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1#! /usr/bin/env python3
2
3# Read #define's and translate to Python code.
4# Handle #include statements.
5# Handle #define macros with one argument.
6# Anything that isn't recognized or doesn't translate into valid
7# Python is ignored.
8
9# Without filename arguments, acts as a filter.
10# If one or more filenames are given, output is written to corresponding
11# filenames in the local directory, translated to all uppercase, with
12# the extension replaced by ".py".
13
14# By passing one or more options of the form "-i regular_expression"
15# you can specify additional strings to be ignored.  This is useful
16# e.g. to ignore casts to u_long: simply specify "-i '(u_long)'".
17
18# XXX To do:
19# - turn trailing C comments into Python comments
20# - turn C Boolean operators "&& || !" into Python "and or not"
21# - what to do about #if(def)?
22# - what to do about macros with multiple parameters?
23
24import sys, re, getopt, os
25
26p_define = re.compile(r'^[\t ]*#[\t ]*define[\t ]+([a-zA-Z0-9_]+)[\t ]+')
27
28p_macro = re.compile(
29  r'^[\t ]*#[\t ]*define[\t ]+'
30  r'([a-zA-Z0-9_]+)\(([_a-zA-Z][_a-zA-Z0-9]*)\)[\t ]+')
31
32p_include = re.compile(r'^[\t ]*#[\t ]*include[\t ]+<([^>\n]+)>')
33
34p_comment = re.compile(r'/\*([^*]+|\*+[^/])*(\*+/)?')
35p_cpp_comment = re.compile('//.*')
36
37ignores = [p_comment, p_cpp_comment]
38
39p_char = re.compile(r"'(\\.[^\\]*|[^\\])'")
40
41p_hex = re.compile(r"0x([0-9a-fA-F]+)L?")
42
43filedict = {}
44importable = {}
45
46try:
47    searchdirs=os.environ['include'].split(';')
48except KeyError:
49    try:
50        searchdirs=os.environ['INCLUDE'].split(';')
51    except KeyError:
52        searchdirs=['/usr/include']
53        try:
54            searchdirs.insert(0, os.path.join('/usr/include',
55                                              os.environ['MULTIARCH']))
56        except KeyError:
57            pass
58
59def main():
60    global filedict
61    opts, args = getopt.getopt(sys.argv[1:], 'i:')
62    for o, a in opts:
63        if o == '-i':
64            ignores.append(re.compile(a))
65    if not args:
66        args = ['-']
67    for filename in args:
68        if filename == '-':
69            sys.stdout.write('# Generated by h2py from stdin\n')
70            process(sys.stdin, sys.stdout)
71        else:
72            fp = open(filename, 'r')
73            outfile = os.path.basename(filename)
74            i = outfile.rfind('.')
75            if i > 0: outfile = outfile[:i]
76            modname = outfile.upper()
77            outfile = modname + '.py'
78            outfp = open(outfile, 'w')
79            outfp.write('# Generated by h2py from %s\n' % filename)
80            filedict = {}
81            for dir in searchdirs:
82                if filename[:len(dir)] == dir:
83                    filedict[filename[len(dir)+1:]] = None  # no '/' trailing
84                    importable[filename[len(dir)+1:]] = modname
85                    break
86            process(fp, outfp)
87            outfp.close()
88            fp.close()
89
90def pytify(body):
91    # replace ignored patterns by spaces
92    for p in ignores:
93        body = p.sub(' ', body)
94    # replace char literals by ord(...)
95    body = p_char.sub("ord('\\1')", body)
96    # Compute negative hexadecimal constants
97    start = 0
98    UMAX = 2*(sys.maxsize+1)
99    while 1:
100        m = p_hex.search(body, start)
101        if not m: break
102        s,e = m.span()
103        val = int(body[slice(*m.span(1))], 16)
104        if val > sys.maxsize:
105            val -= UMAX
106            body = body[:s] + "(" + str(val) + ")" + body[e:]
107        start = s + 1
108    return body
109
110def process(fp, outfp, env = {}):
111    lineno = 0
112    while 1:
113        line = fp.readline()
114        if not line: break
115        lineno = lineno + 1
116        match = p_define.match(line)
117        if match:
118            # gobble up continuation lines
119            while line[-2:] == '\\\n':
120                nextline = fp.readline()
121                if not nextline: break
122                lineno = lineno + 1
123                line = line + nextline
124            name = match.group(1)
125            body = line[match.end():]
126            body = pytify(body)
127            ok = 0
128            stmt = '%s = %s\n' % (name, body.strip())
129            try:
130                exec(stmt, env)
131            except:
132                sys.stderr.write('Skipping: %s' % stmt)
133            else:
134                outfp.write(stmt)
135        match = p_macro.match(line)
136        if match:
137            macro, arg = match.group(1, 2)
138            body = line[match.end():]
139            body = pytify(body)
140            stmt = 'def %s(%s): return %s\n' % (macro, arg, body)
141            try:
142                exec(stmt, env)
143            except:
144                sys.stderr.write('Skipping: %s' % stmt)
145            else:
146                outfp.write(stmt)
147        match = p_include.match(line)
148        if match:
149            regs = match.regs
150            a, b = regs[1]
151            filename = line[a:b]
152            if filename in importable:
153                outfp.write('from %s import *\n' % importable[filename])
154            elif filename not in filedict:
155                filedict[filename] = None
156                inclfp = None
157                for dir in searchdirs:
158                    try:
159                        inclfp = open(dir + '/' + filename)
160                        break
161                    except IOError:
162                        pass
163                if inclfp:
164                    outfp.write(
165                            '\n# Included from %s\n' % filename)
166                    process(inclfp, outfp, env)
167                else:
168                    sys.stderr.write('Warning - could not find file %s\n' %
169                                     filename)
170
171if __name__ == '__main__':
172    main()
173