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bpo-42739: Don't use sentinels to mark end of line table. (GH-25657)

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* Add length parameter to PyLineTable_InitAddressRange and doen't use sentinel values at end of table. Makes the line number table more robust.

* Update PyCodeAddressRange to match PEP 626.
This commit is contained in:
Mark Shannon 2021-04-29 13:12:51 +01:00 • committed by GitHub
parent 53dd6c99b3
commit c76da79b37
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13 changed files with 4968 additions and 4986 deletions
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4
Objects/lnotab_notes.txt
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@ -39,7 +39,6 @@ Note that the end - start value is always positive.
Finally, in order to fit into a single byte we need to convert start deltas to the range 0 <= delta <= 254,
and line deltas to the range -127 <= delta <= 127.
A line delta of -128 is used to indicate no line number.
A start delta of 255 is used as a sentinel to mark the end of the table.
Also note that a delta of zero indicates that there are no bytecodes in the given range,
which means we can use an invalid line number for that range.
@ -54,7 +53,6 @@ Final form:
16 +1
0 +127 (line 135, but the range is empty as no bytecodes are at line 135)
4 +73
255 (end mark) ---
Iterating over the table.
-------------------------
@ -68,8 +66,6 @@ def co_lines(code):
end = 0
table_iter = iter(code.internal_line_table):
for sdelta, ldelta in table_iter:
if sdelta == 255:
break
if ldelta == 0: # No change to line number, just accumulate changes to end
end += odelta
continue