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1 /* |
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2 * $Xorg: ifparser.c,v 1.3 2000/08/17 19:41:50 cpqbld Exp $ |
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3 * |
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4 * Copyright 1992 Network Computing Devices, Inc. |
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5 * |
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6 * Permission to use, copy, modify, and distribute this software and its |
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7 * documentation for any purpose and without fee is hereby granted, provided |
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8 * that the above copyright notice appear in all copies and that both that |
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9 * copyright notice and this permission notice appear in supporting |
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10 * documentation, and that the name of Network Computing Devices may not be |
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11 * used in advertising or publicity pertaining to distribution of the software |
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12 * without specific, written prior permission. Network Computing Devices makes |
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13 * no representations about the suitability of this software for any purpose. |
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14 * It is provided ``as is'' without express or implied warranty. |
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15 * |
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16 * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS |
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17 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, |
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18 * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL, |
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19 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM |
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20 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE |
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21 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR |
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22 * PERFORMANCE OF THIS SOFTWARE. |
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23 * |
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24 * Author: Jim Fulton |
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25 * Network Computing Devices, Inc. |
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26 * |
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27 * Simple if statement processor |
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28 * |
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29 * This module can be used to evaluate string representations of C language |
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30 * if constructs. It accepts the following grammar: |
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31 * |
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32 * EXPRESSION := VALUE |
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33 * | VALUE BINOP EXPRESSION |
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34 * | VALUE '?' EXPRESSION ':' EXPRESSION |
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35 * |
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36 * VALUE := '(' EXPRESSION ')' |
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37 * | '!' VALUE |
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38 * | '-' VALUE |
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39 * | '+' VALUE |
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40 * | '~' VALUE |
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41 * | 'defined' '(' variable ')' |
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42 * | 'defined' variable |
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43 * | # variable '(' variable-list ')' |
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44 * | variable |
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45 * | number |
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46 * |
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47 * BINOP := '*' | '/' | '%' |
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48 * | '+' | '-' |
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49 * | '<<' | '>>' |
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50 * | '<' | '>' | '<=' | '>=' |
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51 * | '==' | '!=' |
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52 * | '&' | '^' | '|' |
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53 * | '&&' | '||' |
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54 * |
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55 * The normal C order of precedence is supported. |
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56 * |
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57 * |
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58 * External Entry Points: |
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59 * |
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60 * ParseIfExpression parse a string for #if |
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61 */ |
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62 /* $XFree86: xc/config/makedepend/ifparser.c,v 3.11 2002/09/23 01:48:08 tsi Exp $ */ |
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63 |
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64 #include "ifparser.h" |
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65 #include <ctype.h> |
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66 #include <stdlib.h> |
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67 #include <string.h> |
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68 |
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69 /**************************************************************************** |
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70 Internal Macros and Utilities for Parser |
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71 ****************************************************************************/ |
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72 |
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73 #define DO(val) if (!(val)) return NULL |
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74 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff)) |
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75 #define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++ |
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76 #define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_') |
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77 |
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78 |
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79 static const char * |
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80 parse_variable (IfParser *g, const char *cp, const char **varp) |
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81 { |
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82 SKIPSPACE (cp); |
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83 |
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84 if (!isvarfirstletter (*cp)) |
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85 return CALLFUNC(g, handle_error) (g, cp, "variable name"); |
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86 |
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87 *varp = cp; |
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88 /* EMPTY */ |
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89 for (cp++; isalnum(*cp) || *cp == '_'; cp++) ; |
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90 return cp; |
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91 } |
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92 |
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93 |
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94 static const char * |
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95 parse_number (IfParser *g, const char *cp, long *valp) |
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96 { |
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97 long base = 10; |
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98 SKIPSPACE (cp); |
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99 |
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100 if (!isdigit(*cp)) |
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101 return CALLFUNC(g, handle_error) (g, cp, "number"); |
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102 |
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103 *valp = 0; |
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104 |
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105 if (*cp == '0') { |
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106 cp++; |
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107 if ((*cp == 'x') || (*cp == 'X')) { |
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108 base = 16; |
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109 cp++; |
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110 } else { |
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111 base = 8; |
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112 } |
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113 } |
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114 |
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115 /* Ignore overflows and assume ASCII, what source is usually written in */ |
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116 while (1) { |
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117 int increment = -1; |
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118 if (base == 8) { |
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119 if ((*cp >= '0') && (*cp <= '7')) |
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120 increment = *cp++ - '0'; |
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121 } else if (base == 16) { |
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122 if ((*cp >= '0') && (*cp <= '9')) |
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123 increment = *cp++ - '0'; |
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124 else if ((*cp >= 'A') && (*cp <= 'F')) |
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125 increment = *cp++ - ('A' - 10); |
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126 else if ((*cp >= 'a') && (*cp <= 'f')) |
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127 increment = *cp++ - ('a' - 10); |
