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334
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1 /*
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2 lwexpr.c
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3
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4 Copyright © 2010 William Astle
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5
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6 This file is part of LWTOOLS.
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7
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8 LWTOOLS is free software: you can redistribute it and/or modify it under the
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9 terms of the GNU General Public License as published by the Free Software
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10 Foundation, either version 3 of the License, or (at your option) any later
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11 version.
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12
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13 This program is distributed in the hope that it will be useful, but WITHOUT
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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16 more details.
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17
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18 You should have received a copy of the GNU General Public License along with
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19 this program. If not, see <http://www.gnu.org/licenses/>.
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20 */
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21
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22 #include <config.h>
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23
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24 #include <stdarg.h>
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25 #include <stdio.h>
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26 #include <string.h>
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27
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28 #define ___lw_expr_c_seen___
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29 #include "lw_alloc.h"
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30 #include "lw_expr.h"
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31 #include "lw_error.h"
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32 #include "lw_string.h"
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33
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337
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34 static lw_expr_t (*evaluate_special)(int t, void *ptr) = NULL;
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35 static lw_expr_t (*evaluate_var)(char *var) = NULL;
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36
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37 void lw_expr_set_special_handler(lw_expr_t (*fn)(int t, void *ptr))
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38 {
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39 evaluate_special = fn;
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40 }
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41
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42 void lw_expr_set_var_handler(lw_expr_t (*fn)(char *var))
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43 {
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44 evaluate_var = fn;
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45 }
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46
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334
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47 lw_expr_t lw_expr_create(void)
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48 {
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49 lw_expr_t r;
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50
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51 r = lw_alloc(sizeof(struct lw_expr_priv));
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52 r -> operands = NULL;
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53
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54 return r;
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55 }
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56
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57 void lw_expr_destroy(lw_expr_t E)
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58 {
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337
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59 struct lw_expr_opers *o;
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60 for (o = E -> operands; o; o = o -> next)
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61 lw_expr_destroy(o -> p);
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62 if (E -> type == lw_expr_type_var)
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63 lw_free(E -> value2);
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64 lw_free(E);
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334
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65 }
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66
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337
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67 /* actually duplicates the entire expression */
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68 void lw_expr_add_operand(lw_expr_t E, lw_expr_t O);
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334
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69 lw_expr_t lw_expr_copy(lw_expr_t E)
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70 {
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337
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71 lw_expr_t r, t;
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72 struct lw_expr_opers *o;
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73
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74 r = lw_alloc(sizeof(struct lw_expr_priv));
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75 *r = *E;
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76 r -> operands = NULL;
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77
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78 if (E -> type == lw_expr_type_var)
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79 r -> value2 = lw_strdup(E -> value2);
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80 for (o = E -> operands; o; o = o -> next)
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81 {
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82 lw_expr_add_operand(r, lw_expr_copy(o -> p));
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83 }
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84
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85 return r;
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334
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86 }
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87
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88 void lw_expr_add_operand(lw_expr_t E, lw_expr_t O)
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89 {
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90 struct lw_expr_opers *o, *t;
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91
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92 o = lw_alloc(sizeof(struct lw_expr_opers));
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93 o -> p = lw_expr_copy(O);
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94 o -> next = NULL;
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95 for (t = E -> operands; t && t -> next; t = t -> next)
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96 /* do nothing */ ;
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97
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98 if (t)
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99 t -> next = o;
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100 else
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101 E -> operands = o;
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102 }
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103
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335
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104 lw_expr_t lw_expr_build_aux(int exprtype, va_list args)
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334
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105 {
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106 lw_expr_t r;
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107 int t;
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108 void *p;
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109
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110 lw_expr_t te1, te2;
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111
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112 r = lw_expr_create();
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113
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114 switch (exprtype)
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115 {
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116 case lw_expr_type_int:
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117 t = va_arg(args, int);
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118 r -> type = lw_expr_type_int;
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119 r -> value = t;
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120 break;
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121
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122 case lw_expr_type_var:
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123 p = va_arg(args, char *);
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124 r -> type = lw_expr_type_var;
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125 r -> value2 = lw_strdup(p);
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126 break;
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127
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128 case lw_expr_type_special:
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129 t = va_arg(args, int);
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130 p = va_arg(args, char *);
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131 r -> type = lw_expr_type_special;
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337
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132 r -> value = t;
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334
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133 r -> value2 = p;
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134 break;
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135
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136 case lw_expr_type_oper:
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137 t = va_arg(args, int);
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138 te1 = va_arg(args, lw_expr_t);
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139 if (t != lw_expr_oper_com && t != lw_expr_oper_neg)
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140 te2 = va_arg(args, lw_expr_t);
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141 else
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142 te2 = NULL;
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143
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144 r -> type = lw_expr_type_oper;
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145 r -> value = t;
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146 lw_expr_add_operand(r, te1);
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147 lw_expr_add_operand(r, te2);
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148 break;
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149
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150 default:
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151 lw_error("Invalid expression type specified to lw_expr_build");
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152 }
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153
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335
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154 return r;
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155 }
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156
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157 lw_expr_t lw_expr_build(int exprtype, ...)
