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| 46 | |
46 | |
| 47 | typedef std::tr1::unordered_set<const char *, hash, equal> HT; |
47 | typedef std::tr1::unordered_set<const char *, hash, equal> HT; |
| 48 | |
48 | |
| 49 | static HT ht; |
49 | static HT ht; |
| 50 | |
50 | |
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51 | static const char *makevec (const char *s) |
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52 | { |
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53 | int len = strlen (s); |
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54 | |
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55 | const char *v = (const char *)(2 + (int *)malloc (sizeof (int) * 2 + len + 1)); |
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56 | |
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57 | shstr::length (v) = len; |
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58 | shstr::refcnt (v) = 1; |
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59 | |
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60 | memcpy ((char *)v, s, len + 1); |
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61 | |
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62 | return s; |
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63 | } |
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64 | |
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65 | const char *shstr::null = makevec ("<nil>"); |
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66 | |
| 51 | const char * |
67 | const char * |
| 52 | shstr::find (const char *s) |
68 | shstr::find (const char *s) |
| 53 | { |
69 | { |
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70 | if (!s) |
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71 | return s; |
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72 | |
| 54 | HT::iterator i = ht.find (s); |
73 | HT::iterator i = ht.find (s); |
| 55 | |
74 | |
| 56 | return i != ht.end () |
75 | return i != ht.end () |
| 57 | ? (char *)*i |
76 | ? *i |
| 58 | : 0; |
77 | : 0; |
| 59 | } |
78 | } |
| 60 | |
79 | |
| 61 | const char * |
80 | const char * |
| 62 | shstr::intern (const char *s) |
81 | shstr::intern (const char *s) |
| 63 | { |
82 | { |
| 64 | HT::iterator i = ht.find (s); |
83 | if (!s) |
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84 | return null; |
| 65 | |
85 | |
| 66 | if (i != ht.end ()) |
86 | if (const char *found = find (s)) |
| 67 | return (char *)*i; |
87 | { |
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88 | ++refcnt (found); |
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89 | return found; |
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90 | } |
| 68 | |
91 | |
| 69 | int len = strlen (s); |
92 | s = makevec (s); |
| 70 | |
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| 71 | int *v = (int *)malloc (sizeof (int) * 2 + len + 1); |
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| 72 | |
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| 73 | v [0] = len; |
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| 74 | v [1] = 0; |
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| 75 | |
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| 76 | v += 2; |
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| 77 | |
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| 78 | memcpy (v, s, len + 1); |
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| 79 | |
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| 80 | ht.insert ((char *)v); |
93 | ht.insert (s); |
| 81 | |
94 | return s; |
| 82 | return (char *)v; |
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| 83 | } |
95 | } |
| 84 | |
96 | |
| 85 | // TODO: periodically test refcounts == 0 for a few strings (e.g. one hash bucket, |
97 | // periodically test refcounts == 0 for a few strings |
| 86 | // exploiting the fatc that iterators stay valid for unordered_set). |
98 | // this is the ONLY thing that erases stuff from ht. keep it that way. |
| 87 | void |
99 | void |
| 88 | shstr::gc () |
100 | shstr::gc () |
| 89 | { |
101 | { |
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102 | static const char *curpos; |
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103 | |
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104 | HT::iterator i = curpos ? ht.find (curpos) : ht.begin (); |
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105 | |
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106 | if (i == ht.end ()) |
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107 | i = ht.begin (); |
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108 | |
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109 | // go through all strings roughly once every 4 minutes |
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110 | int n = ht.size () / 256 + 16; |
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111 | |
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112 | for (;;) |
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113 | { |
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114 | if (i == ht.end ()) |
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115 | { |
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116 | curpos = 0; |
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117 | return; |
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118 | } |
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119 | else if (!--n) |
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120 | break; |
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121 | else if (!refcnt (*i)) |
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122 | { |
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123 | HT::iterator o = i++; |
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124 | const char *s = *o; |
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125 | ht.erase (o); |
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126 | |
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127 | //printf ("GC %4d %3d %d >%s<%d\n", (int)ht.size (), n, shstr::refcnt (s), s, shstr::length (s)); |
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128 | free (-2 + (int *)s); |
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129 | } |
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130 | else |
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131 | ++i; |
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132 | } |
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133 | |
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134 | curpos = *i; |
| 90 | } |
135 | } |
| 91 | |
136 | |
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137 | //TODO: this should of course not be here |
| 92 | /* buf_overflow() - we don't want to exceed the buffer size of |
138 | /* buf_overflow() - we don't want to exceed the buffer size of |
| 93 | * buf1 by adding on buf2! Returns true if overflow will occur. |
139 | * buf1 by adding on buf2! Returns true if overflow will occur. |
| 94 | */ |
140 | */ |
| 95 | |
141 | |
| 96 | int |
142 | int |
