+/* This file is part of the YAZ toolkit.
+ * Copyright (C) 1995-2009 Index Data
+ * See the file LICENSE for details.
+ */
+
+/**
+ * \file json.c
+ * \brief JSON encoding/decoding
+ */
+
+#include <yaz/json.h>
+
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+
+#include <yaz/xmalloc.h>
+
+struct json_parser_s {
+ const char *buf;
+ const char *cp;
+ const char *err_msg;
+};
+
+json_parser_t json_parser_create(void)
+{
+ json_parser_t p = (json_parser_t) xmalloc(sizeof(*p));
+
+ p->buf = 0;
+ p->cp = 0;
+ p->err_msg = 0;
+ return p;
+}
+
+void json_parser_destroy(json_parser_t p)
+{
+ xfree(p);
+}
+
+static int look_ch(json_parser_t p)
+{
+ while (*p->cp && strchr(" \t\r\n\f", *p->cp))
+ (p->cp)++;
+ return *p->cp;
+}
+
+static void move_ch(json_parser_t p)
+{
+ if (*p->cp)
+ (p->cp)++;
+}
+
+static struct json_node *json_new_node(json_parser_t p, enum json_node_type type)
+{
+ struct json_node *n = (struct json_node *) xmalloc(sizeof(*n));
+ n->type = type;
+ n->u.link[0] = n->u.link[1] = 0;
+ return n;
+}
+
+void json_remove_node(struct json_node *n)
+{
+ if (!n)
+ return;
+ switch (n->type)
+ {
+ case json_node_object:
+ case json_node_array:
+ case json_node_list:
+ case json_node_pair:
+ json_remove_node(n->u.link[0]);
+ json_remove_node(n->u.link[1]);
+ break;
+ case json_node_string:
+ xfree(n->u.string);
+ break;
+ case json_node_number:
+ case json_node_true:
+ case json_node_false:
+ case json_node_null:
+ break;
+ }
+ xfree(n);
+}
+
+static struct json_node *json_parse_object(json_parser_t p);
+static struct json_node *json_parse_array(json_parser_t p);
+
+static int json_one_char(const char **p, char *out)
+{
+ if (**p == '\\' && p[0][1])
+ {
+ (*p)++;
+ switch(**p)
+ {
+ case '"':
+ *out = '"'; break;
+ case '\\':
+ *out = '\\'; break;
+ case '/':
+ *out = '/'; break;
+ case 'b':
+ *out = '\b'; break;
+ case 'f':
+ *out = '\b'; break;
+ case 'n':
+ *out = '\n'; break;
+ case 'r':
+ *out = '\r'; break;
+ case 't':
+ *out = '\t'; break;
+ case 'u':
+ if (p[0][1])
+ {
+ unsigned code;
+ char *outp = out;
+ int error;
+ size_t outbytesleft = 6;
+ sscanf(*p + 1, "%4x", &code);
+ if (!yaz_write_UTF8_char(code, &outp, &outbytesleft, &error))
+ {
+ *p += 5;
+ return outp - out;
+ }
+ }
+ default:
+ *out = '_'; break;
+ break;
+ }
+ (*p)++;
+ return 1;
+ }
+ else
+ {
+ *out = **p;
+ (*p)++;
+ return 1;
+ }
+}
+
+static struct json_node *json_parse_string(json_parser_t p)
+{
+ struct json_node *n;
+ const char *cp;
+ char *dst;
+ int l = 0;
+ if (look_ch(p) != '\"')
+ {
+ p->err_msg = "string expected";
+ return 0;
+ }
+ move_ch(p);
+
+ cp = p->cp;
+ while (*cp && *cp != '"')
+ {
+ char out[6];
+ l += json_one_char(&cp, out);
+ }
+ if (!*cp)
+ {
+ p->err_msg = "missing \"";
+ return 0;
+ }
+ n = json_new_node(p, json_node_string);
+ dst = n->u.string = (char *) xmalloc(l + 1);
+
+ cp = p->cp;
+ while (*cp && *cp != '"')
+ {
+ char out[6];
+
+ l = json_one_char(&cp, out);
+ memcpy(dst, out, l);
+ dst += l;
+ }
+ *dst = '\0';
+ p->cp = cp+1;
+ return n;
+}
+
+static struct json_node *json_parse_number(json_parser_t p)
+{
+ struct json_node *n;
+ char *endptr;
+ double v;
+
+ look_ch(p); // skip spaces
+ v = strtod(p->cp, &endptr);
+
+ if (endptr == p->cp)
+ {
+ p->err_msg = "bad number";
+ return 0;
+ }
+ p->cp = endptr;
+ n = json_new_node(p, json_node_number);
+ n->u.number = v;
+ return n;
+}
+
+static struct json_node *json_parse_value(json_parser_t p)
+{
+ int c = look_ch(p);
+ if (c == '\"')
+ return json_parse_string(p);
+ else if (strchr("0123456789-+", c))
+ return json_parse_number(p);
+ else if (c == '{')
+ return json_parse_object(p);
+ else if (c == '[')
+ return json_parse_array(p);
+ else
+ {
+ char tok[8];
+ int i = 0;
+ while (c >= 'a' && c <= 'z' && i < 7)
+ {
+ tok[i++] = c;
+ p->cp++;
+ c = *p->cp;
+ }
+ tok[i] = 0;
+ if (!strcmp(tok, "true"))
+ return json_new_node(p, json_node_true);
+ else if (!strcmp(tok, "false"))
+ return json_new_node(p, json_node_false);
+ else if (!strcmp(tok, "null"))
+ return json_new_node(p, json_node_null);
+ else
+ {
+ p->err_msg = "bad value";
