util: put convenience helpers into util.[ch]

Also introduces get_ncpus(), in preparation for threaded rendering.

1 files changed, 22 insertions, 0 deletions

diff --git a/util.c b/util.c
new file mode 100644
index 0000000..c07589e
--- /dev/null
+++ b/util.c
@@ -0,0 +1,22 @@
+#include <limits.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "util.h"
+
+#define SYSFS_CPU	"/sys/devices/system/cpu/cpu"
+#define MAXCPUS		1024
+
+unsigned get_ncpus(void)
+{
+	char		path[cstrlen(SYSFS_CPU "1024") + 1];
+	unsigned	n;
+
+	for (n = 0; n < MAXCPUS; n++) {
+		snprintf(path, sizeof(path), "%s%u", SYSFS_CPU, n);
+		if (access(path, F_OK) == -1)
+			break;
+	}
+
+	return n == 0 ? 1 : n;
+}