1 | /* Parse C expressions for CCCP. |
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2 | Copyright (C) 1987, 1992, 1994, 1995 Free Software Foundation. |
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3 | |
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4 | This program is free software; you can redistribute it and/or modify it |
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5 | under the terms of the GNU General Public License as published by the |
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6 | Free Software Foundation; either version 2, or (at your option) any |
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7 | later version. |
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8 | |
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9 | This program is distributed in the hope that it will be useful, |
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10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 | GNU General Public License for more details. |
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13 | |
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14 | You should have received a copy of the GNU General Public License |
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15 | along with this program; if not, write to the Free Software |
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16 | Foundation, 59 Temple Place - Suite 330, |
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17 | Boston, MA 02111-1307, USA. |
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18 | |
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19 | In other words, you are welcome to use, share and improve this program. |
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20 | You are forbidden to forbid anyone else to use, share and improve |
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21 | what you give them. Help stamp out software-hoarding! |
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22 | |
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23 | Written by Per Bothner 1994. */ |
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24 | |
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25 | /* Parse a C expression from text in a string */ |
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26 | |
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27 | #include "config.h" |
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28 | #include "cpplib.h" |
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29 | |
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30 | extern char *xmalloc PARAMS ((unsigned)); |
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31 | extern char *xrealloc PARAMS ((char *, unsigned)); |
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32 | |
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33 | #ifdef MULTIBYTE_CHARS |
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34 | #include <stdlib.h> |
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35 | #include <locale.h> |
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36 | #endif |
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37 | |
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38 | #include <stdio.h> |
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39 | |
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40 | /* This is used for communicating lists of keywords with cccp.c. */ |
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41 | struct arglist { |
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42 | struct arglist *next; |
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43 | U_CHAR *name; |
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44 | int length; |
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45 | int argno; |
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46 | }; |
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47 | |
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48 | /* Define a generic NULL if one hasn't already been defined. */ |
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49 | |
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50 | #ifndef NULL |
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51 | #define NULL 0 |
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52 | #endif |
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53 | |
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54 | #ifndef GENERIC_PTR |
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55 | #if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__) |
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56 | #define GENERIC_PTR void * |
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57 | #else |
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58 | #define GENERIC_PTR char * |
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59 | #endif |
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60 | #endif |
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61 | |
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62 | #ifndef NULL_PTR |
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63 | #define NULL_PTR ((GENERIC_PTR)0) |
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64 | #endif |
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65 | |
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66 | extern char *xmalloc (); |
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67 | |
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68 | #ifndef CHAR_TYPE_SIZE |
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69 | #define CHAR_TYPE_SIZE BITS_PER_UNIT |
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70 | #endif |
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71 | |
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72 | #ifndef INT_TYPE_SIZE |
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73 | #define INT_TYPE_SIZE BITS_PER_WORD |
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74 | #endif |
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75 | |
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76 | #ifndef LONG_TYPE_SIZE |
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77 | #define LONG_TYPE_SIZE BITS_PER_WORD |
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78 | #endif |
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79 | |
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80 | #ifndef WCHAR_TYPE_SIZE |
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81 | #define WCHAR_TYPE_SIZE INT_TYPE_SIZE |
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82 | #endif |
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83 | |
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84 | #ifndef MAX_CHAR_TYPE_SIZE |
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85 | #define MAX_CHAR_TYPE_SIZE CHAR_TYPE_SIZE |
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86 | #endif |
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87 | |
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88 | #ifndef MAX_INT_TYPE_SIZE |
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89 | #define MAX_INT_TYPE_SIZE INT_TYPE_SIZE |
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90 | #endif |
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91 | |
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92 | #ifndef MAX_LONG_TYPE_SIZE |
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93 | #define MAX_LONG_TYPE_SIZE LONG_TYPE_SIZE |
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94 | #endif |
