add msgpack_vrefbuffer, msgpack::vrefbuffer

c/vrefbuffer.c

@@ -0,0 +1,135 @@
+/*
+ * MessagePack for C zero-copy buffer implementation
+ *
+ * Copyright (C) 2008-2009 FURUHASHI Sadayuki
+ *
+ *    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.
+ */
+#include "msgpack/vrefbuffer.h"
+#include <stdlib.h>
+#include <string.h>
+
+bool msgpack_vrefbuffer_init(msgpack_vrefbuffer* vbuf,
+		size_t ref_size, size_t chunk_size)
+{
+	if(chunk_size < sizeof(msgpack_vrefbuffer_chunk)+72) {
+		chunk_size = 72;
+	} else {
+		chunk_size -= sizeof(msgpack_vrefbuffer_chunk);
+	}
+
+	vbuf->chunk_size = chunk_size;
+	vbuf->ref_size = ref_size;
+
+	// glibcは72バイト以下のmallocが高速
+	size_t nfirst = (sizeof(struct iovec) < 72/2) ?
+			72 / sizeof(struct iovec) : 8;
+
+	struct iovec* array = (struct iovec*)malloc(
+			sizeof(struct iovec) * nfirst);
+	if(array == NULL) {
+		return false;
+	}
+
+	vbuf->tail  = array;
+	vbuf->end   = array + nfirst;
+	vbuf->array = array;
+
+	vbuf->chunk = (msgpack_vrefbuffer_chunk*)malloc(
+			chunk_size + sizeof(msgpack_vrefbuffer_chunk));
+	if(vbuf->chunk == NULL) {
+		free(array);
+		return false;
+	}
+
+	vbuf->chunk->next = NULL;
+	vbuf->chunk->free = chunk_size;
+
+	return true;
+}
+
+void msgpack_vrefbuffer_destroy(msgpack_vrefbuffer* vbuf)
+{
+	msgpack_vrefbuffer_chunk* c = vbuf->chunk;
+	while(true) {
+		msgpack_vrefbuffer_chunk* n = c->next;
+		free(c);
+		if(n) {
+			c = n;
+		} else {
+			break;
+		}
+	}
+	free(vbuf->array);
+}
+
+int msgpack_vrefbuffer_append_ref(msgpack_vrefbuffer* vbuf,
+		const char* buf, unsigned int len)
+{
+	if(vbuf->tail == vbuf->end) {
+		const size_t nused = vbuf->end - vbuf->array;
+		const size_t nnext = nused * 2;
+
+		struct iovec* nvec = (struct iovec*)realloc(
+				vbuf->array, sizeof(struct iovec)*nnext);
+		if(nvec == NULL) {
+			return -1;
+		}
+
+		vbuf->array = nvec;
+		vbuf->end   = nvec + nnext;
+		vbuf->tail  = nvec + nused;
+	}
+
+	vbuf->tail->iov_base = (char*)buf;
+	vbuf->tail->iov_len  = len;
+	++vbuf->tail;
+
+	return 0;
+}
+
+int msgpack_vrefbuffer_append_copy(msgpack_vrefbuffer* vbuf,
+		const char* buf, unsigned int len)
+{
+	msgpack_vrefbuffer_chunk* chunk = vbuf->chunk;
+	size_t cur_size = vbuf->chunk_size;
+
+	if(chunk->free < len) {
+		cur_size = (cur_size > len) ? cur_size : len;
+
+		chunk = (msgpack_vrefbuffer_chunk*)malloc(
+				cur_size + sizeof(msgpack_vrefbuffer_chunk));
+		if(chunk == NULL) {
+			return -1;
+		}
+
+		chunk->free = cur_size;
+		chunk->next = vbuf->chunk;
+		vbuf->chunk = chunk;
+	}
+
+	char* m = ((char*)chunk) + sizeof(msgpack_vrefbuffer_chunk)
+		+ (cur_size - chunk->free);
+
+	memcpy(m, buf, len);
+	chunk->free -= len;
+
+	if(vbuf->tail != vbuf->array && m ==
+			(const char*)((vbuf->tail-1)->iov_base) + (vbuf->tail-1)->iov_len) {
+		(vbuf->tail-1)->iov_len += len;
+		return 0;
+	} else {
+		return msgpack_vrefbuffer_append_ref(vbuf, m, len);
+	}
+}
+