| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: sym.h,v 1.1 1998/06/17 23:44:42 mdw Exp $ |
| 4 | * |
| 5 | * Symbol table management |
| 6 | * |
| 7 | * (c) 1998 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of the mLib utilities library. |
| 13 | * |
| 14 | * mLib is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * mLib is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with mLib; if not, write to the Free Software Foundation, |
| 26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: sym.h,v $ |
| 32 | * Revision 1.1 1998/06/17 23:44:42 mdw |
| 33 | * Initial revision |
| 34 | * |
| 35 | */ |
| 36 | |
| 37 | #ifndef SYM_H |
| 38 | #define SYM_H |
| 39 | |
| 40 | #ifdef __cplusplus |
| 41 | extern "C" { |
| 42 | #endif |
| 43 | |
| 44 | /*----- Required headers --------------------------------------------------*/ |
| 45 | |
| 46 | #include <stddef.h> |
| 47 | |
| 48 | /*----- Type definitions --------------------------------------------------*/ |
| 49 | |
| 50 | /* --- Symbol table --- * |
| 51 | * |
| 52 | * A @sym_table@ contains the information needed to manage a symbol table. |
| 53 | * Users shouldn't fiddle with this information directly, but it needs to be |
| 54 | * here so that objects of the correct type can be created. |
| 55 | */ |
| 56 | |
| 57 | typedef struct sym_table { |
| 58 | unsigned long mask; /* Bit mask for hashing purposes */ |
| 59 | size_t c; /* Down counter for growing table */ |
| 60 | struct sym_base **a; /* Array of hash bins */ |
| 61 | } sym_table; |
| 62 | |
| 63 | /* --- A symbol table entry --- * |
| 64 | * |
| 65 | * I don't care what actually gets stored in symbol entries because I don't |
| 66 | * create them: that's the responsibility of my client. All I care about |
| 67 | * here is that whatever gets passed to me is a structure whose first member |
| 68 | * is a @sym_base@. The ANSI guarantees about structure layout are |
| 69 | * sufficient to allow me to manipulate such objects. |
| 70 | */ |
| 71 | |
| 72 | #define SYM_BUFSZ 16 /* Size of local string buffer */ |
| 73 | |
| 74 | typedef struct sym_base { |
| 75 | struct sym_base *next; /* Next symbol in hash bin */ |
| 76 | unsigned long hash; /* Hash value for symbol's name */ |
| 77 | union { |
| 78 | char *p; /* Pointer to name string */ |
| 79 | char b[SYM_BUFSZ]; /* Buffer containing a short name */ |
| 80 | } name; /* Name of this symbol */ |
| 81 | size_t len; /* Length of the symbol's name */ |
| 82 | } sym_base; |
| 83 | |
| 84 | /* --- An iterator block --- */ |
| 85 | |
| 86 | typedef struct sym_iter { |
| 87 | sym_table *t; /* Symbol table being iterated */ |
| 88 | sym_base *n; /* Address of next item to return */ |
| 89 | size_t i; /* Index of next hash bin to use */ |
| 90 | } sym_iter; |
| 91 | |
| 92 | /*----- External functions ------------------------------------------------*/ |
| 93 | |
| 94 | /* --- @sym_createTable@ --- * |
| 95 | * |
| 96 | * Arguments: @sym_table *t@ = symbol table to initialise |
| 97 | * |
| 98 | * Returns: --- |
| 99 | * |
| 100 | * Use: Initialises the given symbol table. Raises @EXC_NOMEM@ if |
| 101 | * there isn't enough memory. |
| 102 | */ |
| 103 | |
| 104 | extern void sym_createTable(sym_table */*t*/); |
| 105 | |
| 106 | /* --- @sym_destroyTable@ --- * |
| 107 | * |
| 108 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 109 | * |
| 110 | * Returns: --- |
| 111 | * |
