| #!/usr/bin/env python3 |
| |
| '''Using mad regexes, automatically make sure that all structs with sub-byte |
| integers have matching big-endian definitions. The idea is to save a lot of |
| manual effort, and to automatically verify that there are no errors. |
| This script most certainly has numerous holes and shortcomings, but actually, |
| if you hit problems with it, rather adjust your coding style so that this |
| script can deal with it...''' |
| |
| import re |
| import sys |
| import codecs |
| import os.path |
| |
| re_struct_start = re.compile(r'^struct\s*[a-zA-Z_][a-zA-Z_0-9]*\s*{\s*$') |
| re_struct_end = re.compile(r'^}[^;]*;\s*$') |
| |
| re_substruct_start = re.compile(r'^\s+struct\s*{\s*$') |
| re_substruct_end = re.compile(r'^\s+}\s*([^;]*\s)[a-zA-Z_][a-zA-Z_0-9]*\s*;\s*$') |
| re_unnamed_substruct_end = re.compile(r'^\s+}\s*;\s*$') |
| |
| re_int_def = re.compile(r'(^\s*((const|unsigned|signed|char|int|long|int[0-9]+_t|uint[0-9]_t)\s+)+\s*)([^;]*;)', |
| re.DOTALL | re.MULTILINE) |
| re_int_members = re.compile(r'([a-zA-Z_][a-zA-Z_0-9]*|[a-zA-Z_][a-zA-Z_0-9]*\s*:\s*[0-9]+)\s*[,;]\s*', re.DOTALL | re.MULTILINE) |
| |
| re_little_endian_ifdef = re.compile(r'#\s*(if|elif)\s+OSMO_IS_LITTLE_ENDIAN\s*(==\s*1\s*|)'); |
| re_big_endian_ifdef = re.compile(r'#\s*(if|elif)\s+OSMO_IS_BIG_ENDIAN\s*'); |
| re_else = re.compile(r'#\s*else\s*'); |
| re_endif = re.compile(r'#\s*endif\s*'); |
| |
| re_c_comment = re.compile(r'(/\*[^*]+\*/|//.?$)') |
| |
| def remove_c_comments(code_str): |
| return ''.join(re_c_comment.split(code_str)[::2]) |
| |
| def section_struct_body(struct_body_lines): |
| '''divide a top-level-struct body into sections of |
| ['arbitrary string', ['body;\n', 'lines;\n'], 'arbitrary string', ...] |
| Aim: handle each sub-struct on its own, and if there already are ifdefs for |
| little and big endian, keep just the little endian bit and derive big |
| endian from it. |
| An arbitrary string is anything other than struct member definitions, like |
| a 'struct {', '} sub_name;', ... |
| "body lines" are lines that define struct members (possibly with comments). |
| Return: list of alternate arbitrary strings and variable definitions. |
| ''' |
| |
| # these globals are needed so that end_def() can change them from inside |
| # the function. Not very nice style, but easiest implementation. |
| global struct_body_parts |
| global arbitrary_part |
| global def_part |
| |
| struct_body_parts = [] |
| arbitrary_part = [] |
| def_part = [] |
| |
| def end_def(): |
| '''if there is any content, flush out recorded parts (def_part, |
| arbitrary_part) and start a new part. In short, cut a section |
| boundary.''' |
| global struct_body_parts |
| global arbitrary_part |
| global def_part |
| |
| if def_part: |
| struct_body_parts.append(arbitrary_part) |
| arbitrary_part = [] |
| struct_body_parts.append(def_part) |
| def_part = [] |
| |
| j = 0 |
| while j < len(struct_body_lines): |
| line = struct_body_lines[j] |
| |
| if (re_substruct_start.fullmatch(line) |
| or re_substruct_end.fullmatch(line) |
| or re_unnamed_substruct_end.fullmatch(line)): |
| end_def() |
| arbitrary_part.append(line) |
| j += 1 |
| continue |
| |
| if re_big_endian_ifdef.fullmatch(line): |
| end_def() |
| # discard big endian section |
| j += 1 |
| while j < len(struct_body_lines): |
| line = struct_body_lines[j] |
| if re_endif.fullmatch(line): |
| end_def() |
| j += 1 |
| break; |
| if re_little_endian_ifdef.fullmatch(line): |
| end_def() |
| # keep that start of little endian section, not j++ |
| break; |
| if re_else.fullmatch(line): |
| # there's an '#else' after big-endian. Shim a little-endian header in just for the loop. |
| struct_body_lines[j] = '#if OSMO_IS_LITTLE_ENDIAN\n' |
| break; |
| j += 1 |
| continue |
| |
| if re_little_endian_ifdef.fullmatch(line): |
| end_def() |
| j += 1 |
| while j < len(struct_body_lines): |
| line = struct_body_lines[j] |
| if re_endif.fullmatch(line): |
| end_def() |
| j += 1 |
| break; |
| if re_big_endian_ifdef.fullmatch(line): |
| end_def() |
| # keep that start of big endian section, not j++ |
