1 | /* Part of CPP library. (Macro hash table support.) |
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2 | Copyright (C) 1986, 87, 89, 92-95, 1996 Free Software Foundation, Inc. |
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3 | Written by Per Bothner, 1994. |
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4 | Based on CCCP program by by Paul Rubin, June 1986 |
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5 | Adapted to ANSI C, Richard Stallman, Jan 1987 |
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6 | |
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7 | This program is free software; you can redistribute it and/or modify it |
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8 | under the terms of the GNU General Public License as published by the |
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9 | Free Software Foundation; either version 2, or (at your option) any |
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10 | later version. |
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11 | |
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12 | This program is distributed in the hope that it will be useful, |
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13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | GNU General Public License for more details. |
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16 | |
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17 | You should have received a copy of the GNU General Public License |
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18 | along with this program; if not, write to the Free Software |
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19 | Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 | |
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21 | In other words, you are welcome to use, share and improve this program. |
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22 | You are forbidden to forbid anyone else to use, share and improve |
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23 | what you give them. Help stamp out software-hoarding! */ |
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24 | |
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25 | #include "cpplib.h" |
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26 | #include "cpphash.h" |
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27 | #include "gansidecl.h" |
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28 | |
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29 | extern char *xmalloc PARAMS ((unsigned)); |
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30 | |
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31 | /* Return hash function on name. must be compatible with the one |
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32 | computed a step at a time, elsewhere */ |
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33 | |
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34 | int |
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35 | hashf (name, len, hashsize) |
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36 | register const U_CHAR *name; |
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37 | register int len; |
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38 | int hashsize; |
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39 | { |
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40 | register int r = 0; |
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41 | |
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42 | while (len--) |
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43 | r = HASHSTEP (r, *name++); |
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44 | |
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45 | return MAKE_POS (r) % hashsize; |
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46 | } |
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47 | |
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48 | /* Find the most recent hash node for name name (ending with first |
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49 | non-identifier char) installed by install |
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50 | |
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51 | If LEN is >= 0, it is the length of the name. |
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52 | Otherwise, compute the length by scanning the entire name. |
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53 | |
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54 | If HASH is >= 0, it is the precomputed hash code. |
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55 | Otherwise, compute the hash code. */ |
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56 | |
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57 | HASHNODE * |
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58 | cpp_lookup (pfile, name, len, hash) |
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59 | cpp_reader *pfile; |
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60 | const U_CHAR *name; |
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61 | int len; |
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62 | int hash; |
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63 | { |
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64 | register const U_CHAR *bp; |
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65 | register HASHNODE *bucket; |
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66 | |
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67 | if (len < 0) |
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68 | { |
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69 | for (bp = name; is_idchar[*bp]; bp++) ; |
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70 | len = bp - name; |
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71 | } |
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72 | |
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73 | if (hash < 0) |
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74 | hash = hashf (name, len, HASHSIZE); |
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75 | |
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76 | bucket = hashtab[hash]; |
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77 | while (bucket) { |
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78 | if (bucket->length == len && strncmp (bucket->name, name, len) == 0) |
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79 | return bucket; |
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80 | bucket = bucket->next; |
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81 | } |
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82 | return (HASHNODE *) 0; |
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83 | } |
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84 | |
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85 | /* |
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86 | * Delete a hash node. Some weirdness to free junk from macros. |
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87 | * More such weirdness will have to be added if you define more hash |
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88 | * types that need it. |
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89 | */ |
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90 | |
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91 | /* Note that the DEFINITION of a macro is removed from the hash table |
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92 | but its storage is not freed. This would be a storage leak |
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93 | except that it is not reasonable to keep undefining and redefining |
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94 | large numbers of macros many times. |
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95 | In any case, this is necessary, because a macro can be #undef'd |
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96 | in the middle of reading the arguments to a call to it. |
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97 | If #undef freed the DEFINITION, that would crash. */ |
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98 | |
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99 | void |
