Prevent excessive calling of getenv by debugging code for better performance

1 files changed, 17 insertions, 0 deletions

diff --git a/pcilib/env.c b/pcilib/env.c
new file mode 100644
index 0000000..16444db
--- /dev/null
+++ b/pcilib/env.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "env.h"
+
+
+static const char *pcilib_env_cache[PCILIB_MAX_ENV] = {0};
+
+const char *pcilib_getenv(pcilib_env_t env, const char *var) {
+    if (!pcilib_env_cache[env]) {
+	const char *var_env = getenv(var);
+	pcilib_env_cache[env] = var_env?var_env:(void*)-1;
+	return var_env;
+    }
+
+    return (pcilib_env_cache[env] == (void*)-1)?NULL:pcilib_env_cache[env];
+}
+