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// -*- 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
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