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158 {
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159 va_list args;
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160 lw_expr_t r;
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161
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162 va_start(args, exprtype);
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163 r = lw_expr_build_aux(exprtype, args);
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164 va_end(args);
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165 return r;
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166 }
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167
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334
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168 void lw_expr_print(lw_expr_t E)
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169 {
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170 struct lw_expr_opers *o;
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335
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171 int c = 0;
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172
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334
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173 for (o = E -> operands; o; o = o -> next)
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174 {
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335
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175 c++;
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334
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176 lw_expr_print(o -> p);
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177 }
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178
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179 switch (E -> type)
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180 {
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181 case lw_expr_type_int:
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182 printf("%d ", E -> value);
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183 break;
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335
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184
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185 case lw_expr_type_var:
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186 printf("V(%s) ", (char *)(E -> value2));
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187 break;
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188
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189 case lw_expr_type_special:
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190 printf("S(%d,%p) ", E -> value, E -> value2);
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191 break;
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192
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334
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193 case lw_expr_type_oper:
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335
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194 printf("[%d]", c);
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334
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195 switch (E -> value)
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196 {
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197 case lw_expr_oper_plus:
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198 printf("+ ");
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199 break;
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200
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201 case lw_expr_oper_minus:
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202 printf("- ");
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203 break;
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204
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205 case lw_expr_oper_times:
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206 printf("* ");
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207 break;
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208
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209 case lw_expr_oper_divide:
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210 printf("/ ");
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211 break;
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212
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213 case lw_expr_oper_mod:
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214 printf("%% ");
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215 break;
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216
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217 case lw_expr_oper_intdiv:
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218 printf("\\ ");
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219 break;
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220
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221 case lw_expr_oper_bwand:
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222 printf("BWAND ");
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223 break;
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224
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225 case lw_expr_oper_bwor:
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226 printf("BWOR ");
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227 break;
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228
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229 case lw_expr_oper_bwxor:
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230 printf("BWXOR ");
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231 break;
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232
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233 case lw_expr_oper_and:
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234 printf("AND ");
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235 break;
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236
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237 case lw_expr_oper_or:
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238 printf("OR ");
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239 break;
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240
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241 case lw_expr_oper_neg:
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242 printf("NEG ");
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243 break;
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244
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245 case lw_expr_oper_com:
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246 printf("COM ");
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247 break;
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248
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249 default:
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250 printf("OPER ");
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251 break;
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252 }
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253 break;
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254 default:
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255 printf("ERR ");
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256 break;
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257 }
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258 }
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259
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260 /*
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261 Return:
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262 nonzero if expressions are the same (identical pointers or matching values)
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263 zero if expressions are not the same
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264
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265 */
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266 int lw_expr_compare(lw_expr_t E1, lw_expr_t E2)
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267 {
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268 struct lw_expr_opers *o1, *o2;
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269
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270 if (E1 == E2)
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271 return 1;
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272
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273 if (!(E1 -> type == E2 -> type && E1 -> value == E2 -> value))
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274 return 0;
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275
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276 if (E1 -> type == lw_expr_type_var)
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277 {
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278 if (!strcmp(E1 -> value2, E2 -> value2))
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279 return 1;
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280 else
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281 return 0;
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282 }
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283
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284 if (E1 -> type == lw_expr_type_special)
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285 {
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286 if (E1 -> value2 == E2 -> value2)
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287 return 1;
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288 else
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289 return 0;
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290 }
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291
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292 for (o1 = E1 -> operands, o2 = E2 -> operands; o1 && o2; o1 = o1 -> next, o2 = o2 -> next)
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293 if (lw_expr_compare(o1 -> p, o2 -> p) == 0)
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294 return 0;
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295 if (o1 || o2)
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296 return 0;
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297
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298 return 1;
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299 }
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300
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301 /* return true if E is an operator of type oper */
