Diffstat (limited to 'inputmethods/dasher/AlphabetMap.cpp') (more/less context) (ignore whitespace changes)
-rw-r--r-- | inputmethods/dasher/AlphabetMap.cpp | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/inputmethods/dasher/AlphabetMap.cpp b/inputmethods/dasher/AlphabetMap.cpp new file mode 100644 index 0000000..09e2c72 --- a/dev/null +++ b/inputmethods/dasher/AlphabetMap.cpp | |||
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1 | // AlphabetMap.cpp | ||
2 | // | ||
3 | ///////////////////////////////////////////////////////////////////////////// | ||
4 | // | ||
5 | // Copyright (c) 2002 Iain Murray | ||
6 | // | ||
7 | ///////////////////////////////////////////////////////////////////////////// | ||
8 | |||
9 | #include "AlphabetMap.h" | ||
10 | |||
11 | using namespace Dasher; | ||
12 | using namespace std; | ||
13 | |||
14 | alphabet_map::alphabet_map(unsigned int InitialTableSize) | ||
15 | : Undefined(0), HashTable(InitialTableSize<<1) | ||
16 | { | ||
17 | Entries.reserve(InitialTableSize); | ||
18 | } | ||
19 | |||
20 | |||
21 | void alphabet_map::Add(const string& Key, symbol Value) | ||
22 | { | ||
23 | RecursiveAdd(Key, Value, false); | ||
24 | } | ||
25 | |||
26 | |||
27 | void alphabet_map::RecursiveAdd(const string& Key, symbol Value, bool PrefixFlag) | ||
28 | { | ||
29 | Entry*& HashEntry = HashTable[Hash(Key)]; | ||
30 | |||
31 | // Loop through Entries with the correct Hash value. | ||
32 | for (Entry* i = HashEntry; i; i=i->Next) { | ||
33 | if (i->Key==Key) { | ||
34 | if (PrefixFlag) { | ||
35 | // Just tagging - don't change symbol. Recurse if necessary | ||
36 | i->KeyIsPrefix = true; | ||
37 | if (Key.size()>1) | ||
38 | RecursiveAdd(Key.substr(Key.size()-1), Undefined, true); | ||
39 | } else { | ||
40 | // Add symbol and leave | ||
41 | i->Symbol = Value; | ||
42 | } | ||
43 | return; | ||
44 | } | ||
45 | } | ||
46 | |||
47 | // When hash table gets 1/2 full... | ||
48 | // (no I haven't optimised when to resize) | ||
49 | if (Entries.size()<<1 >= HashTable.size()) { | ||
50 | // Double up all the storage | ||
51 | HashTable.clear(); | ||
52 | HashTable.resize(Entries.size()<<2); | ||
53 | Entries.reserve(Entries.size()<<1); | ||
54 | |||
55 | // Rehash as the pointers will all be mangled. | ||
56 | for (uint j=0; j<Entries.size(); j++) { | ||
57 | Entry*& HashEntry2 = HashTable[Hash(Entries[j].Key)]; | ||
58 | Entries[j].Next = HashEntry2; | ||
59 | HashEntry2 = &Entries[j]; | ||
60 | } | ||
61 | |||
62 | // Have to recall this function as the key's hash needs recalculating | ||
63 | RecursiveAdd(Key, Value, PrefixFlag); | ||
64 | return; | ||
65 | } | ||
66 | |||
67 | Entries.push_back(Entry(Key, Value, HashEntry)); | ||
68 | HashEntry = &Entries.back(); | ||
69 | } | ||
70 | |||
71 | |||
72 | symbol alphabet_map::Get(const string& Key, bool* KeyIsPrefix) const | ||
73 | { | ||
74 | // Loop through Entries with the correct Hash value. | ||
75 | for (Entry* i = HashTable[Hash(Key)]; i; i=i->Next) { | ||
76 | if (i->Key==Key) { | ||
77 | if (KeyIsPrefix!=0) | ||
78 | *KeyIsPrefix = i->KeyIsPrefix; | ||
79 | return i->Symbol; | ||
80 | } | ||
81 | } | ||
82 | |||
83 | if (KeyIsPrefix!=0) | ||
84 | *KeyIsPrefix = false; | ||
85 | return Undefined; | ||
86 | } | ||