make `_fast*()` decoder generate a deprecation warning

updated modification

2 files changed, 25 insertions, 9 deletions

diff --git a/lib/README.md b/lib/README.md
index e9b221f..be8eba0 100644
--- a/lib/README.md
+++ b/lib/README.md
@@ -7,8 +7,8 @@ not all of them are necessary.
 #### Minimal LZ4 build
 
 The minimum required is **`lz4.c`** and **`lz4.h`**,
-which provides the fast compression and decompression algorithm.
-They generate and decode data using [LZ4 block format].
+which provides the fast compression and decompression algorithms.
+They generate and decode data using the [LZ4 block format].
 
 
 #### High Compression variant
@@ -49,9 +49,17 @@ The following build macro can be determined at compilation time :
 - `LZ4_FAST_DEC_LOOP` : this triggers the optimized decompression loop.
   This loops works great on x86/x64 cpus, and is automatically enabled on this platform.
   It's possible to enable or disable it manually, by passing `LZ4_FAST_DEC_LOOP=1` or `0` to the preprocessor.
-  Typically with `gcc` : `-DLZ4_FAST_DEC_LOOP=1`,
+  For example, with `gcc` : `-DLZ4_FAST_DEC_LOOP=1`,
   and with `make` : `CPPFLAGS+=-DLZ4_FAST_DEC_LOOP=1 make lz4`.
 
+- `LZ4_DISABLE_DEPRECATE_WARNINGS` : invoking a deprecated function will make the compiler generate a warning.
+  This is meant to invite users to update their source code.
+  Should this be a problem, it's generally to make the compiler ignore these warnings,
+  for example with `-Wno-deprecated-declarations` on `gcc`,
+  or `_CRT_SECURE_NO_WARNINGS` for Visual Studio.
+  Another method is to define `LZ4_DISABLE_DEPRECATE_WARNINGS`
+  before including the LZ4 header files.
+
 
 #### Amalgamation
 
diff --git a/lib/lz4.h b/lib/lz4.h
index c848f5f..1dc8e00 100644
--- a/lib/lz4.h
+++ b/lib/lz4.h
@@ -563,11 +563,16 @@ union LZ4_streamDecode_u {
 **************************************/
 
 /*! Deprecation warnings
- *  Should deprecation warnings be a problem,
- *  it is generally possible to disable them,
+ *
+ *  Deprecated functions make the compiler generate a warning when invoked.
+ *  This is meant to invite users to update their source code.
+ *  Should deprecation warnings be a problem, it is generally possible to disable them,
  *  typically with -Wno-deprecated-declarations for gcc
  *  or _CRT_SECURE_NO_WARNINGS in Visual.
- *  Otherwise, it's also possible to define LZ4_DISABLE_DEPRECATE_WARNINGS */
+ *
+ *  Another method is to define LZ4_DISABLE_DEPRECATE_WARNINGS
+ *  before including the header file.
+ */
 #ifdef LZ4_DISABLE_DEPRECATE_WARNINGS
 #  define LZ4_DEPRECATED(message)   /* disable deprecation warnings */
 #else
@@ -640,9 +645,12 @@ LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") LZ4LIB_API int LZ4
  *         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**.
  */
-LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
-LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* src, char* dst, int originalSize);
-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);
 
 
 #endif /* LZ4_H_2983827168210 */