created zstd_decompress_block module

isolate all logic associated with block decompression
into its own module.

zstd_decompress is still in charge
of context creation/destruction,
frames, headers, streaming, special blocks, etc.

Compressed blocks themselves are now handled within zstd_decompress_block .

build/cmake/lib/CMakeLists.txt

@@ -46,6 +46,7 @@ SET(Sources
         ${LIBRARY_DIR}/compress/zstd_ldm.c
         ${LIBRARY_DIR}/decompress/huf_decompress.c
         ${LIBRARY_DIR}/decompress/zstd_decompress.c
+        ${LIBRARY_DIR}/decompress/zstd_decompress_block.c
         ${LIBRARY_DIR}/decompress/zstd_ddict.c
         ${LIBRARY_DIR}/dictBuilder/cover.c
         ${LIBRARY_DIR}/dictBuilder/fastcover.c
@@ -75,8 +76,9 @@ SET(Headers
         ${LIBRARY_DIR}/compress/zstd_opt.h
         ${LIBRARY_DIR}/compress/zstd_ldm.h
         ${LIBRARY_DIR}/compress/zstdmt_compress.h
-        ${LIBRARY_DIR}/decompress/zstd_ddict.h
         ${LIBRARY_DIR}/decompress/zstd_decompress_internal.h
+        ${LIBRARY_DIR}/decompress/zstd_decompress_block.h
+        ${LIBRARY_DIR}/decompress/zstd_ddict.h
         ${LIBRARY_DIR}/dictBuilder/zdict.h
         ${LIBRARY_DIR}/dictBuilder/cover.h
         ${LIBRARY_DIR}/deprecated/zbuff.h)