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302 int lw_expr_isoper(lw_expr_t E, int oper)
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303 {
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304 if (E -> type == lw_expr_type_oper && E -> value == oper)
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305 return 1;
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306 return 0;
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307 }
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335
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308
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309
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310 void lw_expr_simplify_sortconstfirst(lw_expr_t E)
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311 {
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312 struct lw_expr_opers *o;
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313
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314 for (o = E -> operands; o; o = o -> next)
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315 lw_expr_simplify_sortconstfirst(o -> p);
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316
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317 for (o = E -> operands; o; o = o -> next)
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318 {
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319 if (o -> p -> type == lw_expr_type_int && o != E -> operands)
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320 {
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321 struct lw_expr_opers *o2;
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322 for (o2 = E -> operands; o2 -> next != o; o2 = o2 -> next)
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323 /* do nothing */ ;
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324 o2 -> next = o -> next;
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325 o -> next = E -> operands;
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326 E -> operands = o;
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327 o = o2;
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328 }
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329 }
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330 }
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331
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336
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332 void lw_expr_sortoperandlist(struct lw_expr_opers **o)
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333 {
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334 fprintf(stderr, "lw_expr_sortoperandlist() not yet implemented\n");
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335 }
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336
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335
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337 // return 1 if the operand lists match, 0 if not
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338 // may re-order the argument lists
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339 int lw_expr_simplify_compareoperandlist(struct lw_expr_opers **ol1, struct lw_expr_opers **ol2)
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340 {
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341 struct lw_expr_opers *o1, *o2;
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342
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343 lw_expr_sortoperandlist(ol1);
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344 lw_expr_sortoperandlist(ol2);
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345
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346 for (o1 = *ol1, o2 = *ol2; o1 && o2; o1 = o1 -> next, o2 = o2 -> next)
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347 {
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348 if (!lw_expr_compare(o1 -> p, o2 -> p))
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349 return 0;
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350 }
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351 if (o1 || o2)
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352 return 0;
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353 return 1;
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354 }
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355
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356 void lw_expr_simplify(lw_expr_t E)
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357 {
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358 struct lw_expr_opers *o;
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359
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337
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360 again:
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361 // try to resolve non-constant terms to constants here
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362 if (E -> type == lw_expr_type_special && evaluate_special)
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363 {
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364 lw_expr_t te;
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365
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366 te = evaluate_special(E -> value, E -> value2);
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367 if (te)
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368 {
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369 for (o = E -> operands; o; o = o -> next)
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370 lw_expr_destroy(o -> p);
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371 if (E -> type == lw_expr_type_var)
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372 lw_free(E -> value2);
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373 *E = *te;
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374 E -> operands = NULL;
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375
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376 if (te -> type == lw_expr_type_var)
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377 E -> value2 = lw_strdup(te -> value2);
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378 for (o = te -> operands; o; o = o -> next)
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379 {
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380 lw_expr_add_operand(E, lw_expr_copy(o -> p));
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381 }
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382 lw_expr_destroy(te);
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383 goto again;
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384 }
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385 return;
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386 }
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387
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388 if (E -> type == lw_expr_type_var && evaluate_var)
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389 {
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390 lw_expr_t te;
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391
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392 te = evaluate_var(E -> value2);
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393 if (te)
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394 {
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395 for (o = E -> operands; o; o = o -> next)
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396 lw_expr_destroy(o -> p);
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397 if (E -> type == lw_expr_type_var)
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398 lw_free(E -> value2);
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399 *E = *te;
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400 E -> operands = NULL;
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401
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402 if (te -> type == lw_expr_type_var)
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403 E -> value2 = lw_strdup(te -> value2);
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404 for (o = te -> operands; o; o = o -> next)
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405 {
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406 lw_expr_add_operand(E, lw_expr_copy(o -> p));
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407 }
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408 lw_expr_destroy(te);
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409 goto again;
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410 }
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411 return;
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412 }
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413
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414 // non-operators have no simplification to do!
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415 if (E -> type != lw_expr_type_oper)
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416 return;
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|
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417
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|
335
|
418 // sort "constants" to the start of each operand list for + and *
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|
|
419 lw_expr_simplify_sortconstfirst(E);
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|
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420
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337
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421 // simplify operands
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422 for (o = E -> operands; o; o = o -> next)
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|
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423 lw_expr_simplify(o -> p);
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424
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425 for (o = E -> operands; o; o = o -> next)
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426 {
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427 if (o -> p -> type != lw_expr_type_int)
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428 break;
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|
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429 }
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430
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431 if (!o)
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432 {
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433 // we can do the operation here!
