Clarified license (#115, #244)

1 files changed, 26 insertions, 7 deletions

diff --git a/lib/README.md b/lib/README.md
index f6ebf5e..f932d42 100644
--- a/lib/README.md
+++ b/lib/README.md
@@ -1,21 +1,40 @@
 LZ4 - Library Files
 ================================
 
-The __lib__ directory contains several files, but you don't necessarily need them all.
+All source material within __lib__ directory are BSD 2-Clause licensed.
+See [LICENSE](LICENSE) for details.
+The license is also repeated at the top of each source file.
 
-To integrate fast LZ4 compression/decompression into your program, you basically just need "**lz4.c**" and "**lz4.h**".
+The directory contains many files, but depending on project's objectives,
+not all of them are necessary.
 
-For more compression at the cost of compression speed (while preserving decompression speed), use **lz4hc** on top of regular lz4. `lz4hc` only provides compression functions. It also needs `lz4` to compile properly.
+The minimum required is **`lz4.c`** and **`lz4.h`**,
+which will provide the fast compression and decompression algorithm.
 
-If you want to produce files or data streams compatible with `lz4` command line utility, use **lz4frame**. This library encapsulates lz4-compressed blocks into the [official interoperable frame format]. In order to work properly, lz4frame needs lz4 and lz4hc, and also **xxhash**, which provides error detection algorithm.
-(_Advanced stuff_ : It's possible to hide xxhash symbols into a local namespace. This is what `liblz4` does, to avoid symbol duplication in case a user program would link to several libraries containing xxhash symbols.)
+For more compression at the cost of compression speed,
+the High Compression variant **lz4hc** is available.
+It's necessary to add **`lz4hc.c`** and **`lz4hc.h`**.
+The variant still depends on regular `lz4` source files.
+In particular, the decompression is still provided by `lz4.c`.
 
-A more complex "lz4frame_static.h" is also provided, although its usage is not recommended. It contains definitions which are not guaranteed to remain stable within future versions. Use for static linking ***only***.
+In order to produce files or streams compatible with `lz4` command line utility,
+it's necessary to encode lz4-compressed blocks using the [official interoperable frame format].
+This format is generated and decoded automatically by the **lz4frame** library.
+In order to work properly, lz4frame needs lz4 and lz4hc, and also **xxhash**,
+which provides error detection.
+(_Advanced stuff_ : It's possible to hide xxhash symbols into a local namespace.
+This is what `liblz4` does, to avoid symbol duplication
+in case a user program would link to several libraries containing xxhash symbols.)
 
-The other files are not source code. There are :
+A more complex `lz4frame_static.h` is also provided.
+It contains definitions which are not guaranteed to remain stable within future versions.
+It must be used with static linking ***only***.
+
+Other files present in the directory are not source code. There are :
 
  - LICENSE : contains the BSD license text
  - Makefile : script to compile or install lz4 library (static or dynamic)
  - liblz4.pc.in : for pkg-config (make install)
+ - README.md : this file
 
 [official interoperable frame format]: ../lz4_Frame_format.md