Utility functions and test program for JSON processing.

jsonutil.c

@@ -0,0 +1,34 @@
+#include <string.h>
+#include "jsonutil.h"
+
+json_value *findEntryInObject(json_value *obj, json_char *name, json_type type) {
+    if (obj == NULL || obj->type != json_object)
+        return NULL;
+    json_object_entry *entry = obj->u.object.values;
+    for (unsigned int i = 0; i < obj->u.object.length; i++,entry++) {
+        if (entry->name_length != strlen(name)) {
+            continue;
+        }
+        if (memcmp(name, entry->name, entry->name_length) == 0) {
+            if (entry->value->type == type)
+                return entry->value;
+            else
+                return NULL;
+        }
+    }
+    return NULL;
+}
+
+
+boolean processArray(json_value *arr, json_type member_type, boolean (*f)(json_value*)) {
+    if (arr == NULL || arr->type != json_array)
+        return false;
+    for (unsigned int i = 0; i < arr->u.array.length; i++) {
+        json_value *v = arr->u.array.values[i];
+        if (v->type != member_type)
+            continue;
+        if (f(v) == false)
+            return false;
+    }
+    return true;
+}

jsonutil.h

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+#ifndef JSONUTIL_H
+#define JSONUTIL_H
+
+#include "json.h"
+
+#ifdef __ORCAC__
+#include <types.h>
+#else
+#include <stdbool.h>
+typedef _Bool boolean;
+#endif
+
+/*
+ * Find an entry with specified name and type in a json object.
+ */
+json_value *findEntryInObject(json_value *obj, json_char *name, json_type type);
+
+/*
+ * Call f on each member of type member_type in a json array.
+ * Stops and returns false if any call to f returns false.
+ */
+boolean processArray(json_value *arr, json_type member_type, boolean (*f)(json_value*));
+
+#endif

test.c

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+#pragma lint -1
+
+#include <stdio.h>
+#include <string.h>
+#include "json.h"
+#include "jsonutil.h"
+
+char jsonData[] = "{\"responseHeader\":{\"status\":0,\"QTime\":10,\"params\":{\"query\":\"emulator:apple2gs\",\"qin\":\"emulator:apple2gs\",\"fields\":\"identifier,title\",\"wt\":\"json\",\"rows\":\"3\",\"json.wrf\":\"callback\",\"start\":0}},\"response\":{\"numFound\":2428,\"start\":0,\"docs\":[{\"identifier\":\"TypeWest_disk_1_no_boot\",\"title\":\"TypeWest disk 1 (no boot)\"},{\"identifier\":\"a2gs_mindshadow\",\"title\":\"Mindshadow\"},{\"identifier\":\"a2gs_Impossible_Mission_II_1989_Epyx_a\",\"title\":\"Apple IIgs: Impossible Mission II (1989)(Epyx)[a]\"}]}}";
+
+
+boolean processDoc(json_value *docObj) {
+    if (docObj == NULL || docObj->type != json_object)
+        return false;
+    json_value *id = findEntryInObject(docObj, "identifier", json_string);
+    json_value *title = findEntryInObject(docObj, "title", json_string);
+    if (id == NULL || title == NULL)
+        return true;
+    printf("Document:\n");
+    printf("  id = %s\n", id->u.string.ptr);
+    printf("  title = %s\n", title->u.string.ptr);
+    return true;
+}
+
+
+int main(void) {
+    json_value *value = json_parse(jsonData, sizeof(jsonData)-1);
+
+    if (value == NULL)
+        return -1;
+    
+    json_value *response = findEntryInObject(value, "response", json_object);
+    
+    json_value *numFound = findEntryInObject(response, "numFound", json_integer);
+    if (numFound != NULL) {
+        printf("numFound = %li\n", (long)numFound->u.integer);
+    }
+    
+    json_value *docs = findEntryInObject(response, "docs", json_array);
+    processArray(docs, json_object, processDoc);
+    
+    json_value_free(value);
+}