diff options
Diffstat (limited to 'Lib/fontTools/misc/sstruct.py')
| -rw-r--r-- | Lib/fontTools/misc/sstruct.py | 228 |
1 files changed, 116 insertions, 112 deletions
diff --git a/Lib/fontTools/misc/sstruct.py b/Lib/fontTools/misc/sstruct.py index 6db8b515..d35bc9a5 100644 --- a/Lib/fontTools/misc/sstruct.py +++ b/Lib/fontTools/misc/sstruct.py @@ -56,68 +56,72 @@ __copyright__ = "Copyright 1998, Just van Rossum <just@letterror.com>" class Error(Exception): - pass + pass + def pack(fmt, obj): - formatstring, names, fixes = getformat(fmt, keep_pad_byte=True) - elements = [] - if not isinstance(obj, dict): - obj = obj.__dict__ - for name in names: - value = obj[name] - if name in fixes: - # fixed point conversion - value = fl2fi(value, fixes[name]) - elif isinstance(value, str): - value = tobytes(value) - elements.append(value) - data = struct.pack(*(formatstring,) + tuple(elements)) - return data + formatstring, names, fixes = getformat(fmt, keep_pad_byte=True) + elements = [] + if not isinstance(obj, dict): + obj = obj.__dict__ + for name in names: + value = obj[name] + if name in fixes: + # fixed point conversion + value = fl2fi(value, fixes[name]) + elif isinstance(value, str): + value = tobytes(value) + elements.append(value) + data = struct.pack(*(formatstring,) + tuple(elements)) + return data + def unpack(fmt, data, obj=None): - if obj is None: - obj = {} - data = tobytes(data) - formatstring, names, fixes = getformat(fmt) - if isinstance(obj, dict): - d = obj - else: - d = obj.__dict__ - elements = struct.unpack(formatstring, data) - for i in range(len(names)): - name = names[i] - value = elements[i] - if name in fixes: - # fixed point conversion - value = fi2fl(value, fixes[name]) - elif isinstance(value, bytes): - try: - value = tostr(value) - except UnicodeDecodeError: - pass - d[name] = value - return obj + if obj is None: + obj = {} + data = tobytes(data) + formatstring, names, fixes = getformat(fmt) + if isinstance(obj, dict): + d = obj + else: + d = obj.__dict__ + elements = struct.unpack(formatstring, data) + for i in range(len(names)): + name = names[i] + value = elements[i] + if name in fixes: + # fixed point conversion + value = fi2fl(value, fixes[name]) + elif isinstance(value, bytes): + try: + value = tostr(value) + except UnicodeDecodeError: + pass + d[name] = value + return obj + def unpack2(fmt, data, obj=None): - length = calcsize(fmt) - return unpack(fmt, data[:length], obj), data[length:] + length = calcsize(fmt) + return unpack(fmt, data[:length], obj), data[length:] + def calcsize(fmt): - formatstring, names, fixes = getformat(fmt) - return struct.calcsize(formatstring) + formatstring, names, fixes = getformat(fmt) + return struct.calcsize(formatstring) # matches "name:formatchar" (whitespace is allowed) _elementRE = re.compile( - r"\s*" # whitespace - r"([A-Za-z_][A-Za-z_0-9]*)" # name (python identifier) - r"\s*:\s*" # whitespace : whitespace - r"([xcbB?hHiIlLqQfd]|" # formatchar... - r"[0-9]+[ps]|" # ...formatchar... - r"([0-9]+)\.([0-9]+)(F))" # ...formatchar - r"\s*" # whitespace - r"(#.*)?$" # [comment] + end of string - ) + r"\s*" # whitespace + r"([A-Za-z_][A-Za-z_0-9]*)" # name (python identifier) + r"\s*:\s*" # whitespace : whitespace + r"([xcbB?hHiIlLqQfd]|" # formatchar... + r"[0-9]+[ps]|" # ...formatchar... + r"([0-9]+)\.([0-9]+)(F))" # ...formatchar + r"\s*" # whitespace + r"(#.*)?$" # [comment] + end of string +) # matches the special struct fmt chars and 'x' (pad byte) _extraRE = re.compile(r"\s*([x@=<>!])