader);
uint count = LEB128.ReadUInt32(reader);
if (count > int.MaxValue)
{
throw new NotImplementedException($"Count larger than {int.MaxValue} bytes not supported.");
}
data = reader.ReadBytes((int)count);
}
public ElementSegment(BinaryReader reader)
{
table_index = LEB128.ReadUInt32(reader);
offset = new InitExpr(reader);
uint num_elem = LEB128.ReadUInt32(reader);
function_index = new uint[num_elem];
for (uint i = 0; i < num_elem; i++)
{
function_index[i] = LEB128.ReadUInt32(reader);
}
}
internal static ValueObject GetInitExpr(InitExpr init, List <GlobalInstance> initialized_globals)
{
if (init.expr.Length < 3)
{
throw new Exception("Unexpected init expression.");
}
uint pc = 0;
ValueObject ret = null;
switch (init.expr[0])
{
case (byte)WebAssemblyOpcode.I32_CONST:
ret = new ValueObject(LEB128.ReadUInt32(init.expr, ref pc));
break;
case (byte)WebAssemblyOpcode.I64_CONST:
ret = new ValueObject(LEB128.ReadUInt64(init.expr, ref pc));
break;
case (byte)WebAssemblyOpcode.F32_CONST:
ret = new ValueObject(BitConverter.ToSingle(init.expr, (int)pc));
break;
case (byte)WebAssemblyOpcode.F64_CONST:
ret = new ValueObject(BitConverter.ToDouble(init.expr, (int)pc));
break;
case (byte)WebAssemblyOpcode.GLOBAL_GET:
GlobalInstance gi = initialized_globals[LEB128.ReadInt32(init.expr, ref pc)];
if (!gi.is_mutable)
{
throw new Exception("Unexpected init expression.");
}
ret = gi.value;
break;
default:
throw new Exception("Invalid init expression. Expected only simple constant load instruction or global get.");
}
pc++;
if (init.expr[pc] != (byte)WebAssemblyOpcode.END || init.expr.Length > pc)
{
throw new Exception("Invalid init expression.");
}
return(ret);
}
internal static uint GetOffset(InitExpr init)
{
if (init.expr.Length < 3 || init.expr.Length > 6 || init.expr[0] != (byte)WebAssemblyOpcode.I32_CONST || init.expr[init.expr.Length - 1] != (byte)WebAssemblyOpcode.END)
{
throw new Exception("Unexpected init expression.");
}
uint value = 0;
for (int i = init.expr.Length - 2; i > 0; i--)
{
value = value << 8 | init.expr[i];
}
return(value);
}
public ElementSegment(uint table_index, InitExpr offset, uint[] function_index)
{
this.table_index = table_index;
this.offset = offset ?? throw new ArgumentException(nameof(offset));
this.function_index = function_index ?? throw new ArgumentException(nameof(function_index));
}
public DataSegment(uint memory_index, InitExpr offset, byte[] data)
{
this.memory_index = memory_index;
this.offset = offset ?? throw new ArgumentException(nameof(offset));
this.data = data ?? throw new ArgumentException(nameof(data));
}