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95 | |
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96 | #ifndef MAX_WCHAR_TYPE_SIZE |
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97 | #define MAX_WCHAR_TYPE_SIZE WCHAR_TYPE_SIZE |
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98 | #endif |
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99 | |
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100 | /* Yield nonzero if adding two numbers with A's and B's signs can yield a |
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101 | number with SUM's sign, where A, B, and SUM are all C integers. */ |
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102 | #define possible_sum_sign(a, b, sum) ((((a) ^ (b)) | ~ ((a) ^ (sum))) < 0) |
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103 | |
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104 | static void integer_overflow (); |
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105 | static long left_shift (); |
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106 | static long right_shift (); |
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107 | |
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108 | #define ERROR 299 |
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109 | #define OROR 300 |
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110 | #define ANDAND 301 |
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111 | #define EQUAL 302 |
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112 | #define NOTEQUAL 303 |
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113 | #define LEQ 304 |
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114 | #define GEQ 305 |
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115 | #define LSH 306 |
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116 | #define RSH 307 |
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117 | #define NAME 308 |
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118 | #define INT 309 |
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119 | #define CHAR 310 |
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120 | |
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121 | #define LEFT_OPERAND_REQUIRED 1 |
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122 | #define RIGHT_OPERAND_REQUIRED 2 |
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123 | #define HAVE_VALUE 4 |
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124 | /*#define UNSIGNEDP 8*/ |
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125 | |
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126 | #ifndef HOST_BITS_PER_WIDE_INT |
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127 | |
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128 | #if HOST_BITS_PER_LONG > HOST_BITS_PER_INT |
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129 | #define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_LONG |
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130 | #define HOST_WIDE_INT long |
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131 | #else |
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132 | #define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_INT |
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133 | #define HOST_WIDE_INT int |
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134 | #endif |
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135 | |
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136 | #endif |
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137 | |
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138 | struct operation { |
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139 | short op; |
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140 | char rprio; /* Priority of op (relative to it right operand). */ |
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141 | char flags; |
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142 | char unsignedp; /* true if value should be treated as unsigned */ |
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143 | HOST_WIDE_INT value; /* The value logically "right" of op. */ |
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144 | }; |
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145 | |
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146 | /* Take care of parsing a number (anything that starts with a digit). |
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147 | LEN is the number of characters in it. */ |
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148 | |
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149 | /* maybe needs to actually deal with floating point numbers */ |
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150 | |
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151 | struct operation |
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152 | parse_number (pfile, start, olen) |
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153 | cpp_reader *pfile; |
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154 | char *start; |
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155 | int olen; |
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156 | { |
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157 | struct operation op; |
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158 | register char *p = start; |
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159 | register int c; |
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160 | register unsigned long n = 0, nd, ULONG_MAX_over_base; |
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161 | register int base = 10; |
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162 | register int len = olen; |
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163 | register int overflow = 0; |
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164 | register int digit, largest_digit = 0; |
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165 | int spec_long = 0; |
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166 | |
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167 | op.unsignedp = 0; |
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168 | |
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169 | for (c = 0; c < len; c++) |
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170 | if (p[c] == '.') { |
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171 | /* It's a float since it contains a point. */ |
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172 | cpp_error (pfile, |
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173 | "floating point numbers not allowed in #if expressions"); |
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174 | op.op = ERROR; |
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175 | return op; |
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176 | } |
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177 | |
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178 | if (len >= 3 && (!strncmp (p, "0x", 2) || !strncmp (p, "0X", 2))) { |
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179 | p += 2; |
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180 | base = 16; |
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181 | len -= 2; |
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182 | } |
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183 | else if (*p == '0') |
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184 | base = 8; |