+ return 0;
+ }
+ }
+}
+
+static struct json_node *json_parse_elements(json_parser_t p)
+{
+ struct json_node *n1 = json_parse_value(p);
+ struct json_node *m0, *m1;
+ if (!n1)
+ return 0;
+ m0 = m1 = json_new_node(p, json_node_list);
+ m1->u.link[0] = n1;
+ while (look_ch(p) == ',')
+ {
+ struct json_node *n2, *m2;
+ move_ch(p);
+ n2 = json_parse_value(p);
+ if (!n2)
+ {
+ json_remove_node(m0);
+ return 0;
+ }
+ m2 = json_new_node(p, json_node_list);
+ m2->u.link[0] = n2;
+
+ m1->u.link[1] = m2;
+ m1 = m2;
+ }
+ return m0;
+}
+
+static struct json_node *json_parse_array(json_parser_t p)
+{
+ struct json_node *n;
+ if (look_ch(p) != '[')
+ {
+ p->err_msg = "expecting [";
+ return 0;
+ }
+ move_ch(p);
+ n = json_new_node(p, json_node_array);
+ if (look_ch(p) != ']')
+ n->u.link[0] = json_parse_elements(p);
+
+ if (look_ch(p) != ']')
+ {
+ p->err_msg = "expecting ]";
+ json_remove_node(n);
+ return 0;
+ }
+ move_ch(p);
+ return n;
+}
+
+static struct json_node *json_parse_pair(json_parser_t p)
+{
+ struct json_node *s = json_parse_string(p);
+ struct json_node *v, *n;
+ if (!s)
+ return 0;
+ if (look_ch(p) != ':')
+ {
+ json_remove_node(s);
+ return 0;
+ }
+ move_ch(p);
+ v = json_parse_value(p);
+ if (!v)
+ {
+ json_remove_node(s);
+ return 0;
+ }
+ n = json_new_node(p, json_node_pair);
+ n->u.link[0] = s;
+ n->u.link[1] = v;
+ return n;
+}
+
+static struct json_node *json_parse_members(json_parser_t p)
+{
+ struct json_node *n1 = json_parse_pair(p);
+ struct json_node *m0, *m1;
+ if (!n1)
+ return 0;
+ m0 = m1 = json_new_node(p, json_node_list);
+ m1->u.link[0] = n1;
+ while (look_ch(p) == ',')
+ {
+ struct json_node *n2, *m2;
+ move_ch(p);
+ n2 = json_parse_pair(p);
+ if (!n2)
+ {
+ json_remove_node(m0);
+ return 0;
+ }
+ m2 = json_new_node(p, json_node_list);
+ m2->u.link[0] = n2;
+
+ m1->u.link[1] = m2;
+ m1 = m2;
+ }
+ return m0;
+}
+
+static struct json_node *json_parse_object(json_parser_t p)
+{
+ struct json_node *n;
+ if (look_ch(p) != '{')
+ {
+ p->err_msg = "{ expected";
+ return 0;
+ }
+ move_ch(p);
+
+ n = json_new_node(p, json_node_object);
+ if (look_ch(p) != '}')
+ {
+ struct json_node *m = json_parse_members(p);
+ if (!m)
+ {
+ json_remove_node(n);
+ return 0;
+ }
+ n->u.link[0] = m;
+ }
+ if (look_ch(p) != '}')
+ {
+ p->err_msg = "Missing }";
+ json_remove_node(n);
+ return 0;
+ }
+ move_ch(p);
+ return n;
+}
+
+struct json_node *json_parser_parse(json_parser_t p, const char *json_str)
+{
+ int c;
+ struct json_node *n;
+ p->buf = json_str;
+ p->cp = p->buf;
+
+ n = json_parse_object(p);
+ c = look_ch(p);
+ if (c != 0)
+ {
+ p->err_msg = "extra characters";
+ json_remove_node(n);
+ return 0;
+ }
+ return n;
+}
+
+void json_write_wrbuf(struct json_node *node, WRBUF result)
+{
+ switch (node->type)
+ {
+ case json_node_object:
+ wrbuf_puts(result, "{");
+ if (node->u.link[0])
+ json_write_wrbuf(node->u.link[0], result);
+ wrbuf_puts(result, "}");
+ break;
+ case json_node_array:
+ wrbuf_puts(result, "[");
+ if (node->u.link[0])
+ json_write_wrbuf(node->u.link[0], result);
+ wrbuf_puts(result, "]");
+ break;
+ case json_node_list:
+ json_write_wrbuf(node->u.link[0], result);
+ if (node->u.link[1])
+ {
+ wrbuf_puts(result, ",");
+ json_write_wrbuf(node->u.link[1], result);
+ }
+ break;
+ case json_node_pair:
+ json_write_wrbuf(node->u.link[0], result);
+ wrbuf_puts(result, ":");
+ json_write_wrbuf(node->u.link[1], result);
+ break;
+ case json_node_string:
+ wrbuf_puts(result, "\"");
+ wrbuf_puts(result, node->u.string);
+ wrbuf_puts(result, "\"");
+ break;
+ case json_node_number:
+ wrbuf_printf(result, "%lg", node->u.number);
+ break;
+ case json_node_true:
+ wrbuf_puts(result, "true");
+ break;
+ case json_node_false:
+ wrbuf_puts(result, "false");
+ break;
+ case json_node_null:
+ wrbuf_puts(result, "null");
+ break;
+ }
+}
+
+const char *json_parser_get_errmsg(json_parser_t p)
+{
+ return p->err_msg;
+}
+
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * c-file-style: "Stroustrup"
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
projects / yaz-moved-to-github.git / commitdiff