1 files changed, 150 insertions, 0 deletions
diff --git a/src/include/inline_memory.h b/src/include/inline_memory.h
new file mode 100644
index 000000000..48d889763
--- /dev/null
+++ b/src/include/inline_memory.h
@@ -0,0 +1,150 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+#ifndef CEPH_INLINE_MEMORY_H
+#define CEPH_INLINE_MEMORY_H
+
+#if defined(__GNUC__)
+
+// optimize for the common case, which is very small copies
+static inline void *maybe_inline_memcpy(void *dest, const void *src, size_t l,
+				       size_t inline_len)
+  __attribute__((always_inline));
+
+void *maybe_inline_memcpy(void *dest, const void *src, size_t l,
+			 size_t inline_len)
+{
+  if (l > inline_len) {
+    return memcpy(dest, src, l);
+  }
+  switch (l) {
+  case 8:
+    return __builtin_memcpy(dest, src, 8);
+  case 4:
+    return __builtin_memcpy(dest, src, 4);
+  case 3:
+    return __builtin_memcpy(dest, src, 3);
+  case 2:
+    return __builtin_memcpy(dest, src, 2);
+  case 1:
+    return __builtin_memcpy(dest, src, 1);
+  default:
+    int cursor = 0;
+    while (l >= sizeof(uint64_t)) {
+      __builtin_memcpy((char*)dest + cursor, (char*)src + cursor,
+		       sizeof(uint64_t));
+      cursor += sizeof(uint64_t);
+      l -= sizeof(uint64_t);
+    }
+    while (l >= sizeof(uint32_t)) {
+      __builtin_memcpy((char*)dest + cursor, (char*)src + cursor,
+		       sizeof(uint32_t));
+      cursor += sizeof(uint32_t);
+      l -= sizeof(uint32_t);
+    }
+    while (l > 0) {
+      *((char*)dest + cursor) = *((char*)src + cursor);
+      cursor++;
+      l--;
+    }
+  }
+  return dest;
+}
+
+#else
+
+#define maybe_inline_memcpy(d, s, l, x) memcpy(d, s, l)
+
+#endif
+
+
+#if defined(__GNUC__) && defined(__x86_64__)
+
+namespace ceph {
+typedef unsigned uint128_t __attribute__ ((mode (TI)));
+}
+using ceph::uint128_t;
+
+static inline bool mem_is_zero(const char *data, size_t len)
+  __attribute__((always_inline));
+
+bool mem_is_zero(const char *data, size_t len)
+{
+  // we do have XMM registers in x86-64, so if we need to check at least
+  // 16 bytes, make use of them
+  if (len / sizeof(uint128_t) > 0) {
+    // align data pointer to 16 bytes, otherwise it'll segfault due to bug
+    // in (at least some) GCC versions (using MOVAPS instead of MOVUPS).
+    // check up to 15 first bytes while at it.
+    while (((unsigned long long)data) & 15) {
+      if (*(uint8_t*)data != 0) {
+	return false;
+      }
+      data += sizeof(uint8_t);
+      --len;
+    }
+
+    const char* data_start = data;
+    const char* max128 = data + (len / sizeof(uint128_t))*sizeof(uint128_t);
+
+    while (data < max128) {
+      if (*(uint128_t*)data != 0) {
+	return false;
+      }
+      data += sizeof(uint128_t);
+    }
+    len -= (data - data_start);
+  }
+
+  const char* max = data + len;
+  const char* max32 = data + (len / sizeof(uint32_t))*sizeof(uint32_t);
+  while (data < max32) {
+    if (*(uint32_t*)data != 0) {
+      return false;
+    }
+    data += sizeof(uint32_t);
+  }
+  while (data < max) {
+    if (*(uint8_t*)data != 0) {
+      return false;
+    }
+    data += sizeof(uint8_t);
+  }
+  return true;
+}
+
+#else  // gcc and x86_64
+
+static inline bool mem_is_zero(const char *data, size_t len) {
+  const char *end = data + len;
+  const char* end64 = data + (len / sizeof(uint64_t))*sizeof(uint64_t);
+
+  while (data < end64) {
+    if (*(uint64_t*)data != 0) {
+      return false;
+    }
+    data += sizeof(uint64_t);
+  }
+
+  while (data < end) {
+    if (*data != 0) {
+      return false;
+    }
+    ++data;
+  }
+  return true;
+}
+
+#endif  // !x86_64
+
+#endif