From af47a3fd347dd5ad85e5267e7b2ae2c21ecca5af Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Wed, 13 May 2020 20:16:29 +0200
Subject: [PATCH] chg: copied from pm3 repo

---
 tools/hitag2crack/crack5/ht2crack5.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/tools/hitag2crack/crack5/ht2crack5.c b/tools/hitag2crack/crack5/ht2crack5.c
index 7f10ccd6b..d07d03b64 100644
--- a/tools/hitag2crack/crack5/ht2crack5.c
+++ b/tools/hitag2crack/crack5/ht2crack5.c
@@ -93,6 +93,24 @@ const uint64_t unbitslice(const bitslice_t *restrict b, const uint8_t s, const u
     return result;
 }
 
+
+// determine number of logical CPU cores (use for multithreaded functions)
+static int num_CPUs(void) {
+#if defined(_WIN32)
+#include <sysinfoapi.h>
+    SYSTEM_INFO sysinfo;
+    GetSystemInfo(&sysinfo);
+    return sysinfo.dwNumberOfProcessors;
+#else
+#include <unistd.h>
+    int count = sysconf(_SC_NPROCESSORS_ONLN);
+    if (count < 2)
+        count = 2;
+    return count;
+#endif
+}
+
+
 uint32_t uid, nR1, aR1, nR2, aR2;
 
 uint64_t candidates[(1 << 20)];
@@ -116,12 +134,7 @@ int main(int argc, char *argv[]) {
 
     uint32_t target = 0;
 
-#ifndef __WIN32
-    thread_count = sysconf(_SC_NPROCESSORS_CONF);
-    if (thread_count < 2)
-        thread_count = 2;
-#endif  /* _WIN32 */
-
+    thread_count = num_CPUs();
 
     if (!strncmp(argv[1], "0x", 2) || !strncmp(argv[1], "0X", 2)) {
         uid = rev32(hexreversetoulong(argv[1] + 2));