#!/usr/bin/env python # # Copyright 2007, Google Inc. # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above # copyright notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # * Neither the name of Google Inc. nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR # A PARTICULAR PURPOSE ARE DISCLAIMED. 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"""Tokenize C++ source code.""" try: # Python 3.x import builtins except ImportError: # Python 2.x import __builtin__ as builtins import sys from cpp import utils if not hasattr(builtins, 'set'): # Nominal support for Python 2.3. from sets import Set as set # Add $ as a valid identifier char since so much code uses it. _letters = 'abcdefghijklmnopqrstuvwxyz' VALID_IDENTIFIER_CHARS = set(_letters + _letters.upper() + '_0123456789$') HEX_DIGITS = set('0123456789abcdefABCDEF') INT_OR_FLOAT_DIGITS = set('01234567890eE-+') # C++0x string preffixes. _STR_PREFIXES = set(('R', 'u8', 'u8R', 'u', 'uR', 'U', 'UR', 'L', 'LR')) # Token types. UNKNOWN = 'UNKNOWN' SYNTAX = 'SYNTAX' CONSTANT = 'CONSTANT' NAME = 'NAME' PREPROCESSOR = 'PREPROCESSOR' # Where the token originated from. This can be used for backtracking. # It is always set to WHENCE_STREAM in this code. WHENCE_STREAM, WHENCE_QUEUE = range(2) class Token(object): """Data container to represent a C++ token. Tokens can be identifiers, syntax char(s), constants, or pre-processor directives. start contains the index of the first char of the token in the source end contains the index of the last char of the token in the source """ def __init__(self, token_type, name, start, end): self.token_type = token_type self.name = name self.start = start self.end = end self.whence = WHENCE_STREAM def __str__(self): if not utils.DEBUG: return 'Token(%r)' % self.name return 'Token(%r, %s, %s)' % (self.name, self.start, self.end) __repr__ = __str__ def _GetString(source, start, i): i = source.find('"', i+1) while source[i-1] == '\\': # Count the trailing backslashes. backslash_count = 1 j = i - 2 while source[j] == '\\': backslash_count += 1 j -= 1 # When trailing backslashes are even, they escape each other. if (backslash_count % 2) == 0: break i = source.find('"', i+1) return i + 1 def _GetChar(source, start, i): # NOTE(nnorwitz): may not be quite correct, should be good enough. i = source.find("'", i+1) while source[i-1] == '\\': # Need to special case '\\'. if (i - 2) > start and source[i-2] == '\\': break i = source.find("'", i+1) # Try to handle unterminated single quotes (in a #if 0 block). if i < 0: i = start return i + 1 def GetTokens(source): """Returns a sequence of Tokens. Args: source: string of C++ source code. Yields: Token that represents the next token in the source. """ # Cache various valid character sets for speed. valid_identifier_chars = VALID_IDENTIFIER_CHARS hex_digits = HEX_DIGITS int_or_float_digits = INT_OR_FLOAT_DIGITS int_or_float_digits2 = int_or_float_digits | set('.') # Only ignore errors while in a #if 0 block. ignore_errors = False count_ifs = 0 i = 0 end = len(source) while i < end: # Skip whitespace. while i < end and source[i].isspace(): i += 1 if i >= end: return token_type = UNKNOWN start = i c = source[i] if c.isalpha() or c == '_': # Find a string token. token_type = NAME while source[i] in valid_identifier_chars: i += 1 # String and character constants can look like a name if # they are something like L"". if (source[i] == "'" and (i - start) == 1 and source[start:i] in 'uUL'): # u, U, and L are valid C++0x character preffixes. token_type = CONSTANT i = _GetChar(source, start, i) elif source[i] == "'" and source[start:i] in _STR_PREFIXES: token_type = CONSTANT i = _GetString(source, start, i) elif c == '/' and source[i+1] == '/': # Find // comments. i = source.find('\n', i) if i == -1: # Handle EOF. i = end continue elif c == '/' and source[i+1] == '*': # Find /* comments. */ i = source.find('*/', i) + 2 continue elif c in ':+-<>&|*=': # : or :: (plus other chars). token_type = SYNTAX i += 1 new_ch = source[i] if new_ch == c and c != '>': # Treat ">>" as two tokens. i += 1 elif c == '-' and new_ch == '>': i += 1 elif new_ch == '=': i += 1 elif c in '()[]{}~!?^%;/.,': # Handle single char tokens. token_type = SYNTAX i += 1 if c == '.' and source[i].isdigit(): token_type = CONSTANT i += 1 while source[i] in int_or_float_digits: i += 1 # Handle float suffixes. for suffix in ('l', 'f'): if suffix == source[i:i+1].lower(): i += 1 break elif c.isdigit(): # Find integer. token_type = CONSTANT if c == '0' and source[i+1] in 'xX': # Handle hex digits. i += 2 while source[i] in hex_digits: i += 1 else: while source[i] in int_or_float_digits2: i += 1 # Handle integer (and float) suffixes. for suffix in ('ull', 'll', 'ul', 'l', 'f', 'u'): size = len(suffix) if suffix == source[i:i+size].lower(): i += size break elif c == '"': # Find string. token_type = CONSTANT i = _GetString(source, start, i) elif c == "'": # Find char. token_type = CONSTANT i = _GetChar(source, start, i) elif c == '#': # Find pre-processor command. token_type = PREPROCESSOR got_if = source[i:i+3] == '#if' and source[i+3:i+4].isspace() if got_if: count_ifs += 1 elif source[i:i+6] == '#endif': count_ifs -= 1 if count_ifs == 0: ignore_errors = False # TODO(nnorwitz): handle preprocessor statements (\ continuations). while 1: i1 = source.find('\n', i) i2 = source.find('//', i) i3 = source.find('/*', i) i4 = source.find('"', i) # NOTE(nnorwitz): doesn't handle comments in #define macros. # Get the first important symbol (newline, comment, EOF/end). i = min([x for x in (i1, i2, i3, i4, end) if x != -1]) # Handle #include "dir//foo.h" properly. if source[i] == '"': i = source.find('"', i+1) + 1 assert i > 0 continue # Keep going if end of the line and the line ends with \. if not (i == i1 and source[i-1] == '\\'): if got_if: condition = source[start+4:i].lstrip() if (condition.startswith('0') or condition.startswith('(0)')): ignore_errors = True break i += 1 elif c == '\\': # Handle \ in code. # This is different from the pre-processor \ handling. i += 1 continue elif ignore_errors: # The tokenizer seems to be in pretty good shape. This # raise is conditionally disabled so that bogus code # in an #if 0 block can be handled. Since we will ignore # it anyways, this is probably fine. So disable the # exception and return the bogus char. i += 1 else: sys.stderr.write('Got invalid token in %s @ %d token:%s: %r\n' % ('?', i, c, source[i-10:i+10])) raise RuntimeError('unexpected token') if i <= 0: print('Invalid index, exiting now.') return yield Token(token_type, source[start:i], start, i) if __name__ == '__main__': def main(argv): """Driver mostly for testing purposes.""" for filename in argv[1:]: source = utils.ReadFile(filename) if source is None: continue for token in GetTokens(source): print('%-12s: %s' % (token.token_type, token.name)) # print('\r%6.2f%%' % (100.0 * index / token.end),) sys.stdout.write('\n') main(sys.argv)