Preprocess #include <...> directive

includec.py

#!/usr/bin/python
import re
import sys
import os.path
import argparse

parser = argparse.ArgumentParser(description='Preprocess #include <...> directive')
parser.add_argument('-I', dest='paths', action='append',
        help='add directory to include search path')
parser.add_argument('-o', '--output', dest='out', type=argparse.FileType('w'), default=sys.stdout,
        help='write output to OUT')
parser.add_argument('infile', type=argparse.FileType('r'), default=sys.stdin,
        help='input filename', metavar='<file>')
args = parser.parse_args()

pattern = re.compile('\s*#\s*include\s+(<(.*)>|"(.*)")\s*$')
included = []
lines = []

def compile_include(f):
    for no, line in enumerate(f):
        match = pattern.match(line)
        if match:
            include_name = match.group(2) or match.group(3)

            search_paths = []
            if match.group(3):
                file_path = os.path.dirname(os.path.relpath(f.name))
                search_paths.append(os.path.join(file_path, include_name))
            if args.paths:
                search_paths.extend(os.path.join(i, include_name) for i in args.paths)

            for include_path in search_paths:
                if os.path.exists(include_path):
                    if include_path not in included:
                        lines.append('#line %d "%s"\n' % (1, include_path))
                        with open(include_path, 'r') as include_file:
                            compile_include(include_file)
                        lines.append('#line %d "%s"\n' % (no + 1, f.name))
                        included.append(include_path)
                        break
            else:
                print '%s:%d: fatal error: %s: file not found' % (f.name, no, include_name)
                print ' \n'.join(search_paths)
                exit(1)
        else:
            lines.append(line)

compile_include(args.infile)
args.out.writelines(lines)