| break; |
| if re_else.fullmatch(line): |
| # there's an '#else' after little-endian. Shim a big-endian header in just for the loop. |
| struct_body_lines[j] = '#if OSMO_IS_BIG_ENDIAN\n' |
| break; |
| def_part.append(line) |
| j += 1 |
| |
| continue |
| |
| def_part.append(line) |
| j += 1 |
| |
| # flush the last section remaining that didn't see an explicit end |
| end_def() |
| # end_def() only flushes arbitrary_part if there was a def_part, so: |
| if arbitrary_part: |
| struct_body_parts.append(arbitrary_part) |
| |
| return struct_body_parts |
| |
| def struct_body_to_big_endian(body_str): |
| '''Input: a multi-line string containing the body of a struct, i.e. without |
| sub-structs and without #if OSMO_IS_BIG_ENDIAN. like |
| |
| '\tconst char *foo;\n\tuint8_t moo:3, goo:2;\n\tuint8_t loo:3;\n\tvoid *baz;\n' |
| |
| Return None to indicate that there is no little/big endian split |
| required, or return a multi-line string of the big-endian version of this |
| same struct body, where sub-byte ints are reversed at byte boundaries, and |
| all others are copied 1:1. If there are no sub-byte integers, return None, |
| to indicate that there is no little/big endian split required.''' |
| |
| # kick comments out of the code analysis. They will end up being stripped |
| # from big-endian only. |
| body_str = remove_c_comments(body_str) |
| |
| def_strs = body_str.split(';') |
| def_strs = ('%s;' % def_str for def_str in def_strs if def_str.strip()) |
| |
| # classify defs as containing sub-byte members or not |
| # defs = [ (true, 'uint8_t ', ('foo:3', 'bar:5')), |
| # (false, 'int baz;'),...] |
| defs = [] |
| any_sub_byte_ints = False |
| for one_def in def_strs: |
| |
| # does it have sub-string integers? |
| int_def = re_int_def.fullmatch(one_def) |
| if not int_def: |
| # not even a number, same for big and little endian |
| defs.append((False, one_def)) |
| continue |
| |
| int_type = int_def.group(1) |
| members_str = int_def.groups()[-1] |
| has_sub_byte_ints = False |
| |
| members = [] |
| for int_member in re_int_members.finditer(members_str): |
| member = int_member.group(1) |
| members.append(member) |
| if ':' in member: |
| has_sub_byte_ints = True |
| |
| if not has_sub_byte_ints: |
| defs.append((False, one_def)) |
| else: |
| defs.append((True, one_def, int_type, members)) |
| any_sub_byte_ints = True |
| |
| if not any_sub_byte_ints: |
| return None |
| |
| # now the interesting part, go over the defs, and reverse the sub-byte ints |
| # at byte boundaries. |
| |
| i = 0 |
| got_bits = 0 |
| byte_type = None |
| members_within_a_byte = [] |
| big_endian_defs = [] |
| |
| big_defs = [] |
| for classified_def in defs: |
| has_sub_byte_ints = classified_def[0] |
| |
| # now the big endian part |
| if has_sub_byte_ints: |
| _, one_def, int_type, members = classified_def |
| |
| if byte_type and byte_type.strip() != int_type.strip(): |
| raise Exception('mismatching type continuation after incomplete byte: %r %r to %r' |
| % (byte_type, members_within_a_byte, int_type)) |
| byte_type = int_type |
| |
| for member in members: |
| member_name, bits_str = member.split(':') |
| member_name = member_name.strip() |
| bits = int(bits_str) |
| member = '%s:%d' % (member_name, bits) |
| members_within_a_byte.append(member) |
| got_bits += bits |
| |
| if got_bits == 8: |
| # reverse these. |
| big_endian_defs.append('%s%s;' % (byte_type, ', '.join(reversed(members_within_a_byte)))) |
| members_within_a_byte = [] |
| byte_type = None |
| got_bits = 0 |
| |
| elif got_bits > 8: |
| raise Exception('sub-byte int breaks clean byte bounds: %s -- %d + %d = %d bits' |
| % (member, got_bits - bits, bits, got_bits)) |
| |
| elif not has_sub_byte_ints: |
| if got_bits: |
| raise Exception('sub-byte members do not add up to clean byte bounds: %r' % members_within_a_byte) |
| |
| big_endian_defs.append(classified_def[1]) |
| |
| # strip empty lines |
| lines = [l for l in (''.join(big_endian_defs).split('\n')) if l.strip()] |
| # clean lines' whitespace errors we might have taken in with the type names |
