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Add extra warnings about not modifying the ZSTD_outBuffer

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Nick Terrell 2020-04-28 12:07:42 -07:00
parent 1343b815f8
commit 55a57d46be
1 changed files with 9 additions and 1 deletions
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lib/zstd.h
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@ -1656,7 +1656,9 @@ ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowS
* caller must not modify pos). This is checked by the decompressor, and * caller must not modify pos). This is checked by the decompressor, and
* decompression will fail if it ever changes. Therefore the ZSTD_outBuffer * decompression will fail if it ever changes. Therefore the ZSTD_outBuffer
* MUST be large enough to fit the entire decompressed frame. This will be * MUST be large enough to fit the entire decompressed frame. This will be
* checked when the frame content size is known. * checked when the frame content size is known. The data in the ZSTD_outBuffer
* in the range [dst, dst + pos) MUST not be modified during decompression
* or you will get data corruption.
* *
* When this flags is enabled zstd won't allocate an output buffer, because * When this flags is enabled zstd won't allocate an output buffer, because
* it can write directly to the ZSTD_outBuffer, but it will still allocate * it can write directly to the ZSTD_outBuffer, but it will still allocate
@ -1668,6 +1670,12 @@ ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowS
* NOTE: So long as the ZSTD_outBuffer always points to valid memory, using * NOTE: So long as the ZSTD_outBuffer always points to valid memory, using
* this flag is ALWAYS memory safe, and will never access out-of-bounds * this flag is ALWAYS memory safe, and will never access out-of-bounds
* memory. However, decompression WILL fail if you violate the preconditions. * memory. However, decompression WILL fail if you violate the preconditions.
*
* WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST
* not be modified during decompression or you will get data corruption. This
* is because zstd needs to reference data in the ZSTD_outBuffer to regenerate
* matches. Normally zstd maintains its own buffer for this purpose, but passing
* this flag tells zstd to use the user provided buffer.
*/ */
#define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2 #define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2