symtab.c 3.8 KB

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  1. /*
  2. * Copyright (c) 1989 The Regents of the University of California.
  3. * All rights reserved.
  4. *
  5. * This code is derived from software contributed to Berkeley by
  6. * Robert Paul Corbett.
  7. *
  8. * Redistribution and use in source and binary forms, with or without
  9. * modification, are permitted provided that the following conditions
  10. * are met:
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. * 2. Redistributions in binary form must reproduce the above copyright
  14. * notice, this list of conditions and the following disclaimer in the
  15. * documentation and/or other materials provided with the distribution.
  16. * 3. All advertising materials mentioning features or use of this software
  17. * must display the following acknowledgement:
  18. * This product includes software developed by the University of
  19. * California, Berkeley and its contributors.
  20. * 4. Neither the name of the University nor the names of its contributors
  21. * may be used to endorse or promote products derived from this software
  22. * without specific prior written permission.
  23. *
  24. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34. * SUCH DAMAGE.
  35. */
  36. #ifndef lint
  37. static char sccsid[] = "@(#)symtab.c 5.3 (Berkeley) 6/1/90";
  38. #endif /* not lint */
  39. #include "defs.h"
  40. /* TABLE_SIZE is the number of entries in the symbol table. */
  41. /* TABLE_SIZE must be a power of two. */
  42. #define TABLE_SIZE 1024
  43. bucket **symbol_table;
  44. bucket *first_symbol;
  45. bucket *last_symbol;
  46. int
  47. hash(name)
  48. char *name;
  49. {
  50. register char *s;
  51. register int c, k;
  52. assert(name && *name);
  53. s = name;
  54. k = *s;
  55. while (c = *++s)
  56. k = (31*k + c) & (TABLE_SIZE - 1);
  57. return (k);
  58. }
  59. bucket *
  60. make_bucket(name)
  61. char *name;
  62. {
  63. register bucket *bp;
  64. assert(name);
  65. bp = (bucket *) MALLOC(sizeof(bucket));
  66. if (bp == 0) no_space();
  67. bp->link = 0;
  68. bp->next = 0;
  69. bp->name = MALLOC(strlen(name) + 1);
  70. if (bp->name == 0) no_space();
  71. bp->tag = 0;
  72. bp->value = UNDEFINED;
  73. bp->index = 0;
  74. bp->prec = 0;
  75. bp-> class = UNKNOWN;
  76. bp->assoc = TOKEN;
  77. if (bp->name == 0) no_space();
  78. strcpy(bp->name, name);
  79. return (bp);
  80. }
  81. bucket *
  82. lookup(name)
  83. char *name;
  84. {
  85. register bucket *bp, **bpp;
  86. bpp = symbol_table + hash(name);
  87. bp = *bpp;
  88. while (bp)
  89. {
  90. if (strcmp(name, bp->name) == 0) return (bp);
  91. bpp = &bp->link;
  92. bp = *bpp;
  93. }
  94. *bpp = bp = make_bucket(name);
  95. last_symbol->next = bp;
  96. last_symbol = bp;
  97. return (bp);
  98. }
  99. create_symbol_table()
  100. {
  101. register int i;
  102. register bucket *bp;
  103. symbol_table = (bucket **) MALLOC(TABLE_SIZE*sizeof(bucket *));
  104. if (symbol_table == 0) no_space();
  105. for (i = 0; i < TABLE_SIZE; i++)
  106. symbol_table[i] = 0;
  107. bp = make_bucket("error");
  108. bp->index = 1;
  109. bp->class = TERM;
  110. first_symbol = bp;
  111. last_symbol = bp;
  112. symbol_table[hash("error")] = bp;
  113. }
  114. free_symbol_table()
  115. {
  116. FREE(symbol_table);
  117. symbol_table = 0;
  118. }
  119. free_symbols()
  120. {
  121. register bucket *p, *q;
  122. for (p = first_symbol; p; p = q)
  123. {
  124. q = p->next;
  125. FREE(p);
  126. }
  127. }