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128 } else { /* Decimal */ |
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129 if ((*cp >= '0') && (*cp <= '9')) |
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130 increment = *cp++ - '0'; |
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131 } |
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132 if (increment < 0) |
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133 break; |
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134 *valp = (*valp * base) + increment; |
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135 } |
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136 |
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137 /* Skip trailing qualifiers */ |
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138 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++; |
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139 return cp; |
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140 } |
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141 |
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142 static const char * |
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143 parse_character (IfParser *g, const char *cp, long *valp) |
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144 { |
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145 char val; |
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146 |
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147 SKIPSPACE (cp); |
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148 if (*cp == '\\') |
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149 switch (cp[1]) { |
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150 case 'n': val = '\n'; break; |
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151 case 't': val = '\t'; break; |
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152 case 'v': val = '\v'; break; |
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153 case 'b': val = '\b'; break; |
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154 case 'r': val = '\r'; break; |
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155 case 'f': val = '\f'; break; |
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156 case 'a': val = '\a'; break; |
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157 case '\\': val = '\\'; break; |
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158 case '?': val = '\?'; break; |
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159 case '\'': val = '\''; break; |
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160 case '\"': val = '\"'; break; |
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161 case 'x': val = (char) strtol (cp + 2, NULL, 16); break; |
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162 default: val = (char) strtol (cp + 1, NULL, 8); break; |
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163 } |
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164 else |
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165 val = *cp; |
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166 while (*cp != '\'') cp++; |
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167 *valp = (long) val; |
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168 return cp; |
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169 } |
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170 |
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171 static const char * |
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172 parse_value (IfParser *g, const char *cp, long *valp) |
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173 { |
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174 const char *var, *varend; |
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175 |
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176 *valp = 0; |
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177 |
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178 SKIPSPACE (cp); |
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179 if (!*cp) |
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180 return cp; |
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181 |
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182 switch (*cp) { |
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183 case '(': |
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184 DO (cp = ParseIfExpression (g, cp + 1, valp)); |
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185 SKIPSPACE (cp); |
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186 if (*cp != ')') |
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187 return CALLFUNC(g, handle_error) (g, cp, ")"); |
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188 |
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189 return cp + 1; /* skip the right paren */ |
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190 |
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191 case '!': |
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192 DO (cp = parse_value (g, cp + 1, valp)); |
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193 *valp = !(*valp); |
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194 return cp; |
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195 |
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196 case '-': |
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197 DO (cp = parse_value (g, cp + 1, valp)); |
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198 *valp = -(*valp); |
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199 return cp; |
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200 |
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201 case '+': |
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202 DO (cp = parse_value (g, cp + 1, valp)); |
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203 return cp; |
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204 |
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205 case '~': |
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206 DO (cp = parse_value (g, cp + 1, valp)); |
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207 *valp = ~(*valp); |
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208 return cp; |
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209 |
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210 case '#': |
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211 DO (cp = parse_variable (g, cp + 1, &var)); |
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212 SKIPSPACE (cp); |
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213 if (*cp != '(') |
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214 return CALLFUNC(g, handle_error) (g, cp, "("); |
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215 do { |
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216 DO (cp = parse_variable (g, cp + 1, &var)); |
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217 SKIPSPACE (cp); |
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218 } while (*cp && *cp != ')'); |
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219 if (*cp != ')') |
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220 return CALLFUNC(g, handle_error) (g, cp, ")"); |
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221 *valp = 1; /* XXX */ |
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222 return cp + 1; |
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223 |
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224 case '\'': |
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225 DO (cp = parse_character (g, cp + 1, valp)); |
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226 if (*cp != '\'') |
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227 return CALLFUNC(g, handle_error) (g, cp, "'"); |
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228 return cp + 1; |
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229 |
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230 case 'd': |
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231 if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) { |
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232 int paren = 0; |
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233 int len; |
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234 |
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235 cp += 7; |
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236 SKIPSPACE (cp); |
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237 if (*cp == '(') { |
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238 paren = 1; |
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239 cp++; |
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240 } |
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241 DO (cp = parse_variable (g, cp, &var)); |
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242 len = cp - var; |
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243 SKIPSPACE (cp); |
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244 if (paren && *cp != ')') |
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245 return CALLFUNC(g, handle_error) (g, cp, ")"); |
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246 *valp = (*(g->funcs.eval_defined)) (g, var, len); |
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247 return cp + paren; /* skip the right paren */ |
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248 } |
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249 /* fall out */ |
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250 } |
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251 |
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252 if (isdigit(*cp)) { |
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253 DO (cp = parse_number (g, cp, valp)); |
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254 } else if (!isvarfirstletter(*cp)) |
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255 return CALLFUNC(g, handle_error) (g, cp, "variable or number"); |
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256 else { |
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257 DO (cp = parse_variable (g, cp, &var)); |
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258 varend = cp; |
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259 SKIPSPACE(cp); |
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260 if (*cp != '(') { |
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261 *valp = (*(g->funcs.eval_variable)) (g, var, varend - var); |
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262 } else { |
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263 do { |
