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decompress*_fast() function do not generate deprecation warnings

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they are classified as deprecated in the API documentation (lz4.h)
but do not yet trigger a warning,
to give time to existing applications to move away.

Also, the _fast() variants are still ~5% faster than the _safe() ones
after Dave's patch.
This commit is contained in:
Yann Collet 2019-04-15 10:33:40 -07:00
parent 481a37fe47
commit 1f4a412646
1 changed files with 14 additions and 13 deletions
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27
lib/lz4.h
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@ -631,11 +631,11 @@ LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") LZ4LIB_API int LZ4
LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize);
/*! LZ4_decompress_fast() : **unsafe!**
* These functions used to be a bit faster than LZ4_decompress_safe(),
* but situation has changed in recent versions.
* Now, `LZ4_decompress_safe()` is as fast and sometimes even faster than `LZ4_decompress_fast()`.
* Moreover, LZ4_decompress_safe() is protected vs malformed input, while `LZ4_decompress_fast()` is not, making it a security liability.
* These functions are generally slightly faster than LZ4_decompress_safe(),
* though the difference is small (generally ~5%).
* However, the real cost is a risk : LZ4_decompress_safe() is protected vs malformed input, while `LZ4_decompress_fast()` is not, making it a security liability.
* As a consequence, LZ4_decompress_fast() is strongly discouraged, and deprecated.
* These functions will generate a deprecation warning in the future.
*
* Last LZ4_decompress_fast() specificity is that it can decompress a block without knowing its compressed size.
* Note that even that functionality could be achieved in a more secure manner if need be,
@ -648,18 +648,19 @@ LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4
* The function expects to finish at block's end exactly.
* If the source stream is detected malformed, the function stops decoding and returns a negative result.
* note : LZ4_decompress_fast*() requires originalSize. Thanks to this information, it never writes past the output buffer.
* However, since it doesn't know its 'src' size, it may read an unknown amount of input, and overflow input buffer.
* Also, since match offsets are not validated, match reads from 'src' may underflow.
* These issues never happen if input data is correct.
* However, since it doesn't know its 'src' size, it may read an unknown amount of input, past input buffer bounds.
* Also, since match offsets are not validated, match reads from 'src' may underflow too.
* These issues never happen if input (compressed) data is correct.
* But they may happen if input data is invalid (error or intentional tampering).
* As a consequence, use these functions in trusted environments with trusted data **only**.
*/
LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe() instead") LZ4LIB_API
int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_continue() instead") LZ4LIB_API
int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_usingDict() instead") LZ4LIB_API
int LZ4_decompress_fast_usingDict (const char* src, char* dst, int originalSize, const char* dictStart, int dictSize);
/* LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe() instead") */
LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
/* LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_continue() instead") */
LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
/* LZ4_DEPRECATED("This function is deprecated and unsafe. Consider using LZ4_decompress_safe_usingDict() instead") */
LZ4LIB_API int LZ4_decompress_fast_usingDict (const char* src, char* dst, int originalSize, const char* dictStart, int dictSize);
/*! LZ4_resetStream() :
* An LZ4_stream_t structure must be initialized at least once.