Add JSON encoder and decoder

[yaz-moved-to-github.git] / include / yaz / json.h

diff --git a/include/yaz/json.h b/include/yaz/json.h
new file mode 100644 (file)
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--- /dev/null
+++ b/include/yaz/json.h
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+/* This file is part of the YAZ toolkit.
+ * Copyright (C) 1995-2009 Index Data.
+ * All rights reserved.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Index Data nor the names of its contributors
+ *       may be used to endorse or promote products derived from this
+ *       software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file json.h
+    \brief Header for JSON functions
+*/
+
+#ifndef YAZ_JSON_H
+#define YAZ_JSON_H
+#include <yaz/wrbuf.h>
+
+YAZ_BEGIN_CDECL
+
+/** \brief JSON node type for json_node */
+enum json_node_type {
+    json_node_object, /**< JSON object, u.link[0] is object content */
+    json_node_array,  /**< JSON array, u.link[0] is array content */
+    json_node_list,   /**< JSON elements or JSON members,
+                         u.link[0] is value, u.link[1] is next elemen in list */
+    json_node_pair,   /**< JSON pair, u.link[0] is name, u.link[1] is value */
+    json_node_string, /**< JSON string, u.string is content */
+    json_node_number, /**< JSON number (floating point), u.number is content */
+    json_node_true,   /**< JSON true */
+    json_node_false,  /**< JSON false */
+    json_node_null    /**< JSON null */
+};
+
+/** \brief JSON node */
+struct json_node {
+    enum json_node_type type;
+    union {
+        char *string; 
+        double number; 
+        struct json_node *link[2];
+    } u;
+};
+
+/** \brief JSON parser (opaque) */
+typedef struct json_parser_s *json_parser_t;
+
+/** \brief create JSON parser
+    \returns JSON parser handle
+*/
+YAZ_EXPORT
+json_parser_t json_parser_create(void);
+
+/** \brief destroys JSON parser
+    \param p JSON parser handle
+*/
+YAZ_EXPORT
+void json_parser_destroy(json_parser_t p);
+
+/** \brief parses JSON string
+    \param p JSON parser handle
+    \param json_str JSON string
+    \returns JSON tree or NULL if parse error occurred.
+
+    The resulting tree should be removed with a call to json_remove_node.
+*/
+YAZ_EXPORT
+struct json_node *json_parser_parse(json_parser_t p, const char *json_str);
+
+/** \brief returns parser error
+    \param p JSON parser handle
+    \returns parse error msg 
+
+    This function should be called if json_parser_parse returns NULL .
+*/
+YAZ_EXPORT
+const char *json_parser_get_errmsg(json_parser_t p);
+
+/** \brief destroys JSON tree node and its children
+    \param n JSON node
+*/
+YAZ_EXPORT
+void json_remove_node(struct json_node *n);
+
+/** \brief converts JSON tree to JSON string
+    \param node JSON tree
+    \param result resulting JSON string buffer
+*/
+YAZ_EXPORT
+void json_write_wrbuf(struct json_node *node, WRBUF result);
+
+YAZ_END_CDECL
+
+#endif
+
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * c-file-style: "Stroustrup"
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
+