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185 | |
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186 | /* Some buggy compilers (e.g. MPW C) seem to need both casts. */ |
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187 | ULONG_MAX_over_base = ((unsigned long) -1) / ((unsigned long) base); |
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188 | |
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189 | for (; len > 0; len--) { |
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190 | c = *p++; |
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191 | |
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192 | if (c >= '0' && c <= '9') |
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193 | digit = c - '0'; |
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194 | else if (base == 16 && c >= 'a' && c <= 'f') |
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195 | digit = c - 'a' + 10; |
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196 | else if (base == 16 && c >= 'A' && c <= 'F') |
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197 | digit = c - 'A' + 10; |
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198 | else { |
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199 | /* `l' means long, and `u' means unsigned. */ |
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200 | while (1) { |
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201 | if (c == 'l' || c == 'L') |
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202 | { |
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203 | if (spec_long) |
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204 | cpp_error (pfile, "two `l's in integer constant"); |
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205 | spec_long = 1; |
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206 | } |
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207 | else if (c == 'u' || c == 'U') |
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208 | { |
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209 | if (op.unsignedp) |
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210 | cpp_error (pfile, "two `u's in integer constant"); |
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211 | op.unsignedp = 1; |
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212 | } |
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213 | else |
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214 | break; |
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215 | |
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216 | if (--len == 0) |
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217 | break; |
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218 | c = *p++; |
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219 | } |
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220 | /* Don't look for any more digits after the suffixes. */ |
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221 | break; |
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222 | } |
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223 | if (largest_digit < digit) |
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224 | largest_digit = digit; |
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225 | nd = n * base + digit; |
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226 | overflow |= ULONG_MAX_over_base < n | nd < n; |
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227 | n = nd; |
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228 | } |
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229 | |
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230 | if (len != 0) |
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231 | { |
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232 | cpp_error (pfile, "Invalid number in #if expression"); |
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233 | op.op = ERROR; |
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234 | return op; |
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235 | } |
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236 | |
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237 | if (base <= largest_digit) |
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238 | cpp_warning (pfile, "integer constant contains digits beyond the radix"); |
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239 | |
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240 | if (overflow) |
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241 | cpp_warning (pfile, "integer constant out of range"); |
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242 | |
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243 | /* If too big to be signed, consider it unsigned. */ |
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244 | if ((long) n < 0 && ! op.unsignedp) |
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245 | { |
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246 | if (base == 10) |
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247 | cpp_warning (pfile, "integer constant is so large that it is unsigned"); |
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248 | op.unsignedp = 1; |
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249 | } |
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250 | |
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251 | op.value = n; |
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252 | op.op = INT; |
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253 | return op; |
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254 | } |
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255 | |
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256 | struct token { |
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257 | char *operator; |
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258 | int token; |
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259 | }; |
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260 | |
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261 | static struct token tokentab2[] = { |
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262 | {"&&", ANDAND}, |
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263 | {"||", OROR}, |
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264 | {"<<", LSH}, |
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265 | {">>", RSH}, |
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266 | {"==", EQUAL}, |
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267 | {"!=", NOTEQUAL}, |
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268 | {"<=", LEQ}, |
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269 | {">=", GEQ}, |
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270 | {"++", ERROR}, |
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271 | {"--", ERROR}, |
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272 | {NULL, ERROR} |
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273 | }; |
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274 | |
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275 | /* Read one token. */ |
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276 | |
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277 | struct operation |
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278 | cpp_lex (pfile) |
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279 | cpp_reader *pfile; |
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280 | { |
