1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef LATINIME_TERMINAL_ATTRIBUTES_H
18#define LATINIME_TERMINAL_ATTRIBUTES_H
19
20#include "binary_format.h"
21
22namespace latinime {
23
24/**
25 * This class encapsulates information about a terminal that allows to
26 * retrieve local node attributes like the list of shortcuts without
27 * exposing the format structure to the client.
28 */
29class TerminalAttributes {
30 public:
31    class ShortcutIterator {
32        const uint8_t *const mDict;
33        int mPos;
34        bool mHasNextShortcutTarget;
35
36     public:
37        ShortcutIterator(const uint8_t *dict, const int pos, const uint8_t flags)
38                : mDict(dict), mPos(pos),
39                  mHasNextShortcutTarget(0 != (flags & BinaryFormat::FLAG_HAS_SHORTCUT_TARGETS)) {
40        }
41
42        inline bool hasNextShortcutTarget() const {
43            return mHasNextShortcutTarget;
44        }
45
46        // Gets the shortcut target itself as a uint16_t string. For parameters and return value
47        // see BinaryFormat::getWordAtAddress.
48        // TODO: make the output an uint32_t* to handle the whole unicode range.
49        inline int getNextShortcutTarget(const int maxDepth, uint16_t *outWord, int *outFreq) {
50            const int shortcutFlags = BinaryFormat::getFlagsAndForwardPointer(mDict, &mPos);
51            mHasNextShortcutTarget =
52                    0 != (shortcutFlags & BinaryFormat::FLAG_ATTRIBUTE_HAS_NEXT);
53            unsigned int i;
54            for (i = 0; i < MAX_WORD_LENGTH_INTERNAL; ++i) {
55                const int codePoint = BinaryFormat::getCodePointAndForwardPointer(mDict, &mPos);
56                if (NOT_A_CODE_POINT == codePoint) break;
57                outWord[i] = (uint16_t)codePoint;
58            }
59            *outFreq = BinaryFormat::getAttributeFrequencyFromFlags(shortcutFlags);
60            return i;
61        }
62    };
63
64    TerminalAttributes(const uint8_t *const dict, const uint8_t flags, const int pos)
65            : mDict(dict), mFlags(flags), mStartPos(pos) {
66    }
67
68    inline ShortcutIterator getShortcutIterator() const {
69        // The size of the shortcuts is stored here so that the whole shortcut chunk can be
70        // skipped quickly, so we ignore it.
71        return ShortcutIterator(mDict, mStartPos + BinaryFormat::SHORTCUT_LIST_SIZE_SIZE, mFlags);
72    }
73
74    bool isBlacklistedOrNotAWord() const {
75        return mFlags & (BinaryFormat::FLAG_IS_BLACKLISTED | BinaryFormat::FLAG_IS_NOT_A_WORD);
76    }
77
78 private:
79    DISALLOW_IMPLICIT_CONSTRUCTORS(TerminalAttributes);
80    const uint8_t *const mDict;
81    const uint8_t mFlags;
82    const int mStartPos;
83};
84} // namespace latinime
85#endif // LATINIME_TERMINAL_ATTRIBUTES_H
86