| for i in range(len(lines)): |
| line = lines[i] |
| while len(line) and line[-1] in ' \t': |
| line = line[:-1] |
| lines[i] = line |
| return '\n'.join(lines) |
| |
| def handle_struct_body(body_str): |
| |
| big_endian_body_str = struct_body_to_big_endian(body_str) |
| |
| if big_endian_body_str: |
| new_lines = ['#if OSMO_IS_LITTLE_ENDIAN\n'] |
| new_lines.append(body_str) |
| new_lines.append('#elif OSMO_IS_BIG_ENDIAN\n' |
| '/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianess.py) */\n') |
| new_lines.append(big_endian_body_str) |
| new_lines.append('\n#endif\n') |
| return ''.join(new_lines) |
| else: |
| return body_str |
| |
| def _check_file(f): |
| if not (f.endswith('.h') or f.endswith('.c') or f.endswith('.cpp')): |
| return |
| |
| # section the file into |
| # [ ["no struct def"], ["struct {...};"], ["no struct def"], ... ] |
| sections = [] |
| in_struct = False |
| buf = [] |
| for line in codecs.open(f, "r", "utf-8").readlines(): |
| |
| if not in_struct and re_struct_start.fullmatch(line): |
| # flush whatever might still be in buf from before |
| sections.append(buf) |
| # start an in_struct section |
| buf = [line] |
| in_struct = True |
| elif in_struct and re_struct_end.fullmatch(line): |
| # add this end to the in_struct section and then start a non-struct section |
| buf.append(line) |
| sections.append(buf) |
| in_struct = False |
| buf = [] |
| else: |
| buf.append(line) |
| # flush any leftovers in buf |
| if buf: |
| sections.append(buf) |
| |
| # examine each struct, i.e. every second item in 'sections' |
| for i in range(len(sections)): |
| if not (i & 1): |
| continue |
| |
| struct = sections[i] |
| |
| # If the struct isn't packed, we need not bother. |
| # The practical use of this: in some structs we have booleans in the |
| # form of |
| # integer flag:1; |
| # and these don't add up to bytes, and cause errors. So let's skip all |
| # non-packed structs, then all of those are out of the picture. |
| if not 'packed' in struct[-1]: |
| continue |
| |
| try: |
| |
| # assume the 'struct foo {' is on the first line, the closing brace |
| # '} __attribute...;' on the last, and the rest are individual |
| # definitions split by ';'. |
| struct_body_lines = struct[1:-1] |
| struct_body_parts = section_struct_body(struct_body_lines) |
| |
| new_struct_body_parts = [] |
| for j in range(len(struct_body_parts)): |
| part = ''.join(struct_body_parts[j]) |
| if not (j & 1): |
| new_struct_body_parts.append(part) |
| else: |
| new_struct_body_parts.append(handle_struct_body(part)) |
| |
| new_struct = [struct[0], ''.join(new_struct_body_parts), struct[-1]] |
| sections[i] = new_struct |
| except Exception as e: |
| raise Exception('ERROR in struct %r' % struct[0]) |
| |
| # phew. result. |
| result = ''.join((''.join(s) for s in sections)) |
| |
| # see if osmocom/core/endian.h is needed and included. |
| if (not f.endswith('endian.h') |
| and 'OSMO_IS_LITTLE_ENDIAN' in result |
| and '#include <osmocom/core/endian.h>' not in result): |
| # add the include after the last 'osmocom/core' include |
| last_include_start = result.rfind('#include <osmocom/core/') |
| if last_include_start < 0: |
| last_include_start = result.rfind('#include <osmocom/') |
| if last_include_start < 0: |
| last_include_start = result.rfind('#include') |
| |
| if last_include_start < 0: |
| raise Exception('do not know where to include osmocom/core/endian.h in %r' % f) |
| |
| insert_at = result.find('\n', last_include_start) |
| |
| result = result[:insert_at] + '\n#include <osmocom/core/endian.h>' + result[insert_at:] |
| |
| with codecs.open(f, "w", "utf-8") as fd: |
| fd.write(result) |
| |
| def check_file(f): |
| try: |
| _check_file(f) |
| except Exception as e: |
| raise Exception('ERROR IN FILE %r' % f) |
| |
| args = sys.argv[1:] |
| if not args: |
| args = ['.'] |
| |
| for f in args: |
| if os.path.isdir(f): |
| for parent_path, subdirs, files in os.walk(f, None, None): |
| for ff in files: |
| check_file(os.path.join(parent_path, ff)) |
| else: |
| check_file(f) |
| |
| # vim: tabstop=4 shiftwidth=4 expandtab |