Initial OpenECOMP Demo commit

Change-Id: Ibf8696196a7ac2c84ac8aa7cde1982c9c89fb64d
Signed-off-by: platania <platania@research.att.com>

1 files changed, 853 insertions, 0 deletions

diff --git a/vnfs/VES/code/evel_library/evel_json_buffer.c b/vnfs/VES/code/evel_library/evel_json_buffer.c
new file mode 100644
index 00000000..7ae3453b
--- /dev/null
+++ b/vnfs/VES/code/evel_library/evel_json_buffer.c
@@ -0,0 +1,853 @@
+/**************************************************************************//**
+ * @file
+ * Source module relating to internal EVEL_JSON_BUFFER manipulation functions.
+ *
+ * License
+ * -------
+ *
+ * Copyright(c) <2016>, AT&T Intellectual Property.  All other 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:  This product includes
+ *    software developed by the AT&T.
+ * 4. Neither the name of AT&T nor the names of its contributors may be used to
+ *    endorse or promote products derived from this software without specific
+ *    prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY AT&T INTELLECTUAL PROPERTY ''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 AT&T INTELLECTUAL PROPERTY 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.
+ *****************************************************************************/
+
+#include <assert.h>
+#include <string.h>
+
+#include "evel_throttle.h"
+
+/*****************************************************************************/
+/* Local prototypes.                                                         */
+/*****************************************************************************/
+static char * evel_json_kv_comma(EVEL_JSON_BUFFER * jbuf);
+
+/**************************************************************************//**
+ * Initialize a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to the ::EVEL_JSON_BUFFER to initialise.
+ * @param json          Pointer to the underlying working buffer to use.
+ * @param max_size      Size of storage available in the JSON buffer.
+ * @param throttle_spec Pointer to throttle specification. Can be NULL.
+ *****************************************************************************/
+void evel_json_buffer_init(EVEL_JSON_BUFFER * jbuf,
+                           char * const json,
+                           const int max_size,
+                           EVEL_THROTTLE_SPEC * throttle_spec)
+{
+  EVEL_ENTER();
+
+  assert(jbuf != NULL);
+  assert(json != NULL);
+  jbuf->json = json;
+  jbuf->max_size = max_size;
+  jbuf->offset = 0;
+  jbuf->throttle_spec = throttle_spec;
+  jbuf->depth = 0;
+  jbuf->checkpoint = -1;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode an integer value to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param value         The integer to add to it.
+ *****************************************************************************/
+void evel_enc_int(EVEL_JSON_BUFFER * jbuf,
+                  const int value)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%d", value);
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a string key and string value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param option        Pointer to holder of the corresponding value to encode.
+ * @return true if the key, value was added, false if it was suppressed.
+ *****************************************************************************/
+bool evel_enc_kv_opt_string(EVEL_JSON_BUFFER * jbuf,
+                            const char * const key,
+                            const EVEL_OPTION_STRING * const option)
+{
+  bool added = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(option != NULL);
+
+  if (option->is_set)
+  {
+    if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+        (jbuf->throttle_spec != NULL) &&
+        evel_throttle_suppress_field(jbuf->throttle_spec, key))
+    {
+      EVEL_INFO("Suppressed: %s, %s", key, option->value);
+    }
+    else
+    {
+      EVEL_DEBUG("Encoded: %s, %s", key, option->value);
+      evel_enc_kv_string(jbuf, key, option->value);
+      added = true;
+    }
+  }
+
+  EVEL_EXIT();
+
+  return added;
+}
+
+/**************************************************************************//**
+ * Encode a string key and string value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param value         Pointer to the corresponding value to encode.
