llvm-6502/include/llvm/ADT/StringMap.h
Chris Lattner 8ee0769612 Add a method to get a StringMapEntry from a pointer to the string
data it contains (similar to GetStringMapEntryFromValue).  
Patch by Greg Clayton!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99371 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-24 00:53:27 +00:00

487 lines
15 KiB
C++

//===--- StringMap.h - String Hash table map interface ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the StringMap class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_STRINGMAP_H
#define LLVM_ADT_STRINGMAP_H
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include <cstring>
#include <string>
namespace llvm {
template<typename ValueT>
class StringMapConstIterator;
template<typename ValueT>
class StringMapIterator;
template<typename ValueTy>
class StringMapEntry;
/// StringMapEntryInitializer - This datatype can be partially specialized for
/// various datatypes in a stringmap to allow them to be initialized when an
/// entry is default constructed for the map.
template<typename ValueTy>
class StringMapEntryInitializer {
public:
template <typename InitTy>
static void Initialize(StringMapEntry<ValueTy> &T, InitTy InitVal) {
T.second = InitVal;
}
};
/// StringMapEntryBase - Shared base class of StringMapEntry instances.
class StringMapEntryBase {
unsigned StrLen;
public:
explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}
unsigned getKeyLength() const { return StrLen; }
};
/// StringMapImpl - This is the base class of StringMap that is shared among
/// all of its instantiations.
class StringMapImpl {
public:
/// ItemBucket - The hash table consists of an array of these. If Item is
/// non-null, this is an extant entry, otherwise, it is a hole.
struct ItemBucket {
/// FullHashValue - This remembers the full hash value of the key for
/// easy scanning.
unsigned FullHashValue;
/// Item - This is a pointer to the actual item object.
StringMapEntryBase *Item;
};
protected:
ItemBucket *TheTable;
unsigned NumBuckets;
unsigned NumItems;
unsigned NumTombstones;
unsigned ItemSize;
protected:
explicit StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
// Initialize the map with zero buckets to allocation.
TheTable = 0;
NumBuckets = 0;
NumItems = 0;
NumTombstones = 0;
}
StringMapImpl(unsigned InitSize, unsigned ItemSize);
void RehashTable();
/// ShouldRehash - Return true if the table should be rehashed after a new
/// element was recently inserted.
bool ShouldRehash() const {
// If the hash table is now more than 3/4 full, or if fewer than 1/8 of
// the buckets are empty (meaning that many are filled with tombstones),
// grow the table.
return NumItems*4 > NumBuckets*3 ||
NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
}
/// LookupBucketFor - Look up the bucket that the specified string should end
/// up in. If it already exists as a key in the map, the Item pointer for the
/// specified bucket will be non-null. Otherwise, it will be null. In either
/// case, the FullHashValue field of the bucket will be set to the hash value
/// of the string.
unsigned LookupBucketFor(StringRef Key);
/// FindKey - Look up the bucket that contains the specified key. If it exists
/// in the map, return the bucket number of the key. Otherwise return -1.
/// This does not modify the map.
int FindKey(StringRef Key) const;
/// RemoveKey - Remove the specified StringMapEntry from the table, but do not
/// delete it. This aborts if the value isn't in the table.
void RemoveKey(StringMapEntryBase *V);
/// RemoveKey - Remove the StringMapEntry for the specified key from the
/// table, returning it. If the key is not in the table, this returns null.
StringMapEntryBase *RemoveKey(StringRef Key);
private:
void init(unsigned Size);
public:
static StringMapEntryBase *getTombstoneVal() {
return (StringMapEntryBase*)-1;
}
unsigned getNumBuckets() const { return NumBuckets; }
unsigned getNumItems() const { return NumItems; }
bool empty() const { return NumItems == 0; }
unsigned size() const { return NumItems; }
};
/// StringMapEntry - This is used to represent one value that is inserted into
/// a StringMap. It contains the Value itself and the key: the string length
/// and data.
template<typename ValueTy>
class StringMapEntry : public StringMapEntryBase {
public:
ValueTy second;
explicit StringMapEntry(unsigned strLen)
: StringMapEntryBase(strLen), second() {}
StringMapEntry(unsigned strLen, const ValueTy &V)
: StringMapEntryBase(strLen), second(V) {}
StringRef getKey() const {
return StringRef(getKeyData(), getKeyLength());
}
const ValueTy &getValue() const { return second; }
ValueTy &getValue() { return second; }
void setValue(const ValueTy &V) { second = V; }
/// getKeyData - Return the start of the string data that is the key for this
/// value. The string data is always stored immediately after the
/// StringMapEntry object.