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264 long dummy; |
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265 DO (cp = ParseIfExpression (g, cp + 1, &dummy)); |
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266 SKIPSPACE(cp); |
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267 if (*cp == ')') |
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268 break; |
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269 if (*cp != ',') |
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270 return CALLFUNC(g, handle_error) (g, cp, ","); |
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271 } while (1); |
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272 |
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273 *valp = 1; /* XXX */ |
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274 cp++; |
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275 } |
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276 } |
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277 |
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278 return cp; |
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279 } |
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280 |
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281 |
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282 |
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283 static const char * |
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284 parse_product (IfParser *g, const char *cp, long *valp) |
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285 { |
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286 long rightval; |
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287 |
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288 DO (cp = parse_value (g, cp, valp)); |
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289 SKIPSPACE (cp); |
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290 |
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291 switch (*cp) { |
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292 case '*': |
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293 DO (cp = parse_product (g, cp + 1, &rightval)); |
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294 *valp = (*valp * rightval); |
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295 break; |
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296 |
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297 case '/': |
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298 DO (cp = parse_product (g, cp + 1, &rightval)); |
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299 if (rightval == 0) |
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300 return CALLFUNC(g, handle_error) (g, cp, "0"); |
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301 *valp = (*valp / rightval); |
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302 break; |
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303 |
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304 case '%': |
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305 DO (cp = parse_product (g, cp + 1, &rightval)); |
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306 *valp = (*valp % rightval); |
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307 break; |
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308 } |
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309 return cp; |
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310 } |
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311 |
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312 |
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313 static const char * |
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314 parse_sum (IfParser *g, const char *cp, long *valp) |
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315 { |
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316 long rightval; |
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317 |
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318 DO (cp = parse_product (g, cp, valp)); |
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319 SKIPSPACE (cp); |
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320 |
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321 switch (*cp) { |
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322 case '+': |
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323 DO (cp = parse_sum (g, cp + 1, &rightval)); |
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324 *valp = (*valp + rightval); |
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325 break; |
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326 |
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327 case '-': |
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328 DO (cp = parse_sum (g, cp + 1, &rightval)); |
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329 *valp = (*valp - rightval); |
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330 break; |
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331 } |
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332 return cp; |
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333 } |
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334 |
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335 |
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336 static const char * |
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337 parse_shift (IfParser *g, const char *cp, long *valp) |
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338 { |
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339 long rightval; |
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340 |
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341 DO (cp = parse_sum (g, cp, valp)); |
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342 SKIPSPACE (cp); |
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343 |
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344 switch (*cp) { |
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345 case '<': |
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346 if (cp[1] == '<') { |
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347 DO (cp = parse_shift (g, cp + 2, &rightval)); |
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348 *valp = (*valp << rightval); |
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349 } |
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350 break; |
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351 |
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352 case '>': |
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353 if (cp[1] == '>') { |
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354 DO (cp = parse_shift (g, cp + 2, &rightval)); |
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355 *valp = (*valp >> rightval); |
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356 } |
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357 break; |
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358 } |
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359 return cp; |
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360 } |
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361 |
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362 |
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363 static const char * |
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364 parse_inequality (IfParser *g, const char *cp, long *valp) |
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365 { |
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366 long rightval; |
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367 |
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368 DO (cp = parse_shift (g, cp, valp)); |
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369 SKIPSPACE (cp); |
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370 |
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371 switch (*cp) { |
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372 case '<': |
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373 if (cp[1] == '=') { |
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374 DO (cp = parse_inequality (g, cp + 2, &rightval)); |
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375 *valp = (*valp <= rightval); |
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376 } else { |
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377 DO (cp = parse_inequality (g, cp + 1, &rightval)); |
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378 *valp = (*valp < rightval); |
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379 } |
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380 break; |
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381 |
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382 case '>': |
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383 if (cp[1] == '=') { |
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384 DO (cp = parse_inequality (g, cp + 2, &rightval)); |
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385 *valp = (*valp >= rightval); |
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386 } else { |
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387 DO (cp = parse_inequality (g, cp + 1, &rightval)); |
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388 *valp = (*valp > rightval); |
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389 } |
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390 break; |
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391 } |
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392 return cp; |
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393 } |
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394 |
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395 |
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396 static const char * |
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397 parse_equality (IfParser *g, const char *cp, long *valp) |
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398 { |
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399 long rightval; |
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400 |
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401 DO (cp = parse_inequality (g, cp, valp)); |
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402 SKIPSPACE (cp); |
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403 |
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404 switch (*cp) { |
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405 case '=': |
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406 if (cp[1] == '=') |
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407 cp++; |
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408 DO (cp = parse_equality (g, cp + 1, &rightval)); |
