1 /*
2  * Copyright (C) 2013, 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 #include "dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
18 
19 #include <cstddef>
20 #include <cstdint>
21 #include <cstdlib>
22 
23 #include "dictionary/utils/buffer_with_extendable_buffer.h"
24 
25 namespace latinime {
26 
27 const size_t DynamicPtWritingUtils::MAX_PTNODE_ARRAY_SIZE_TO_USE_SMALL_SIZE_FIELD = 0x7F;
28 const size_t DynamicPtWritingUtils::MAX_PTNODE_ARRAY_SIZE = 0x7FFF;
29 const int DynamicPtWritingUtils::SMALL_PTNODE_ARRAY_SIZE_FIELD_SIZE = 1;
30 const int DynamicPtWritingUtils::LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE = 2;
31 const int DynamicPtWritingUtils::LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE_FLAG = 0x8000;
32 const int DynamicPtWritingUtils::DICT_OFFSET_FIELD_SIZE = 3;
33 const int DynamicPtWritingUtils::MAX_DICT_OFFSET_VALUE = 0x7FFFFF;
34 const int DynamicPtWritingUtils::MIN_DICT_OFFSET_VALUE = -0x7FFFFF;
35 const int DynamicPtWritingUtils::DICT_OFFSET_NEGATIVE_FLAG = 0x800000;
36 const int DynamicPtWritingUtils::NODE_FLAG_FIELD_SIZE = 1;
37 
writeEmptyDictionary(BufferWithExtendableBuffer * const buffer,const int rootPos)38 /* static */ bool DynamicPtWritingUtils::writeEmptyDictionary(
39         BufferWithExtendableBuffer *const buffer, const int rootPos) {
40     int writingPos = rootPos;
41     if (!writePtNodeArraySizeAndAdvancePosition(buffer, 0 /* arraySize */, &writingPos)) {
42         return false;
43     }
44     return writeForwardLinkPositionAndAdvancePosition(buffer, NOT_A_DICT_POS /* forwardLinkPos */,
45             &writingPos);
46 }
47 
writeForwardLinkPositionAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const int forwardLinkPos,int * const forwardLinkFieldPos)48 /* static */ bool DynamicPtWritingUtils::writeForwardLinkPositionAndAdvancePosition(
49         BufferWithExtendableBuffer *const buffer, const int forwardLinkPos,
50         int *const forwardLinkFieldPos) {
51     return writeDictOffset(buffer, forwardLinkPos, (*forwardLinkFieldPos), forwardLinkFieldPos);
52 }
53 
writePtNodeArraySizeAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const size_t arraySize,int * const arraySizeFieldPos)54 /* static */ bool DynamicPtWritingUtils::writePtNodeArraySizeAndAdvancePosition(
55         BufferWithExtendableBuffer *const buffer, const size_t arraySize,
56         int *const arraySizeFieldPos) {
57     // Currently, all array size field to be created has LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE to
58     // simplify updating process.
59     // TODO: Use SMALL_PTNODE_ARRAY_SIZE_FIELD_SIZE for small arrays.
60     /*if (arraySize <= MAX_PTNODE_ARRAY_SIZE_TO_USE_SMALL_SIZE_FIELD) {
61         return buffer->writeUintAndAdvancePosition(arraySize, SMALL_PTNODE_ARRAY_SIZE_FIELD_SIZE,
62                 arraySizeFieldPos);
63     } else */
64     if (arraySize <= MAX_PTNODE_ARRAY_SIZE) {
65         uint32_t data = arraySize | LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE_FLAG;
66         return buffer->writeUintAndAdvancePosition(data, LARGE_PTNODE_ARRAY_SIZE_FIELD_SIZE,
67                 arraySizeFieldPos);
68     } else {
69         AKLOGI("PtNode array size cannot be written because arraySize is too large: %zd",
70                 arraySize);
71         ASSERT(false);
72         return false;
73     }
74 }
75 
writeFlagsAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const DynamicPtReadingUtils::NodeFlags nodeFlags,int * const nodeFlagsFieldPos)76 /* static */ bool DynamicPtWritingUtils::writeFlagsAndAdvancePosition(
77         BufferWithExtendableBuffer *const buffer,
78         const DynamicPtReadingUtils::NodeFlags nodeFlags, int *const nodeFlagsFieldPos) {
79     return buffer->writeUintAndAdvancePosition(nodeFlags, NODE_FLAG_FIELD_SIZE, nodeFlagsFieldPos);
80 }
81 
82 // Note that parentOffset is offset from node's head position.
writeParentPosOffsetAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const int parentPos,const int basePos,int * const parentPosFieldPos)83 /* static */ bool DynamicPtWritingUtils::writeParentPosOffsetAndAdvancePosition(
84         BufferWithExtendableBuffer *const buffer, const int parentPos, const int basePos,
85         int *const parentPosFieldPos) {
86     return writeDictOffset(buffer, parentPos, basePos, parentPosFieldPos);
87 }
88 
writeCodePointsAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const int * const codePoints,const int codePointCount,int * const codePointFieldPos)89 /* static */ bool DynamicPtWritingUtils::writeCodePointsAndAdvancePosition(
90         BufferWithExtendableBuffer *const buffer, const int *const codePoints,
91         const int codePointCount, int *const codePointFieldPos) {
92     if (codePointCount <= 0) {
93         AKLOGI("code points cannot be written because codePointCount is invalid: %d",
94                 codePointCount);
95         ASSERT(false);
96         return false;
97     }
98     const bool hasMultipleCodePoints = codePointCount > 1;
99     return buffer->writeCodePointsAndAdvancePosition(codePoints, codePointCount,
100             hasMultipleCodePoints, codePointFieldPos);
101 }
102 
writeChildrenPositionAndAdvancePosition(BufferWithExtendableBuffer * const buffer,const int childrenPosition,int * const childrenPositionFieldPos)103 /* static */ bool DynamicPtWritingUtils::writeChildrenPositionAndAdvancePosition(
104         BufferWithExtendableBuffer *const buffer, const int childrenPosition,
105         int *const childrenPositionFieldPos) {
106     return writeDictOffset(buffer, childrenPosition, (*childrenPositionFieldPos),
107             childrenPositionFieldPos);
108 }
109 
writeDictOffset(BufferWithExtendableBuffer * const buffer,const int targetPos,const int basePos,int * const offsetFieldPos)110 /* static */ bool DynamicPtWritingUtils::writeDictOffset(BufferWithExtendableBuffer *const buffer,
111         const int targetPos, const int basePos, int *const offsetFieldPos) {
112     int offset = targetPos - basePos;
113     if (targetPos == NOT_A_DICT_POS) {
114         offset = DynamicPtReadingUtils::DICT_OFFSET_INVALID;
115     } else if (offset == 0) {
116         offset = DynamicPtReadingUtils::DICT_OFFSET_ZERO_OFFSET;
117     }
118     if (offset > MAX_DICT_OFFSET_VALUE || offset < MIN_DICT_OFFSET_VALUE) {
119         AKLOGI("offset cannot be written because the offset is too large or too small: %d",
120                 offset);
121         ASSERT(false);
122         return false;
123     }
124     uint32_t data = 0;
125     if (offset >= 0) {
126         data = offset;
127     } else {
128         data = abs(offset) | DICT_OFFSET_NEGATIVE_FLAG;
129     }
130     return buffer->writeUintAndAdvancePosition(data, DICT_OFFSET_FIELD_SIZE, offsetFieldPos);
131 }
132 }
133