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100 | delete_macro (hp) |
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101 | HASHNODE *hp; |
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102 | { |
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103 | |
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104 | if (hp->prev != NULL) |
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105 | hp->prev->next = hp->next; |
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106 | if (hp->next != NULL) |
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107 | hp->next->prev = hp->prev; |
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108 | |
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109 | /* make sure that the bucket chain header that |
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110 | the deleted guy was on points to the right thing afterwards. */ |
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111 | if (hp == *hp->bucket_hdr) |
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112 | *hp->bucket_hdr = hp->next; |
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113 | |
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114 | if (hp->type == T_MACRO) |
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115 | { |
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116 | DEFINITION *d = hp->value.defn; |
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117 | struct reflist *ap, *nextap; |
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118 | |
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119 | for (ap = d->pattern; ap != NULL; ap = nextap) |
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120 | { |
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121 | nextap = ap->next; |
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122 | free (ap); |
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123 | } |
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124 | if (d->nargs >= 0) |
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125 | free (d->args.argnames); |
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126 | free (d); |
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127 | } |
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128 | |
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129 | free (hp); |
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130 | } |
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131 | |
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132 | /* Install a name in the main hash table, even if it is already there. |
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133 | name stops with first non alphanumeric, except leading '#'. |
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134 | caller must check against redefinition if that is desired. |
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135 | delete_macro () removes things installed by install () in fifo order. |
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136 | this is important because of the `defined' special symbol used |
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137 | in #if, and also if pushdef/popdef directives are ever implemented. |
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138 | |
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139 | If LEN is >= 0, it is the length of the name. |
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140 | Otherwise, compute the length by scanning the entire name. |
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141 | |
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142 | If HASH is >= 0, it is the precomputed hash code. |
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143 | Otherwise, compute the hash code. */ |
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144 | |
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145 | HASHNODE * |
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146 | install (name, len, type, ivalue, value, hash) |
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147 | U_CHAR *name; |
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148 | int len; |
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149 | enum node_type type; |
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150 | int ivalue; |
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151 | char *value; |
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152 | int hash; |
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153 | { |
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154 | register HASHNODE *hp; |
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155 | register int i, bucket; |
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156 | register U_CHAR *p, *q; |
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157 | |
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158 | if (len < 0) { |
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159 | p = name; |
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160 | while (is_idchar[*p]) |
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161 | p++; |
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162 | len = p - name; |
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163 | } |
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164 | |
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165 | if (hash < 0) |
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166 | hash = hashf (name, len, HASHSIZE); |
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167 | |
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168 | i = sizeof (HASHNODE) + len + 1; |
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169 | hp = (HASHNODE *) xmalloc (i); |
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170 | bucket = hash; |
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171 | hp->bucket_hdr = &hashtab[bucket]; |
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172 | hp->next = hashtab[bucket]; |
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173 | hashtab[bucket] = hp; |
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174 | hp->prev = NULL; |
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175 | if (hp->next != NULL) |
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176 | hp->next->prev = hp; |
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177 | hp->type = type; |
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178 | hp->length = len; |
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179 | if (hp->type == T_CONST) |
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180 | hp->value.ival = ivalue; |
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181 | else |
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182 | hp->value.cpval = value; |
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183 | hp->name = ((U_CHAR *) hp) + sizeof (HASHNODE); |
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184 | p = hp->name; |
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185 | q = name; |
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186 | for (i = 0; i < len; i++) |
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187 | *p++ = *q++; |
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188 | hp->name[len] = 0; |
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189 | return hp; |
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190 | } |
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191 | |
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192 | void |
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193 | cpp_hash_cleanup (pfile) |
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194 | cpp_reader *pfile; |
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195 | { |
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196 | register int i; |
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197 | for (i = HASHSIZE; --i >= 0; ) |
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198 | { |
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199 | while (hashtab[i]) |
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200 | delete_macro (hashtab[i]); |
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201 | } |
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202 | } |
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