1  #! /usr/bin/env python3
       2  # This script generates Modules/_sre/sre_constants.h from Lib/re/_constants.py.
       3  
       4  SCRIPT_NAME = 'Tools/build/generate_sre_constants.py'
       5  
       6  
       7  def update_file(file, content):
       8      try:
       9          with open(file, 'r') as fobj:
      10              if fobj.read() == content:
      11                  return False
      12      except (OSError, ValueError):
      13          pass
      14      with open(file, 'w') as fobj:
      15          fobj.write(content)
      16      return True
      17  
      18  sre_constants_header = f"""\
      19  /*
      20   * Secret Labs' Regular Expression Engine
      21   *
      22   * regular expression matching engine
      23   *
      24   * Auto-generated by {SCRIPT_NAME} from
      25   * Lib/re/_constants.py.
      26   *
      27   * Copyright (c) 1997-2001 by Secret Labs AB.  All rights reserved.
      28   *
      29   * See the sre.c file for information on usage and redistribution.
      30   */
      31  
      32  """
      33  
      34  def main(
      35      infile="Lib/re/_constants.py",
      36      outfile_constants="Modules/_sre/sre_constants.h",
      37      outfile_targets="Modules/_sre/sre_targets.h",
      38  ):
      39      ns = {}
      40      with open(infile) as fp:
      41          code = fp.read()
      42      exec(code, ns)
      43  
      44      def dump(d, prefix):
      45          items = sorted(d)
      46          for item in items:
      47              yield "#define %s_%s %d\n" % (prefix, item, item)
      48  
      49      def dump2(d, prefix):
      50          items = [(value, name) for name, value in d.items()
      51                   if name.startswith(prefix)]
      52          for value, name in sorted(items):
      53              yield "#define %s %d\n" % (name, value)
      54  
      55      def dump_gotos(d, prefix):
      56          for i, item in enumerate(sorted(d)):
      57              assert i == item
      58              yield f"    &&{prefix}_{item},\n"
      59  
      60      content = [sre_constants_header]
      61      content.append("#define SRE_MAGIC %d\n" % ns["MAGIC"])
      62      content.extend(dump(ns["OPCODES"], "SRE_OP"))
      63      content.extend(dump(ns["ATCODES"], "SRE"))
      64      content.extend(dump(ns["CHCODES"], "SRE"))
      65      content.extend(dump2(ns, "SRE_FLAG_"))
      66      content.extend(dump2(ns, "SRE_INFO_"))
      67  
      68      update_file(outfile_constants, ''.join(content))
      69  
      70      content = [sre_constants_header]
      71      content.append(f"static void *sre_targets[{len(ns['OPCODES'])}] = {{\n")
      72      content.extend(dump_gotos(ns["OPCODES"], "TARGET_SRE_OP"))
      73      content.append("};\n")
      74  
      75      update_file(outfile_targets, ''.join(content))
      76  
      77  
      78  if __name__ == '__main__':
      79      import sys
      80      main(*sys.argv[1:])