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annotate src/expr.c @ 17:df0c4a46af8f
Started adding expression handling infrastructure
| author | lost |
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| date | Thu, 01 Jan 2009 02:26:26 +0000 |
| parents | 1f598d89b9b0 |
| children | 218aabbc3b1a |
| rev | line source |
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1 /* |
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2 expr.c |
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3 Copyright © 2008 William Astle |
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4 |
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5 This file is part of LWASM. |
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6 |
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7 LWASM is free software: you can redistribute it and/or modify it under the |
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8 terms of the GNU General Public License as published by the Free Software |
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9 Foundation, either version 3 of the License, or (at your option) any later |
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10 version. |
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11 |
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12 This program is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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15 more details. |
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16 |
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17 You should have received a copy of the GNU General Public License along with |
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18 this program. If not, see <http://www.gnu.org/licenses/>. |
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19 */ |
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20 |
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21 /* |
| 15 | 22 This file contains the actual expression evaluator which uses the LWVAL |
| 23 mechanism to store results. | |
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24 */ |
| 14 | 25 |
| 26 #define __expr_c_seen__ | |
| 15 | 27 |
| 17 | 28 #include <stdio.h> |
| 15 | 29 #include <stdlib.h> |
| 30 | |
| 14 | 31 #include "expr.h" |
| 17 | 32 #include "util.h" |
| 33 | |
| 34 lwasm_expr_stack_t *lwasm_expr_stack_create(void) | |
| 35 { | |
| 36 lwasm_expr_stack_t *s; | |
| 37 | |
| 38 s = lwasm_alloc(sizeof(lwasm_expr_stack_t)); | |
| 39 s -> head = NULL; | |
| 40 s -> tail = NULL; | |
| 41 return s; | |
| 42 } | |
| 15 | 43 |
| 17 | 44 void lwasm_expr_stack_free(lwasm_expr_stack_t *s) |
| 45 { | |
| 46 while (s -> head) | |
| 47 { | |
| 48 s -> tail = s -> head; | |
| 49 s -> head = s -> head -> next; | |
| 50 lwasm_expr_term_free(s -> tail -> term); | |
| 51 lwasm_free(s -> tail); | |
| 52 } | |
| 53 lwasm_free(s); | |
| 54 } | |
| 14 | 55 |
| 17 | 56 void lwasm_expr_term_free(lwasm_expr_term_t *t) |
| 57 { | |
| 58 if (t) | |
| 59 { | |
| 60 if (t -> symbol) | |
| 61 lwasm_free(t -> symbol); | |
| 62 lwasm_free(t); | |
| 63 } | |
| 64 } | |
| 65 | |
| 66 lwasm_expr_term_t *lwasm_expr_term_create_oper(int oper) | |
| 67 { | |
| 68 lwasm_expr_term_t *t; | |
| 69 | |
| 70 t = lwasm_alloc(sizeof(lwasm_expr_term_t)); | |
| 71 t -> term_type = LWASM_TERM_OPER; | |
| 72 t -> value = oper; | |
| 73 return t; | |
| 74 } | |
| 15 | 75 |
| 17 | 76 lwasm_expr_term_t *lwasm_expr_term_create_int(int val) |
| 14 | 77 { |
| 17 | 78 lwasm_expr_term_t *t; |
| 79 | |
| 80 t = lwasm_alloc(sizeof(lwasm_expr_term_t)); | |
| 81 t -> term_type = LWASM_TERM_INT; | |
| 82 t -> value = val; | |
| 83 return t; | |
| 84 } | |
| 85 | |
| 86 lwasm_expr_term_t *lwasm_expr_term_create_sym(char *sym) | |
| 87 { | |
| 88 lwasm_expr_term_t *t; | |
| 14 | 89 |
| 17 | 90 t = lwasm_alloc(sizeof(lwasm_expr_term_t)); |
| 91 t -> term_type = LWASM_TERM_SYM; | |
| 92 t -> symbol = lwasm_strdup(sym); | |
| 93 return t; | |
| 94 } | |
| 15 | 95 |
| 17 | 96 lwasm_expr_term_t *lwasm_expr_term_dup(lwasm_expr_term_t *t) |
| 97 { | |
| 98 switch (t -> term_type) | |
| 15 | 99 { |
| 17 | 100 case LWASM_TERM_INT: |
| 101 return lwasm_expr_term_create_int(t -> value); | |
| 102 | |
| 103 case LWASM_TERM_OPER: | |
| 104 return lwasm_expr_term_create_oper(t -> value); | |
| 105 | |
| 106 case LWASM_TERM_SYM: | |
| 107 return lwasm_expr_term_create_sym(t -> symbol); | |
| 108 | |
| 109 default: | |
| 110 fprintf(stderr, "lwasm_expr_term_dup(): invalid term type %d\n", t -> term_type); | |
| 111 exit(1); | |
| 112 } | |
| 113 // can't get here | |
| 114 } | |
| 115 | |
| 116 void lwasm_expr_stack_push(lwasm_expr_stack_t *s, lwasm_expr_term_t *t) | |
| 117 { | |
| 118 lwasm_expr_stack_node_t *n; | |
| 119 | |
| 120 if (!s) | |
| 121 { | |
| 122 fprintf(stderr, "lwasm_expr_stack_push(): invalid stack pointer\n"); | |
| 123 exit(1); | |
| 15 | 124 } |
| 125 | |
| 17 | 126 n = lwasm_alloc(sizeof(lwasm_expr_stack_node_t)); |
| 127 n -> next = NULL; | |
| 128 n -> prev = s -> tail; | |
| 129 n -> term = lwasm_expr_term_dup(t); | |
| 130 | |
| 131 if (s -> head) | |
| 132 { | |
| 133 s -> tail -> next = n; | |
| 134 s -> tail = n; | |
| 135 } | |
| 136 else | |
| 15 | 137 { |
| 17 | 138 s -> head = n; |
| 139 s -> tail = n; | |
| 140 } | |
| 141 } | |
| 142 | |
| 143 lwasm_expr_term_t *lwasm_expr_stack_pop(lwasm_expr_stack_t *s) | |
| 144 { | |
| 145 lwasm_expr_term_t *t; | |
| 146 lwasm_expr_stack_node_t *n; | |
| 147 | |
| 148 if (!(s -> tail)) | |
| 149 return NULL; | |
| 150 | |
| 151 n = s -> tail; | |
| 152 s -> tail = n -> prev; | |
| 153 if (!(n -> prev)) | |
| 154 { | |
| 155 s -> head = NULL; | |
| 15 | 156 } |
| 14 | 157 |
| 17 | 158 t = n -> term; |
| 159 n -> term = NULL; | |
| 160 | |
| 161 lwasm_free(n); | |
| 162 | |
| 163 return t; | |
| 14 | 164 } |