def partial_sha_to_index(self, partial_bin_sha, canonical_length):
"""
:return: index as in `sha_to_index` or None if the sha was not found in this
index file
:param partial_bin_sha: an at least two bytes of a partial binary sha
:param canonical_length: lenght of the original hexadecimal representation of the
given partial binary sha
:raise AmbiguousObjectName:"""
if len(partial_bin_sha) < 2:
raise ValueError("Require at least 2 bytes of partial sha")
first_byte = ord(partial_bin_sha[0])
get_sha = self.sha
lo = 0 # lower index, the left bound of the bisection
if first_byte != 0:
lo = self._fanout_table[first_byte - 1]
hi = self._fanout_table[
first_byte] # the upper, right bound of the bisection
# fill the partial to full 20 bytes
filled_sha = partial_bin_sha + '\0' * (20 - len(partial_bin_sha))
# find lowest
while lo < hi:
mid = (lo + hi) / 2
c = cmp(filled_sha, get_sha(mid))
if c < 0:
hi = mid
elif not c:
# perfect match
lo = mid
break
else:
lo = mid + 1
# END handle midpoint
# END bisect
if lo < self.size():
cur_sha = get_sha(lo)
if is_equal_canonical_sha(canonical_length, partial_bin_sha,
cur_sha):
next_sha = None
if lo + 1 < self.size():
next_sha = get_sha(lo + 1)
if next_sha and next_sha == cur_sha:
raise AmbiguousObjectName(partial_bin_sha)
return lo
# END if we have a match
# END if we found something
return None
def partial_sha_to_index(self, partial_bin_sha, canonical_length):
"""
:return: index as in `sha_to_index` or None if the sha was not found in this
index file
:param partial_bin_sha: an at least two bytes of a partial binary sha
:param canonical_length: lenght of the original hexadecimal representation of the
given partial binary sha
:raise AmbiguousObjectName:"""
if len(partial_bin_sha) < 2:
raise ValueError("Require at least 2 bytes of partial sha")
first_byte = ord(partial_bin_sha[0])
get_sha = self.sha
lo = 0 # lower index, the left bound of the bisection
if first_byte != 0:
lo = self._fanout_table[first_byte-1]
hi = self._fanout_table[first_byte] # the upper, right bound of the bisection
# fill the partial to full 20 bytes
filled_sha = partial_bin_sha + '\0'*(20 - len(partial_bin_sha))
# find lowest
while lo < hi:
mid = (lo + hi) / 2
c = cmp(filled_sha, get_sha(mid))
if c < 0:
hi = mid
elif not c:
# perfect match
lo = mid
break
else:
lo = mid + 1
# END handle midpoint
# END bisect
if lo < self.size():
cur_sha = get_sha(lo)
if is_equal_canonical_sha(canonical_length, partial_bin_sha, cur_sha):
next_sha = None
if lo+1 < self.size():
next_sha = get_sha(lo+1)
if next_sha and next_sha == cur_sha:
raise AmbiguousObjectName(partial_bin_sha)
return lo
# END if we have a match
# END if we found something
return None