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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            with open(filename) as fp:
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                with open(outfile, 'w') as outfp:
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
88def pytify(body):
89    # replace ignored patterns by spaces
90    for p in ignores:
91        body = p.sub(' ', body)
92    # replace char literals by ord(...)
93    body = p_char.sub("ord('\\1')", body)
94    # Compute negative hexadecimal constants
95    start = 0
96    UMAX = 2*(sys.maxsize+1)
97    while 1:
98        m = p_hex.search(body, start)
99        if not m: break
100        s,e = m.span()
101        val = int(body[slice(*m.span(1))], 16)
102        if val > sys.maxsize:
103            val -= UMAX
104            body = body[:s] + "(" + str(val) + ")" + body[e:]
105        start = s + 1
106    return body
107
108def process(fp, outfp, env = {}):
109    lineno = 0
110    while 1:
111        line = fp.readline()
112        if not line: break
113        lineno = lineno + 1
114        match = p_define.match(line)
115        if match:
116            # gobble up continuation lines
117            while line[-2:] == '\\\n':
118                nextline = fp.readline()
119                if not nextline: break
120                lineno = lineno + 1
121                line = line + nextline
122            name = match.group(1)
123            body = line[match.end():]
124            body = pytify(body)
125            ok = 0
126            stmt = '%s = %s\n' % (name, body.strip())
127            try:
128                exec(stmt, env)
129            except:
130                sys.stderr.write('Skipping: %s' % stmt)
131            else:
132                outfp.write(stmt)
133        match = p_macro.match(line)
134        if match:
135            macro, arg = match.group(1, 2)
136            body = line[match.end():]
137            body = pytify(body)
138            stmt = 'def %s(%s): return %s\n' % (macro, arg, body)
139            try:
140                exec(stmt, env)
141            except:
142                sys.stderr.write('Skipping: %s' % stmt)
143            else:
144                outfp.write(stmt)
145        match = p_include.match(line)
146        if match:
147            regs = match.regs
148            a, b = regs[1]
149            filename = line[a:b]
150            if filename in importable:
151                outfp.write('from %s import *\n' % importable[filename])
152            elif filename not in filedict:
153                filedict[filename] = None
154                inclfp = None
155                for dir in searchdirs:
156                    try:
157                        inclfp = open(dir + '/' + filename)
158                        break
159                    except IOError:
160                        pass
161                if inclfp:
162                    with inclfp:
163                        outfp.write(
164                                '\n# Included from %s\n' % filename)
165                        process(inclfp, outfp, env)
166                else:
167                    sys.stderr.write('Warning - could not find file %s\n' %
168                                     filename)
169
170if __name__ == '__main__':
171    main()
172