/usr/include/clang/Basic/OnDiskHashTable.h is in libclang-dev 3.0-6ubuntu3.
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//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines facilities for reading and writing on-disk hash
// tables.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_BASIC_ON_DISK_HASH_TABLE_H
#define LLVM_CLANG_BASIC_ON_DISK_HASH_TABLE_H
#include "llvm/Support/Allocator.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Host.h"
#include <cassert>
#include <cstdlib>
namespace clang {
namespace io {
typedef uint32_t Offset;
inline void Emit8(raw_ostream& Out, uint32_t V) {
Out << (unsigned char)(V);
}
inline void Emit16(raw_ostream& Out, uint32_t V) {
Out << (unsigned char)(V);
Out << (unsigned char)(V >> 8);
assert((V >> 16) == 0);
}
inline void Emit24(raw_ostream& Out, uint32_t V) {
Out << (unsigned char)(V);
Out << (unsigned char)(V >> 8);
Out << (unsigned char)(V >> 16);
assert((V >> 24) == 0);
}
inline void Emit32(raw_ostream& Out, uint32_t V) {
Out << (unsigned char)(V);
Out << (unsigned char)(V >> 8);
Out << (unsigned char)(V >> 16);
Out << (unsigned char)(V >> 24);
}
inline void Emit64(raw_ostream& Out, uint64_t V) {
Out << (unsigned char)(V);
Out << (unsigned char)(V >> 8);
Out << (unsigned char)(V >> 16);
Out << (unsigned char)(V >> 24);
Out << (unsigned char)(V >> 32);
Out << (unsigned char)(V >> 40);
Out << (unsigned char)(V >> 48);
Out << (unsigned char)(V >> 56);
}
inline void Pad(raw_ostream& Out, unsigned A) {
Offset off = (Offset) Out.tell();
uint32_t n = ((uintptr_t)(off+A-1) & ~(uintptr_t)(A-1)) - off;
for (; n ; --n)
Emit8(Out, 0);
}
inline uint16_t ReadUnalignedLE16(const unsigned char *&Data) {
uint16_t V = ((uint16_t)Data[0]) |
((uint16_t)Data[1] << 8);
Data += 2;
return V;
}
inline uint32_t ReadUnalignedLE32(const unsigned char *&Data) {
uint32_t V = ((uint32_t)Data[0]) |
((uint32_t)Data[1] << 8) |
((uint32_t)Data[2] << 16) |
((uint32_t)Data[3] << 24);
Data += 4;
return V;
}
inline uint64_t ReadUnalignedLE64(const unsigned char *&Data) {
uint64_t V = ((uint64_t)Data[0]) |
((uint64_t)Data[1] << 8) |
((uint64_t)Data[2] << 16) |
((uint64_t)Data[3] << 24) |
((uint64_t)Data[4] << 32) |
((uint64_t)Data[5] << 40) |
((uint64_t)Data[6] << 48) |
((uint64_t)Data[7] << 56);
Data += 8;
return V;
}
inline uint32_t ReadLE32(const unsigned char *&Data) {
// Hosts that directly support little-endian 32-bit loads can just
// use them. Big-endian hosts need a bswap.
uint32_t V = *((uint32_t*)Data);
if (llvm::sys::isBigEndianHost())
V = llvm::ByteSwap_32(V);
Data += 4;
return V;
}
} // end namespace io
template<typename Info>
class OnDiskChainedHashTableGenerator {
unsigned NumBuckets;
unsigned NumEntries;
llvm::BumpPtrAllocator BA;
class Item {
public:
typename Info::key_type key;
typename Info::data_type data;
Item *next;
const uint32_t hash;
Item(typename Info::key_type_ref k, typename Info::data_type_ref d,
Info &InfoObj)
: key(k), data(d), next(0), hash(InfoObj.ComputeHash(k)) {}
};
class Bucket {
public:
io::Offset off;
Item* head;
unsigned length;
Bucket() {}
};
Bucket* Buckets;
private:
void insert(Bucket* b, size_t size, Item* E) {
unsigned idx = E->hash & (size - 1);
Bucket& B = b[idx];
E->next = B.head;
++B.length;
B.head = E;
}
void resize(size_t newsize) {
Bucket* newBuckets = (Bucket*) std::calloc(newsize, sizeof(Bucket));
// Populate newBuckets with the old entries.
