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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=4:et:sw=4:
/* 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
/*
* Code to sort cells by their colspan, used by BasicTableLayoutStrategy.
*/
#include "SpanningCellSorter.h"
#include "nsTArray.h"
#include "mozilla/HashFunctions.h"
using namespace mozilla;
// #define DEBUG_SPANNING_CELL_SORTER
SpanningCellSorter::SpanningCellSorter()
: mState(ADDING), mHashTable(&HashTableOps, sizeof(HashTableEntry)) {
memset(mArray, 0, sizeof(mArray));
}
SpanningCellSorter::~SpanningCellSorter() = default;
/* static */ const PLDHashTableOps SpanningCellSorter::HashTableOps = {
HashTableHashKey, HashTableMatchEntry, PLDHashTable::MoveEntryStub,
PLDHashTable::ClearEntryStub, nullptr};
/* static */
PLDHashNumber SpanningCellSorter::HashTableHashKey(const void* key) {
return HashGeneric(key);
}
/* static */
bool SpanningCellSorter::HashTableMatchEntry(const PLDHashEntryHdr* hdr,
const void* key) {
const HashTableEntry* entry = static_cast<const HashTableEntry*>(hdr);
return NS_PTR_TO_INT32(key) == entry->mColSpan;
}
bool SpanningCellSorter::AddCell(int32_t aColSpan, int32_t aRow, int32_t aCol) {
NS_ASSERTION(mState == ADDING, "cannot call AddCell after GetNext");
NS_ASSERTION(aColSpan >= ARRAY_BASE, "cannot add cells with colspan<2");
Item* i = (Item*)mozilla::AutoStackArena::Allocate(sizeof(Item));
NS_ENSURE_TRUE(i != nullptr, false);
i->row = aRow;
i->col = aCol;
if (UseArrayForSpan(aColSpan)) {
int32_t index = SpanToIndex(aColSpan);
i->next = mArray[index];
mArray[index] = i;
} else {
auto entry = static_cast<HashTableEntry*>(
mHashTable.Add(NS_INT32_TO_PTR(aColSpan), fallible));
NS_ENSURE_TRUE(entry, false);
NS_ASSERTION(entry->mColSpan == 0 || entry->mColSpan == aColSpan,
"wrong entry");
NS_ASSERTION((entry->mColSpan == 0) == (entry->mItems == nullptr),
"entry should be either new or properly initialized");
entry->mColSpan = aColSpan;
i->next = entry->mItems;
entry->mItems = i;
}
return true;
}
SpanningCellSorter::Item* SpanningCellSorter::GetNext(int32_t* aColSpan) {
NS_ASSERTION(mState != DONE, "done enumerating, stop calling");
// Our comparator needs the SpanningCellSorter private HashTableEntry
class HashTableEntryComparator {
public:
bool Equals(HashTableEntry* left, HashTableEntry* right) const {
return left->mColSpan == right->mColSpan;
}
bool LessThan(HashTableEntry* left, HashTableEntry* right) const {
return left->mColSpan < right->mColSpan;
}
};
switch (mState) {
case ADDING:
/* prepare to enumerate the array */
mState = ENUMERATING_ARRAY;
mEnumerationIndex = 0;
[[fallthrough]];
case ENUMERATING_ARRAY:
while (mEnumerationIndex < ARRAY_SIZE && !mArray[mEnumerationIndex])
++mEnumerationIndex;
if (mEnumerationIndex < ARRAY_SIZE) {
Item* result = mArray[mEnumerationIndex];
*aColSpan = IndexToSpan(mEnumerationIndex);
NS_ASSERTION(result, "logic error");
#ifdef DEBUG_SPANNING_CELL_SORTER
printf(
"SpanningCellSorter[%p]:"
" returning list for colspan=%d from array\n",
static_cast<void*>(this), *aColSpan);
#endif
++mEnumerationIndex;
return result;
}
/* prepare to enumerate the hash */
mState = ENUMERATING_HASH;
mEnumerationIndex = 0;
if (mHashTable.EntryCount() > 0) {
// This clear is a no-op if the array is empty and it makes us
// resilient against re-entrance.
mSortedHashTable.ClearAndRetainStorage();
mSortedHashTable.SetCapacity(mHashTable.EntryCount());
for (auto iter = mHashTable.ConstIter(); !iter.Done(); iter.Next()) {
mSortedHashTable.AppendElement(
static_cast<HashTableEntry*>(iter.Get()));
}
mSortedHashTable.Sort(HashTableEntryComparator());
}
[[fallthrough]];
case ENUMERATING_HASH:
if (mEnumerationIndex < mHashTable.EntryCount()) {
Item* result = mSortedHashTable[mEnumerationIndex]->mItems;
*aColSpan = mSortedHashTable[mEnumerationIndex]->mColSpan;
NS_ASSERTION(result, "holes in hash table");
#ifdef DEBUG_SPANNING_CELL_SORTER
printf(
"SpanningCellSorter[%p]:"
" returning list for colspan=%d from hash\n",
static_cast<void*>(this), *aColSpan);
#endif
++mEnumerationIndex;
return result;
}
mState = DONE;
[[fallthrough]];
case DONE:;
}
return nullptr;
}