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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() |