esp-link/user/user_json.c

/******************************************************************************
* Copyright 2013-2014 Espressif Systems (Wuxi)
*
* FileName: user_json.c
*
* Description: JSON format set up and parse.
*              Check your hardware transmation while use this data format.
*
* Modification history:
*     2014/5/09, v1.0 create this file.
*******************************************************************************/
#include "user_json.h"

LOCAL char* json_buf;
LOCAL int pos;
LOCAL int size;

/******************************************************************************
* FunctionName : find_json_path
* Description  : find the JSON format tree's path
* Parameters   : json -- A pointer to a JSON set up
*                path -- A pointer to the JSON format tree's path
* Returns      : A pointer to the JSON format tree
*******************************************************************************/
struct jsontree_value*ICACHE_FLASH_ATTR
find_json_path(struct jsontree_context* json, const char* path) {
  struct jsontree_value* v;
  const char* start;
  const char* end;
  int len;

  v = json->values[0];
  start = path;

  do {
    end = (const char *)os_strstr(start, "/");

    if (end == start) {
      break;
    }

    if (end != NULL) {
      len = end - start;
      end++;
    }
    else {
      len = os_strlen(start);
    }

    if (v->type != JSON_TYPE_OBJECT) {
      v = NULL;
    }
    else {
      struct jsontree_object* o;
      int i;

      o = (struct jsontree_object *)v;
      v = NULL;

      for (i = 0; i < o->count; i++) {
        if (os_strncmp(start, o->pairs[i].name, len) == 0) {
          v = o->pairs[i].value;
          json->index[json->depth] = i;
          json->depth++;
          json->values[json->depth] = v;
          json->index[json->depth] = 0;
          break;
        }
      }
    }

    start = end;
  }
  while (end != NULL && *end != '\0' && v != NULL);

  json->callback_state = 0;
  return v;
}

/******************************************************************************
* FunctionName : json_putchar
* Description  : write the value to the JSON  format tree
* Parameters   : c -- the value which write the JSON format tree
* Returns      : result
*******************************************************************************/
int ICACHE_FLASH_ATTR
json_putchar(int c) {
  if (json_buf != NULL && pos <= size) {
    json_buf[pos++] = c;
    return c;
  }

  return 0;
}

/******************************************************************************
* FunctionName : json_ws_send
* Description  : set up the JSON format tree for string
* Parameters   : tree -- A pointer to the JSON format tree
*                path -- A pointer to the JSON format tree's path
*                pbuf -- A pointer for the data sent
* Returns      : none
*******************************************************************************/
void ICACHE_FLASH_ATTR
json_ws_send(struct jsontree_value* tree, const char* path, char* pbuf) {
  struct jsontree_context json;
  /* maxsize = 128 bytes */
  json_buf = (char *)os_malloc(JSON_SIZE);

  /* reset state and set max-size */
  /* NOTE: packet will be truncated at 512 bytes */
  pos = 0;
  size = JSON_SIZE;

  json.values[0] = (struct jsontree_value *)tree;
  jsontree_reset(&json);
  find_json_path(&json, path);
  json.path = json.depth;
  json.putchar = json_putchar;

  while (jsontree_print_next(&json) && json.path <= json.depth);

  json_buf[pos] = 0;
  os_memcpy(pbuf, json_buf, pos);
  os_free(json_buf);
}

/******************************************************************************
* FunctionName : json_parse
* Description  : parse the data as a JSON format
* Parameters   : js_ctx -- A pointer to a JSON set up
*                ptrJSONMessage -- A pointer to the data
* Returns      : none
*******************************************************************************/
void ICACHE_FLASH_ATTR
json_parse(struct jsontree_context* json, char* ptrJSONMessage) {
  /* Set value */
  struct jsontree_value* v;
  struct jsontree_callback* c;
  struct jsontree_callback* c_bak = NULL;

  while ((v = jsontree_find_next(json, JSON_TYPE_CALLBACK)) != NULL) {
    c = (struct jsontree_callback *)v;

    if (c == c_bak) {
      continue;
    }

    c_bak = c;

    if (c->set != NULL) {
      struct jsonparse_state js;

      jsonparse_setup(&js, ptrJSONMessage, os_strlen(ptrJSONMessage));
      c->set(json, &js);
    }
  }
}