gecko-dev/layout/tables/SpanningCellSorter.cpp
2012-05-21 12:12:37 +01:00

192 lines
6.1 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"
//#define DEBUG_SPANNING_CELL_SORTER
SpanningCellSorter::SpanningCellSorter(nsIPresShell *aPresShell)
: mPresShell(aPresShell)
, mState(ADDING)
, mSortedHashTable(nsnull)
{
memset(mArray, 0, sizeof(mArray));
mHashTable.entryCount = 0;
}
SpanningCellSorter::~SpanningCellSorter()
{
if (mHashTable.entryCount) {
PL_DHashTableFinish(&mHashTable);
mHashTable.entryCount = 0;
}
delete [] mSortedHashTable;
}
/* static */ PLDHashTableOps
SpanningCellSorter::HashTableOps = {
PL_DHashAllocTable,
PL_DHashFreeTable,
HashTableHashKey,
HashTableMatchEntry,
PL_DHashMoveEntryStub,
PL_DHashClearEntryStub,
PL_DHashFinalizeStub,
nsnull
};
/* static */ PLDHashNumber
SpanningCellSorter::HashTableHashKey(PLDHashTable *table, const void *key)
{
return NS_PTR_TO_INT32(key);
}
/* static */ bool
SpanningCellSorter::HashTableMatchEntry(PLDHashTable *table,
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(PRInt32 aColSpan, PRInt32 aRow, PRInt32 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 != nsnull, false);
i->row = aRow;
i->col = aCol;
if (UseArrayForSpan(aColSpan)) {
PRInt32 index = SpanToIndex(aColSpan);
i->next = mArray[index];
mArray[index] = i;
} else {
if (!mHashTable.entryCount &&
!PL_DHashTableInit(&mHashTable, &HashTableOps, nsnull,
sizeof(HashTableEntry), PL_DHASH_MIN_SIZE)) {
NS_NOTREACHED("table init failed");
mHashTable.entryCount = 0;
return false;
}
HashTableEntry *entry = static_cast<HashTableEntry*>
(PL_DHashTableOperate(&mHashTable, NS_INT32_TO_PTR(aColSpan),
PL_DHASH_ADD));
NS_ENSURE_TRUE(entry, false);
NS_ASSERTION(entry->mColSpan == 0 || entry->mColSpan == aColSpan,
"wrong entry");
NS_ASSERTION((entry->mColSpan == 0) == (entry->mItems == nsnull),
"entry should be either new or properly initialized");
entry->mColSpan = aColSpan;
i->next = entry->mItems;
entry->mItems = i;
}
return true;
}
/* static */ PLDHashOperator
SpanningCellSorter::FillSortedArray(PLDHashTable *table, PLDHashEntryHdr *hdr,
PRUint32 number, void *arg)
{
HashTableEntry *entry = static_cast<HashTableEntry*>(hdr);
HashTableEntry **sh = static_cast<HashTableEntry**>(arg);
sh[number] = entry;
return PL_DHASH_NEXT;
}
/* static */ int
SpanningCellSorter::SortArray(const void *a, const void *b, void *closure)
{
PRInt32 spanA = (*static_cast<HashTableEntry*const*>(a))->mColSpan;
PRInt32 spanB = (*static_cast<HashTableEntry*const*>(b))->mColSpan;
if (spanA < spanB)
return -1;
if (spanA == spanB)
return 0;
return 1;
}
SpanningCellSorter::Item*
SpanningCellSorter::GetNext(PRInt32 *aColSpan)
{
NS_ASSERTION(mState != DONE, "done enumerating, stop calling");
switch (mState) {
case ADDING:
/* prepare to enumerate the array */
mState = ENUMERATING_ARRAY;
mEnumerationIndex = 0;
/* fall through */
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) {
HashTableEntry **sh =
new HashTableEntry*[mHashTable.entryCount];
if (!sh) {
// give up
mState = DONE;
return nsnull;
}
PL_DHashTableEnumerate(&mHashTable, FillSortedArray, sh);
NS_QuickSort(sh, mHashTable.entryCount, sizeof(sh[0]),
SortArray, nsnull);
mSortedHashTable = sh;
}
/* fall through */
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;
/* fall through */
case DONE:
;
}
return nsnull;
}