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281 | register int c; |
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282 | register int namelen; |
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283 | register struct token *toktab; |
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284 | enum cpp_token token; |
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285 | struct operation op; |
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286 | U_CHAR *tok_start, *tok_end; |
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287 | int old_written; |
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288 | |
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289 | retry: |
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290 | |
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291 | old_written = CPP_WRITTEN (pfile); |
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292 | cpp_skip_hspace (pfile); |
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293 | c = CPP_BUF_PEEK (CPP_BUFFER (pfile)); |
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294 | if (c == '#') |
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295 | return parse_number (pfile, |
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296 | cpp_read_check_assertion (pfile) ? "1" : "0", 1); |
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297 | |
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298 | if (c == '\n') |
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299 | { |
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300 | op.op = 0; |
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301 | return op; |
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302 | } |
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303 | |
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304 | token = cpp_get_token (pfile); |
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305 | tok_start = pfile->token_buffer + old_written; |
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306 | tok_end = CPP_PWRITTEN (pfile); |
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307 | pfile->limit = tok_start; |
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308 | switch (token) |
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309 | { |
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310 | case CPP_EOF: /* Should not happen ... */ |
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311 | op.op = 0; |
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312 | return op; |
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313 | case CPP_VSPACE: |
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314 | case CPP_POP: |
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315 | if (CPP_BUFFER (pfile)->fname != NULL) |
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316 | { |
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317 | op.op = 0; |
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318 | return op; |
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319 | } |
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320 | goto retry; |
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321 | case CPP_HSPACE: case CPP_COMMENT: |
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322 | goto retry; |
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323 | case CPP_NUMBER: |
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324 | return parse_number (pfile, tok_start, tok_end - tok_start); |
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325 | case CPP_STRING: |
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326 | cpp_error (pfile, "string constants not allowed in #if expressions"); |
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327 | op.op = ERROR; |
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328 | return op; |
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329 | case CPP_CHAR: |
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330 | /* This code for reading a character constant |
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331 | handles multicharacter constants and wide characters. |
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332 | It is mostly copied from c-lex.c. */ |
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333 | { |
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334 | register int result = 0; |
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335 | register num_chars = 0; |
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336 | unsigned width = MAX_CHAR_TYPE_SIZE; |
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337 | int wide_flag = 0; |
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338 | int max_chars; |
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339 | U_CHAR *ptr = tok_start; |
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340 | #ifdef MULTIBYTE_CHARS |
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341 | char token_buffer[MAX_LONG_TYPE_SIZE/MAX_CHAR_TYPE_SIZE + MB_CUR_MAX]; |
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342 | #else |
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343 | char token_buffer[MAX_LONG_TYPE_SIZE/MAX_CHAR_TYPE_SIZE + 1]; |
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344 | #endif |
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345 | |
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346 | if (*ptr == 'L') |
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347 | { |
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348 | ptr++; |
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349 | wide_flag = 1; |
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350 | width = MAX_WCHAR_TYPE_SIZE; |
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351 | #ifdef MULTIBYTE_CHARS |
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352 | max_chars = MB_CUR_MAX; |
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353 | #else |
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354 | max_chars = 1; |
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355 | #endif |
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356 | } |
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357 | else |
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358 | max_chars = MAX_LONG_TYPE_SIZE / width; |
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359 | |
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360 | ++ptr; |
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361 | while (ptr < tok_end && ((c = *ptr++) != '\'')) |
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362 | { |
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363 | if (c == '\\') |
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364 | { |
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365 | c = cpp_parse_escape (pfile, &ptr); |
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366 | if (width < HOST_BITS_PER_INT |
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367 | && (unsigned) c >= (1 << width)) |
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368 | cpp_pedwarn (pfile, |
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369 | "escape sequence out of range for character"); |
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370 | } |
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371 | |
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372 | num_chars++; |
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373 | |
