#!/usr/bin/env python
#
# Copyright 2007 Neal Norwitz
# Portions Copyright 2007 Google Inc.
#
# 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.
"""Tokenize C++ source code."""
__author__ = 'nnorwitz@google.com (Neal Norwitz)'
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)