+ *****************************************************************************/
+void evel_enc_kv_string(EVEL_JSON_BUFFER * jbuf,
+                        const char * const key,
+                        const char * const value)
+{
+  int index;
+  int length;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": \"",
+                           evel_json_kv_comma(jbuf),
+                           key);
+
+  /***************************************************************************/
+  /* We need to escape quotation marks and backslashes in the value.         */
+  /***************************************************************************/
+  length = strlen(value);
+
+  for (index = 0; index < length; index++)
+  {
+    /*************************************************************************/
+    /* Drop out if no more space.                                            */
+    /*************************************************************************/
+    if (jbuf->max_size - jbuf->offset < 2)
+    {
+      break;
+    }
+
+    /*************************************************************************/
+    /* Add an escape character if necessary, then write the character        */
+    /* itself.                                                               */
+    /*************************************************************************/
+    if ((value[index] == '\"') || (value[index] == '\\'))
+    {
+      jbuf->json[jbuf->offset] = '\\';
+      jbuf->offset++;
+    }
+
+    jbuf->json[jbuf->offset] = value[index];
+    jbuf->offset++;
+  }
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "\"");
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a string key and integer value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param option        Pointer to holder of the corresponding value to encode.
+ * @return true if the key, value was added, false if it was suppressed.
+ *****************************************************************************/
+bool evel_enc_kv_opt_int(EVEL_JSON_BUFFER * jbuf,
+                         const char * const key,
+                         const EVEL_OPTION_INT * const option)
+{
+  bool added = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(option != NULL);
+
+  if (option->is_set)
+  {
+    if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+        (jbuf->throttle_spec != NULL) &&
+        evel_throttle_suppress_field(jbuf->throttle_spec, key))
+    {
+      EVEL_INFO("Suppressed: %s, %d", key, option->value);
+    }
+    else
+    {
+      EVEL_DEBUG("Encoded: %s, %d", key, option->value);
+      evel_enc_kv_int(jbuf, key, option->value);
+      added = true;
+    }
+  }
+
+  EVEL_EXIT();
+
+  return added;
+}
+
+/**************************************************************************//**
+ * Encode a string key and integer value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param value         The corresponding value to encode.
+ *****************************************************************************/
+void evel_enc_kv_int(EVEL_JSON_BUFFER * jbuf,
+                     const char * const key,
+                     const int value)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": %d",
+                           evel_json_kv_comma(jbuf),
+                           key,
+                           value);
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a string key and double value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param option        Pointer to holder of the corresponding value to encode.
+ * @return true if the key, value was added, false if it was suppressed.
+ *****************************************************************************/
+bool evel_enc_kv_opt_double(EVEL_JSON_BUFFER * jbuf,
+                            const char * const key,
+                            const EVEL_OPTION_DOUBLE * const option)
+{
+  bool added = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(option != NULL);
+
+  if (option->is_set)
+  {
+    if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+        (jbuf->throttle_spec != NULL) &&
+        evel_throttle_suppress_field(jbuf->throttle_spec, key))
+    {
+      EVEL_INFO("Suppressed: %s, %1f", key, option->value);
+    }
+    else
+    {
+      EVEL_DEBUG("Encoded: %s, %1f", key, option->value);
+      evel_enc_kv_double(jbuf, key, option->value);
+      added = true;
+    }
+  }
+
+  EVEL_EXIT();
+
+  return added;
+}
+
+/**************************************************************************//**
+ * Encode a string key and double value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param value         The corresponding value to encode.
+ *****************************************************************************/
+void evel_enc_kv_double(EVEL_JSON_BUFFER * jbuf,
+                        const char * const key,
+                        const double value)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": %1f",
+                           evel_json_kv_comma(jbuf),
+                           key,
+                           value);
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a string key and unsigned long long value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param option        Pointer to holder of the corresponding value to encode.
+ * @return true if the key, value was added, false if it was suppressed.
+ *****************************************************************************/
+bool evel_enc_kv_opt_ull(EVEL_JSON_BUFFER * jbuf,
+                         const char * const key,
+                         const EVEL_OPTION_ULL * const option)
+{
+  bool added = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(option != NULL);
+
+  if (option->is_set)
+  {
+    if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+        (jbuf->throttle_spec != NULL) &&
+        evel_throttle_suppress_field(jbuf->throttle_spec, key))
+    {
+      EVEL_INFO("Suppressed: %s, %1lu", key, option->value);
+    }
+    else
+    {
+      EVEL_DEBUG("Encoded: %s, %1lu", key, option->value);
+      evel_enc_kv_ull(jbuf, key, option->value);
+      added = true;
+    }
+  }
+
+  EVEL_EXIT();
+
+  return added;
+}
+
+/**************************************************************************//**
+ * Encode a string key and unsigned long long value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param value         The corresponding value to encode.