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409 *valp = (*valp == rightval); |
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410 break; |
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411 |
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412 case '!': |
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413 if (cp[1] != '=') |
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414 break; |
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415 DO (cp = parse_equality (g, cp + 2, &rightval)); |
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416 *valp = (*valp != rightval); |
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417 break; |
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418 } |
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419 return cp; |
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420 } |
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421 |
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422 |
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423 static const char * |
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424 parse_band (IfParser *g, const char *cp, long *valp) |
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425 { |
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426 long rightval; |
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427 |
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428 DO (cp = parse_equality (g, cp, valp)); |
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429 SKIPSPACE (cp); |
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430 |
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431 switch (*cp) { |
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432 case '&': |
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433 if (cp[1] != '&') { |
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434 DO (cp = parse_band (g, cp + 1, &rightval)); |
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435 *valp = (*valp & rightval); |
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436 } |
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437 break; |
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438 } |
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439 return cp; |
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440 } |
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441 |
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442 |
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443 static const char * |
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444 parse_bxor (IfParser *g, const char *cp, long *valp) |
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445 { |
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446 long rightval; |
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447 |
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448 DO (cp = parse_band (g, cp, valp)); |
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449 SKIPSPACE (cp); |
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450 |
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451 switch (*cp) { |
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452 case '^': |
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453 DO (cp = parse_bxor (g, cp + 1, &rightval)); |
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454 *valp = (*valp ^ rightval); |
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455 break; |
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456 } |
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457 return cp; |
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458 } |
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459 |
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460 |
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461 static const char * |
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462 parse_bor (IfParser *g, const char *cp, long *valp) |
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463 { |
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464 long rightval; |
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465 |
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466 DO (cp = parse_bxor (g, cp, valp)); |
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467 SKIPSPACE (cp); |
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468 |
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469 switch (*cp) { |
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470 case '|': |
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471 if (cp[1] != '|') { |
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472 DO (cp = parse_bor (g, cp + 1, &rightval)); |
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473 *valp = (*valp | rightval); |
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474 } |
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475 break; |
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476 } |
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477 return cp; |
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478 } |
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479 |
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480 |
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481 static const char * |
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482 parse_land (IfParser *g, const char *cp, long *valp) |
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483 { |
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484 long rightval; |
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485 |
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486 DO (cp = parse_bor (g, cp, valp)); |
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487 SKIPSPACE (cp); |
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488 |
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489 switch (*cp) { |
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490 case '&': |
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491 if (cp[1] != '&') |
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492 return CALLFUNC(g, handle_error) (g, cp, "&&"); |
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493 DO (cp = parse_land (g, cp + 2, &rightval)); |
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494 *valp = (*valp && rightval); |
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495 break; |
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496 } |
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497 return cp; |
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498 } |
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499 |
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500 |
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501 static const char * |
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502 parse_lor (IfParser *g, const char *cp, long *valp) |
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503 { |
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504 long rightval; |
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505 |
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506 DO (cp = parse_land (g, cp, valp)); |
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507 SKIPSPACE (cp); |
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508 |
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509 switch (*cp) { |
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510 case '|': |
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511 if (cp[1] != '|') |
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512 return CALLFUNC(g, handle_error) (g, cp, "||"); |
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513 DO (cp = parse_lor (g, cp + 2, &rightval)); |
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514 *valp = (*valp || rightval); |
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515 break; |
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516 } |
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517 return cp; |
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518 } |
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519 |
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520 |
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521 static const char * |
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522 parse_cond(IfParser *g, const char *cp, long *valp) |
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523 { |
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524 long trueval, falseval; |
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525 |
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526 DO (cp = parse_lor (g, cp, valp)); |
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527 SKIPSPACE (cp); |
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528 |
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529 switch (*cp) { |
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530 case '?': |
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531 DO (cp = parse_cond (g, cp + 1, &trueval)); |
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532 SKIPSPACE (cp); |
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533 if (*cp != ':') |
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534 return CALLFUNC(g, handle_error) (g, cp, ":"); |
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535 DO (cp = parse_cond (g, cp + 1, &falseval)); |
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536 *valp = (*valp ? trueval : falseval); |
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537 break; |
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538 } |
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539 return cp; |
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540 } |
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541 |
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542 |
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543 /**************************************************************************** |
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544 External Entry Points |
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545 ****************************************************************************/ |
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546 |
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547 const char * |
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548 ParseIfExpression (IfParser *g, const char *cp, long *valp) |
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549 { |
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550 return parse_cond (g, cp, valp); |
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551 } |