/*
- * Copyright 2012 Facebook, Inc.
+ * Copyright 2015 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#ifndef FOLLY_GROUPVARINT_H_
#define FOLLY_GROUPVARINT_H_
-#ifndef __GNUC__
-#error GroupVarint.h requires GCC
+#if !defined(__GNUC__) && !defined(_MSC_VER)
+#error GroupVarint.h requires GCC or MSVC
#endif
-#if !defined(__x86_64__) && !defined(__i386__)
-#error GroupVarint.h requires x86_64 or i386
-#endif
+#include <folly/Portability.h>
+
+#if FOLLY_X64 || defined(__i386__) || FOLLY_PPC64
+#define HAVE_GROUP_VARINT 1
#include <cstdint>
#include <limits>
-#include "folly/detail/GroupVarintDetail.h"
-#include "folly/Range.h"
+#include <folly/detail/GroupVarintDetail.h>
+#include <folly/Bits.h>
+#include <folly/Range.h>
#include <glog/logging.h>
-#ifdef __SSSE3__
+#if FOLLY_SSE >= 3
#include <x86intrin.h>
namespace folly {
namespace detail {
uint8_t b2key = key(c);
uint8_t b3key = key(d);
*p++ = (b3key << 6) | (b2key << 4) | (b1key << 2) | b0key;
- *reinterpret_cast<uint32_t*>(p) = a;
+ storeUnaligned(p, a);
p += b0key+1;
- *reinterpret_cast<uint32_t*>(p) = b;
+ storeUnaligned(p, b);
p += b1key+1;
- *reinterpret_cast<uint32_t*>(p) = c;
+ storeUnaligned(p, c);
p += b2key+1;
- *reinterpret_cast<uint32_t*>(p) = d;
+ storeUnaligned(p, d);
p += b3key+1;
return p;
}
*/
static const char* decode_simple(const char* p, uint32_t* a, uint32_t* b,
uint32_t* c, uint32_t* d) {
- size_t k = *reinterpret_cast<const uint8_t*>(p);
+ size_t k = loadUnaligned<uint8_t>(p);
const char* end = p + detail::groupVarintLengths[k];
++p;
size_t k0 = b0key(k);
- *a = *reinterpret_cast<const uint32_t*>(p) & kMask[k0];
+ *a = loadUnaligned<uint32_t>(p) & kMask[k0];
p += k0+1;
size_t k1 = b1key(k);
- *b = *reinterpret_cast<const uint32_t*>(p) & kMask[k1];
+ *b = loadUnaligned<uint32_t>(p) & kMask[k1];
p += k1+1;
size_t k2 = b2key(k);
- *c = *reinterpret_cast<const uint32_t*>(p) & kMask[k2];
+ *c = loadUnaligned<uint32_t>(p) & kMask[k2];
p += k2+1;
size_t k3 = b3key(k);
- *d = *reinterpret_cast<const uint32_t*>(p) & kMask[k3];
- p += k3+1;
+ *d = loadUnaligned<uint32_t>(p) & kMask[k3];
+ // p += k3+1;
return end;
}
return decode_simple(p, dest, dest+1, dest+2, dest+3);
}
-#ifdef __SSSE3__
+#if FOLLY_SSE >= 3
+ /**
+ * Just like the non-SSSE3 decode below, but with the additional constraint
+ * that we must be able to read at least 17 bytes from the input pointer, p.
+ */
static const char* decode(const char* p, uint32_t* dest) {
uint8_t key = p[0];
__m128i val = _mm_loadu_si128((const __m128i*)(p+1));
return p + detail::groupVarintLengths[key];
}
+ /**
+ * Just like decode_simple, but with the additional constraint that
+ * we must be able to read at least 17 bytes from the input pointer, p.
+ */
static const char* decode(const char* p, uint32_t* a, uint32_t* b,
uint32_t* c, uint32_t* d) {
uint8_t key = p[0];
__m128i r = _mm_shuffle_epi8(val, mask);
// Extracting 32 bits at a time out of an XMM register is a SSE4 feature
-#ifdef __SSE4__
+#if FOLLY_SSE >= 4
*a = _mm_extract_epi32(r, 0);
*b = _mm_extract_epi32(r, 1);
*c = _mm_extract_epi32(r, 2);
* buffer of size bytes.
*/
static size_t partialCount(const char* p, size_t size) {
- uint16_t v = *reinterpret_cast<const uint16_t*>(p);
+ uint16_t v = loadUnaligned<uint16_t>(p);
size_t s = kHeaderSize;
s += 1 + b0key(v);
if (s > size) return 0;
* return the number of bytes used by the encoding.
