1 | /* The size of the shared strings hashtable. This must be smaller than |
1 | /* |
2 | * 32767, but 947 ought to be plenty enough. |
2 | * This file is part of Deliantra, the Roguelike Realtime MMORPG. |
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3 | * |
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4 | * Copyright (©) 2005,2006,2007 Marc Alexander Lehmann / Robin Redeker / the Deliantra team |
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5 | * |
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6 | * Deliantra is free software: you can redistribute it and/or modify |
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7 | * it under the terms of the GNU General Public License as published by |
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8 | * the Free Software Foundation, either version 3 of the License, or |
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9 | * (at your option) any later version. |
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10 | * |
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11 | * This program is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU General Public License |
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17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
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18 | * |
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19 | * The authors can be reached via e-mail to <support@deliantra.net> |
3 | */ |
20 | */ |
4 | #define TABLESIZE 4133 |
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5 | |
21 | |
6 | /* This specifies how many characters the hashing routine should look at. |
22 | #ifndef SHSTR_H__ |
7 | * You may actually save CPU by increasing this number if the typical string |
23 | #define SHSTR_H__ |
8 | * is large. |
24 | |
9 | */ |
25 | #include <sstream> |
10 | #ifndef MAXSTRING |
26 | |
11 | #define MAXSTRING 20 |
27 | #include "util.h" |
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28 | |
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29 | extern size_t shstr_alloc; |
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30 | |
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31 | extern int buf_overflow (const char *buf1, const char *buf2, int bufsize); |
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32 | |
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33 | struct shstr |
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34 | { |
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35 | static const char *null; |
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36 | |
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37 | const char *s; |
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38 | |
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39 | static int &refcnt (const char *s) |
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40 | { |
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41 | return *((int *)s - 1); |
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42 | } |
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43 | |
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44 | static int &length (const char *s) |
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45 | { |
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46 | return *((int *)s - 2); |
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47 | } |
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48 | |
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49 | int &refcnt () const |
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50 | { |
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51 | return refcnt (s); |
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52 | } |
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53 | |
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54 | int length () const |
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55 | { |
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56 | return length (s); |
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57 | } |
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58 | |
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59 | // returns wether this shared string begins with the given prefix, |
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60 | // used mainly for searched when users give only the start of a name. |
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61 | bool begins_with (const char *prefix) const |
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62 | { |
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63 | int plen = strlen (prefix); |
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64 | return !strncasecmp (s, prefix, plen) && length () >= plen; |
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65 | } |
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66 | |
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67 | static const char *find (const char *s); |
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68 | static const char *intern (const char *s); |
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69 | |
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70 | static void gc (); // garbage collect a few strings |
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71 | |
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72 | // this is used for informational messages and the like |
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73 | const char *operator &() const { return s; } |
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74 | |
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75 | const char &operator [](int i) const { return s[i]; } |
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76 | operator const char *() const { return s == null ? 0 : s; } |
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77 | |
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78 | shstr () |
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79 | : s (null) |
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80 | { |
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81 | } |
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82 | |
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83 | shstr (const shstr &sh) |
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84 | : s (sh.s) |
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85 | { |
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86 | ++refcnt (); |
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87 | } |
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88 | |
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89 | explicit shstr (const char *s) |
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90 | : s (intern (s)) |
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91 | { |
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92 | } |
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93 | |
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94 | ~shstr () |
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95 | { |
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96 | --refcnt (); |
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97 | } |
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98 | |
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99 | const shstr &operator =(const shstr &sh) |
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100 | { |
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101 | --refcnt (); |
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102 | s = sh.s; |
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103 | ++refcnt (); |
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104 | |
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105 | return *this; |
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106 | } |
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107 | |
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108 | const shstr &operator =(const char *str) |
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109 | { |
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110 | --refcnt (); |
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111 | |
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112 | // this optimises the important case of str == constant 0 |
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113 | if (is_constant (str)) |
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114 | s = str ? intern (str) : null; |
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115 | else |
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116 | s = intern (str); |
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117 | |
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118 | return *this; |
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119 | } |
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120 | |
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121 | bool operator ==(const shstr &b) |
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122 | { |
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123 | return s == b.s; |
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124 | } |
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125 | |
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126 | bool operator !=(const shstr &b) |
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127 | { |
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128 | return !(*this == b); |
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129 | } |
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130 | }; |