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434 int tr = -42424242;
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435
|
|
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436 switch (E -> value)
|
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437 {
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438 case lw_expr_oper_neg:
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|
|
439 tr = -(E -> operands -> p -> value);
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440 break;
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|
441
|
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|
442 case lw_expr_oper_com:
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|
|
443 tr = ~(E -> operands -> p -> value);
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444 break;
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445
|
|
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446 case lw_expr_oper_plus:
|
|
|
447 tr = E -> operands -> p -> value;
|
|
|
448 for (o = E -> operands -> next; o; o = o -> next)
|
|
|
449 tr += o -> p -> value;
|
|
|
450 break;
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|
|
451
|
|
|
452 case lw_expr_oper_minus:
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|
|
453 tr = E -> operands -> p -> value;
|
|
|
454 for (o = E -> operands -> next; o; o = o -> next)
|
|
|
455 tr -= o -> p -> value;
|
|
|
456 break;
|
|
|
457
|
|
|
458 case lw_expr_oper_times:
|
|
|
459 tr = E -> operands -> p -> value;
|
|
|
460 for (o = E -> operands -> next; o; o = o -> next)
|
|
|
461 tr *= o -> p -> value;
|
|
|
462 break;
|
|
|
463
|
|
|
464 case lw_expr_oper_divide:
|
|
|
465 tr = E -> operands -> p -> value / E -> operands -> next -> p -> value;
|
|
|
466 break;
|
|
|
467
|
|
|
468 case lw_expr_oper_mod:
|
|
|
469 tr = E -> operands -> p -> value % E -> operands -> next -> p -> value;
|
|
|
470 break;
|
|
|
471
|
|
|
472 case lw_expr_oper_intdiv:
|
|
|
473 tr = E -> operands -> p -> value / E -> operands -> next -> p -> value;
|
|
|
474 break;
|
|
|
475
|
|
|
476 case lw_expr_oper_bwand:
|
|
|
477 tr = E -> operands -> p -> value & E -> operands -> next -> p -> value;
|
|
|
478 break;
|
|
|
479
|
|
|
480 case lw_expr_oper_bwor:
|
|
|
481 tr = E -> operands -> p -> value | E -> operands -> next -> p -> value;
|
|
|
482 break;
|
|
|
483
|
|
|
484 case lw_expr_oper_bwxor:
|
|
|
485 tr = E -> operands -> p -> value ^ E -> operands -> next -> p -> value;
|
|
|
486 break;
|
|
|
487
|
|
|
488 case lw_expr_oper_and:
|
|
|
489 tr = E -> operands -> p -> value && E -> operands -> next -> p -> value;
|
|
|
490 break;
|
|
|
491
|
|
|
492 case lw_expr_oper_or:
|
|
|
493 tr = E -> operands -> p -> value || E -> operands -> next -> p -> value;
|
|
|
494 break;
|
|
|
495
|
|
|
496 }
|
|
|
497
|
|
|
498 while (E -> operands)
|
|
|
499 {
|
|
|
500 o = E -> operands;
|
|
|
501 E -> operands = o -> next;
|
|
|
502 lw_expr_destroy(o -> p);
|
|
|
503 lw_free(o);
|
|
|
504 }
|
|
|
505 E -> type = lw_expr_type_int;
|
|
|
506 E -> value = tr;
|
|
335
|
507 return;
|
|
337
|
508 }
|
|
335
|
509
|
|
|
510 if (E -> value == lw_expr_oper_times)
|
|
|
511 {
|
|
|
512 for (o = E -> operands; o; o = o -> next)
|
|
|
513 {
|
|
|
514 if (o -> p -> type == lw_expr_type_int && o -> p -> value == 0)
|
|
|
515 {
|
|
|
516 // one operand of times is 0, replace operation with 0
