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1 | |
1 | /* |
2 | /* |
2 | * shstr.C |
3 | * shstr.C |
3 | */ |
4 | */ |
4 | |
5 | |
5 | #include <cstring> |
6 | #include <cstring> |
6 | #include <cstdlib> |
7 | #include <cstdlib> |
7 | |
8 | |
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9 | #include <glib.h> |
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10 | |
8 | #include <tr1/unordered_set> |
11 | #include <tr1/unordered_set> |
9 | |
12 | |
10 | #include "shstr.h" |
13 | #include "shstr.h" |
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14 | #include "util.h" |
11 | |
15 | |
12 | struct hash |
16 | typedef |
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17 | std::tr1::unordered_set < const char *, |
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18 | str_hash, |
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19 | str_equal > |
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20 | HT; |
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21 | |
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22 | static HT |
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23 | ht; |
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24 | |
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25 | static const char * |
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26 | makevec (const char *s) |
13 | { |
27 | { |
14 | std::size_t operator ()(const char *s) const |
28 | int |
15 | { |
29 | len = strlen (s); |
16 | unsigned long hash = 0; |
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17 | unsigned int i = 0; |
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18 | |
30 | |
19 | /* use the one-at-a-time hash function, which supposedly is |
31 | const char * |
20 | * better than the djb2-like one used by perl5.005, but |
32 | v = (const char *) (2 + (int *) g_slice_alloc (sizeof (int) * 2 + len + 1)); |
21 | * certainly is better then the bug used here before. |
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22 | * see http://burtleburtle.net/bob/hash/doobs.html |
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23 | */ |
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24 | while (*s) |
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25 | { |
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26 | hash += *s++; |
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27 | hash += hash << 10; |
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28 | hash ^= hash >> 6; |
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29 | } |
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30 | |
33 | |
31 | hash += hash << 3; |
34 | shstr::length (v) = len; |
32 | hash ^= hash >> 11; |
35 | shstr::refcnt (v) = 1; |
33 | hash += hash << 15; |
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34 | |
36 | |
35 | return hash; |
37 | memcpy ((char *) v, s, len + 1); |
36 | } |
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37 | }; |
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38 | |
38 | |
39 | struct equal |
39 | return v; |
40 | { |
40 | } |
41 | bool operator ()(const char *a, const char *b) const |
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42 | { |
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43 | return !strcmp (a, b); |
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44 | } |
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45 | }; |
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46 | |
41 | |
47 | typedef std::tr1::unordered_set<const char *, hash, equal> HT; |
42 | const char * |
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43 | shstr::null = makevec ("<nil>"); |
48 | |
44 | |
49 | static HT ht; |
45 | // what weird misoptimisation is this again? |
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46 | const shstr undead_name ("undead"); |
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47 | |
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48 | shstr skill_names[NUM_SKILLS]; |
50 | |
49 | |
51 | const char * |
50 | const char * |
52 | shstr::find (const char *s) |
51 | shstr::find (const char *s) |
53 | { |
52 | { |
54 | if (!s) |
53 | if (!s) |
55 | return s; |
54 | return s; |
56 | |
55 | |
57 | HT::iterator i = ht.find (s); |
56 | HT::iterator i = ht.find (s); |
58 | |
57 | |
59 | return i != ht.end () |
58 | return i != ht.end ()? *i : 0; |
60 | ? (char *)*i |
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61 | : 0; |
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62 | } |
59 | } |
63 | |
60 | |
64 | const char * |
61 | const char * |
65 | shstr::intern (const char *s) |
62 | shstr::intern (const char *s) |
66 | { |
63 | { |
67 | if (!s) |
64 | if (!s) |
68 | return s; |
65 | return null; |
69 | |
66 | |
70 | if (const char *found = find (s)) |
67 | if (const char *found = find (s)) |
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68 | { |
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69 | ++refcnt (found); |
71 | return found; |
70 | return found; |
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71 | } |
72 | |
72 | |
73 | int len = strlen (s); |
73 | s = makevec (s); |
74 | |
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75 | int *v = (int *)malloc (sizeof (int) * 2 + len + 1); |
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76 | |
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77 | v [0] = len; |
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78 | v [1] = 0; |
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79 | |
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80 | v += 2; |
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81 | |
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82 | memcpy (v, s, len + 1); |
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83 | |
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84 | ht.insert ((char *)v); |
74 | ht.insert (s); |
85 | |
75 | return s; |
86 | return (char *)v; |
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87 | } |
76 | } |
88 | |
77 | |
89 | // TODO: periodically test refcounts == 0 for a few strings (e.g. one hash bucket, |
78 | // periodically test refcounts == 0 for a few strings |
90 | // exploiting the fatc that iterators stay valid for unordered_set). |
79 | // this is the ONLY thing that erases stuff from ht. keep it that way. |
91 | void |
80 | void |
92 | shstr::gc () |
81 | shstr::gc () |
93 | { |
82 | { |
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83 | return; //D |
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84 | //D currently disabled: some datastructures might still store them |
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85 | //D but their pointers will become invalidated |
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86 | static const char *curpos; |
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87 | |
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88 | HT::iterator i = curpos ? ht.find (curpos) : ht.begin (); |
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89 | |
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90 | if (i == ht.end ()) |
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91 | i = ht.begin (); |
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92 | |
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93 | // go through all strings roughly once every 4 minutes |
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94 | int n = ht.size () / 256 + 16; |
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95 | |
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96 | for (;;) |
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97 | { |
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98 | if (i == ht.end ()) |
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99 | { |
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100 | curpos = 0; |
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101 | return; |
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102 | } |
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103 | else if (!--n) |
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104 | break; |
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105 | else if (!refcnt (*i)) |
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106 | { |
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107 | HT::iterator o = i++; |
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108 | const char *s = *o; |
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109 | |
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110 | ht.erase (o); |
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111 | |
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112 | //printf ("GC %4d %3d %d >%s<%d\n", (int)ht.size (), n, shstr::refcnt (s), s, shstr::length (s)); |
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113 | g_slice_free1 (sizeof (int) * 2 + length (s) + 1, -2 + (int *) s); |
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114 | } |
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115 | else |
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116 | ++i; |
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117 | } |
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118 | |
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119 | curpos = *i; |
94 | } |
120 | } |
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121 | |
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122 | //TODO: this should of course not be here |
95 | |
123 | |
96 | /* buf_overflow() - we don't want to exceed the buffer size of |
124 | /* buf_overflow() - we don't want to exceed the buffer size of |
97 | * buf1 by adding on buf2! Returns true if overflow will occur. |
125 | * buf1 by adding on buf2! Returns true if overflow will occur. |
98 | */ |
126 | */ |
99 | |
127 | |
100 | int |
128 | int |
101 | buf_overflow (const char *buf1, const char *buf2, int bufsize) |
129 | buf_overflow (const char *buf1, const char *buf2, int bufsize) |
102 | { |
130 | { |
103 | int len1 = 0, len2 = 0; |
131 | int len1 = 0, len2 = 0; |
104 | |
132 | |
105 | if (buf1) |
133 | if (buf1) |
106 | len1 = strlen (buf1); |
134 | len1 = strlen (buf1); |
107 | if (buf2) |
135 | if (buf2) |
108 | len2 = strlen (buf2); |
136 | len2 = strlen (buf2); |
109 | if ((len1 + len2) >= bufsize) |
137 | if ((len1 + len2) >= bufsize) |
110 | return 1; |
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111 | return 0; |
138 | return 1; |
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139 | return 0; |
112 | } |
140 | } |
113 | |
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