New utility functions

util.c

@@ -1,3 +1,5 @@
+#include <stdio.h>
+#include <stdlib.h>
 #include "util.h"
 
 const char *isotime(time_t t) {
@@ -6,3 +8,101 @@ const char *isotime(time_t t) {
         strftime(buf, sizeof(buf), "%FT%TZ", gmtime(&t));
         return(buf);
 }
+
+char *slurp_file(char *filename, int fold_newlines)
+{
+	FILE *fp;
+	char *buf, *bp;
+	off_t len;
+	int ch;
+
+	if ((fp = fopen(filename, "rb")) == NULL)
+		return (NULL);
+
+	if (fseeko(fp, 0, SEEK_END) != 0) {
+		fclose(fp);
+		return (NULL);
+	}
+	len = ftello(fp);
+	fseeko(fp, 0, SEEK_SET);
+
+	if ((bp = buf = malloc(len + 1)) == NULL) {
+		fclose(fp);
+		return (NULL);
+	}
+	while ((ch = fgetc(fp)) != EOF) {
+		if (ch == '\n') {
+			if (!fold_newlines)
+				*bp++ = ch;
+		} else *bp++ = ch;
+	}
+	*bp = 0;
+	fclose(fp);
+
+	return (buf);
+}
+
+int json_copy_to_object(JsonNode * obj, JsonNode * object_or_array)
+{
+	JsonNode *node;
+
+	if (obj->tag != JSON_OBJECT && obj->tag != JSON_ARRAY)
+		return (FALSE);
+
+	/* should we delete keys which already exist in `obj' ? */
+	json_foreach(node, object_or_array) {
+		if (obj->tag == JSON_OBJECT) {
+			if (node->tag == JSON_STRING)
+				json_append_member(obj, node->key, json_mkstring(node->string_));
+			else if (node->tag == JSON_NUMBER)
+				json_append_member(obj, node->key, json_mknumber(node->number_));
+			else if (node->tag == JSON_BOOL)
+				json_append_member(obj, node->key, json_mkbool(node->bool_));
+			else if (node->tag == JSON_NULL)
+				json_append_member(obj, node->key, json_mknull());
+			else if (node->tag == JSON_ARRAY) {
+				JsonNode       *array = json_mkarray();
+				json_copy_to_object(array, node);
+				json_append_member(obj, node->key, array);
+			} else if (node->tag == JSON_OBJECT) {
+				JsonNode       *newobj = json_mkobject();
+				json_copy_to_object(newobj, node);
+				json_append_member(obj, node->key, newobj);
+			} else
+				printf("PANIC: unhandled JSON type %d\n", node->tag);
+		} else if (obj->tag == JSON_ARRAY) {
+			if (node->tag == JSON_STRING)
+				json_append_element(obj, json_mkstring(node->string_));
+			if (node->tag == JSON_NUMBER)
+				json_append_element(obj, json_mknumber(node->number_));
+			if (node->tag == JSON_BOOL)
+				json_append_element(obj, json_mkbool(node->bool_));
+			if (node->tag == JSON_NULL)
+				json_append_element(obj, json_mknull());
+		}
+	}
+	return (TRUE);
+}
+
+/*
+ * Open filename for reading; slurp in the whole file and attempt
+ * to decode JSON from it into the JSON object at `obj'. TRUE on success, FALSE on failure.
+ */
+
+int json_copy_from_file(JsonNode *obj, char *filename)
+{
+	char *js_string;
+	JsonNode *node;
+
+	if ((js_string = slurp_file(filename, TRUE)) != NULL) {
+		if ((node = json_decode(js_string)) == NULL) {
+			fprintf(stderr, "json_copy_from_file can't decode JSON from %s\n", filename);
+			return (FALSE);
+		}
+		json_copy_to_object(obj, node);
+		json_delete(node);
+
+		free(js_string);
+	}
+	return (TRUE);
+}

util.h

@@ -1,8 +1,17 @@
 #ifndef _UTIL_H_INCL_
 # define  _UTIL_H_INCL_
 
+#ifndef TRUE
+# define TRUE (1)
+# define FALSE (0)
+#endif
+
 #include <time.h>
+#include "json.h"
 
 const char *isotime(time_t t);
+char *slurp_file(char *filename, int fold_newlines);
+int json_copy_to_object(JsonNode * obj, JsonNode * object_or_array);
+int json_copy_from_file(JsonNode * obj, char *filename);
 
 #endif