hash table REFACTOR improve xxhash support

Author: michalvasko

CMakeLists.txt

@@ -242,7 +242,6 @@ else()
     option(ENABLE_TESTS "Build tests" OFF)
     option(ENABLE_VALGRIND_TESTS "Build tests with valgrind" OFF)
 endif()
-option(USE_XXHASH "Use xxhash if available" ON)
 option(ENABLE_PERF_TESTS "Build performance tests" OFF)
 option(ENABLE_COVERAGE "Build code coverage report from tests" OFF)
 option(ENABLE_FUZZ_TARGETS "Build target programs suitable for fuzzing with AFL" OFF)
@@ -414,12 +413,13 @@ target_link_libraries(yang ${PCRE2_LIBRARIES})
 
 # XXHash include and library
 find_package(XXHash)
-if (XXHASH_FOUND AND USE_XXHASH)
-    add_definitions(-DUSE_XXHASH)
+if(XXHASH_FOUND)
+    add_definitions(-DLY_XXHASH_SUPPORT)
     include_directories(${XXHASH_INCLUDE_DIR})
     target_link_libraries(yang ${XXHASH_LIBRARY})
+    message(STATUS "Hash algorithm: xxhash")
 else()
-    set (USE_XXHASH OFF)
+    message(STATUS "Hash algorithm: internal Jenkin's one-at-a-time")
 endif()
 
 # generated header list

README.md

@@ -61,6 +61,7 @@ the `distro` directory.
 
 #### Optional
 
+* xxhash (for faster hashing)
 * doxygen (for generating documentation)
 * cmocka >= 1.0.1 (for [tests](#Tests))
 * valgrind (for enhanced testing)

src/hash_table.c

@@ -4,7 +4,7 @@
  * @author Michal Vasko <[email protected]>
  * @brief libyang generic hash table implementation
  *
- * Copyright (c) 2015 - 2023 CESNET, z.s.p.o.
+ * Copyright (c) 2015 - 2025 CESNET, z.s.p.o.
  *
  * This source code is licensed under BSD 3-Clause License (the "License").
  * You may not use this file except in compliance with the License.
@@ -26,30 +26,20 @@
 #include "log.h"
 #include "ly_common.h"
 
-#ifdef USE_XXHASH
-#include <xxhash.h>
+#ifdef LY_XXHASH_SUPPORT
+# include <xxhash.h>
+#endif
 
 LIBYANG_API_DEF uint32_t
 lyht_hash_multi(uint32_t hash, const char *key_part, size_t len)
 {
+#ifdef LY_XXHASH_SUPPORT
     if (key_part && len) {
         return XXH3_64bits_withSeed(key_part, len, hash);
     }
 
     return XXH3_64bits_withSeed(NULL, 0, hash);
-}
-
-LIBYANG_API_DEF uint32_t
-lyht_hash(const char *key, size_t len)
-{
-    return XXH3_64bits(key, len);
-}
-
 #else
-
-LIBYANG_API_DEF uint32_t
-lyht_hash_multi(uint32_t hash, const char *key_part, size_t len)
-{
     uint32_t i;
 
     if (key_part && len) {
@@ -65,18 +55,21 @@ lyht_hash_multi(uint32_t hash, const char *key_part, size_t len)
     }
 
     return hash;
+#endif
 }
 
 LIBYANG_API_DEF uint32_t
 lyht_hash(const char *key, size_t len)
 {
+#ifdef LY_XXHASH_SUPPORT
+    return XXH3_64bits(key, len);
+#else
     uint32_t hash;
 
     hash = lyht_hash_multi(0, key, len);
     return lyht_hash_multi(hash, NULL, len);
-}
-
 #endif
+}
 
 static LY_ERR
 lyht_init_hlists_and_records(struct ly_ht *ht)

tests/CMakeLists.txt

@@ -30,7 +30,7 @@ function(ly_add_utest)
         endif()
     endif()
 
-    if (USE_XXHASH)
+    if (XXHASH_FOUND)
         target_link_libraries(${TEST_NAME} ${XXHASH_LIBRARY})
     endif()
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})

tests/perf/CMakeLists.txt

@@ -6,11 +6,11 @@ set(format_sources
 add_executable(ly_perf ${CMAKE_CURRENT_SOURCE_DIR}/perf.c $<TARGET_OBJECTS:yangobj>)
 set_target_properties(ly_perf PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/tests")
 target_link_libraries(ly_perf ${CMAKE_THREAD_LIBS_INIT} ${PCRE2_LIBRARIES} ${CMAKE_DL_LIBS})
-if (USE_XXHASH)
+if(XXHASH_FOUND)
     target_link_libraries(ly_perf ${XXHASH_LIBRARY})
 endif()
 
-if (NOT WIN32)
+if(NOT WIN32)
     target_link_libraries(ly_perf m)
 endif()
 

tests/style/CMakeLists.txt

@@ -1,15 +1,15 @@
 add_test(NAME headers
     COMMAND ${CMAKE_SOURCE_DIR}/compat/check_includes.sh ${CMAKE_SOURCE_DIR}/src/ ${CMAKE_SOURCE_DIR}/tools/lint/ ${CMAKE_SOURCE_DIR}/tools/re/)
 
-if (${SOURCE_FORMAT_ENABLED})
+if(${SOURCE_FORMAT_ENABLED})
     add_test(NAME format WORKING_DIRECTORY ${CMAKE_BINARY_DIR} COMMAND cmake --build ${CMAKE_BINARY_DIR} --target format-check)
 endif()
 
 # just compile
 add_executable(cpp_compat cpp_compat.c $<TARGET_OBJECTS:yangobj>)
 target_include_directories(cpp_compat BEFORE PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(cpp_compat ${CMAKE_THREAD_LIBS_INIT} ${PCRE2_LIBRARIES} ${CMAKE_DL_LIBS} m)
-if (USE_XXHASH)
+if(XXHASH_FOUND)
     target_link_libraries(cpp_compat ${XXHASH_LIBRARY})
 endif()