ddidderr/zstd-rs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Changed ZSTD_compressEnd()

Browse Source
This commit is contained in:
Yann Collet
2016-07-28 15:29:08 +02:00
parent e7bf9156d1
commit 62470b4bab
6 changed files with 36 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/zstd.h
+6 -7
View File
@@ -315,15 +315,14 @@ ZSTDLIB_API size_t ZSTD_sizeofDCtx(const ZSTD_DCtx* dctx);
/* This is an advanced API, giving full control over buffer management, for users which need direct control over memory.
* But it's also a complex one, with a lot of restrictions (documented below).
* For an easier streaming API, look into common/zbuff.h
* which removes all restrictions by implementing and managing its own internal buffer */
* which removes all restrictions by allocating and managing its own internal buffer */
ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize);
ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx);
ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity);
ZSTDLIB_API size_t ZSTD_compressContinueThenEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
/*
A ZSTD_CCtx object is required to track streaming operations.
@@ -338,7 +337,7 @@ ZSTDLIB_API size_t ZSTD_compressContinueThenEnd(ZSTD_CCtx* cctx, void* dst, size
Then, consume your input using ZSTD_compressContinue().
There are some important considerations to keep in mind when using this advanced function :
- ZSTD_compressContinue() has no internal buffer. It uses externally provided buffer only.
- Interface is synchronous : input is consumed entirely and produce 1 (or more) compressed blocks.
- Interface is synchronous : input is consumed entirely and produce 1+ (or more) compressed blocks.
- Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario.
Worst case evaluation is provided by ZSTD_compressBound().
ZSTD_compressContinue() doesn't guarantee recover after a failed compression.
@@ -347,9 +346,9 @@ ZSTDLIB_API size_t ZSTD_compressContinueThenEnd(ZSTD_CCtx* cctx, void* dst, size
- ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps.
In which case, it will "discard" the relevant memory section from its history.
Finish a frame with ZSTD_compressEnd(), which will write the epilogue,
or ZSTD_compressContinueThenEnd(), which will write the last block.
Without last block / epilogue mark, frames will be considered unfinished (broken) by decoders.
Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
It's possible to use a NULL,0 src content, in which case, it will write a final empty block to end the frame,
Without last block mark, frames will be considered unfinished (broken) by decoders.
You can then reuse `ZSTD_CCtx` (ZSTD_compressBegin()) to compress some new frame.
*/