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374 | /* Merge character into result; ignore excess chars. */ |
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375 | if (num_chars < max_chars + 1) |
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376 | { |
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377 | if (width < HOST_BITS_PER_INT) |
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378 | result = (result << width) | (c & ((1 << width) - 1)); |
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379 | else |
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380 | result = c; |
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381 | token_buffer[num_chars - 1] = c; |
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382 | } |
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383 | } |
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384 | |
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385 | token_buffer[num_chars] = 0; |
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386 | |
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387 | if (c != '\'') |
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388 | cpp_error (pfile, "malformatted character constant"); |
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389 | else if (num_chars == 0) |
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390 | cpp_error (pfile, "empty character constant"); |
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391 | else if (num_chars > max_chars) |
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392 | { |
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393 | num_chars = max_chars; |
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394 | cpp_error (pfile, "character constant too long"); |
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395 | } |
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396 | else if (num_chars != 1 && ! CPP_TRADITIONAL (pfile)) |
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397 | cpp_warning (pfile, "multi-character character constant"); |
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398 | |
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399 | /* If char type is signed, sign-extend the constant. */ |
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400 | if (! wide_flag) |
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401 | { |
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402 | int num_bits = num_chars * width; |
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403 | |
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404 | if (cpp_lookup (pfile, "__CHAR_UNSIGNED__", |
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405 | sizeof ("__CHAR_UNSIGNED__")-1, -1) |
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406 | || ((result >> (num_bits - 1)) & 1) == 0) |
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407 | op.value |
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408 | = result & ((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits)); |
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409 | else |
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410 | op.value |
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411 | = result | ~((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits)); |
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412 | } |
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413 | else |
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414 | { |
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415 | #ifdef MULTIBYTE_CHARS |
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416 | /* Set the initial shift state and convert the next sequence. */ |
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417 | result = 0; |
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418 | /* In all locales L'\0' is zero and mbtowc will return zero, |
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419 | so don't use it. */ |
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420 | if (num_chars > 1 |
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421 | || (num_chars == 1 && token_buffer[0] != '\0')) |
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422 | { |
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423 | wchar_t wc; |
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424 | (void) mbtowc (NULL_PTR, NULL_PTR, 0); |
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425 | if (mbtowc (& wc, token_buffer, num_chars) == num_chars) |
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426 | result = wc; |
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427 | else |
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428 | cpp_warning (pfile,"Ignoring invalid multibyte character"); |
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429 | } |
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430 | #endif |
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431 | op.value = result; |
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432 | } |
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433 | } |
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434 | |
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435 | /* This is always a signed type. */ |
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436 | op.unsignedp = 0; |
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437 | op.op = CHAR; |
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438 | |
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439 | return op; |
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440 | |
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441 | case CPP_NAME: |
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442 | return parse_number (pfile, "0", 0); |
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443 | |
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444 | case CPP_OTHER: |
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445 | /* See if it is a special token of length 2. */ |
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446 | if (tok_start + 2 == tok_end) |
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447 | { |
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448 | for (toktab = tokentab2; toktab->operator != NULL; toktab++) |
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449 | if (tok_start[0] == toktab->operator[0] |
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450 | && tok_start[1] == toktab->operator[1]) |
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451 | break; |
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452 | if (toktab->token == ERROR) |
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453 | { |
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454 | char *buf = (char *) alloca (40); |
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455 | sprintf (buf, "`%s' not allowed in operand of `#if'", tok_start); |
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456 | cpp_error (pfile, buf); |
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457 | } |
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458 | op.op = toktab->token; |
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459 | return op; |
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460 | } |
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461 | /* fall through */ |
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462 | default: |
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463 | op.op = *tok_start; |