for (unsigned i = 0; i < NumBuckets; ++i)
for (Item* E = Buckets[i].head; E ; ) {
Item* N = E->next;
E->next = 0;
insert(newBuckets, newsize, E);
E = N;
}
free(Buckets);
NumBuckets = newsize;
Buckets = newBuckets;
}
public:
void insert(typename Info::key_type_ref key,
typename Info::data_type_ref data) {
Info InfoObj;
insert(key, data, InfoObj);
}
void insert(typename Info::key_type_ref key,
typename Info::data_type_ref data, Info &InfoObj) {
++NumEntries;
if (4*NumEntries >= 3*NumBuckets) resize(NumBuckets*2);
insert(Buckets, NumBuckets, new (BA.Allocate<Item>()) Item(key, data,
InfoObj));
}
io::Offset Emit(raw_ostream &out) {
Info InfoObj;
return Emit(out, InfoObj);
}
io::Offset Emit(raw_ostream &out, Info &InfoObj) {
using namespace clang::io;
// Emit the payload of the table.
for (unsigned i = 0; i < NumBuckets; ++i) {
Bucket& B = Buckets[i];
if (!B.head) continue;
// Store the offset for the data of this bucket.
B.off = out.tell();
assert(B.off && "Cannot write a bucket at offset 0. Please add padding.");
// Write out the number of items in the bucket.
Emit16(out, B.length);
// Write out the entries in the bucket.
for (Item *I = B.head; I ; I = I->next) {
Emit32(out, I->hash);
const std::pair<unsigned, unsigned>& Len =
InfoObj.EmitKeyDataLength(out, I->key, I->data);
InfoObj.EmitKey(out, I->key, Len.first);
InfoObj.EmitData(out, I->key, I->data, Len.second);
}
}
// Emit the hashtable itself.
Pad(out, 4);
io::Offset TableOff = out.tell();
Emit32(out, NumBuckets);
Emit32(out, NumEntries);
for (unsigned i = 0; i < NumBuckets; ++i) Emit32(out, Buckets[i].off);
return TableOff;
}
OnDiskChainedHashTableGenerator() {
NumEntries = 0;
NumBuckets = 64;
// Note that we do not need to run the constructors of the individual
// Bucket objects since 'calloc' returns bytes that are all 0.
Buckets = (Bucket*) std::calloc(NumBuckets, sizeof(Bucket));
}
~OnDiskChainedHashTableGenerator() {
std::free(Buckets);
}
};
template<typename Info>
class OnDiskChainedHashTable {
const unsigned NumBuckets;
const unsigned NumEntries;
const unsigned char* const Buckets;
const unsigned char* const Base;
Info InfoObj;
public:
typedef typename Info::internal_key_type internal_key_type;
typedef typename Info::external_key_type external_key_type;
typedef typename Info::data_type data_type;
OnDiskChainedHashTable(unsigned numBuckets, unsigned numEntries,
const unsigned char* buckets,
const unsigned char* base,
const Info &InfoObj = Info())
: NumBuckets(numBuckets), NumEntries(numEntries),
Buckets(buckets), Base(base), InfoObj(InfoObj) {
assert((reinterpret_cast<uintptr_t>(buckets) & 0x3) == 0 &&
"'buckets' must have a 4-byte alignment");
}
unsigned getNumBuckets() const { return NumBuckets; }
unsigned getNumEntries() const { return NumEntries; }
const unsigned char* getBase() const { return Base; }
const unsigned char* getBuckets() const { return Buckets; }
bool isEmpty() const { return NumEntries == 0; }
class iterator {
internal_key_type key;
const unsigned char* const data;
const unsigned len;
Info *InfoObj;
public:
iterator() : data(0), len(0) {}
iterator(const internal_key_type k, const unsigned char* d, unsigned l,
Info *InfoObj)
: key(k), data(d), len(l), InfoObj(InfoObj) {}
data_type operator*() const { return InfoObj->ReadData(key, data, len); }
bool operator==(const iterator& X) const { return X.data == data; }
bool operator!=(const iterator& X) const { return X.data != data; }
};
iterator find(const external_key_type& eKey, Info *InfoPtr = 0) {
if (!InfoPtr)
InfoPtr = &InfoObj;
using namespace io;
const internal_key_type& iKey = InfoObj.GetInternalKey(eKey);
unsigned key_hash = InfoObj.ComputeHash(iKey);
// Each bucket is just a 32-bit offset into the hash table file.
