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, 87 insertions, 0 deletions

diff --git a/src/blogc/rusage.c b/src/blogc/rusage.c
new file mode 100644
index 0000000..b04938e
--- /dev/null
+++ b/src/blogc/rusage.c
@@ -0,0 +1,87 @@
+/*
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /* HAVE_CONFIG_H */
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif /* HAVE_SYS_TIME_H */
+
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif /* HAVE_SYS_RESOURCE_H */
+
+#include "../common/utils.h"
+#include "rusage.h"
+
+// FIXME: optimize to use a single syscall for both cpu time and memory?
+
+
+#include <stdio.h>
+long long
+blogc_rusage_get_cpu_time(void)
+{
+    struct rusage usage;
+    if (0 != getrusage(RUSAGE_SELF, &usage))
+        return 0;
+    return (
+        (usage.ru_utime.tv_sec * 1000000) + usage.ru_utime.tv_usec +
+        (usage.ru_stime.tv_sec * 1000000) + usage.ru_stime.tv_usec);
+}
+
+
+char*
+blogc_rusage_format_cpu_time(long long time)
+{
+    if (time > 1000000)
+        return bc_strdup_printf("%.3s", ((float) time) / 1000000.0);
+
+    // this is a special case: some systems may report the cpu time rounded up to the
+    // milisecond. it is useless to show ".000" in this case.
+    if (time > 1000)
+        return bc_strdup_printf("%.*fms", time % 1000 ? 3 : 0, ((float) time) / 1000.0);
+
+    return bc_strdup_printf("%dus", time);
+}
+
+
+char*
+blogc_rusage_cpu_time(void)
+{
+    return blogc_rusage_format_cpu_time(blogc_rusage_get_cpu_time());
+}
+
+
+long
+blogc_rusage_get_memory(void)
+{
+    struct rusage usage;
+    if (0 != getrusage(RUSAGE_SELF, &usage))
+        return 0;
+    return usage.ru_maxrss;
+}
+
+
+char*
+blogc_rusage_format_memory(long mem)
+{
+    if (mem > 1048576)
+        return bc_strdup_printf("%.3fGB", ((float) mem) / 1048576.0);
+    if (mem > 1024)
+        return bc_strdup_printf("%.3fMB", ((float) mem) / 1024.0);
+    return bc_strdup_printf("%dKB", mem);
+}
+
+
+char*
+blogc_rusage_memory(void)
+{
+    return blogc_rusage_format_memory(blogc_rusage_get_memory());
+}