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464 | return op; |
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465 | } |
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466 | } |
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467 | |
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468 | |
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469 | /* Parse a C escape sequence. STRING_PTR points to a variable |
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470 | containing a pointer to the string to parse. That pointer |
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471 | is updated past the characters we use. The value of the |
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472 | escape sequence is returned. |
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473 | |
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474 | A negative value means the sequence \ newline was seen, |
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475 | which is supposed to be equivalent to nothing at all. |
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476 | |
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477 | If \ is followed by a null character, we return a negative |
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478 | value and leave the string pointer pointing at the null character. |
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479 | |
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480 | If \ is followed by 000, we return 0 and leave the string pointer |
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481 | after the zeros. A value of 0 does not mean end of string. */ |
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482 | |
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483 | int |
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484 | cpp_parse_escape (pfile, string_ptr) |
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485 | cpp_reader *pfile; |
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486 | char **string_ptr; |
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487 | { |
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488 | register int c = *(*string_ptr)++; |
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489 | switch (c) |
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490 | { |
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491 | case 'a': |
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492 | return TARGET_BELL; |
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493 | case 'b': |
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494 | return TARGET_BS; |
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495 | case 'e': |
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496 | case 'E': |
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497 | if (CPP_PEDANTIC (pfile)) |
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498 | cpp_pedwarn (pfile, "non-ANSI-standard escape sequence, `\\%c'", c); |
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499 | return 033; |
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500 | case 'f': |
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501 | return TARGET_FF; |
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502 | case 'n': |
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503 | return TARGET_NEWLINE; |
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504 | case 'r': |
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505 | return TARGET_CR; |
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506 | case 't': |
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507 | return TARGET_TAB; |
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508 | case 'v': |
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509 | return TARGET_VT; |
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510 | case '\n': |
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511 | return -2; |
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512 | case 0: |
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513 | (*string_ptr)--; |
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514 | return 0; |
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515 | |
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516 | case '0': |
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517 | case '1': |
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518 | case '2': |
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519 | case '3': |
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520 | case '4': |
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521 | case '5': |
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522 | case '6': |
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523 | case '7': |
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524 | { |
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525 | register int i = c - '0'; |
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526 | register int count = 0; |
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527 | while (++count < 3) |
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528 | { |
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529 | c = *(*string_ptr)++; |
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530 | if (c >= '0' && c <= '7') |
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531 | i = (i << 3) + c - '0'; |
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532 | else |
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533 | { |
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534 | (*string_ptr)--; |
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535 | break; |
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536 | } |
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537 | } |
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538 | if ((i & ~((1 << MAX_CHAR_TYPE_SIZE) - 1)) != 0) |
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539 | { |
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540 | i &= (1 << MAX_CHAR_TYPE_SIZE) - 1; |
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541 | cpp_warning (pfile, |
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542 | "octal character constant does not fit in a byte"); |
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543 | } |
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544 | return i; |
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545 | } |
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546 | case 'x': |
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547 | { |
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548 | register unsigned i = 0, overflow = 0, digits_found = 0, digit; |
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549 | for (;;) |
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550 | { |
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551 | c = *(*string_ptr)++; |
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552 | if (c >= '0' && c <= '9') |
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553 | digit = c - '0'; |
---|
554 | else if (c >= 'a' && c <= 'f') |
---|
555 | digit = c - 'a' + 10; |
---|
556 | else if (c >= 'A' && c <= 'F') |
---|
557 | digit = c - 'A' + 10; |
---|
558 | else |
---|
559 | { |
---|
560 | (*string_ptr)--; |
---|
561 | break; |
---|
562 | } |
---|
563 | overflow |= i ^ (i << 4 >> 4); |
---|
564 | i = (i << 4) + digit; |
---|
565 | digits_found = 1; |
---|
566 | } |
---|
567 | if (!digits_found) |
