src/wasm2c_tmpl.py

#!/usr/bin/env python3
#
# Copyright 2018 WebAssembly Community Group participants
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

import argparse
import io
import os
import sys


def EscapeCString(s):
    out = ''
    for b in bytearray(s.encode('utf-8')):
        if b in (34, 92):
            # " or \
            out += '\\' + chr(b)
        elif b == 10:
            # newline
            out += '\\n'
        elif 32 <= b <= 127:
            # printable char
            out += chr(b)
        else:
            # non-printable; write as \xab
            out += '\\x%02x' % b

    return out


def main(args):
    arg_parser = argparse.ArgumentParser()
    arg_parser.add_argument('-o', '--output', metavar='PATH',
                            help='output file.')
    arg_parser.add_argument('file', help='input file.')
    options = arg_parser.parse_args(args)

    section_name = None
    output = io.StringIO()

    output.write('/* Generated from \'%s\' by wasm2c_tmpl.py, do not edit! */\n' %
                 os.path.basename(options.file))

    with open(options.file) as f:
        for line in f.readlines():
            if line.startswith('%%'):
                if section_name is not None:
                    output.write(';\n\n')
                section_name = line[2:-1]
                output.write('const char SECTION_NAME(%s)[] =\n' % section_name)
            else:
                output.write('"%s"\n' % EscapeCString(line))

    output.write(';\n')
    if options.output:
        with open(options.output, 'w') as outf:
            outf.write(output.getvalue())
    else:
        sys.stdout.write(output.getvalue())

    return 0


if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))