/// <summary>
/// Reads the non-custom section with the given header.
/// </summary>
/// <param name="Header">The section header.</param>
/// <returns>The parsed section.</returns>
protected Section ReadKnownSectionPayload(SectionHeader Header)
{
switch (Header.Name.Code)
{
case SectionCode.Type:
return(TypeSection.ReadSectionPayload(Header, this));
case SectionCode.Import:
return(ImportSection.ReadSectionPayload(Header, this));
case SectionCode.Function:
return(FunctionSection.ReadSectionPayload(Header, this));
case SectionCode.Table:
return(TableSection.ReadSectionPayload(Header, this));
case SectionCode.Memory:
return(MemorySection.ReadSectionPayload(Header, this));
case SectionCode.Global:
return(GlobalSection.ReadSectionPayload(Header, this));
case SectionCode.Export:
return(ExportSection.ReadSectionPayload(Header, this));
case SectionCode.Start:
return(StartSection.ReadSectionPayload(Header, this));
case SectionCode.Element:
return(ElementSection.ReadSectionPayload(Header, this));
case SectionCode.Code:
return(CodeSection.ReadSectionPayload(Header, this));
case SectionCode.Data:
return(DataSection.ReadSectionPayload(Header, this));
default:
return(ReadUnknownSectionPayload(Header));
}
}
// strict parse means all sections must come in order
public void ParseAsWASM(string filename, bool strict_parse = true)
{
if (!BitConverter.IsLittleEndian)
{
throw new NotImplementedException("LEB128 implementation only handles little endian systems");
}
using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read))
{
BinaryReader reader = new BinaryReader(fs);
uint magic = reader.ReadUInt32();
if (magic != MAGIC)
{
throw new Exception("Not a compiled Web Assembly file.");
}
uint version = reader.ReadUInt32();
if (version > SUPPORTED_VERSION)
{
throw new Exception($"Unsupported version. Expected version <= {SUPPORTED_VERSION}, received {version}.");
}
int last_parsed_module = int.MinValue;
/* Read in each module */
while (true)
{
int id = reader.PeekChar();
// EOF
if (id == -1)
{
break;
}
if (strict_parse && id < last_parsed_module)
{
throw new Exception("File contains out of order sections.");
}
last_parsed_module = id;
switch (id)
{
case (int)WebAssemblyModuleID.Custom:
if (strict_parse && custom != null)
{
throw new Exception("File contains a duplicate custom section.");
}
custom = new CustomSection(reader);
break;
case (int)WebAssemblyModuleID.Type:
if (strict_parse && type != null)
{
throw new Exception("File contains a duplicate type section.");
}
type = new TypeSection(reader);
break;
case (int)WebAssemblyModuleID.Import:
if (strict_parse && import != null)
{
throw new Exception("File contains a duplicate import section.");
}
import = new ImportSection(reader);
break;
case (int)WebAssemblyModuleID.Function:
if (strict_parse && function != null)
{
throw new Exception("File contains a duplicate function section.");
}
function = new FunctionSection(reader);
break;
case (int)WebAssemblyModuleID.Table:
if (strict_parse && table != null)
{
throw new Exception("File contains a duplicate table section.");
}
table = new TableSection(reader);
break;
case (int)WebAssemblyModuleID.Memory:
if (strict_parse && memory != null)
{
throw new Exception("File contains a duplicate memory section.");
}
memory = new MemorySection(reader);
break;
case (int)WebAssemblyModuleID.Global:
if (strict_parse && global != null)
{
throw new Exception("File contains a duplicate global section.");
}
global = new GlobalSection(reader);
break;
case (int)WebAssemblyModuleID.Export:
if (strict_parse && export != null)
{
throw new Exception("File contains a duplicate export section.");
}
export = new ExportSection(reader);
break;
case (int)WebAssemblyModuleID.Start:
if (strict_parse && start != null)
{
throw new Exception("File contains a duplicate start section.");
}
start = new StartSection(reader);
break;
case (int)WebAssemblyModuleID.Element:
if (strict_parse && element != null)
{
throw new Exception("File contains a duplicate element section.");
}
element = new ElementSection(reader);
break;
case (int)WebAssemblyModuleID.Code:
if (strict_parse && code != null)
{
throw new Exception("File contains a duplicate code section.");
}
code = new CodeSection(reader);
break;
case (int)WebAssemblyModuleID.Data:
if (strict_parse && data != null)
{
throw new Exception("File contains a duplicate data section.");
}
data = new DataSection(reader);
break;
// Error
default:
throw new Exception($"Unknown section {id}.");
}
}
/* Additional validation */
// The lengths of vectors produced by the (possibly empty) function and code section must match up.
if ((function != null && code == null) || (function == null && code != null))
{
throw new Exception("File corrupt. Must include both function and code sections.");
}
if (function.types.Length != code.bodies.Length)
{
throw new Exception("File corrupt. Function and code sections do not match up.");
}
// TODO: I don't actually check if data overlaps
// TODO: Validate everything in this list
// https://webassembly.github.io/spec/core/valid/modules.html
}
}