*/
static size_t encodedSize(const char* p) {
- uint16_t n = *reinterpret_cast<const uint16_t*>(p);
+ uint16_t n = loadUnaligned<uint16_t>(p);
return (kHeaderSize + kGroupSize +
b0key(n) + b1key(n) + b2key(n) + b3key(n) + b4key(n));
}
uint8_t b2key = key(c);
uint8_t b3key = key(d);
uint8_t b4key = key(e);
- *reinterpret_cast<uint16_t*>(p) =
- (b4key << 12) | (b3key << 9) | (b2key << 6) | (b1key << 3) | b0key;
+ storeUnaligned<uint16_t>(
+ p,
+ (b4key << 12) | (b3key << 9) | (b2key << 6) | (b1key << 3) | b0key);
p += 2;
- *reinterpret_cast<uint64_t*>(p) = a;
+ storeUnaligned(p, a);
p += b0key+1;
- *reinterpret_cast<uint64_t*>(p) = b;
+ storeUnaligned(p, b);
p += b1key+1;
- *reinterpret_cast<uint64_t*>(p) = c;
+ storeUnaligned(p, c);
p += b2key+1;
- *reinterpret_cast<uint64_t*>(p) = d;
+ storeUnaligned(p, d);
p += b3key+1;
- *reinterpret_cast<uint64_t*>(p) = e;
+ storeUnaligned(p, e);
p += b4key+1;
return p;
}
*/
static const char* decode(const char* p, uint64_t* a, uint64_t* b,
uint64_t* c, uint64_t* d, uint64_t* e) {
- uint16_t k = *reinterpret_cast<const uint16_t*>(p);
+ uint16_t k = loadUnaligned<uint16_t>(p);
p += 2;
uint8_t k0 = b0key(k);
- *a = *reinterpret_cast<const uint64_t*>(p) & kMask[k0];
+ *a = loadUnaligned<uint64_t>(p) & kMask[k0];
p += k0+1;
uint8_t k1 = b1key(k);
- *b = *reinterpret_cast<const uint64_t*>(p) & kMask[k1];
+ *b = loadUnaligned<uint64_t>(p) & kMask[k1];
p += k1+1;
uint8_t k2 = b2key(k);
- *c = *reinterpret_cast<const uint64_t*>(p) & kMask[k2];
+ *c = loadUnaligned<uint64_t>(p) & kMask[k2];
p += k2+1;
uint8_t k3 = b3key(k);
- *d = *reinterpret_cast<const uint64_t*>(p) & kMask[k3];
+ *d = loadUnaligned<uint64_t>(p) & kMask[k3];
p += k3+1;
uint8_t k4 = b4key(k);
- *e = *reinterpret_cast<const uint64_t*>(p) & kMask[k4];
+ *e = loadUnaligned<uint64_t>(p) & kMask[k4];
p += k4+1;
return p;
}
typedef GroupVarint<T> Base;
typedef T type;
- GroupVarintDecoder() { }
+ GroupVarintDecoder() = default;
explicit GroupVarintDecoder(StringPiece data,
size_t maxCount = (size_t)-1)
- : p_(data.data()),
- end_(data.data() + data.size()),
+ : rrest_(data.end()),
+ p_(data.data()),
+ end_(data.end()),
+ limit_(end_),
pos_(0),
count_(0),
remaining_(maxCount) {
}
- void reset(StringPiece data, size_t maxCount=(size_t)-1) {
+ void reset(StringPiece data, size_t maxCount = (size_t)-1) {
+ rrest_ = data.end();
p_ = data.data();
- end_ = data.data() + data.size();
+ end_ = data.end();
+ limit_ = end_;
pos_ = 0;
count_ = 0;
remaining_ = maxCount;
// The best way to ensure this is to ensure that data has at least
// Base::kMaxSize - 1 bytes readable *after* the end, otherwise we'll copy
// into a temporary buffer.
- if (rem < Base::kMaxSize) {
+ if (limit_ - p_ < Base::kMaxSize) {
memcpy(tmp_, p_, rem);
p_ = tmp_;
end_ = p_ + rem;
+ limit_ = tmp_ + sizeof(tmp_);
}
pos_ = 0;
const char* n = Base::decode(p_, buf_);
StringPiece rest() const {
// This is only valid after next() returned false
CHECK(pos_ == count_ && (p_ == end_ || remaining_ == 0));
- return StringPiece(p_, end_ - p_);
+ // p_ may point to the internal buffer (tmp_), but we want
+ // to return subpiece of the original data
+ size_t size = end_ - p_;
+ return StringPiece(rrest_ - size, rrest_);
}
private:
+ const char* rrest_;
const char* p_;
const char* end_;
- char tmp_[Base::kMaxSize];
+ const char* limit_;
+ char tmp_[2 * Base::kMaxSize];
type buf_[Base::kGroupSize];
size_t pos_;
size_t count_;
} // namespace folly
+#endif /* FOLLY_X64 || defined(__i386__) || FOLLY_PPC64 */
#endif /* FOLLY_GROUPVARINT_H_ */
-
projects / folly.git / blobdiff