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131 | |
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132 | inline int strlen (const shstr &sh) |
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133 | { |
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134 | return sh.length (); |
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135 | } |
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136 | |
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137 | inline int strcmp (const shstr &a, const shstr &b) |
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138 | { |
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139 | // TODO: use this to find all the occurences of people using strcmp |
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140 | // all uses should be bogus, as we should be never interested in |
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141 | // comparing shstr's alphabetically |
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142 | #if 0 |
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143 | extern void do_not_use_strcmp_to_compare_shstr_values (); |
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144 | do_not_use_strcmp_to_compare_shstr_values (); |
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145 | #endif |
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146 | return a != b; |
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147 | } |
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148 | |
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149 | static std::ostream &operator <<(std::ostream &o, const shstr &sh) |
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150 | { |
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151 | o.write (sh.s, sh.length ()); |
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152 | return o; |
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153 | } |
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154 | |
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155 | // only good for mass comparisons to shstr objects |
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156 | struct shstr_cmp |
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157 | { |
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158 | const char *s; |
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159 | |
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160 | explicit shstr_cmp (const char *s) |
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161 | : s (shstr::find (s)) |
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162 | { |
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163 | } |
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164 | |
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165 | shstr_cmp (const shstr_cmp &sh) |
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166 | : s (sh.s) |
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167 | { |
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168 | } |
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169 | |
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170 | shstr_cmp &operator =(const shstr_cmp sh) { s = sh.s; return *this; } |
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171 | operator const char *() const { return s; } |
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172 | }; |
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173 | |
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174 | inline bool operator ==(const shstr_cmp &a, const shstr &b) |
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175 | { |
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176 | return a.s == b.s; |
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177 | } |
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178 | |
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179 | inline bool operator ==(const shstr &a, const shstr_cmp &b) |
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180 | { |
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181 | return b == a; |
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182 | } |
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183 | |
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184 | extern const shstr shstr_null; |
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185 | |
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186 | #define def(str) extern const shstr shstr_ ## str; |
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187 | # include "shstrinc.h" |
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188 | #undef def |
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189 | |
12 | #endif |
190 | #endif |
13 | |
191 | |
14 | /* In the unlikely occurence that 16383 references to a string are too |
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15 | * few, you can modify the below type to something bigger. |
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16 | * (The top bit of "refcount" is used to signify that "u.array" points |
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17 | * at the array entry.) |
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18 | */ |
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19 | #define REFCOUNT_TYPE int |
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20 | |
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21 | /* The offsetof macro is part of ANSI C, but many compilers lack it, for |
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22 | * example "gcc -ansi" |
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23 | */ |
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24 | #if !defined (offsetof) |
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25 | #define offsetof(type, member) (int)&(((type *)0)->member) |
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26 | #endif |
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27 | |
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28 | /* SS(string) will return the address of the shared_string struct which |
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29 | * contains "string". |
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30 | */ |
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31 | #define SS(x) ((shared_string *) ((x) - offsetof(shared_string, string))) |
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32 | |
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33 | #define SS_STATISTICS |
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34 | |
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35 | #define SS_DUMP_TABLE 1 |
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36 | #define SS_DUMP_TOTALS 2 |
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37 | |
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38 | #ifdef SS_STATISTICS |
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39 | static struct statistics { |
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40 | int calls; |
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41 | int hashed; |
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42 | int strcmps; |
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43 | int search; |
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44 | int linked; |
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45 | } add_stats, add_ref_stats, free_stats, find_stats, hash_stats; |
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46 | #define GATHER(n) (++n) |
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47 | #else /* !SS_STATISTICS */ |
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48 | #define GATHER(n) |
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49 | #endif /* SS_STATISTICS */ |
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50 | |
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51 | #define TOPBIT ((unsigned REFCOUNT_TYPE) 1 << (sizeof(REFCOUNT_TYPE) * CHAR_BIT - 1)) |
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52 | |
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53 | #define PADDING ((2 * sizeof(long) - sizeof(REFCOUNT_TYPE)) % sizeof(long)) + 1 |
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54 | |
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55 | typedef struct _shared_string { |
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56 | union { |
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57 | struct _shared_string **array; |
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58 | struct _shared_string *previous; |
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59 | } u; |
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60 | struct _shared_string *next; |
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61 | /* The top bit of "refcount" is used to signify that "u.array" points |
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62 | * at the array entry. |
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63 | */ |
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64 | unsigned REFCOUNT_TYPE refcount; |
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65 | /* Padding will be unused memory, since we can't know how large |
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66 | * the padding when allocating memory. We assume here that |
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67 | * sizeof(long) is a good boundary. |
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68 | */ |
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69 | char string[PADDING]; |
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70 | } shared_string; |
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