unsigned idx = key_hash & (NumBuckets - 1);
const unsigned char* Bucket = Buckets + sizeof(uint32_t)*idx;
unsigned offset = ReadLE32(Bucket);
if (offset == 0) return iterator(); // Empty bucket.
const unsigned char* Items = Base + offset;
// 'Items' starts with a 16-bit unsigned integer representing the
// number of items in this bucket.
unsigned len = ReadUnalignedLE16(Items);
for (unsigned i = 0; i < len; ++i) {
// Read the hash.
uint32_t item_hash = ReadUnalignedLE32(Items);
// Determine the length of the key and the data.
const std::pair<unsigned, unsigned>& L = Info::ReadKeyDataLength(Items);
unsigned item_len = L.first + L.second;
// Compare the hashes. If they are not the same, skip the entry entirely.
if (item_hash != key_hash) {
Items += item_len;
continue;
}
// Read the key.
const internal_key_type& X =
InfoPtr->ReadKey((const unsigned char* const) Items, L.first);
// If the key doesn't match just skip reading the value.
if (!InfoPtr->EqualKey(X, iKey)) {
Items += item_len;
continue;
}
// The key matches!
return iterator(X, Items + L.first, L.second, InfoPtr);
}
return iterator();
}
iterator end() const { return iterator(); }
/// \brief Iterates over all of the keys in the table.
class key_iterator {
const unsigned char* Ptr;
unsigned NumItemsInBucketLeft;
unsigned NumEntriesLeft;
Info *InfoObj;
public:
typedef external_key_type value_type;
key_iterator(const unsigned char* const Ptr, unsigned NumEntries,
Info *InfoObj)
: Ptr(Ptr), NumItemsInBucketLeft(0), NumEntriesLeft(NumEntries),
InfoObj(InfoObj) { }
key_iterator()
: Ptr(0), NumItemsInBucketLeft(0), NumEntriesLeft(0), InfoObj(0) { }
friend bool operator==(const key_iterator &X, const key_iterator &Y) {
return X.NumEntriesLeft == Y.NumEntriesLeft;
}
friend bool operator!=(const key_iterator& X, const key_iterator &Y) {
return X.NumEntriesLeft != Y.NumEntriesLeft;
}
key_iterator& operator++() { // Preincrement
if (!NumItemsInBucketLeft) {
// 'Items' starts with a 16-bit unsigned integer representing the
// number of items in this bucket.
NumItemsInBucketLeft = io::ReadUnalignedLE16(Ptr);
}
Ptr += 4; // Skip the hash.
