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authorBjörn Gustavsson <[email protected]>2014-01-22 16:19:32 +0100
committerBjörn Gustavsson <[email protected]>2014-01-22 16:19:32 +0100
commite99633a51cbd22b16606c2669c575c22cf1c511f (patch)
tree784ef6b3eec7461e7b8962fee2d1ba6858b516b6 /erts/doc/src
parent990b655c92f889d2c45e6f43ee6fdae29ffc8464 (diff)
parent9f57d8c4f86323cf7481c9a7e512486087bb5542 (diff)
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Merge branch 'bjorn/erts/zlib-1.2.8'
* bjorn/erts/zlib-1.2.8: configure: Prefer the system's zlib over own our zlib source Update preloaded modules Add the 'rle' zstrategy Don't make gzio.c dependent on the zutil.h header file Update zlib to 1.2.8 erts/zlib: Remove unused file example.c
Diffstat (limited to 'erts/doc/src')
-rw-r--r--erts/doc/src/zlib.xml30
1 files changed, 16 insertions, 14 deletions
diff --git a/erts/doc/src/zlib.xml b/erts/doc/src/zlib.xml
index afc597b729..11a7437f5a 100644
--- a/erts/doc/src/zlib.xml
+++ b/erts/doc/src/zlib.xml
@@ -161,20 +161,22 @@ list_to_binary([Compressed|Last])</pre>
state. <c><anno>MemLevel</anno></c>=1 uses minimum memory but is slow and
reduces compression ratio; <c><anno>MemLevel</anno></c>=9 uses maximum
memory for optimal speed. The default value is 8.</p>
- <p>The <c><anno>Strategy</anno></c> parameter is used to tune the
- compression algorithm. Use the value <c>default</c> for
- normal data, <c>filtered</c> for data produced by a filter
- (or predictor), or <c>huffman_only</c> to force Huffman
- encoding only (no string match). Filtered data consists
- mostly of small values with a somewhat random
- distribution. In this case, the compression algorithm is
- tuned to compress them better. The effect of
- <c>filtered</c>is to force more Huffman coding and less
- string matching; it is somewhat intermediate between
- <c>default</c> and <c>huffman_only</c>. The <c><anno>Strategy</anno></c>
- parameter only affects the compression ratio but not the
- correctness of the compressed output even if it is not set
- appropriately.</p>
+ <p>The <c><anno>Strategy</anno></c> parameter is used to tune
+ the compression algorithm. Use the value <c>default</c> for
+ normal data, <c>filtered</c> for data produced by a filter (or
+ predictor), <c>huffman_only</c> to force Huffman encoding
+ only (no string match), or <c>rle</c> to limit match
+ distances to one (run-length encoding). Filtered data
+ consists mostly of small values with a somewhat random
+ distribution. In this case, the compression algorithm is tuned
+ to compress them better. The effect of <c>filtered</c>is to
+ force more Huffman coding and less string matching; it is
+ somewhat intermediate between <c>default</c> and
+ <c>huffman_only</c>. <c>rle</c> is designed to be almost as
+ fast as <c>huffman_only</c>, but give better compression for PNG
+ image data. The <c><anno>Strategy</anno></c> parameter only
+ affects the compression ratio but not the correctness of the
+ compressed output even if it is not set appropriately.</p>
</desc>
</func>
<func>