+ *****************************************************************************/
+void evel_enc_kv_ull(EVEL_JSON_BUFFER * jbuf,
+                     const char * const key,
+                     const unsigned long long value)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": %llu",
+                           evel_json_kv_comma(jbuf),
+                           key,
+                           value);
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a string key and time value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param option        Pointer to holder of the corresponding value to encode.
+ * @return true if the key, value was added, false if it was suppressed.
+ *****************************************************************************/
+bool evel_enc_kv_opt_time(EVEL_JSON_BUFFER * jbuf,
+                          const char * const key,
+                          const EVEL_OPTION_TIME * const option)
+{
+  bool added = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(option != NULL);
+
+  if (option->is_set)
+  {
+    if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+        (jbuf->throttle_spec != NULL) &&
+        evel_throttle_suppress_field(jbuf->throttle_spec, key))
+    {
+      EVEL_INFO("Suppressed time: %s", key);
+    }
+    else
+    {
+      EVEL_DEBUG("Encoded time: %s", key);
+      evel_enc_kv_time(jbuf, key, &option->value);
+      added = true;
+    }
+  }
+
+  EVEL_EXIT();
+
+  return added;
+}
+
+/**************************************************************************//**
+ * Encode a string key and time value to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param time          Pointer to the time to encode.
+ *****************************************************************************/
+void evel_enc_kv_time(EVEL_JSON_BUFFER * jbuf,
+                      const char * const key,
+                      const time_t * time)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+  assert(time != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": \"",
+                           evel_json_kv_comma(jbuf),
+                           key);
+  jbuf->offset += strftime(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           EVEL_RFC2822_STRFTIME_FORMAT,
+                           localtime(time));
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "\"");
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a key and version.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @param major_version The major version to encode.
+ * @param minor_version The minor version to encode.
+ *****************************************************************************/
+void evel_enc_version(EVEL_JSON_BUFFER * jbuf,
+                      const char * const key,
+                      const int major_version,
+                      const int minor_version)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  evel_enc_kv_int(jbuf, key, major_version);
+  if (minor_version != 0)
+  {
+    jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                             jbuf->max_size - jbuf->offset,
+                             ".%d",
+                             minor_version);
+  }
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Add the key and opening bracket of an optional named list to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @return true if the list was opened, false if it was suppressed.
+ *****************************************************************************/
+bool evel_json_open_opt_named_list(EVEL_JSON_BUFFER * jbuf,
+                                   const char * const key)
+{
+  bool opened = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+      (jbuf->throttle_spec != NULL) &&
+      evel_throttle_suppress_field(jbuf->throttle_spec, key))
+  {
+    EVEL_INFO("Suppressed: %s", key);
+    opened = false;
+  }
+  else
+  {
+    evel_json_open_named_list(jbuf, key);
+    opened = true;
+  }
+
+  EVEL_EXIT();
+
+  return opened;
+}
+
+/**************************************************************************//**
+ * Add the key and opening bracket of a named list to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ *****************************************************************************/
+void evel_json_open_named_list(EVEL_JSON_BUFFER * jbuf,
+                               const char * const key)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": [",
+                           evel_json_kv_comma(jbuf),
+                           key);
+  jbuf->depth++;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Add the closing bracket of a list to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ *****************************************************************************/
+void evel_json_close_list(EVEL_JSON_BUFFER * jbuf)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "]");
+  jbuf->depth--;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Encode a list item with format and param list to a ::EVEL_JSON_BUFFER.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param format        Format string in standard printf format.
+ * @param ...           Variable parameters for format string.
+ *****************************************************************************/
+void evel_enc_list_item(EVEL_JSON_BUFFER * jbuf,
+                        const char * const format,
+                        ...)
