talksik/uWebSockets
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add memory limited dedicated compressors

Browse Source
This commit is contained in:
Alex Hultman
2020-02-29 04:06:27 +01:00
parent 7313e0168d
commit 3a856b610b
4 changed files with 70 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/PerMessageDeflate.h
+58 -2
View File
@@ -20,6 +20,28 @@
#ifndef UWS_PERMESSAGEDEFLATE_H
#define UWS_PERMESSAGEDEFLATE_H
/* We always define these options no matter if ZLIB is enabled or not */
namespace uWS {
/* Compress options (really more like PerMessageDeflateOptions) */
enum CompressOptions : int {
/* Compression disabled */
DISABLED = 0,
/* We compress using a shared non-sliding window. No added memory usage, worse compression. */
SHARED_COMPRESSOR = 1,
/* We compress using a dedicated sliding window. Major memory usage added, better compression of similarly repeated messages. */
DEDICATED_COMPRESSOR = 2,
/* Flags for limiting memory usage of dedicated compressor */
DEDICATED_COMPRESSOR_2KB = 2 | 4,
DEDICATED_COMPRESSOR_4KB = 2 | 8,
DEDICATED_COMPRESSOR_8KB = 2 | 16,
DEDICATED_COMPRESSOR_16KB = 2 | 32,
DEDICATED_COMPRESSOR_32KB = 2 | 64,
DEDICATED_COMPRESSOR_64KB = 2 | 128,
DEDICATED_COMPRESSOR_128KB = 2 | 256,
DEDICATED_COMPRESSOR_256KB = 2 | 512
};
}
#ifndef UWS_NO_ZLIB
#include <zlib.h>
#endif
@@ -68,8 +90,42 @@ struct ZlibContext {
struct DeflationStream {
z_stream deflationStream = {};
DeflationStream() {
deflateInit2(&deflationStream, 1, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY);
DeflationStream(int compressOptions) {
/* Sliding inflator should be about 44kb by default, less than compressor */
/* Memory usage is given by 2 ^ (windowBits + 2) + 2 ^ (memLevel + 9) */
int windowBits = -15, memLevel = 8;
if (compressOptions == DEDICATED_COMPRESSOR_2KB) {
windowBits = -8;
memLevel = 1;
} else if (compressOptions == DEDICATED_COMPRESSOR_4KB) {
windowBits = -9;
memLevel = 2;
} else if (compressOptions == DEDICATED_COMPRESSOR_8KB) {
windowBits = -10;
memLevel = 3;
} else if (compressOptions == DEDICATED_COMPRESSOR_16KB) {
windowBits = -11;
memLevel = 4;
} else if (compressOptions == DEDICATED_COMPRESSOR_32KB) {
windowBits = -12;
memLevel = 5;
} else if (compressOptions == DEDICATED_COMPRESSOR_64KB) {
windowBits = -13;
memLevel = 6;
} else if (compressOptions == DEDICATED_COMPRESSOR_128KB) {
windowBits = -14;
memLevel = 7;
} else if (compressOptions == DEDICATED_COMPRESSOR_256KB) {
windowBits = -15;
memLevel = 8;
}
/* DEDICATED_COMPRESSOR_256KB is the same as DEDICATED_COMPRESSOR */
deflateInit2(&deflationStream, 1, Z_DEFLATED, windowBits, memLevel, Z_DEFAULT_STRATEGY);
}
/* Deflate and optionally reset */