Add C API

CMakeLists.txt

@@ -287,3 +287,4 @@ add_custom_target (version
                    -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/GenerateVersionHeader.cmake
   )
 add_dependencies (vsag version)
+add_dependencies (vsag_static version)

README.md

@@ -33,6 +33,8 @@ include_directories (vsag-cmake-example PRIVATE ${vsag_SOURCE_DIR}/include)
 # compile executable and link to vsag
 add_executable (vsag-cmake-example src/main.cpp)
 target_link_libraries (vsag-cmake-example PRIVATE vsag)
+# If you want static linking
+# target_link_libraries (vsag-cmake-example PRIVATE vsag_static)
 
 # add dependency
 add_dependencies (vsag-cmake-example vsag)

include/vsag/c.h

@@ -0,0 +1,85 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifndef VSAG_MAX_ERROR_MESSAGE_LENGTH
+#define VSAG_MAX_ERROR_MESSAGE_LENGTH 256
+#endif
+
+typedef struct CError {
+    int type_;
+    char message[VSAG_MAX_ERROR_MESSAGE_LENGTH];
+} CError;
+
+CError*
+new_error(int type_, const char* msg);
+void
+free_error(const CError*);
+
+const CError*
+create_index(const char* in_index_type,
+             const char* in_parameters,
+
+             void** out_index_ptr);
+
+const CError*
+build_index(void* in_index_ptr,
+            size_t in_num_vectors,
+            size_t in_dim,
+            const int64_t* in_ids,
+            const float* in_vectors,
+
+            const int64_t** out_failed_ids,
+            size_t* out_num_failed);
+
+const CError*
+knn_search_index(void* in_index_ptr,
+                 size_t in_dim,
+                 const float* in_query_vector,
+                 size_t in_k,
+                 const char* in_search_parameters,
+
+                 const int64_t** out_ids,
+                 const float** out_distances,
+                 size_t* out_num_results);
+
+const CError*
+dump_index(void* in_index_ptr, const char* in_file_path);
+
+const CError*
+load_index(const char* in_file_path,
+           const char* in_index_type,
+           const char* in_parameters,
+
+           void** out_index_ptr);
+
+void
+free_index(void* index_ptr);
+void
+free_i64_vector(int64_t* vector);
+void
+free_f32_vector(float* vector);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif