gecko-dev/layout/tables/SpanningCellSorter.cpp

162 lines
5.1 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
// 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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* Code to sort cells by their colspan, used by BasicTableLayoutStrategy.
*/
#include "SpanningCellSorter.h"
#include "nsQuickSort.h"
#include "nsIPresShell.h"
#include "mozilla/HashFunctions.h"
//#define DEBUG_SPANNING_CELL_SORTER
SpanningCellSorter::SpanningCellSorter()
: mState(ADDING)
, mHashTable(&HashTableOps, sizeof(HashTableEntry))
, mSortedHashTable(nullptr)
{
memset(mArray, 0, sizeof(mArray));
}
SpanningCellSorter::~SpanningCellSorter()
{
delete [] mSortedHashTable;
}
/* 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;
}
/* static */ int
SpanningCellSorter::SortArray(const void *a, const void *b, void *closure)
{
int32_t spanA = (*static_cast<HashTableEntry*const*>(a))->mColSpan;
int32_t spanB = (*static_cast<HashTableEntry*const*>(b))->mColSpan;
if (spanA < spanB)
return -1;
if (spanA == spanB)
return 0;
return 1;
}
SpanningCellSorter::Item*
SpanningCellSorter::GetNext(int32_t *aColSpan)
{
NS_ASSERTION(mState != DONE, "done enumerating, stop calling");
switch (mState) {
case ADDING:
/* prepare to enumerate the array */
mState = ENUMERATING_ARRAY;
mEnumerationIndex = 0;
MOZ_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) {
HashTableEntry **sh =
new HashTableEntry*[mHashTable.EntryCount()];
int32_t j = 0;
for (auto iter = mHashTable.Iter(); !iter.Done(); iter.Next()) {
sh[j++] = static_cast<HashTableEntry*>(iter.Get());
}
NS_QuickSort(sh, mHashTable.EntryCount(), sizeof(sh[0]),
SortArray, nullptr);
mSortedHashTable = sh;
}
MOZ_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;
MOZ_FALLTHROUGH;
case DONE:
;
}
return nullptr;
}