+{
+  va_list largs;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(format != NULL);
+
+  /***************************************************************************/
+  /* Add a comma unless we're at the start of the list.                      */
+  /***************************************************************************/
+  if (jbuf->json[jbuf->offset - 1] != '[')
+  {
+    jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                             jbuf->max_size - jbuf->offset,
+                             ", ");
+  }
+
+  va_start(largs, format);
+  jbuf->offset += vsnprintf(jbuf->json + jbuf->offset,
+                            jbuf->max_size - jbuf->offset,
+                            format,
+                            largs);
+  va_end(largs);
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Add the opening bracket of an optional named object to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ *****************************************************************************/
+bool evel_json_open_opt_named_object(EVEL_JSON_BUFFER * jbuf,
+                                     const char * const key)
+{
+  bool opened = false;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  if ((jbuf->depth == EVEL_THROTTLE_FIELD_DEPTH) &&
+      (jbuf->throttle_spec != NULL) &&
+      evel_throttle_suppress_field(jbuf->throttle_spec, key))
+  {
+    EVEL_INFO("Suppressed: %s", key);
+    opened = false;
+  }
+  else
+  {
+    evel_json_open_named_object(jbuf, key);
+    opened = true;
+  }
+
+  EVEL_EXIT();
+
+  return opened;
+}
+
+/**************************************************************************//**
+ * Add the opening bracket of an object to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @param key           Pointer to the key to encode.
+ * @return true if the object was opened, false if it was suppressed.
+ *****************************************************************************/
+void evel_json_open_named_object(EVEL_JSON_BUFFER * jbuf,
+                                 const char * const key)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(key != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s\"%s\": {",
+                           evel_json_kv_comma(jbuf),
+                           key);
+  jbuf->depth++;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Add the opening bracket of an object to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ *****************************************************************************/
+void evel_json_open_object(EVEL_JSON_BUFFER * jbuf)
+{
+  char * comma;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  if ((jbuf->offset != 0) && (jbuf->json[jbuf->offset-1] == '}'))
+  {
+    comma = ", ";
+  }
+  else
+  {
+    comma = "";
+  }
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "%s{",
+                           comma);
+  jbuf->depth++;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Add the closing bracket of an object to a JSON buffer.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ *****************************************************************************/
+void evel_json_close_object(EVEL_JSON_BUFFER * jbuf)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  jbuf->offset += snprintf(jbuf->json + jbuf->offset,
+                           jbuf->max_size - jbuf->offset,
+                           "}");
+  jbuf->depth--;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Determine whether to add a comma when adding a key-value pair.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ * @returns A string containing the comma if it is required.
+ *****************************************************************************/
+char * evel_json_kv_comma(EVEL_JSON_BUFFER * jbuf)
+{
+  char * result;
+
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  if ((jbuf->offset == 0) ||
+      (jbuf->json[jbuf->offset-1] == '{') ||
+      (jbuf->json[jbuf->offset-1] == '['))
+  {
+    result = "";
+  }
+  else
+  {
+    result = ", ";
+  }
+
+  EVEL_EXIT();
+
+  return result;
+}
+
+/**************************************************************************//**
+ * Add a checkpoint - a stake in the ground to which we can rewind.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ *****************************************************************************/
+void evel_json_checkpoint(EVEL_JSON_BUFFER * jbuf)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+
+  /***************************************************************************/
+  /* Store the current offset.                                               */
+  /***************************************************************************/
+  jbuf->checkpoint = jbuf->offset;
+
+  EVEL_EXIT();
+}
+
+/**************************************************************************//**
+ * Rewind to the latest checkoint.
+ *
+ * @param jbuf          Pointer to working ::EVEL_JSON_BUFFER.
+ *****************************************************************************/
+void evel_json_rewind(EVEL_JSON_BUFFER * jbuf)
+{
+  EVEL_ENTER();
+
+  /***************************************************************************/
+  /* Check preconditions.                                                    */
+  /***************************************************************************/
+  assert(jbuf != NULL);
+  assert(jbuf->checkpoint >= 0);
+  assert(jbuf->checkpoint <= jbuf->offset);
+
+  /***************************************************************************/
+  /* Reinstate the offset from the last checkpoint.                          */
+  /***************************************************************************/
+  jbuf->offset = jbuf->checkpoint;
+  jbuf->checkpoint = -1;
+
+  EVEL_EXIT();
+}