Clarify dstCapacity requirements #3531
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Clarify `dstCapacity` requirements for single-pass functions. Fixes facebook#3524.
Cyan4973
reviewed
Mar 8, 2023
| @@ -578,7 +579,8 @@ ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); | |||
| * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. | |||
| * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() | |||
| * - The function is always blocking, returns when compression is completed. | |||
| * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. | |||
| * NOTE: Providing `dstCapacity >= ZSTD_compressBound(srcSize)` guarantees that zstd will have | |||
| * enough space to successfully compress the data, though it is possible it fails for other reasons. | |||
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though it is possible it fails for other reasons
What other reasons do you have in mind ?
Memory allocation failures ?
Providing dstCapacity >= ZSTD_compressBound(srcSize) should be enough to avoid #3524.
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I mean ZSTD_compress2() can let you specify a lot of options. E.g. compression could fail to allocate a thread. We could run out of memory.
I only mentioned this in ZSTD_compress2(), and skipped it in ZSTD_compress(), but I just mean that you still have to check the error code.
Cyan4973
approved these changes
Mar 9, 2023
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Clarify
dstCapacityrequirements for single-pass functions.Fixes #3524.