// Determine the length of the key and the data.
const std::pair<unsigned, unsigned>& L = Info::ReadKeyDataLength(Ptr);
Ptr += L.first + L.second;
assert(NumItemsInBucketLeft);
--NumItemsInBucketLeft;
assert(NumEntriesLeft);
--NumEntriesLeft;
return *this;
}
key_iterator operator++(int) { // Postincrement
key_iterator tmp = *this; ++*this; return tmp;
}
value_type operator*() const {
const unsigned char* LocalPtr = Ptr;
if (!NumItemsInBucketLeft)
LocalPtr += 2; // number of items in bucket
LocalPtr += 4; // Skip the hash.
// Determine the length of the key and the data.
const std::pair<unsigned, unsigned>& L
= Info::ReadKeyDataLength(LocalPtr);
// Read the key.
const internal_key_type& Key = InfoObj->ReadKey(LocalPtr, L.first);
return InfoObj->GetExternalKey(Key);
}
};
key_iterator key_begin() {
return key_iterator(Base + 4, getNumEntries(), &InfoObj);
}
key_iterator key_end() { return key_iterator(); }
/// \brief Iterates over all the entries in the table, returning
/// a key/data pair.
class item_iterator {
const unsigned char* Ptr;
unsigned NumItemsInBucketLeft;
unsigned NumEntriesLeft;
Info *InfoObj;
public:
typedef std::pair<external_key_type, data_type> value_type;
item_iterator(const unsigned char* const Ptr, unsigned NumEntries,
Info *InfoObj)
: Ptr(Ptr), NumItemsInBucketLeft(0), NumEntriesLeft(NumEntries),
InfoObj(InfoObj) { }
item_iterator()
: Ptr(0), NumItemsInBucketLeft(0), NumEntriesLeft(0), InfoObj(0) { }
bool operator==(const item_iterator& X) const {
return X.NumEntriesLeft == NumEntriesLeft;
}
bool operator!=(const item_iterator& X) const {
return X.NumEntriesLeft != NumEntriesLeft;
}
item_iterator& operator++() { // Preincrement
if (!NumItemsInBucketLeft) {
// 'Items' starts with a 16-bit unsigned integer representing the
// number of items in this bucket.
NumItemsInBucketLeft = io::ReadUnalignedLE16(Ptr);
}
Ptr += 4; // Skip the hash.
// Determine the length of the key and the data.
const std::pair<unsigned, unsigned>& L = Info::ReadKeyDataLength(Ptr);
Ptr += L.first + L.second;
assert(NumItemsInBucketLeft);
--NumItemsInBucketLeft;
assert(NumEntriesLeft);
--NumEntriesLeft;
return *this;
}
item_iterator operator++(int) { // Postincrement
item_iterator tmp = *this; ++*this; return tmp;
}
value_type operator*() const {
const unsigned char* LocalPtr = Ptr;
if (!NumItemsInBucketLeft)
LocalPtr += 2; // number of items in bucket
LocalPtr += 4; // Skip the hash.
// Determine the length of the key and the data.
const std::pair<unsigned, unsigned>& L = Info::ReadKeyDataLength(LocalPtr);
// Read the key.
const internal_key_type& Key =
InfoObj->ReadKey(LocalPtr, L.first);
return std::make_pair(InfoObj->GetExternalKey(Key),
InfoObj->ReadData(Key, LocalPtr + L.first, L.second));
}
};
item_iterator item_begin() {
return item_iterator(Base + 4, getNumEntries(), &InfoObj);
}
item_iterator item_end() { return item_iterator(); }
Info &getInfoObj() { return InfoObj; }
static OnDiskChainedHashTable* Create(const unsigned char* buckets,
const unsigned char* const base,
const Info &InfoObj = Info()) {
using namespace io;
assert(buckets > base);
assert((reinterpret_cast<uintptr_t>(buckets) & 0x3) == 0 &&
"buckets should be 4-byte aligned.");
unsigned numBuckets = ReadLE32(buckets);
unsigned numEntries = ReadLE32(buckets);
return new OnDiskChainedHashTable<Info>(numBuckets, numEntries, buckets,
base, InfoObj);
}
};
} // end namespace clang
#endif
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