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| 1 | +#! /usr/local/bin/python |
| 2 | + |
| 3 | +# Selectively preprocess #ifdef / #ifndef statements. |
| 4 | +# Usage: |
| 5 | +# ifdef [-Dname] ... [-Uname] ... [file] ... |
| 6 | +# |
| 7 | +# This scans the file(s), looking for #ifdef and #ifndef preprocessor |
| 8 | +# commands that test for one of the names mentioned in the -D and -U |
| 9 | +# options. On standard output it writes a copy of the input file(s) |
| 10 | +# minus those code sections that are suppressed by the selected |
| 11 | +# combination of defined/undefined symbols. The #if(n)def/#else/#else |
| 12 | +# lines themselfs (if the #if(n)def tests for one of the mentioned |
| 13 | +# names) are removed as well. |
| 14 | + |
| 15 | +# Features: Arbitrary nesting of recognized and unrecognized |
| 16 | +# preprocesor statements works correctly. Unrecognized #if* commands |
| 17 | +# are left in place, so it will never remove too much, only too |
| 18 | +# little. It does accept whitespace around the '#' character. |
| 19 | + |
| 20 | +# Restrictions: There should be no comments or other symbols on the |
| 21 | +# #if(n)def lines. The effect of #define/#undef commands in the input |
| 22 | +# file or in included files is not taken into account. Tests using |
| 23 | +# #if and the defined() pseudo function are not recognized. The #elif |
| 24 | +# command is not recognized. Improperly nesting is not detected. |
| 25 | +# Lines that look like preprocessor commands but which are actually |
| 26 | +# part of comments or string literals will be mistaken for |
| 27 | +# preprocessor commands. |
| 28 | + |
| 29 | +import sys |
| 30 | +import regex |
| 31 | +import getopt |
| 32 | +import string |
| 33 | + |
| 34 | +defs = [] |
| 35 | +undefs = [] |
| 36 | + |
| 37 | +def main(): |
| 38 | + opts, args = getopt.getopt(sys.argv[1:], 'D:U:') |
| 39 | + for o, a in opts: |
| 40 | + if o == '-D': |
| 41 | + defs.append(a) |
| 42 | + if o == '-U': |
| 43 | + undefs.append(a) |
| 44 | + if not args: |
| 45 | + args = ['-'] |
| 46 | + for file in args: |
| 47 | + if file == '-': |
| 48 | + process(sys.stdin, sys.stdout) |
| 49 | + else: |
| 50 | + f = open(file, 'r') |
| 51 | + process(f, sys.stdout) |
| 52 | + f.close() |
| 53 | + |
| 54 | +def process(fpi, fpo): |
| 55 | + keywords = ('if', 'ifdef', 'ifndef', 'else', 'endif') |
| 56 | + ok = 1 |
| 57 | + stack = [] |
| 58 | + while 1: |
| 59 | + line = fpi.readline() |
| 60 | + if not line: break |
| 61 | + while line[-2:] == '\\\n': |
| 62 | + nextline = fpi.readline() |
| 63 | + if not nextline: break |
| 64 | + line = line + nextline |
| 65 | + tmp = string.strip(line) |
| 66 | + if tmp[:1] != '#': |
| 67 | + if ok: fpo.write(line) |
| 68 | + continue |
| 69 | + tmp = string.strip(tmp[1:]) |
| 70 | + words = string.split(tmp) |
| 71 | + keyword = words[0] |
| 72 | + if keyword not in keywords: |
| 73 | + if ok: fpo.write(line) |
| 74 | + continue |
| 75 | + if keyword in ('ifdef', 'ifndef') and len(words) == 2: |
| 76 | + if keyword == 'ifdef': |
| 77 | + ko = 1 |
| 78 | + else: |
| 79 | + ko = 0 |
| 80 | + word = words[1] |
| 81 | + if word in defs: |
| 82 | + stack.append(ok, ko, word) |
| 83 | + if not ko: ok = 0 |
| 84 | + elif word in undefs: |
| 85 | + stack.append(ok, not ko, word) |
| 86 | + if ko: ok = 0 |
| 87 | + else: |
| 88 | + stack.append(ok, -1, word) |
| 89 | + if ok: fpo.write(line) |
| 90 | + elif keyword == 'if': |
| 91 | + stack.append(ok, -1, '') |
| 92 | + if ok: fpo.write(line) |
| 93 | + elif keyword == 'else' and stack: |
| 94 | + s_ok, s_ko, s_word = stack[-1] |
| 95 | + if s_ko < 0: |
| 96 | + if ok: fpo.write(line) |
| 97 | + else: |
| 98 | + s_ko = not s_ko |
| 99 | + ok = s_ok |
| 100 | + if not s_ko: ok = 0 |
| 101 | + stack[-1] = s_ok, s_ko, s_word |
| 102 | + elif keyword == 'endif' and stack: |
| 103 | + s_ok, s_ko, s_word = stack[-1] |
| 104 | + if s_ko < 0: |
| 105 | + if ok: fpo.write(line) |
| 106 | + del stack[-1] |
| 107 | + ok = s_ok |
| 108 | + else: |
| 109 | + sys.stderr.write('Unknown keyword %s\n' % keyword) |
| 110 | + if stack: |
| 111 | + sys.stderr.write('stack: %s\n' % stack) |
| 112 | + |
| 113 | +main() |
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