"""Defines data structures used in WASM (binary) modules."""

from __future__ import print_function, absolute_import, division, unicode_literals

from .wasmtypes import *

from .opcodes import OP_END

from .types import (

Structure, CondField, RepeatField,

ChoiceField, WasmField, ConstField, BytesField,

)

class ModuleHeader(Structure):

magic = UInt32Field()

version = UInt32Field()

class FunctionImportEntryData(Structure):

type = VarUInt32Field()

class ResizableLimits(Structure):

flags = VarUInt32Field()

initial = VarUInt32Field()

maximum = CondField(VarUInt32Field(), lambda x: x.flags & 1)

class TableType(Structure):

element_type = ElementTypeField()

limits = ResizableLimits()

class MemoryType(Structure):

limits = ResizableLimits()

class GlobalType(Structure):

content_type = ValueTypeField()

mutability = VarUInt1Field()

class ImportEntry(Structure):

module_len = VarUInt32Field()

module_str = BytesField(lambda x: x.module_len, is_str=True)

field_len = VarUInt32Field()

field_str = BytesField(lambda x: x.field_len, is_str=True)

kind = ExternalKindField()

type = ChoiceField({

0: FunctionImportEntryData(),

1: TableType(),

2: MemoryType(),

3: GlobalType(),

}, lambda x: x.kind)

class ImportSection(Structure):

count = VarUInt32Field()

entries = RepeatField(ImportEntry(), lambda x: x.count)

class FuncType(Structure):

form = VarInt7Field()

param_count = VarUInt32Field()

param_types = RepeatField(ValueTypeField(), lambda x: x.param_count)

return_count = VarUInt1Field()

return_type = CondField(ValueTypeField(), lambda x: bool(x.return_count))

class TypeSection(Structure):

count = VarUInt32Field()

entries = RepeatField(FuncType(), lambda x: x.count)

class FunctionSection(Structure):

count = VarUInt32Field()

types = RepeatField(VarUInt32Field(), lambda x: x.count)

class TableSection(Structure):

count = VarUInt32Field()

entries = RepeatField(TableType(), lambda x: x.count)

class MemorySection(Structure):

count = VarUInt32Field()

entries = RepeatField(MemoryType(), lambda x: x.count)

class InitExpr(WasmField):

def from_raw(self, struct, raw):

from .decode import decode_bytecode

offs = 0

instrs = []

for cur_insn in decode_bytecode(raw):

offs += cur_insn.len

instrs.append(cur_insn)

if cur_insn.op.id == OP_END:

break

return offs, instrs, self

class GlobalEntry(Structure):

type = GlobalType()

init = InitExpr()

class GlobalSection(Structure):

count = VarUInt32Field()

globals = RepeatField(GlobalEntry(), lambda x: x.count)

class ExportEntry(Structure):

field_len = VarUInt32Field()

field_str = BytesField(lambda x: x.field_len, is_str=True)

kind = ExternalKindField()

index = VarUInt32Field()

class ExportSection(Structure):

count = VarUInt32Field()

entries = RepeatField(ExportEntry(), lambda x: x.count)

class StartSection(Structure):

index = VarUInt32Field()

class ElementSegment(Structure):

index = VarUInt32Field()

offset = InitExpr()

num_elem = VarUInt32Field()

elems = RepeatField(VarUInt32Field(), lambda x: x.num_elem)

class ElementSection(Structure):

count = VarUInt32Field()

entries = RepeatField(ElementSegment(), lambda x: x.count)

class LocalEntry(Structure):

count = VarUInt32Field()

type = ValueTypeField()

class FunctionBody(Structure):

body_size = VarUInt32Field()

local_count = VarUInt32Field()

locals = RepeatField(

LocalEntry(),

lambda x: x.local_count,

)

code = BytesField(

lambda x: (

x.body_size -

x.get_decoder_meta()['lengths']['local_count'] -

x.get_decoder_meta()['lengths']['locals']

)

)

class CodeSection(Structure):

count = VarUInt32Field()

bodies = RepeatField(FunctionBody(), lambda x: x.count)

class DataSegment(Structure):

index = VarUInt32Field()

offset = InitExpr()

size = VarUInt32Field()

data = BytesField(lambda x: x.size)

class DataSection(Structure):

count = VarUInt32Field()

entries = RepeatField(DataSegment(), lambda x: x.count)

class DataCountSection(Structure):

count = VarUInt32Field()

class Naming(Structure):

index = VarUInt32Field()

name_len = VarUInt32Field()

name_str = BytesField(lambda x: x.name_len, is_str=True)

class NameMap(Structure):

count = VarUInt32Field()

names = RepeatField(Naming(), lambda x: x.count)

class LocalNames(Structure):

index = VarUInt32Field()

local_map = NameMap()

class LocalNameMap(Structure):

count = VarUInt32Field()

funcs = RepeatField(LocalNames, lambda x: x.count)

class NameSubSection(Structure):

name_type = VarUInt7Field()

payload_len = VarUInt32Field()

payload = ChoiceField({

NAME_SUBSEC_FUNCTION: NameMap(),

NAME_SUBSEC_LOCAL: LocalNameMap(),

}, lambda x: x.name_type)

class Section(Structure):

id = VarUInt7Field()

payload_len = VarUInt32Field()

name_len = CondField(

VarUInt32Field(),

lambda x: x.id == 0,

)

name = CondField(

BytesField(lambda x: x.name_len, is_str=True),

lambda x: x.id == 0,

)

payload = ChoiceField({

SEC_UNK: BytesField(lambda x: (

x.payload_len -

x.get_decoder_meta()['lengths']['name'] -

x.get_decoder_meta()['lengths']['name_len']

)),

SEC_TYPE: TypeSection(),

SEC_IMPORT: ImportSection(),

SEC_FUNCTION: FunctionSection(),

SEC_TABLE: TableSection(),

SEC_MEMORY: MemorySection(),

SEC_GLOBAL: GlobalSection(),

SEC_EXPORT: ExportSection(),

SEC_START: StartSection(),

SEC_ELEMENT: ElementSection(),

SEC_CODE: CodeSection(),

SEC_DATA: DataSection(),

SEC_DATACOUNT: DataCountSection(),

}, lambda x: x.id)

overhang = BytesField(lambda x: max(0, (

x.payload_len -

x.get_decoder_meta()['lengths']['name'] -

x.get_decoder_meta()['lengths']['name_len'] -

x.get_decoder_meta()['lengths']['payload']

)))