const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
const char *first() const { return getKeyData(); }
/// Create - Create a StringMapEntry for the specified key and default
/// construct the value.
template<typename AllocatorTy, typename InitType>
static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
AllocatorTy &Allocator,
InitType InitVal) {
unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
// Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
// in. Allocate a new item with space for the string at the end and a null
// terminator.
unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
KeyLength+1;
unsigned Alignment = alignof<StringMapEntry>();
StringMapEntry *NewItem =
static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
// Default construct the value.
new (NewItem) StringMapEntry(KeyLength);
// Copy the string information.
char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
memcpy(StrBuffer, KeyStart, KeyLength);
StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
// Initialize the value if the client wants to.
StringMapEntryInitializer<ValueTy>::Initialize(*NewItem, InitVal);
return NewItem;
}
template<typename AllocatorTy>
static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
AllocatorTy &Allocator) {
return Create(KeyStart, KeyEnd, Allocator, 0);
}
/// Create - Create a StringMapEntry with normal malloc/free.
template<typename InitType>
static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
InitType InitVal) {
MallocAllocator A;
return Create(KeyStart, KeyEnd, A, InitVal);
}
static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
return Create(KeyStart, KeyEnd, ValueTy());
}
/// GetStringMapEntryFromValue - Given a value that is known to be embedded
/// into a StringMapEntry, return the StringMapEntry itself.
static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
StringMapEntry *EPtr = 0;
char *Ptr = reinterpret_cast<char*>(&V) -
(reinterpret_cast<char*>(&EPtr->second) -
reinterpret_cast<char*>(EPtr));
return *reinterpret_cast<StringMapEntry*>(Ptr);
}
static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
}
/// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
/// into a StringMapEntry, return the StringMapEntry itself.
static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
return *reinterpret_cast<StringMapEntry*>(Ptr);
}
/// Destroy - Destroy this StringMapEntry, releasing memory back to the
/// specified allocator.
template<typename AllocatorTy>
void Destroy(AllocatorTy &Allocator) {
// Free memory referenced by the item.
this->~StringMapEntry();
Allocator.Deallocate(this);
}
/// Destroy this object, releasing memory back to the malloc allocator.
void Destroy() {
MallocAllocator A;
Destroy(A);
}
};
/// StringMap - This is an unconventional map that is specialized for handling
/// keys that are "strings", which are basically ranges of bytes. This does some
/// funky memory allocation and hashing things to make it extremely efficient,
/// storing the string data *after* the value in the map.
template<typename ValueTy, typename AllocatorTy = MallocAllocator>
class StringMap : public StringMapImpl {
AllocatorTy Allocator;
typedef StringMapEntry<ValueTy> MapEntryTy;
public:
StringMap() : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {}
explicit StringMap(unsigned InitialSize)
: StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))) {}
explicit StringMap(const StringMap &RHS)
: StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
assert(RHS.empty() &&
"Copy ctor from non-empty stringmap not implemented yet!");
}
void operator=(const StringMap &RHS) {
assert(RHS.empty() &&
"assignment from non-empty stringmap not implemented yet!");
clear();
}
AllocatorTy &getAllocator() { return Allocator; }
const AllocatorTy &getAllocator() const { return Allocator; }
typedef const char* key_type;
typedef ValueTy mapped_type;
typedef StringMapEntry<ValueTy> value_type;
typedef size_t size_type;
typedef StringMapConstIterator<ValueTy> const_iterator;
typedef StringMapIterator<ValueTy> iterator;
iterator begin() {
return iterator(TheTable, NumBuckets == 0);
}
iterator end() {
return iterator(TheTable+NumBuckets, true);
}
const_iterator begin() const {
return const_iterator(TheTable, NumBuckets == 0);
}
const_iterator end() const {
return const_iterator(TheTable+NumBuckets, true);
}
iterator find(StringRef Key) {
int Bucket = FindKey(Key);
if (Bucket == -1) return end();
return iterator(TheTable+Bucket);
}
const_iterator find(StringRef Key) const {
int Bucket = FindKey(Key);
if (Bucket == -1) return end();
return const_iterator(TheTable+Bucket);
}
/// lookup - Return the entry for the specified key, or a default
/// constructed value if no such entry exists.
