lib: cmetrics: Include a decoder of prometheus remote write

Signed-off-by: Hiroshi Hatake <[email protected]>

lib/cmetrics/include/cmetrics/cmt_decode_prometheus_remote_write.h

@@ -0,0 +1,54 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+
+/*  CMetrics
+ *  ========
+ *  Copyright 2021-2024 The CMetrics Authors
+ *
+ *  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.
+ */
+
+
+#ifndef CMT_DECODE_PROMETHEUS_REMOTE_WRITE_H
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_H
+
+#include <cmetrics/cmetrics.h>
+#include <prometheus_remote_write/remote.pb-c.h>
+
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_SUCCESS                 0
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_ALLOCATION_ERROR        1
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_UNEXPECTED_ERROR        2
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_INVALID_ARGUMENT_ERROR  3
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_UNEXPECTED_METRIC_TYPE  4
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_DECODE_ERROR            5
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_UNPACK_ERROR            6
+#define CMT_DECODE_PROMETHEUS_REMOTE_WRITE_UNSUPPORTED_METRIC_TYPE 7
+
+static void *__cmt_allocator_alloc(void *data, size_t size) {
+    return malloc(size);
+}
+static void __cmt_allocator_free(void *data, void *ptr) {
+    free(ptr);
+}
+
+static ProtobufCAllocator __cmt_allocator = {
+  .alloc = __cmt_allocator_alloc,
+  .free = __cmt_allocator_free,
+  .allocator_data = NULL
+};
+
+#define cmt_system_allocator __cmt_allocator
+
+int cmt_decode_prometheus_remote_write_create(struct cmt **out_cmt, char *in_buf, size_t in_size);
+void cmt_decode_prometheus_remote_write_destroy(struct cmt *cmt);
+
+#endif