#! /usr/bin/env python

#
# A simple-minded style checker for C++ code.
# This only catches the most obvious style mistakes, and occasionally
# flags stuff that isn't wrong.
#

import sys, string, re

#
# Constants.
#

MAX_LINE_LENGTH = 78

#
# Regular expressions corresponding to style violations.
#

tabs                = re.compile(r"\t+")
comma_space         = re.compile(",[^ ]")

# This one is really tough to get right, so we settle for catching the
# most common mistakes.  Add other operators as necessary and/or feasible.
operator_space      = re.compile("(\w(\+|\-|\*|\<|\>|\=)\w)" + \
                                 "|(\w(\=\=|\<\=|\>\=)\w)")
comment_line        = re.compile("^\s*\/\*.*\*\/\s*$")
cpp_comment_line    = re.compile("^\s*\/\/.*$")
open_comment_space  = re.compile("\/\*[^ *\n]")
close_comment_space = re.compile("[^ *]\*\/")
cpp_comment_space   = re.compile("\/\/[^ *\n]")
paren_curly_space   = re.compile("\)\{")
semi_space          = re.compile(";[^ \s]")


def check_line(filename, line, n):
    """
    Check a line of code for style mistakes.
    """
    # Strip the terminal newline.
    line = line[:-1]

    if tabs.search(line):
        print "File %s, line %d: [TABS]:\n%s" % \
              (filename, n, line)
    if len(line) > MAX_LINE_LENGTH:
        print "File %s, line %d: [TOO LONG (%d CHARS)]:\n%s" % \
              (filename, n, len(line), line)
    if comma_space.search(line):
        print "File %s, line %d: [PUT SPACE AFTER COMMA]:\n%s" % \
              (filename, n, line)
    if operator_space.search(line):
        if not comment_line.search(line) \
           and not cpp_comment_line.search(line):
            print "File %s, line %d: [PUT SPACE AROUND OPERATORS]:\n%s" % \
                  (filename, n, line)
    if open_comment_space.search(line):
        print "File %s, line %d: [PUT SPACE AFTER OPEN COMMENT]:\n%s" % \
              (filename, n, line)
    if close_comment_space.search(line):
        print "File %s, line %d: [PUT SPACE BEFORE CLOSE COMMENT]:\n%s" % \
              (filename, n, line)
    if cpp_comment_space.search(line):
        print "File %s, line %d: [PUT SPACE AFTER OPEN COMMENT]:\n%s" % \
              (filename, n, line)
    if paren_curly_space.search(line):
        print "File %s, line %d: [PUT SPACE BETWEEN ) AND {]:\n%s" % \
              (filename, n, line)
    if semi_space.search(line):
        print "File %s, line %d: [PUT SPACE/NEWLINE AFTER SEMICOLON]:\n%s" % \
              (filename, n, line)


def check_file(filename):
    file = open(filename, "r")
    lines = file.readlines()
    file.close()

    for i in range(len(lines)):
        check_line(filename, lines[i], i + 1)  # Start on line 1.

#
# Main body of program.
#

usage = "usage: c++_style_check filename1 [filename2 ...]"

if len(sys.argv) < 2:
    print usage
    raise SystemExit

for filename in sys.argv[1:]:
    check_file(filename)