|
|
|
517 while (E -> operands)
|
|
|
518 {
|
|
|
519 o = E -> operands;
|
|
|
520 E -> operands = o -> next;
|
|
|
521 lw_expr_destroy(o -> p);
|
|
|
522 lw_free(o);
|
|
|
523 }
|
|
|
524 E -> type = lw_expr_type_int;
|
|
|
525 E -> value = 0;
|
|
|
526 return;
|
|
|
527 }
|
|
|
528 }
|
|
|
529 }
|
|
|
530
|
|
|
531 // look for like terms and collect them together
|
|
|
532 if (E -> value == lw_expr_oper_plus)
|
|
|
533 {
|
|
|
534 for (o = E -> operands; o; o = o -> next)
|
|
|
535 {
|
|
|
536 if (o -> p -> type == lw_expr_type_oper && o -> p -> value == lw_expr_oper_times)
|
|
|
537 {
|
|
|
538 // we have a "times" here
|
|
|
539 // find first non-const operand
|
|
|
540 struct lw_expr_opers *op1, *op2, *o2;
|
|
|
541 for (op1 = o -> p -> operands; op1; op1 = op1 -> next)
|
|
|
542 if (op1 -> p -> type != lw_expr_type_int)
|
|
|
543 break;
|
|
|
544
|
|
|
545 for (o2 = o -> next; o2; o2 = o2 -> next)
|
|
|
546 {
|
|
|
547 if (o2 -> p -> type == lw_expr_type_oper && o2 -> p -> value == lw_expr_oper_times)
|
|
|
548 {
|
|
|
549 // another "times"
|
|
|
550 for (op2 = o2 -> p -> operands; op2; op2 = op2 -> next)
|
|
|
551 if (op2 -> p -> type != lw_expr_type_int)
|
|
|
552 break;
|
|
|
553
|
|
336
|
554 if (lw_expr_simplify_compareoperandlist(&op1, &op2))
|
|
335
|
555 {
|
|
|
556 // we have like terms here
|
|
|
557 // do something about it
|
|
|
558 }
|
|
|
559 }
|
|
|
560 }
|
|
|
561 }
|
|
|
562 }
|
|
|
563 }
|
|
|
564
|
|
|
565
|
|
|
566 if (E -> value == lw_expr_oper_plus)
|
|
|
567 {
|
|
|
568 int c = 0, t = 0;
|
|
|
569 for (o = E -> operands; o; o = o -> next)
|
|
|
570 {
|
|
|
571 t++;
|
|
|
572 if (!(o -> p -> type == lw_expr_type_int && o -> p -> value == 0))
|
|
|
573 {
|
|
|
574 c++;
|
|
|
575 }
|
|
|
576 }
|
|
|
577 if (c == 1)
|
|
|
578 {
|
|
|
579 lw_expr_t r;
|
|
|
580 // find the value and "move it up"
|
|
|
581 while (E -> operands)
|
|
|
582 {
|
|
|
583 o = E -> operands;
|
|
|
584 if (o -> p -> type != lw_expr_type_int || o -> p -> value != 0)
|
|
|
585 {
|
|
337
|
586 r = lw_expr_copy(o -> p);
|
|
335
|
587 }
|
|
|
588 E -> operands = o -> next;
|
|
|
589 lw_expr_destroy(o -> p);
|
|
|
590 lw_free(o);
|
|
|
591 }
|
|
|
592 *E = *r;
|
|
|
593 return;
|
|
|
594 }
|
|
|
595 else if (c == 0)
|
|
|
596 {
|
|
|
597 // replace with 0
|
|
|
598 while (E -> operands)
|
|
|
599 {
|
|
|
600 o = E -> operands;
|
|
|
601 E -> operands = o -> next;
|
|
|
602 lw_expr_destroy(o -> p);
|
|
|
603 lw_free(o);
|
|
|
604 }
|
|
|
605 E -> type = lw_expr_type_int;
|
|
|
606 E -> value = 0;
|
|
|
607 return;
|
|
|
608 }
|
|
|
609 else if (c != t)
|
|
|
610 {
|
|
|
611 // collapse out zero terms
|
|
|
612 struct lw_expr_opers *o2;
|
|
|
613
|
|
|
614 for (o = E -> operands; o; o = o -> next)
|
|
|
615 {
|
|
|
616 if (o -> p -> type == lw_expr_type_int && o -> p -> value == 0)
|
|
|
617 {
|
|
|
618 if (o == E -> operands)
|
|
|
619 {
|
|
|
620 E -> operands = o -> next;
|
|
|
621 lw_expr_destroy(o -> p);
|
|
|
622 lw_free(o);
|
|
|
623 o = E -> operands;
|
|
|
624 }
|
|
|
625 else
|
|
|
626 {
|
|
|
627 for (o2 = E -> operands; o2 -> next == o; o2 = o2 -> next)
|
|
|
628 /* do nothing */ ;
|
|
|
629 o2 -> next = o -> next;
|
|
|
630 lw_expr_destroy(o -> p);
|
|
|
631 lw_free(o);
|
|
|
632 o = o2;
|
|
|
633 }
|
|
|
634 }
|
|
|
635 }
|
|
|
636 }
|
|
|
637 return;
|
|
|
638 }
|
|
|
639 }
|
