Gzip: compatibility with recent zlib-ng versions.

It now uses custom alloc_aligned() wrapper for all allocations,
therefore all allocations are larger than expected by (64 + sizeof(void*)).
Further, they are seen as allocations of 1 element.  Relevant calculations
were adjusted to reflect this, and state allocation is now protected
with a flag to avoid misinterpreting other allocations as the zlib
deflate_state allocation.

Further, it no longer forces window bits to 13 on compression level 1,
so the comment was adjusted to reflect this.
This commit is contained in:
Maxim Dounin 2023-03-27 21:25:05 +03:00
parent 7b24b93d67
commit 87471918b2

View File

@ -57,6 +57,7 @@ typedef struct {
unsigned nomem:1;
unsigned buffering:1;
unsigned zlib_ng:1;
unsigned state_allocated:1;
size_t zin;
size_t zout;
@ -514,9 +515,10 @@ ngx_http_gzip_filter_memory(ngx_http_request_t *r, ngx_http_gzip_ctx_t *ctx)
} else {
/*
* Another zlib variant, https://github.com/zlib-ng/zlib-ng.
* It forces window bits to 13 for fast compression level,
* uses 16-byte padding in one of window-sized buffers, and
* uses 128K hash.
* It used to force window bits to 13 for fast compression level,
* uses (64 + sizeof(void*)) additional space on all allocations
* for alignment, 16-byte padding in one of window-sized buffers,
* and 128K hash.
*/
if (conf->level == 1) {
@ -524,7 +526,8 @@ ngx_http_gzip_filter_memory(ngx_http_request_t *r, ngx_http_gzip_ctx_t *ctx)
}
ctx->allocated = 8192 + 16 + (1 << (wbits + 2))
+ 131072 + (1 << (memlevel + 8));
+ 131072 + (1 << (memlevel + 8))
+ 4 * (64 + sizeof(void*));
ctx->zlib_ng = 1;
}
}
@ -926,13 +929,16 @@ ngx_http_gzip_filter_alloc(void *opaque, u_int items, u_int size)
alloc = items * size;
if (items == 1 && alloc % 512 != 0 && alloc < 8192) {
if (items == 1 && alloc % 512 != 0 && alloc < 8192
&& !ctx->state_allocated)
{
/*
* The zlib deflate_state allocation, it takes about 6K,
* we allocate 8K. Other allocations are divisible by 512.
*/
ctx->state_allocated = 1;
alloc = 8192;
}