summaryrefslogtreecommitdiffstats
path: root/layout/tables/SpanningCellSorter.cpp
blob: 686b02d89b4519d4bbc61a6b070705dc71d10787 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/* -*- 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"

using mozilla::fallible;

//#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 NS_PTR_TO_INT32(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;
}