\s*(#.*)?$") @@ -125,54 +129,53 @@ _extraRE = re.compile(r"\s*([x@=<>!])\s*(#.*)?$") # matches an "empty" string, possibly containing whitespace and/or a comment _emptyRE = re.compile(r"\s*(#.*)?$") -_fixedpointmappings = { - 8: "b", - 16: "h", - 32: "l"} +_fixedpointmappings = {8: "b", 16: "h", 32: "l"} _formatcache = {} + def getformat(fmt, keep_pad_byte=False): - fmt = tostr(fmt, encoding="ascii") - try: - formatstring, names, fixes = _formatcache[fmt] - except KeyError: - lines = re.split("[\n;]", fmt) - formatstring = "" - names = [] - fixes = {} - for line in lines: - if _emptyRE.match(line): - continue - m = _extraRE.match(line) - if m: - formatchar = m.group(1) - if formatchar != 'x' and formatstring: - raise Error("a special fmt char must be first") - else: - m = _elementRE.match(line) - if not m: - raise Error("syntax error in fmt: '%s'" % line) - name = m.group(1) - formatchar = m.group(2) - if keep_pad_byte or formatchar != "x": - names.append(name) - if m.group(3): - # fixed point - before = int(m.group(3)) - after = int(m.group(4)) - bits = before + after - if bits not in [8, 16, 32]: - raise Error("fixed point must be 8, 16 or 32 bits long") - formatchar = _fixedpointmappings[bits] - assert m.group(5) == "F" - fixes[name] = after - formatstring = formatstring + formatchar - _formatcache[fmt] = formatstring, names, fixes - return formatstring, names, fixes + fmt = tostr(fmt, encoding="ascii") + try: + formatstring, names, fixes = _formatcache[fmt] + except KeyError: + lines = re.split("[\n;]", fmt) + formatstring = "" + names = [] + fixes = {} + for line in lines: + if _emptyRE.match(line): + continue + m = _extraRE.match(line) + if m: + formatchar = m.group(1) + if formatchar != "x" and formatstring: + raise Error("a special fmt char must be first") + else: + m = _elementRE.match(line) + if not m: + raise Error("syntax error in fmt: '%s'" % line) + name = m.group(1) + formatchar = m.group(2) + if keep_pad_byte or formatchar != "x": + names.append(name) + if m.group(3): + # fixed point + before = int(m.group(3)) + after = int(m.group(4)) + bits = before + after + if bits not in [8, 16, 32]: + raise Error("fixed point must be 8, 16 or 32 bits long") + formatchar = _fixedpointmappings[bits] + assert m.group(5) == "F" + fixes[name] = after + formatstring = formatstring + formatchar + _formatcache[fmt] = formatstring, names, fixes + return formatstring, names, fixes + def _test(): - fmt = """ + fmt = """ # comments are allowed > # big endian (see documentation for struct) # empty lines are allowed: @@ -188,29 +191,30 @@ def _test(): apad: x """ - print('size:', calcsize(fmt)) + print("size:", calcsize(fmt)) + + class foo(object): + pass - class foo(object): - pass + i = foo() - i = foo() + i.ashort = 0x7FFF + i.along = 0x7FFFFFFF + i.abyte = 0x7F + i.achar = "a" + i.astr = "12345" + i.afloat = 0.5 + i.adouble = 0.5 + i.afixed = 1.5 + i.abool = True - i.ashort = 0x7fff - i.along = 0x7fffffff - i.abyte = 0x7f - i.achar = "a" - i.astr = "12345" - i.afloat = 0.5 - i.adouble = 0.5 - i.afixed = 1.5 - i.abool = True + data = pack(fmt, i) + print("data:", repr(data)) + print(unpack(fmt, data)) + i2 = foo() + unpack(fmt, data, i2) + print(vars(i2)) - data = pack(fmt, i) - print('data:', repr(data)) - print(unpack(fmt, data)) - i2 = foo() - unpack(fmt, data, i2) - print(vars(i2)) if __name__ == "__main__": - _test() + _test() |