---|
568 | cpp_error (pfile, "\\x used with no following hex digits"); |
---|
569 | if (overflow | (i & ~((1 << BITS_PER_UNIT) - 1))) |
---|
570 | { |
---|
571 | i &= (1 << BITS_PER_UNIT) - 1; |
---|
572 | cpp_warning (pfile, |
---|
573 | "hex character constant does not fit in a byte"); |
---|
574 | } |
---|
575 | return i; |
---|
576 | } |
---|
577 | default: |
---|
578 | return c; |
---|
579 | } |
---|
580 | } |
---|
581 | |
---|
582 | static void |
---|
583 | integer_overflow (pfile) |
---|
584 | cpp_reader *pfile; |
---|
585 | { |
---|
586 | if (CPP_PEDANTIC (pfile)) |
---|
587 | cpp_pedwarn (pfile, "integer overflow in preprocessor expression"); |
---|
588 | } |
---|
589 | |
---|
590 | static long |
---|
591 | left_shift (pfile, a, unsignedp, b) |
---|
592 | cpp_reader *pfile; |
---|
593 | long a; |
---|
594 | int unsignedp; |
---|
595 | unsigned long b; |
---|
596 | { |
---|
597 | if (b >= HOST_BITS_PER_LONG) |
---|
598 | { |
---|
599 | if (! unsignedp && a != 0) |
---|
600 | integer_overflow (pfile); |
---|
601 | return 0; |
---|
602 | } |
---|
603 | else if (unsignedp) |
---|
604 | return (unsigned long) a << b; |
---|
605 | else |
---|
606 | { |
---|
607 | long l = a << b; |
---|
608 | if (l >> b != a) |
---|
609 | integer_overflow (pfile); |
---|
610 | return l; |
---|
611 | } |
---|
612 | } |
---|
613 | |
---|
614 | static long |
---|
615 | right_shift (pfile, a, unsignedp, b) |
---|
616 | cpp_reader *pfile; |
---|
617 | long a; |
---|
618 | int unsignedp; |
---|
619 | unsigned long b; |
---|
620 | { |
---|
621 | if (b >= HOST_BITS_PER_LONG) |
---|
622 | return unsignedp ? 0 : a >> (HOST_BITS_PER_LONG - 1); |
---|
623 | else if (unsignedp) |
---|
624 | return (unsigned long) a >> b; |
---|
625 | else |
---|
626 | return a >> b; |
---|
627 | } |
---|
628 | |
---|
629 | /* These priorities are all even, so we can handle associatively. */ |
---|
630 | #define PAREN_INNER_PRIO 0 |
---|
631 | #define COMMA_PRIO 4 |
---|
632 | #define COND_PRIO (COMMA_PRIO+2) |
---|
633 | #define OROR_PRIO (COND_PRIO+2) |
---|
634 | #define ANDAND_PRIO (OROR_PRIO+2) |
---|
635 | #define OR_PRIO (ANDAND_PRIO+2) |
---|
636 | #define XOR_PRIO (OR_PRIO+2) |
---|
637 | #define AND_PRIO (XOR_PRIO+2) |
---|
638 | #define EQUAL_PRIO (AND_PRIO+2) |
---|
639 | #define LESS_PRIO (EQUAL_PRIO+2) |
---|
640 | #define SHIFT_PRIO (LESS_PRIO+2) |
---|
641 | #define PLUS_PRIO (SHIFT_PRIO+2) |
---|
642 | #define MUL_PRIO (PLUS_PRIO+2) |
---|
643 | #define UNARY_PRIO (MUL_PRIO+2) |
---|
644 | #define PAREN_OUTER_PRIO (UNARY_PRIO+2) |
---|
645 | |
---|
646 | #define COMPARE(OP) \ |
---|
647 | top->unsignedp = 0;\ |
---|
648 | top->value = (unsigned1 || unsigned2) ? (unsigned long) v1 OP v2 : (v1 OP v2) |
---|
649 | |
---|
650 | /* Parse and evaluate a C expression, reading from PFILE. |
---|
651 | Returns the value of the expression. */ |
---|
652 | |
---|
653 | HOST_WIDE_INT |
---|
654 | cpp_parse_expr (pfile) |
---|
655 | cpp_reader *pfile; |
---|
656 | { |
---|
657 | /* The implementation is an operator precedence parser, |
---|
658 | i.e. a bottom-up parser, using a stack for not-yet-reduced tokens. |
---|
659 | |
---|
660 | The stack base is 'stack', and the current stack pointer is 'top'. |
---|
661 | There is a stack element for each operator (only), |
---|
662 | and the most recently pushed operator is 'top->op'. |
---|
663 | An operand (value) is stored in the 'value' field of the stack |
---|
664 | element of the operator that precedes it. |
---|
665 | In that case the 'flags' field has the HAVE_VALUE flag set. */ |
---|
666 | |
---|
667 | #define INIT_STACK_SIZE 20 |
---|
668 | struct operation init_stack[INIT_STACK_SIZE]; |
---|
669 | struct operation *stack = init_stack; |
---|
670 | struct operation *limit = stack + INIT_STACK_SIZE; |
---|
671 | register struct operation *top = stack; |
---|
672 | int lprio, rprio; |
---|
673 | |
---|
674 | top->rprio = 0; |
---|
675 | top->flags = 0; |
---|
676 | for (;;) |
---|
677 | { |
---|
678 | struct operation op; |
---|
679 | char flags = 0; |
---|
680 | |
---|
681 | /* Read a token */ |
---|
682 | op = cpp_lex (pfile); |
---|
683 | |
---|
684 | /* See if the token is an operand, in which case go to set_value. |
---|
685 | If the token is an operator, figure out its left and right |
---|
686 | priorities, and then goto maybe_reduce. */ |
---|
687 | |
---|
688 | switch (op.op) |
---|
689 | { |
---|
690 | case NAME: |
---|
691 | top->value = 0, top->unsignedp = 0; |
---|
692 | goto set_value; |
---|
693 | case INT: case CHAR: |
---|
694 | top->value = op.value; |
---|
695 | top->unsignedp = op.unsignedp; |
---|
696 | goto set_value; |
---|
697 | case 0: |
---|
698 | lprio = 0; goto maybe_reduce; |
---|
699 | case '+': case '-': |
---|
700 | /* Is this correct if unary ? FIXME */ |
---|
701 | flags = RIGHT_OPERAND_REQUIRED; |
---|
702 | lprio = PLUS_PRIO; rprio = lprio + 1; goto maybe_reduce; |
---|
703 | case '!': case '~': |
---|
704 | flags = RIGHT_OPERAND_REQUIRED; |
---|
705 | rprio = UNARY_PRIO; lprio = rprio + 1; goto maybe_reduce; |
---|
706 | case '*': case '/': case '%': |
---|
707 | lprio = MUL_PRIO; goto binop; |
---|
708 | case '<': case '>': case LEQ: case GEQ: |
---|
709 | lprio = LESS_PRIO; goto binop; |
---|
710 | case EQUAL: case NOTEQUAL: |
---|
711 | lprio = EQUAL_PRIO; goto binop; |
---|
712 | case LSH: case RSH: |
---|
713 | lprio = SHIFT_PRIO; goto binop; |
---|
714 | case '&': lprio = AND_PRIO; goto binop; |
---|
715 | case '^': lprio = XOR_PRIO; goto binop; |
---|
716 | case '|': lprio = OR_PRIO; goto binop; |
---|
717 | case ANDAND: lprio = ANDAND_PRIO; goto binop; |
---|
718 | case OROR: lprio = OROR_PRIO; goto binop; |
---|
719 | case ',': |
---|
720 | lprio = COMMA_PRIO; goto binop; |
---|
721 | case '(': |
---|
722 | lprio = PAREN_OUTER_PRIO; rprio = PAREN_INNER_PRIO; |
---|
723 | goto maybe_reduce; |
---|
724 | case ')': |
---|
725 | lprio = PAREN_INNER_PRIO; rprio = PAREN_OUTER_PRIO; |
---|
726 | goto maybe_reduce; |
---|
727 | case ':': |
---|
728 | lprio = COND_PRIO; rprio = COND_PRIO; |
---|
729 | goto maybe_reduce; |
---|
730 | case '?': |
---|
731 | lprio = COND_PRIO + 1; rprio = COND_PRIO; |
---|
732 | goto maybe_reduce; |
---|
733 | binop: |
---|
734 | flags = LEFT_OPERAND_REQUIRED|RIGHT_OPERAND_REQUIRED; |
---|
735 | rprio = lprio + 1; |
---|
736 | goto maybe_reduce; |
---|
737 | default: |
---|
738 | cpp_error (pfile, "invalid character in #if"); |
---|
739 | goto syntax_error; |
---|
740 | } |
---|
741 | |
---|
742 | set_value: |
---|
743 | /* Push a value onto the stack. */ |
---|
744 | if (top->flags & HAVE_VALUE) |
---|
745 | { |
---|
746 | cpp_error (pfile, "syntax error in #if"); |
---|
747 | goto syntax_error; |
---|
748 | } |
---|
749 | top->flags |= HAVE_VALUE; |
---|
750 | continue; |
---|
751 | |
---|
752 | maybe_reduce: |
---|
753 | /* Push an operator, and check if we can reduce now. */ |
---|
754 | while (top->rprio > lprio) |
---|
755 | { |
---|
756 | long v1 = top[-1].value, v2 = top[0].value; |
---|
757 | int unsigned1 = top[-1].unsignedp, unsigned2 = top[0].unsignedp; |
---|
758 | top--; |
---|
759 | if ((top[1].flags & LEFT_OPERAND_REQUIRED) |
---|
760 | && ! (top[0].flags & HAVE_VALUE)) |
---|
761 | { |
---|
762 | cpp_error (pfile, "syntax error - missing left operand"); |
---|
763 | goto syntax_error; |
---|
764 | } |
---|
765 | if ((top[1].flags & RIGHT_OPERAND_REQUIRED) |
---|
766 | && ! (top[1].flags & HAVE_VALUE)) |
---|
767 | { |
---|
768 | cpp_error (pfile, "syntax error - missing right operand"); |
---|
769 | goto syntax_error; |
---|
770 | } |
