This will be used for the first time in an upcoming commit.
Signed-off-by: Ben Pfaff <b...@nicira.com>
---
lib/json.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
lib/json.h | 4 +-
tests/test-json.c | 3 +-
3 files changed, 129 insertions(+), 3 deletions(-)
diff --git a/lib/json.c b/lib/json.c
index 5c96851..457d72d 100644
--- a/lib/json.c
+++ b/lib/json.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2009, 2010, 2011, 2012 Nicira, Inc.
+ * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -1639,3 +1639,126 @@ json_serialize_string(const char *string, struct ds *ds)
}
ds_put_char(ds, '"');
}
+
+static size_t
+json_string_serialized_length(const char *string)
+{
+ size_t length;
+ uint8_t c;
+
+ /* "" */
+ length = 2;
+
+ while ((c = *string++) != '\0') {
+ switch (c) {
+ case '"':
+ case '\\':
+ case '\b':
+ case '\f':
+ case '\n':
+ case '\r':
+ case '\t':
+ length += 2;
+ break;
+
+ default:
+ if (c >= 32) {
+ length++;
+ } else {
+ /* \uXXXX */
+ length += 6;
+ }
+ break;
+ }
+ }
+
+ return length;
+}
+
+static size_t
+json_object_serialized_length(const struct shash *object)
+{
+ size_t length;
+
+ /* {} */
+ length = 2;
+
+ if (!shash_is_empty(object)) {
+ struct shash_node *node;
+
+ /* Commas and colons. */
+ length += 2 * shash_count(object) - 1;
+
+ SHASH_FOR_EACH (node, object) {
+ const struct json *value = node->data;
+
+ length += json_string_serialized_length(node->name);
+ length += json_serialized_length(value);
+ }
+ }
+
+ return length;
+}
+
+static size_t
+json_array_serialized_length(const struct json_array *array)
+{
+ size_t length;
+
+ /* [] */
+ length = 2;
+
+ if (array->n) {
+ size_t i;
+
+ /* Commas. */
+ length += array->n - 1;
+
+ for (i = 0; i < array->n; i++) {
+ length += json_serialized_length(array->elems[i]);
+ }
+ }
+
+ return length;
+}
+
+/* Returns strlen(json_to_string(json, 0)).
+ *
+ * JSSF_SORT does not affect the length of json_to_string()'s output, but
+ * JSSF_PRETTY does. */
+size_t
+json_serialized_length(const struct json *json)
+{
+ switch (json->type) {
+ case JSON_NULL:
+ return strlen("null");
+ break;
+
+ case JSON_FALSE:
+ return strlen("false");
+ break;
+
+ case JSON_TRUE:
+ return strlen("true");
+ break;
+
+ case JSON_OBJECT:
+ return json_object_serialized_length(json->u.object);
+
+ case JSON_ARRAY:
+ return json_array_serialized_length(&json->u.array);
+
+ case JSON_INTEGER:
+ return snprintf(NULL, 0, "%lld", json->u.integer);
+
+ case JSON_REAL:
+ return snprintf(NULL, 0, "%.*g", DBL_DIG, json->u.real);
+
+ case JSON_STRING:
+ return json_string_serialized_length(json->u.string);
+
+ case JSON_N_TYPES:
+ default:
+ NOT_REACHED();
+ }
+}
diff --git a/lib/json.h b/lib/json.h
index cfe9457..ef23124 100644
--- a/lib/json.h
+++ b/lib/json.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2009, 2010 Nicira, Inc.
+ * Copyright (c) 2009, 2010, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -127,6 +127,8 @@ enum {
};
char *json_to_string(const struct json *, int flags);
void json_to_ds(const struct json *, int flags, struct ds *);
+
+size_t json_serialized_length(const struct json *);
/* JSON string formatting operations. */
diff --git a/tests/test-json.c b/tests/test-json.c
index c7c01c8..24bc745 100644
--- a/tests/test-json.c
+++ b/tests/test-json.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2009, 2010 Nicira, Inc.
+ * Copyright (c) 2009, 2010, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -42,6 +42,7 @@ print_and_free_json(struct json *json)
ok = false;
} else {
char *s = json_to_string(json, JSSF_SORT | (pretty ? JSSF_PRETTY : 0));
+ ovs_assert(pretty || json_serialized_length(json) == strlen(s));
puts(s);
free(s);
ok = true;
--
1.7.2.5
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