| 1 | #! /usr/bin/env python
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| 2 |
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| 3 | # Selectively preprocess #ifdef / #ifndef statements.
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| 4 | # Usage:
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| 5 | # ifdef [-Dname] ... [-Uname] ... [file] ...
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| 6 | #
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| 7 | # This scans the file(s), looking for #ifdef and #ifndef preprocessor
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| 8 | # commands that test for one of the names mentioned in the -D and -U
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| 9 | # options. On standard output it writes a copy of the input file(s)
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| 10 | # minus those code sections that are suppressed by the selected
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| 11 | # combination of defined/undefined symbols. The #if(n)def/#else/#else
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| 12 | # lines themselfs (if the #if(n)def tests for one of the mentioned
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| 13 | # names) are removed as well.
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| 14 |
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| 15 | # Features: Arbitrary nesting of recognized and unrecognized
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| 16 | # preprocesor statements works correctly. Unrecognized #if* commands
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| 17 | # are left in place, so it will never remove too much, only too
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| 18 | # little. It does accept whitespace around the '#' character.
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| 19 |
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| 20 | # Restrictions: There should be no comments or other symbols on the
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| 21 | # #if(n)def lines. The effect of #define/#undef commands in the input
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| 22 | # file or in included files is not taken into account. Tests using
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| 23 | # #if and the defined() pseudo function are not recognized. The #elif
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| 24 | # command is not recognized. Improperly nesting is not detected.
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| 25 | # Lines that look like preprocessor commands but which are actually
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| 26 | # part of comments or string literals will be mistaken for
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| 27 | # preprocessor commands.
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| 28 |
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| 29 | import sys
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| 30 | import getopt
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| 31 |
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| 32 | defs = []
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| 33 | undefs = []
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| 34 |
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| 35 | def main():
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| 36 | opts, args = getopt.getopt(sys.argv[1:], 'D:U:')
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| 37 | for o, a in opts:
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| 38 | if o == '-D':
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| 39 | defs.append(a)
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| 40 | if o == '-U':
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| 41 | undefs.append(a)
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| 42 | if not args:
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| 43 | args = ['-']
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| 44 | for filename in args:
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| 45 | if filename == '-':
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| 46 | process(sys.stdin, sys.stdout)
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| 47 | else:
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| 48 | f = open(filename, 'r')
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| 49 | process(f, sys.stdout)
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| 50 | f.close()
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| 51 |
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| 52 | def process(fpi, fpo):
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| 53 | keywords = ('if', 'ifdef', 'ifndef', 'else', 'endif')
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| 54 | ok = 1
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| 55 | stack = []
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| 56 | while 1:
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| 57 | line = fpi.readline()
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| 58 | if not line: break
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| 59 | while line[-2:] == '\\\n':
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| 60 | nextline = fpi.readline()
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| 61 | if not nextline: break
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| 62 | line = line + nextline
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| 63 | tmp = line.strip()
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| 64 | if tmp[:1] != '#':
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| 65 | if ok: fpo.write(line)
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| 66 | continue
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| 67 | tmp = tmp[1:].strip()
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| 68 | words = tmp.split()
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| 69 | keyword = words[0]
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| 70 | if keyword not in keywords:
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| 71 | if ok: fpo.write(line)
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| 72 | continue
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| 73 | if keyword in ('ifdef', 'ifndef') and len(words) == 2:
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| 74 | if keyword == 'ifdef':
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| 75 | ko = 1
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| 76 | else:
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| 77 | ko = 0
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| 78 | word = words[1]
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| 79 | if word in defs:
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| 80 | stack.append((ok, ko, word))
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| 81 | if not ko: ok = 0
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| 82 | elif word in undefs:
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| 83 | stack.append((ok, not ko, word))
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| 84 | if ko: ok = 0
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| 85 | else:
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| 86 | stack.append((ok, -1, word))
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| 87 | if ok: fpo.write(line)
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| 88 | elif keyword == 'if':
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| 89 | stack.append((ok, -1, ''))
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| 90 | if ok: fpo.write(line)
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| 91 | elif keyword == 'else' and stack:
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| 92 | s_ok, s_ko, s_word = stack[-1]
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| 93 | if s_ko < 0:
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| 94 | if ok: fpo.write(line)
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| 95 | else:
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| 96 | s_ko = not s_ko
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| 97 | ok = s_ok
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| 98 | if not s_ko: ok = 0
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| 99 | stack[-1] = s_ok, s_ko, s_word
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| 100 | elif keyword == 'endif' and stack:
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| 101 | s_ok, s_ko, s_word = stack[-1]
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| 102 | if s_ko < 0:
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| 103 | if ok: fpo.write(line)
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| 104 | del stack[-1]
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| 105 | ok = s_ok
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| 106 | else:
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| 107 | sys.stderr.write('Unknown keyword %s\n' % keyword)
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| 108 | if stack:
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| 109 | sys.stderr.write('stack: %s\n' % stack)
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| 110 |
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| 111 | if __name__ == '__main__':
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| 112 | main()
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