Also Allow/Document/Test Excluding dfast and Up

Author: felixhandte

.github/workflows/dev-short-tests.yml

@@ -349,6 +349,7 @@ jobs:
         make clean && make -j all MOREFLAGS="-Werror -DZSTD_NO_INLINE -DZSTD_STRIP_ERROR_STRINGS"
         make clean && make check MOREFLAGS="-Werror -DZSTD_NO_INLINE -DZSTD_STRIP_ERROR_STRINGS"
         make clean && make check ZSTD_LIB_EXCLUDE_COMPRESSORS_DFAST_AND_UP=1 MOREFLAGS="-Werror"
+        make clean && make check ZSTD_LIB_EXCLUDE_COMPRESSORS_GREEDY_AND_UP=1 MOREFLAGS="-Werror"
 
   dynamic-bmi2:
     runs-on: ubuntu-latest

lib/README.md

@@ -123,7 +123,10 @@ The file structure is designed to make this selection manually achievable for an
   strategies. In environments where the higher compression levels aren't used,
   it is possible to exclude all but the fastest strategy with
   `ZSTD_LIB_EXCLUDE_COMPRESSORS_DFAST_AND_UP=1`. (Note that this will change
-  the behavior of the default compression level.)
+  the behavior of the default compression level.) Or if you want to retain the
+  default compressor as well, you can set
+  `ZSTD_LIB_EXCLUDE_COMPRESSORS_GREEDY_AND_UP=1`, at the cost of an additional
+  ~20KB or so.
 
   For squeezing the last ounce of size out, you can also define
   `ZSTD_NO_INLINE`, which disables inlining, and `ZSTD_STRIP_ERROR_STRINGS`,

lib/libzstd.mk

@@ -48,6 +48,7 @@ endif
 ZSTD_NO_ASM ?= 0
 
 ZSTD_LIB_EXCLUDE_COMPRESSORS_DFAST_AND_UP ?= 0
+ZSTD_LIB_EXCLUDE_COMPRESSORS_GREEDY_AND_UP ?= 0
 
 ##################################################################
 # libzstd helpers
@@ -182,6 +183,10 @@ endif
 
 ifneq ($(ZSTD_LIB_EXCLUDE_COMPRESSORS_DFAST_AND_UP), 0)
   CFLAGS += -DZSTD_EXCLUDE_DFAST_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
+else
+ifneq ($(ZSTD_LIB_EXCLUDE_COMPRESSORS_GREEDY_AND_UP), 0)
+  CFLAGS += -DZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR -DZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
+endif
 endif
 
 ifneq ($(ZSTD_LEGACY_SUPPORT), 0)