---|
771 | /* top[0].value = (top[1].op)(v1, v2);*/ |
---|
772 | switch (top[1].op) |
---|
773 | { |
---|
774 | case '+': |
---|
775 | if (!(top->flags & HAVE_VALUE)) |
---|
776 | { /* Unary '+' */ |
---|
777 | top->value = v2; |
---|
778 | top->unsignedp = unsigned2; |
---|
779 | top->flags |= HAVE_VALUE; |
---|
780 | } |
---|
781 | else |
---|
782 | { |
---|
783 | top->value = v1 + v2; |
---|
784 | top->unsignedp = unsigned1 || unsigned2; |
---|
785 | if (! top->unsignedp |
---|
786 | && ! possible_sum_sign (v1, v2, top->value)) |
---|
787 | integer_overflow (pfile); |
---|
788 | } |
---|
789 | break; |
---|
790 | case '-': |
---|
791 | if (!(top->flags & HAVE_VALUE)) |
---|
792 | { /* Unary '-' */ |
---|
793 | top->value = - v2; |
---|
794 | if ((top->value & v2) < 0 && ! unsigned2) |
---|
795 | integer_overflow (pfile); |
---|
796 | top->unsignedp = unsigned2; |
---|
797 | top->flags |= HAVE_VALUE; |
---|
798 | } |
---|
799 | else |
---|
800 | { /* Binary '-' */ |
---|
801 | top->value = v1 - v2; |
---|
802 | top->unsignedp = unsigned1 || unsigned2; |
---|
803 | if (! top->unsignedp |
---|
804 | && ! possible_sum_sign (top->value, v2, v1)) |
---|
805 | integer_overflow (pfile); |
---|
806 | } |
---|
807 | break; |
---|
808 | case '*': |
---|
809 | top->unsignedp = unsigned1 || unsigned2; |
---|
810 | if (top->unsignedp) |
---|
811 | top->value = (unsigned long) v1 * v2; |
---|
812 | else |
---|
813 | { |
---|
814 | top->value = v1 * v2; |
---|
815 | if (v1 |
---|
816 | && (top->value / v1 != v2 |
---|
817 | || (top->value & v1 & v2) < 0)) |
---|
818 | integer_overflow (pfile); |
---|
819 | } |
---|
820 | break; |
---|
821 | case '/': |
---|
822 | if (v2 == 0) |
---|
823 | { |
---|
824 | cpp_error (pfile, "division by zero in #if"); |
---|
825 | v2 = 1; |
---|
826 | } |
---|
827 | top->unsignedp = unsigned1 || unsigned2; |
---|
828 | if (top->unsignedp) |
---|
829 | top->value = (unsigned long) v1 / v2; |
---|
830 | else |
---|
831 | { |
---|
832 | top->value = v1 / v2; |
---|
833 | if ((top->value & v1 & v2) < 0) |
---|
834 | integer_overflow (pfile); |
---|
835 | } |
---|
836 | break; |
---|
837 | case '%': |
---|
838 | if (v2 == 0) |
---|
839 | { |
---|
840 | cpp_error (pfile, "division by zero in #if"); |
---|
841 | v2 = 1; |
---|
842 | } |
---|
843 | top->unsignedp = unsigned1 || unsigned2; |
---|
844 | if (top->unsignedp) |
---|
845 | top->value = (unsigned long) v1 % v2; |
---|
846 | else |
---|
847 | top->value = v1 % v2; |
---|
848 | break; |
---|
849 | case '!': |
---|
850 | if (top->flags & HAVE_VALUE) |
---|
851 | { |
---|
852 | cpp_error (pfile, "syntax error"); |
---|
853 | goto syntax_error; |
---|
854 | } |
---|
855 | top->value = ! v2; |
---|
856 | top->unsignedp = 0; |
---|
857 | top->flags |= HAVE_VALUE; |
---|
858 | break; |
---|
859 | case '~': |
---|
860 | if (top->flags & HAVE_VALUE) |
---|
861 | { |
---|
862 | cpp_error (pfile, "syntax error"); |
---|
863 | goto syntax_error; |
---|
864 | } |
---|
865 | top->value = ~ v2; |
---|
866 | top->unsignedp = unsigned2; |
---|
867 | top->flags |= HAVE_VALUE; |
---|
868 | break; |
---|
869 | case '<': COMPARE(<); break; |
---|
870 | case '>': COMPARE(>); break; |
---|
871 | case LEQ: COMPARE(<=); break; |
---|
872 | case GEQ: COMPARE(>=); break; |
---|
873 | case EQUAL: |
---|
874 | top->value = (v1 == v2); |
---|
875 | top->unsignedp = 0; |
---|
876 | break; |
---|
877 | case NOTEQUAL: |
---|
878 | top->value = (v1 != v2); |
---|
879 | top->unsignedp = 0; |
---|
880 | break; |
---|
881 | case LSH: |
---|
882 | top->unsignedp = unsigned1; |
---|
883 | if (v2 < 0 && ! unsigned2) |
---|
884 | top->value = right_shift (pfile, v1, unsigned1, -v2); |
---|
885 | else |
---|
886 | top->value = left_shift (pfile, v1, unsigned1, v2); |
---|
887 | break; |
---|
888 | case RSH: |
---|
889 | top->unsignedp = unsigned1; |
---|
890 | if (v2 < 0 && ! unsigned2) |
---|
891 | top->value = left_shift (pfile, v1, unsigned1, -v2); |
---|
892 | else |
---|
893 | top->value = right_shift (pfile, v1, unsigned1, v2); |
---|
894 | break; |
---|
895 | #define LOGICAL(OP) \ |
---|
896 | top->value = v1 OP v2;\ |
---|
897 | top->unsignedp = unsigned1 || unsigned2; |
---|
898 | case '&': LOGICAL(&); break; |
---|
899 | case '^': LOGICAL(^); break; |
---|
900 | case '|': LOGICAL(|); break; |
---|
901 | case ANDAND: |
---|
902 | top->value = v1 && v2; top->unsignedp = 0; break; |
---|
903 | case OROR: |
---|
904 | top->value = v1 || v2; top->unsignedp = 0; break; |
---|
905 | case ',': |
---|
906 | if (CPP_PEDANTIC (pfile)) |
---|
907 | cpp_pedwarn (pfile, "comma operator in operand of `#if'"); |
---|
908 | top->value = v2; |
---|
909 | top->unsignedp = unsigned2; |
---|
910 | break; |
---|
911 | case '(': case '?': |
---|
912 | cpp_error (pfile, "syntax error in #if"); |
---|
913 | goto syntax_error; |
---|
914 | case ':': |
---|
915 | if (top[0].op != '?') |
---|
916 | { |
---|
917 | cpp_error (pfile, |
---|
918 | "syntax error ':' without preceding '?'"); |
---|
919 | goto syntax_error; |
---|
920 | } |
---|
921 | else if (! (top[1].flags & HAVE_VALUE) |
---|
922 | || !(top[-1].flags & HAVE_VALUE) |
---|
923 | || !(top[0].flags & HAVE_VALUE)) |
---|
924 | { |
---|
925 | cpp_error (pfile, "bad syntax for ?: operator"); |
---|
926 | goto syntax_error; |
---|
927 | } |
---|
928 | else |
---|
929 | { |
---|
930 | top--; |
---|
931 | top->value = top->value ? v1 : v2; |
---|
932 | top->unsignedp = unsigned1 || unsigned2; |
---|
933 | } |
---|
934 | break; |
---|
935 | case ')': |
---|
936 | if ((top[1].flags & HAVE_VALUE) |
---|
937 | || ! (top[0].flags & HAVE_VALUE) |
---|
938 | || top[0].op != '(' |
---|
939 | || (top[-1].flags & HAVE_VALUE)) |
---|
940 | { |
---|
941 | cpp_error (pfile, "mismatched parentheses in #if"); |
---|
942 | goto syntax_error; |
---|
943 | } |
---|
944 | else |
---|
945 | { |
---|
946 | top--; |
---|
947 | top->value = v1; |
---|
948 | top->unsignedp = unsigned1; |
---|
949 | top->flags |= HAVE_VALUE; |
---|
950 | } |
---|
951 | break; |
---|
952 | default: |
---|
953 | fprintf (stderr, |
---|
954 | top[1].op >= ' ' && top[1].op <= '~' |
---|
955 | ? "unimplemented operator '%c'\n" |
---|
956 | : "unimplemented operator '\\%03o'\n", |
---|
957 | top[1].op); |
---|
958 | } |
---|
959 | } |
---|
960 | if (op.op == 0) |
---|
961 | { |
---|
962 | if (top != stack) |
---|
963 | cpp_error (pfile, "internal error in #if expression"); |
---|
964 | if (stack != init_stack) |
---|
965 | free (stack); |
---|
966 | return top->value; |
---|
967 | } |
---|
968 | top++; |
---|
969 | |
---|
970 | /* Check for and handle stack overflow. */ |
---|
971 | if (top == limit) |
---|
972 | { |
---|
973 | struct operation *new_stack; |
---|
974 | int old_size = (char*)limit - (char*)stack; |
---|
975 | int new_size = 2 * old_size; |
---|
976 | if (stack != init_stack) |
---|
977 | new_stack = (struct operation*) xrealloc (stack, new_size); |
---|
978 | else |
---|
979 | { |
---|
980 | new_stack = (struct operation*) xmalloc (new_size); |
---|
981 | bcopy ((char *) stack, (char *) new_stack, old_size); |
---|
982 | } |
---|
983 | stack = new_stack; |
---|
984 | top = (struct operation*)((char*) new_stack + old_size); |
---|
985 | limit = (struct operation*)((char*) new_stack + new_size); |
---|
986 | } |
---|
987 | |
---|
988 | top->flags = flags; |
---|
989 | top->rprio = rprio; |
---|
990 | top->op = op.op; |
---|
991 | } |
---|
992 | syntax_error: |
---|
993 | if (stack != init_stack) |
---|
994 | free (stack); |
---|
995 | skip_rest_of_line (pfile); |
---|
996 | return 0; |
---|
997 | } |
---|