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14bfc3f5 ILT |
1 | // stringpool.cc -- a string pool for gold |
2 | ||
3 | #include "gold.h" | |
4 | ||
5 | #include <cassert> | |
6 | #include <cstring> | |
7 | ||
8 | #include "stringpool.h" | |
9 | ||
10 | namespace gold | |
11 | { | |
12 | ||
13 | Stringpool::Stringpool() | |
14 | : string_set_(), strings_() | |
15 | { | |
16 | } | |
17 | ||
18 | Stringpool::~Stringpool() | |
19 | { | |
20 | for (std::list<stringdata*>::iterator p = this->strings_.begin(); | |
21 | p != this->strings_.end(); | |
22 | ++p) | |
23 | delete[] reinterpret_cast<char*>(*p); | |
24 | } | |
25 | ||
26 | // Hash function. | |
27 | ||
28 | size_t | |
29 | Stringpool::Stringpool_hash::operator()(const char* s) const | |
30 | { | |
31 | // Fowler/Noll/Vo (FNV) hash (type FNV-1a). | |
32 | if (sizeof(size_t) == 8) | |
33 | { | |
34 | size_t result = 14695981039346656037ULL; | |
35 | while (*s != '\0') | |
36 | { | |
37 | result &= (size_t) *s++; | |
38 | result *= 1099511628211ULL; | |
39 | } | |
40 | return result; | |
41 | } | |
42 | else | |
43 | { | |
44 | size_t result = 2166136261UL; | |
45 | while (*s != '\0') | |
46 | { | |
47 | result ^= (size_t) *s++; | |
48 | result *= 16777619UL; | |
49 | } | |
50 | return result; | |
51 | } | |
52 | } | |
53 | ||
54 | // Add a string to the list of canonical strings. Return a pointer to | |
55 | // the canonical string. | |
56 | ||
57 | const char* | |
58 | Stringpool::add_string(const char* s) | |
59 | { | |
60 | const size_t buffer_size = 1000; | |
61 | size_t len = strlen(s); | |
62 | ||
63 | size_t alc; | |
64 | bool front = true; | |
65 | if (len >= buffer_size) | |
66 | { | |
67 | alc = sizeof(stringdata) + len; | |
68 | front = false; | |
69 | } | |
70 | else if (this->strings_.empty()) | |
71 | alc = sizeof(stringdata) + buffer_size; | |
72 | else | |
73 | { | |
74 | stringdata *psd = this->strings_.front(); | |
75 | if (len >= psd->alc - psd->len) | |
76 | alc = sizeof(stringdata) + buffer_size; | |
77 | else | |
78 | { | |
79 | char* ret = psd->data + psd->len; | |
80 | memcpy(ret, s, len + 1); | |
81 | psd->len += len + 1; | |
82 | return ret; | |
83 | } | |
84 | } | |
85 | ||
86 | stringdata *psd = reinterpret_cast<stringdata*>(new char[alc]); | |
87 | psd->alc = alc; | |
88 | memcpy(psd->data, s, len + 1); | |
89 | psd->len = len + 1; | |
90 | if (front) | |
91 | this->strings_.push_front(psd); | |
92 | else | |
93 | this->strings_.push_back(psd); | |
94 | return psd->data; | |
95 | } | |
96 | ||
97 | // Add a string to a string pool. | |
98 | ||
99 | const char* | |
100 | Stringpool::add(const char* s) | |
101 | { | |
102 | // FIXME: This will look up the entry twice in the hash table. The | |
103 | // problem is that we can't insert S before we canonicalize it. I | |
104 | // don't think there is a way to handle this correct with | |
105 | // unordered_set, so this should be replaced with custom code to do | |
106 | // what we need, which is to return the empty slot. | |
107 | ||
108 | String_set_type::const_iterator p = this->string_set_.find(s); | |
109 | if (p != this->string_set_.end()) | |
110 | return *p; | |
111 | ||
112 | const char* ret = this->add_string(s); | |
113 | std::pair<String_set_type::iterator, bool> ins = | |
114 | this->string_set_.insert(ret); | |
115 | assert(ins.second); | |
116 | return ret; | |
117 | } | |
118 | ||
119 | // Add a prefix of a string to a string pool. | |
120 | ||
121 | const char* | |
122 | Stringpool::add(const char* s, size_t len) | |
123 | { | |
124 | // FIXME: This implementation should be rewritten when we rewrite | |
125 | // the hash table to avoid copying. | |
126 | std::string st(s, len); | |
127 | return this->add(st); | |
128 | } | |
129 | ||
130 | } // End namespace gold. |