QubesOS/qubes-linux-utils
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Fix off-by-one error in header length calculation

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int(ceil(log10(100))) is one lower than it should be when max widths are
powers of 10. This means providing a value of 100 when the max is 100
produces an unexpected failure.

Was never triggered because imghdrlen args are only hard-coded
constants, but a bug is a bug.
This commit is contained in:
Jean-Philippe Ouellet 2017-08-11 09:43:41 -04:00
parent 43908b7eaa
commit 349f79bc66
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GPG Key ID: 4747332C27533622
2 changed files with 4 additions and 3 deletions
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6
imgconverter/qubesimgconverter/__init__.py
View File

@ -49,9 +49,9 @@ ICON_MAXSIZE = 512
# header consists of two decimal numbers, SPC and LF # header consists of two decimal numbers, SPC and LF
re_imghdr = re.compile(br'^\d+ \d+\n$') re_imghdr = re.compile(br'^\d+ \d+\n$')
imghdrlen = lambda w, h: int(math.ceil(math.log10(w)) \ def imghdrlen(w, h):
+ math.ceil(math.log10(h)) \ # width & height are inclusive max vals, and +2 for ' ' and '\n'
+ 2) return len(str(w)) + len(str(h)) + 2
class Image(object): class Image(object):
def __init__(self, rgba, size): def __init__(self, rgba, size):

1
imgconverter/qubesimgconverter/test.py
View File

@ -54,6 +54,7 @@ class TestCaseImage(unittest.TestCase):
class TestCaseFunctionsAndConstants(unittest.TestCase): class TestCaseFunctionsAndConstants(unittest.TestCase):
def test_00_imghdrlen(self): def test_00_imghdrlen(self):
self.assertEqual(qubesimgconverter.imghdrlen(8, 15), len('8 15\n')) self.assertEqual(qubesimgconverter.imghdrlen(8, 15), len('8 15\n'))
self.assertEqual(qubesimgconverter.imghdrlen(100, 100), len('100 100\n'))
def test_01_re_imghdr(self): def test_01_re_imghdr(self):
self.assertTrue(qubesimgconverter.re_imghdr.match('8 15\n')) self.assertTrue(qubesimgconverter.re_imghdr.match('8 15\n'))