Format JSON ourselves, without json-c.

To make the library thinner, we now format JSON ourselves: there was
so little we used from json-c, that doing it ourselves is lighter and
faster.

With this commit, we have the architecture in place, with only a few
little things remaining to be done, such as escaping string values.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>

1 files changed, 94 insertions, 0 deletions

diff --git a/lib/buffer.c b/lib/buffer.c
new file mode 100644
index 0000000..4f795eb
--- /dev/null
+++ b/lib/buffer.c
@@ -0,0 +1,94 @@
+/* buffer.c -- Auto-growing string buffers
+ *
+ * Copyright (c) 2012 BalaBit IT Security Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY BALABIT 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 BALABIT OR 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.
+ */
+
+#define _GNU_SOURCE 1
+
+#include "config.h"
+#include "buffer.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static inline ul_buffer_t *
+_ul_buffer_ensure_size (ul_buffer_t *buffer, size_t size)
+{
+  if (buffer->alloc < size)
+    {
+      buffer->alloc += size * 2;
+      buffer->msg = realloc (buffer->msg, buffer->alloc);
+      if (!buffer->msg)
+        return NULL;
+    }
+  return buffer;
+}
+
+ul_buffer_t *
+ul_buffer_reset (ul_buffer_t *buffer)
+{
+  buffer->len = 1;
+  _ul_buffer_ensure_size (buffer, 512);
+  buffer->msg[0] = '{';
+  return buffer;
+}
+
+ul_buffer_t *
+ul_buffer_append (ul_buffer_t *buffer, const char *key, const char *value)
+{
+  size_t lk, lv;
+
+  lk = strlen (key);
+  lv = strlen (value);
+
+  buffer = _ul_buffer_ensure_size (buffer, buffer->len + lk + lv + 6);
+  if (!buffer)
+    return NULL;
+
+  /* FIXME: Escpae stuff here */
+
+  memcpy (buffer->msg + buffer->len, "\"", 1);
+  memcpy (buffer->msg + buffer->len + 1, key, lk);
+  memcpy (buffer->msg + buffer->len + 1 + lk, "\":\"", 3);
+  memcpy (buffer->msg + buffer->len + 1 + lk + 3, value, lv);
+  memcpy (buffer->msg + buffer->len + 1 + lk + 3 + lv, "\",", 2);
+  buffer->len += lk + lv + 6;
+
+  return buffer;
+}
+
+char *
+ul_buffer_finalize (ul_buffer_t *buffer)
+{
+  if (buffer->msg[buffer->len] == ',')
+    buffer->msg[buffer->len] = '}';
+  else
+    {
+      if (!_ul_buffer_ensure_size (buffer, buffer->len + 1))
+        return NULL;
+      buffer->msg[buffer->len++] = '}';
+    }
+  return buffer->msg;
+}