bpo-41486: zlib uses an UINT32_MAX sliding window for the output buffer (GH-26143)
* zlib uses an UINT32_MAX sliding window for the output buffer
These funtions have an initial output buffer size parameter:
- zlib.decompress(data, /, wbits=MAX_WBITS, bufsize=DEF_BUF_SIZE)
- zlib.Decompress.flush([length])
If the initial size > UINT32_MAX, use an UINT32_MAX sliding window, instead of clamping to UINT32_MAX.
Speed up when (the initial size == the actual size).
This fixes a memory consumption and copying performance regression in earlier 3.10 beta releases if someone used an output buffer larger than 4GiB with zlib.decompress.
Reviewed-by: Gregory P. Smith
(cherry picked from commit a9a69bb3ea1e6cf54513717212aaeae0d61b24ee)
Co-authored-by: Ma Lin <animalize@users.noreply.github.com>
2 files changed