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#!/usr/bin/env python3
# Copyright 2019 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be found
# in the LICENSE file.
CUSTOM_SECTION_ID = 0
FUNCTION_SECTION_ID = 3
def peek_uint8(fin):
bs = fin.peek(1)[:1]
if len(bs) != 1:
return None, bs
return ord(bs[0]), bs
def read_uint8(fin):
value, bs = peek_uint8(fin)
fin.read(len(bs))
return value, bs
def peek_uint32(fin):
bs = fin.peek(4)[:4]
if len(bs) != 4:
return None, bs
return ord(bs[0]) | ord(bs[1]) << 8 | ord(bs[2]) << 16 | ord(bs[3]) << 24, bs
def read_uint32(fin):
value, bs = peek_uint32(fin)
fin.read(len(bs))
return value, bs
def peek_varuintN(fin):
value = 0
shift = 0
n = 1
while True:
bs = fin.peek(n)[:n]
if len(bs) < n:
return None, bs
b = ord(bs[-1])
value |= (b & 0x7F) << shift;
if (b & 0x80) == 0x00:
return value, bs
shift += 7;
n += 1
def read_varuintN(fin):
value, bs = peek_varuintN(fin)
fin.read(len(bs))
return value, bs
def to_varuintN(value):
bs = ""
while True:
b = value & 0x7F
value >>= 7
if (value != 0x00):
b |= 0x80
bs += chr(b)
if value == 0x00:
return bs
def write_varuintN(value, fout):
bs = to_varuintN(value)
fout.write(bs)
return bs
def peek_magic_number(fin, expected_magic_number=0x6d736100):
magic_number, bs = peek_uint32(fin)
assert magic_number == expected_magic_number, "unexpected magic number"
return magic_number, bs
def read_magic_number(fin, expected_magic_number=0x6d736100):
magic_number, bs = peek_magic_number(fin, expected_magic_number)
fin.read(len(bs))
return magic_number, bs
def peek_version(fin, expected_version=1):
version, bs = peek_uint32(fin)
assert version == expected_version, "unexpected version"
return version, bs
def read_version(fin, expected_version=1):
version, bs = peek_version(fin, expected_version)
fin.read(len(bs))
return version, bs
def write_custom_section(fout, section_name_bs, payload_bs):
section_name_length_bs = to_varuintN(len(section_name_bs))
payload_length_bs = to_varuintN(len(section_name_bs) \
+ len(section_name_length_bs) + len(payload_bs))
section_id_bs = to_varuintN(CUSTOM_SECTION_ID)
fout.write(section_id_bs)
fout.write(payload_length_bs)
fout.write(section_name_length_bs)
fout.write(section_name_bs)
fout.write(payload_bs)
def write_compilation_hints_section(fout, hints_bs):
num_compilation_hints_bs = to_varuintN(len(hints_bs))
section_name_bs = b"compilationHints"
payload_bs = num_compilation_hints_bs + hints_bs
write_custom_section(fout, section_name_bs, payload_bs)
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