Diff: M2XStreamClient/StreamParseFunctions.h

Revision:

3:78f223d34f36

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/M2XStreamClient/StreamParseFunctions.h	Tue Mar 05 02:34:44 2019 +0000
@@ -0,0 +1,81 @@
+#ifndef StreamParseFunctions_h
+#define StreamParseFunctions_h
+
+// Data structures and functions used to parse stream values
+
+#define STREAM_BUF_LEN 32
+
+typedef struct {
+  uint8_t state;
+  char at_str[STREAM_BUF_LEN + 1];
+  char value_str[STREAM_BUF_LEN + 1];
+  int index;
+
+  stream_value_read_callback callback;
+  void* context;
+} stream_parsing_context_state;
+
+#define WAITING_AT 0x1
+#define GOT_AT 0x2
+#define WAITING_VALUE 0x4
+#define GOT_VALUE 0x8
+
+#define GOT_STREAM (GOT_AT | GOT_VALUE)
+#define TEST_GOT_STREAM(state_) (((state_) & GOT_STREAM) == GOT_STREAM)
+
+#define TEST_IS_AT(state_) (((state_) & (WAITING_AT | GOT_AT)) == WAITING_AT)
+#define TEST_IS_VALUE(state_) (((state_) & (WAITING_VALUE | GOT_VALUE)) == \
+                               WAITING_VALUE)
+
+static void on_stream_key_found(jsonlite_callback_context* context,
+                                jsonlite_token* token)
+{
+  stream_parsing_context_state* state =
+      (stream_parsing_context_state*) context->client_state;
+  if (strncmp((const char*) token->start, "timestamp", 2) == 0) {
+    state->state |= WAITING_AT;
+  } else if ((strncmp((const char*) token->start, "value", 5) == 0) &&
+             (token->start[5] != 's')) { // get rid of "values"
+    state->state |= WAITING_VALUE;
+  }
+}
+
+static void on_stream_value_found(jsonlite_callback_context* context,
+                                  jsonlite_token* token,
+                                  int type)
+{
+  stream_parsing_context_state* state =
+      (stream_parsing_context_state*) context->client_state;
+
+  if (TEST_IS_AT(state->state)) {
+    strncpy(state->at_str, (const char*) token->start,
+            MIN(token->end - token->start, STREAM_BUF_LEN));
+    state->at_str[MIN(token->end - token->start, STREAM_BUF_LEN)] = '\0';
+    state->state |= GOT_AT;
+  } else if (TEST_IS_VALUE(state->state)) {
+    strncpy(state->value_str, (const char*) token->start,
+            MIN(token->end - token->start, STREAM_BUF_LEN));
+    state->value_str[MIN(token->end - token->start, STREAM_BUF_LEN)] = '\0';
+    state->state |= GOT_VALUE;
+  }
+
+  if (TEST_GOT_STREAM(state->state)) {
+    state->callback(state->at_str, state->value_str,
+                    state->index++, state->context, type);
+    state->state = 0;
+  }
+}
+
+static void on_stream_string_found(jsonlite_callback_context* context,
+                                   jsonlite_token* token)
+{
+  on_stream_value_found(context, token, 1);
+}
+
+static void on_stream_number_found(jsonlite_callback_context* context,
+                                   jsonlite_token* token)
+{
+  on_stream_value_found(context, token, 2);
+}
+
+#endif  /* StreamParseFunctions_h */