ValueTy lookup(StringRef Key) const {
const_iterator it = find(Key);
if (it != end())
return it->second;
return ValueTy();
}
ValueTy& operator[](StringRef Key) {
return GetOrCreateValue(Key).getValue();
}
size_type count(StringRef Key) const {
return find(Key) == end() ? 0 : 1;
}
/// insert - Insert the specified key/value pair into the map. If the key
/// already exists in the map, return false and ignore the request, otherwise
/// insert it and return true.
bool insert(MapEntryTy *KeyValue) {
unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
ItemBucket &Bucket = TheTable[BucketNo];
if (Bucket.Item && Bucket.Item != getTombstoneVal())
return false; // Already exists in map.
if (Bucket.Item == getTombstoneVal())
--NumTombstones;
Bucket.Item = KeyValue;
++NumItems;
if (ShouldRehash())
RehashTable();
return true;
}
// clear - Empties out the StringMap
void clear() {
if (empty()) return;
// Zap all values, resetting the keys back to non-present (not tombstone),
// which is safe because we're removing all elements.
for (ItemBucket *I = TheTable, *E = TheTable+NumBuckets; I != E; ++I) {
if (I->Item && I->Item != getTombstoneVal()) {
static_cast<MapEntryTy*>(I->Item)->Destroy(Allocator);
I->Item = 0;
}
}
NumItems = 0;
}
/// GetOrCreateValue - Look up the specified key in the table. If a value
/// exists, return it. Otherwise, default construct a value, insert it, and
/// return.
template <typename InitTy>
StringMapEntry<ValueTy> &GetOrCreateValue(StringRef Key,
InitTy Val) {
unsigned BucketNo = LookupBucketFor(Key);
ItemBucket &Bucket = TheTable[BucketNo];
if (Bucket.Item && Bucket.Item != getTombstoneVal())
return *static_cast<MapEntryTy*>(Bucket.Item);
MapEntryTy *NewItem =
MapEntryTy::Create(Key.begin(), Key.end(), Allocator, Val);
if (Bucket.Item == getTombstoneVal())
--NumTombstones;
++NumItems;
// Fill in the bucket for the hash table. The FullHashValue was already
// filled in by LookupBucketFor.
Bucket.Item = NewItem;
if (ShouldRehash())
RehashTable();
return *NewItem;
}
StringMapEntry<ValueTy> &GetOrCreateValue(StringRef Key) {
return GetOrCreateValue(Key, ValueTy());
}
template <typename InitTy>
StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
const char *KeyEnd,
InitTy Val) {
return GetOrCreateValue(StringRef(KeyStart, KeyEnd - KeyStart), Val);
}
StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
const char *KeyEnd) {
return GetOrCreateValue(StringRef(KeyStart, KeyEnd - KeyStart));
}
/// remove - Remove the specified key/value pair from the map, but do not
/// erase it. This aborts if the key is not in the map.
void remove(MapEntryTy *KeyValue) {
RemoveKey(KeyValue);
}
void erase(iterator I) {
MapEntryTy &V = *I;
remove(&V);
V.Destroy(Allocator);
}
bool erase(StringRef Key) {
iterator I = find(Key);
if (I == end()) return false;
erase(I);
return true;
}
~StringMap() {
clear();
free(TheTable);
}
};
template<typename ValueTy>
class StringMapConstIterator {
protected:
StringMapImpl::ItemBucket *Ptr;
public:
typedef StringMapEntry<ValueTy> value_type;
explicit StringMapConstIterator(StringMapImpl::ItemBucket *Bucket,
bool NoAdvance = false)
: Ptr(Bucket) {
if (!NoAdvance) AdvancePastEmptyBuckets();
}
const value_type &operator*() const {
return *static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
}
const value_type *operator->() const {
return static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
}
bool operator==(const StringMapConstIterator &RHS) const {
return Ptr == RHS.Ptr;
}
bool operator!=(const StringMapConstIterator &RHS) const {
return Ptr != RHS.Ptr;
}
inline StringMapConstIterator& operator++() { // Preincrement
++Ptr;
AdvancePastEmptyBuckets();
return *this;
}
StringMapConstIterator operator++(int) { // Postincrement
StringMapConstIterator tmp = *this; ++*this; return tmp;
}
private:
void AdvancePastEmptyBuckets() {
while (Ptr->Item == 0 || Ptr->Item == StringMapImpl::getTombstoneVal())
++Ptr;
}
};
template<typename ValueTy>
class StringMapIterator : public StringMapConstIterator<ValueTy> {
public:
explicit StringMapIterator(StringMapImpl::ItemBucket *Bucket,
bool NoAdvance = false)
: StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
}
StringMapEntry<ValueTy> &operator*() const {
return *static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
}
StringMapEntry<ValueTy> *operator->() const {
return static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
}
};
}
#endif