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expkg/vendor/lz4/programs/util.c

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+/*
+    util.h - utility functions
+    Copyright (c) Yann Collet. All rights reserved.
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include "util.h"   /* note : ensure that platform.h is included first ! */
+
+/*-****************************************
+*  count the number of cores
+******************************************/
+
+#if defined(_WIN32)
+
+#include <windows.h>
+
+int UTIL_countCores(void)
+{
+    static int numCores = 0;
+    if (numCores != 0) return numCores;
+
+    {   SYSTEM_INFO sysinfo;
+        GetSystemInfo(&sysinfo);
+        numCores = sysinfo.dwNumberOfProcessors;
+    }
+
+    if (numCores == 0) {
+        /* Unexpected result, fall back on 1 */
+        return numCores = 1;
+    }
+
+    return numCores;
+}
+
+#elif defined(__APPLE__)
+
+#include <sys/sysctl.h>
+
+/* Use apple-provided syscall
+ * see: man 3 sysctl */
+int UTIL_countCores(void)
+{
+    static S32 numCores = 0; /* apple specifies int32_t */
+    if (numCores != 0) return (int)numCores;
+
+    {   size_t size = sizeof(S32);
+        int const ret = sysctlbyname("hw.logicalcpu", &numCores, &size, NULL, 0);
+        if (ret != 0) {
+            /* error: fall back on 1 */
+            numCores = 1;
+        }
+    }
+    return (int)numCores;
+}
+
+#elif defined(__linux__)
+
+int UTIL_countCores(void)
+{
+    static int numCores = 0;
+
+    if (numCores != 0) return numCores;
+
+    numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numCores == -1) {
+        /* value not queryable, fall back on 1 */
+        return numCores = 1;
+    }
+
+    return numCores;
+}
+
+#elif defined(__FreeBSD__)
+
+#include <stdio.h>  /* perror */
+#include <errno.h>
+#include <sys/param.h>
+#include <sys/sysctl.h>
+
+/* Use physical core sysctl when available
+ * see: man 4 smp, man 3 sysctl */
+int UTIL_countCores(void)
+{
+    static int numCores = 0; /* freebsd sysctl is native int sized */
+    if (numCores != 0) return numCores;
+
+#if __FreeBSD_version >= 1300008
+    {   size_t size = sizeof(numCores);
+        int ret = sysctlbyname("kern.smp.cores", &numCores, &size, NULL, 0);
+        if (ret == 0) {
+            int perCore = 1;
+            ret = sysctlbyname("kern.smp.threads_per_core", &perCore, &size, NULL, 0);
+            /* default to physical cores if logical cannot be read */
+            if (ret != 0) /* error */
+                return numCores;
+            numCores *= perCore;
+            return numCores;
+        }
+        if (errno != ENOENT) {
+            perror("lz4: can't get number of cpus");
+            exit(1);
+        }
+        /* sysctl not present, fall through to older sysconf method */
+    }
+#endif
+
+    numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numCores == -1) {
+        /* value not queryable, fall back on 1 */
+        numCores = 1;
+    }
+    return numCores;
+}
+
+#elif defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) || defined(__CYGWIN__)
+
+/* Use POSIX sysconf
+ * see: man 3 sysconf */
+int UTIL_countCores(void)
+{
+    static int numCores = 0;
+    if (numCores != 0) return numCores;
+
+    numCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numCores == -1) {
+        /* value not queryable, fall back on 1 */
+        numCores = 1;
+    }
+    return numCores;
+}
+
+#else
+
+int UTIL_countCores(void)
+{
+    /* no clue */
+    return 1;
+}
+
+#endif
+
+#if defined (__cplusplus)
+}
+#endif