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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/* Class to manage lookup of static names in a table. */
#include "mozilla/HashFunctions.h"
#include "mozilla/TextUtils.h"
#include "nsCRT.h"
#include "nscore.h"
#include "nsISupportsImpl.h"
#include "nsStaticNameTable.h"
using namespace mozilla;
struct NameTableKey {
NameTableKey(const nsDependentCString aNameArray[], const nsCString* aKeyStr)
: mNameArray(aNameArray), mIsUnichar(false) {
mKeyStr.m1b = aKeyStr;
}
NameTableKey(const nsDependentCString aNameArray[], const nsString* aKeyStr)
: mNameArray(aNameArray), mIsUnichar(true) {
mKeyStr.m2b = aKeyStr;
}
const nsDependentCString* mNameArray;
union {
const nsCString* m1b;
const nsString* m2b;
} mKeyStr;
bool mIsUnichar;
};
struct NameTableEntry : public PLDHashEntryHdr {
int32_t mIndex;
};
static bool matchNameKeysCaseInsensitive(const PLDHashEntryHdr* aHdr,
const void* aVoidKey) {
auto entry = static_cast<const NameTableEntry*>(aHdr);
auto key = static_cast<const NameTableKey*>(aVoidKey);
const nsDependentCString* name = &key->mNameArray[entry->mIndex];
return key->mIsUnichar ? key->mKeyStr.m2b->LowerCaseEqualsASCII(
name->get(), name->Length())
: key->mKeyStr.m1b->LowerCaseEqualsASCII(
name->get(), name->Length());
}
/*
* caseInsensitiveHashKey is just like PLDHashTable::HashStringKey except it
* uses (*s & ~0x20) instead of simply *s. This means that "aFOO" and
* "afoo" and "aFoo" will all hash to the same thing. It also means
* that some strings that aren't case-insensensitively equal will hash
* to the same value, but it's just a hash function so it doesn't
* matter.
*/
static PLDHashNumber caseInsensitiveStringHashKey(const void* aKey) {
PLDHashNumber h = 0;
const NameTableKey* tableKey = static_cast<const NameTableKey*>(aKey);
if (tableKey->mIsUnichar) {
for (const char16_t* s = tableKey->mKeyStr.m2b->get(); *s != '\0'; s++) {
h = AddToHash(h, *s & ~0x20);
}
} else {
for (const unsigned char* s = reinterpret_cast<const unsigned char*>(
tableKey->mKeyStr.m1b->get());
*s != '\0'; s++) {
h = AddToHash(h, *s & ~0x20);
}
}
return h;
}
static const struct PLDHashTableOps nametable_CaseInsensitiveHashTableOps = {
caseInsensitiveStringHashKey,
matchNameKeysCaseInsensitive,
PLDHashTable::MoveEntryStub,
PLDHashTable::ClearEntryStub,
nullptr,
};
nsStaticCaseInsensitiveNameTable::nsStaticCaseInsensitiveNameTable(
const char* const aNames[], int32_t aLength)
: mNameArray(nullptr),
mNameTable(&nametable_CaseInsensitiveHashTableOps, sizeof(NameTableEntry),
aLength),
mNullStr("") {
MOZ_COUNT_CTOR(nsStaticCaseInsensitiveNameTable);
MOZ_ASSERT(aNames, "null name table");
MOZ_ASSERT(aLength, "0 length");
mNameArray =
(nsDependentCString*)moz_xmalloc(aLength * sizeof(nsDependentCString));
for (int32_t index = 0; index < aLength; ++index) {
const char* raw = aNames[index];
#ifdef DEBUG
{
// verify invariants of contents
nsAutoCString temp1(raw);
nsDependentCString temp2(raw);
ToLowerCase(temp1);
MOZ_ASSERT(temp1.Equals(temp2), "upper case char in table");
MOZ_ASSERT(IsAsciiNullTerminated(raw),
"non-ascii string in table -- "
"case-insensitive matching won't work right");
}
#endif
// use placement-new to initialize the string object
nsDependentCString* strPtr = &mNameArray[index];
new (strPtr) nsDependentCString(raw);
NameTableKey key(mNameArray, strPtr);
auto entry = static_cast<NameTableEntry*>(mNameTable.Add(&key, fallible));
if (!entry) {
continue;
}
// If the entry already exists it's unlikely but possible that its index is
// zero, in which case this assertion won't fail. But if the index is
// non-zero (highly likely) then it will fail. In other words, this
// assertion is likely but not guaranteed to detect if an entry is already
// used.
MOZ_ASSERT(entry->mIndex == 0, "Entry already exists!");
entry->mIndex = index;
}
mNameTable.MarkImmutable();
}
nsStaticCaseInsensitiveNameTable::~nsStaticCaseInsensitiveNameTable() {
// manually call the destructor on placement-new'ed objects
for (uint32_t index = 0; index < mNameTable.EntryCount(); index++) {
mNameArray[index].~nsDependentCString();
}
free((void*)mNameArray);
MOZ_COUNT_DTOR(nsStaticCaseInsensitiveNameTable);
}
int32_t nsStaticCaseInsensitiveNameTable::Lookup(
const nsACString& aName) const {
NS_ASSERTION(mNameArray, "not inited");
const nsCString& str = PromiseFlatCString(aName);
NameTableKey key(mNameArray, &str);
auto entry = static_cast<NameTableEntry*>(mNameTable.Search(&key));
return entry ? entry->mIndex : nsStaticCaseInsensitiveNameTable::NOT_FOUND;
}
int32_t nsStaticCaseInsensitiveNameTable::Lookup(const nsAString& aName) const {
NS_ASSERTION(mNameArray, "not inited");
const nsString& str = PromiseFlatString(aName);
NameTableKey key(mNameArray, &str);
auto entry = static_cast<NameTableEntry*>(mNameTable.Search(&key));
return entry ? entry->mIndex : nsStaticCaseInsensitiveNameTable::NOT_FOUND;
}
const nsCString& nsStaticCaseInsensitiveNameTable::GetStringValue(
int32_t aIndex) {
NS_ASSERTION(mNameArray, "not inited");
if ((NOT_FOUND < aIndex) && ((uint32_t)aIndex < mNameTable.EntryCount())) {
return mNameArray[aIndex];
}
return mNullStr;
}