| 112 | * Use: Destroys a symbol table, freeing all the memory it used to |
| 113 | * occupy. |
| 114 | */ |
| 115 | |
| 116 | extern void sym_destroyTable(sym_table */*t*/); |
| 117 | |
| 118 | /* --- @sym_find@ --- * |
| 119 | * |
| 120 | * Arguments: @sym_table *t@ = pointer to symbol table in question |
| 121 | * @const char *n@ = pointer to symbol table to look up |
| 122 | * @long l@ = length of the name string or negative to measure |
| 123 | * @size_t sz@ = size of desired symbol object, or zero |
| 124 | * @unsigned *f@ = pointer to a flag, or null. |
| 125 | * |
| 126 | * Returns: The address of a @sym_base@ structure, or null if not found |
| 127 | * and @sz@ is zero. |
| 128 | * |
| 129 | * Use: Looks up a symbol in a given symbol table. The name is |
| 130 | * passed by the address of its first character. The length |
| 131 | * may be given, in which case the name may contain arbitrary |
| 132 | * binary data, or it may be given as a negative number, in |
| 133 | * which case the length of the name is calculated as |
| 134 | * @strlen(n)@. |
| 135 | * |
| 136 | * The return value is the address of a pointer to a @sym_base@ |
| 137 | * block (which may have other things on the end, as above). If |
| 138 | * the symbol could be found, the return value points to the |
| 139 | * symbol block. If the symbol wasn't there, then if @sz@ is |
| 140 | * nonzero, a new symbol is created and its address is returned; |
| 141 | * otherwise a null pointer is returned. The exception |
| 142 | * @EXC_NOMEM@ is raised if the block can't be allocated. |
| 143 | * |
| 144 | * The value of @*f@ indicates whether a new symbol entry was |
| 145 | * created: a nonzero value indicates that an old value was |
| 146 | * found. |
| 147 | */ |
| 148 | |
| 149 | extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/, |
| 150 | size_t /*sz*/, unsigned */*f*/); |
| 151 | |
| 152 | /* --- @sym_remove@ --- * |
| 153 | * |
| 154 | * Arguments: @sym_table *i@ = pointer to a symbol table object |
| 155 | * @void *b@ = pointer to symbol table entry |
| 156 | * |
| 157 | * Returns: --- |
| 158 | * |
| 159 | * Use: Removes the object from the symbol table. The space occupied |
| 160 | * by the object and its name is freed; anything else attached |
| 161 | * to the entry should already be gone by this point. |
| 162 | */ |
| 163 | |
| 164 | extern void sym_remove(sym_table */*t*/, void */*b*/); |
| 165 | |
| 166 | /* --- @sym_createIter@ --- * |
| 167 | * |
| 168 | * Arguments: @sym_iter *i@ = pointer to an iterator object |
| 169 | * @sym_table *t@ = pointer to a symbol table object |
| 170 | * |
| 171 | * Returns: --- |
| 172 | * |
| 173 | * Use: Creates a new symbol table iterator which may be used to |
| 174 | * iterate through a symbol table. |
| 175 | */ |
| 176 | |
| 177 | extern void sym_createIter(sym_iter */*i*/, sym_table */*t*/); |
| 178 | |
| 179 | /* --- @sym_next@ --- * |
| 180 | * |
| 181 | * Arguments: @sym_iter *i@ = pointer to iterator object |
| 182 | * |
| 183 | * Returns: Pointer to the next symbol found, or null when finished. |
| 184 | * |
| 185 | * Use: Returns the next symbol from the table. Symbols are not |
| 186 | * returned in any particular order. |
| 187 | */ |
| 188 | |
| 189 | extern void *sym_next(sym_iter */*i*/); |
| 190 | |
| 191 | /*----- That's all, folks -------------------------------------------------*/ |
| 192 | |
| 193 | #ifdef __cplusplus |
| 194 | } |
| 195 | #endif |
| 196 | |
| 197 | #endif |