blogc: added template variables for memory and cpu time resource usage

this include infrastructure required to have variables evaluated as lazy
function calls.

missing tests, docs and improvements.

1 files changed, 47 insertions, 0 deletions

diff --git a/src/blogc/funcvars.c b/src/blogc/funcvars.c
new file mode 100644
index 0000000..a3af274
--- /dev/null
+++ b/src/blogc/funcvars.c
@@ -0,0 +1,47 @@
+/*
+ * blogc: A blog compiler.
+ * Copyright (C) 2014-2019 Rafael G. Martins <rafael@rafaelmartins.eng.br>
+ *
+ * This program can be distributed under the terms of the BSD License.
+ * See the file LICENSE.
+ */
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "funcvars.h"
+#include "rusage.h"
+#include "../common/utils.h"
+
+
+static const struct func_map {
+    const char *variable;
+    const blogc_funcvars_func_t func;
+} funcs[] = {
+    {"BLOGC_RUSAGE_CPU_TIME", blogc_rusage_cpu_time},
+    {"BLOGC_RUSAGE_MEMORY", blogc_rusage_memory},
+    {NULL, NULL},
+};
+
+
+char*
+blogc_funcvars_lookup(const char *name, bc_trie_t *global)
+{
+    // protect against evaluating the same function twice in the same global
+    // context
+    if (NULL != bc_trie_lookup(global, name))
+        return NULL;
+
+    for (size_t i = 0; funcs[i].variable != NULL; i++) {
+        if (0 == strcmp(name, funcs[i].variable)) {
+            char *val = funcs[i].func();
+            if (val == NULL)
+                return NULL;
+            bc_trie_insert(global, name, bc_strdup(val));
+            return val;
+        }
+    }
+
+    return NULL;
+}