char.c

   1 #include <string.h>
   2 #include "target.h"
   3 #include "lib.h"
   4 #include "allocate.h"
   5 #include "token.h"
   6 #include "expression.h"
   7
   8 static const char *parse_escape(const char *p, unsigned *val, const char *end, int bits, struct position pos)
   9 {
  10         unsigned c = *p++;
  11         unsigned d;
  12         if (c != '\\') {
  13                 *val = c;
  14                 return p;
  15         }
  16
  17         c = *p++;
  18         switch (c) {
  19         case 'a': c = '\a'; break;
  20         case 'b': c = '\b'; break;
  21         case 't': c = '\t'; break;
  22         case 'n': c = '\n'; break;
  23         case 'v': c = '\v'; break;
  24         case 'f': c = '\f'; break;
  25         case 'r': c = '\r'; break;
  26         case 'e': c = '\e'; break;
  27         case 'x': {
  28                 unsigned mask = -(1U << (bits - 4));
  29                 for (c = 0; p < end; c = (c << 4) + d) {
  30                         d = hexval(*p);
  31                         if (d > 16)
  32                                 break;
  33                         p++;
  34                         if (c & mask) {
  35                                 warning(pos,
  36                                         "hex escape sequence out of range");
  37                                 mask = 0;
  38                         }
  39                 }
  40                 break;
  41         }
  42         case '0'...'7': {
  43                 if (p + 2 < end)
  44                         end = p + 2;
  45                 c -= '0';
  46                 while (p < end && (d = *p - '0') < 8) {
  47                         c = (c << 3) + d;
  48                         p++;
  49                 }
  50                 if ((c & 0400) && bits < 9)
  51                         warning(pos,
  52                                 "octal escape sequence out of range");
  53                 break;
  54         }
  55         default:        /* everything else is left as is */
  56                 break;
  57         }
  58         *val = c & ~((~0U << (bits - 1)) << 1);
  59         return p;
  60 }
  61
  62 void get_char_constant(struct token *token, unsigned long long *val)
  63 {
  64         const char *p = token->embedded, *end;
  65         unsigned v;
  66         int type = token_type(token);
  67         switch (type) {
  68         case TOKEN_CHAR:
  69         case TOKEN_WIDE_CHAR:
  70                 p = token->string->data;
  71                 end = p + token->string->length - 1;
  72                 break;
  73         case TOKEN_CHAR_EMBEDDED_0 ... TOKEN_CHAR_EMBEDDED_3:
  74                 end = p + type - TOKEN_CHAR;
  75                 break;
  76         default:
  77                 end = p + type - TOKEN_WIDE_CHAR;
  78         }
  79         p = parse_escape(p, &v, end,
  80                         type < TOKEN_WIDE_CHAR ? bits_in_char : 32, token->pos);
  81         if (p != end)
  82                 warning(token->pos,
  83                         "multi-character character constant");
  84         *val = v;
  85 }
  86
  87 struct token *get_string_constant(struct token *token, struct expression *expr)
  88 {
  89         struct string *string = token->string;
  90         struct token *next = token->next, *done = NULL;
  91         int stringtype = token_type(token);
  92         int is_wide = stringtype == TOKEN_WIDE_STRING;
  93         static char buffer[MAX_STRING];
  94         int len = 0;
  95         int bits;
  96         int parts = 0;
  97
  98         while (!done) {
  99                 switch (token_type(next)) {
 100                 case TOKEN_WIDE_STRING:
 101                         is_wide = 1;
 102                 case TOKEN_STRING:
 103                         next = next->next;
 104                         break;
 105                 default:
 106                         done = next;
 107                 }
 108         }
 109         bits = is_wide ? 32 : bits_in_char;
 110         while (token != done) {
 111                 unsigned v;
 112                 const char *p = token->string->data;
 113                 const char *end = p + token->string->length - 1;
 114                 while (p < end) {
 115                         p = parse_escape(p, &v, end, bits, token->pos);
 116                         if (len < MAX_STRING)
 117                                 buffer[len] = v;
 118                         len++;
 119                 }
 120                 token = token->next;
 121                 parts++;
 122         }
 123         if (len > MAX_STRING) {
 124                 warning(token->pos, "trying to concatenate %d-character string (%d bytes max)", len, MAX_STRING);
 125                 len = MAX_STRING;
 126         }
 127
 128         if (len >= string->length || parts > 1) /* safe to reuse the string buffer */
 129                 string = __alloc_string(len+1);
 130         string->length = len+1;
 131         memcpy(string->data, buffer, len);
 132         string->data[len] = '\0';
 133         expr->string = string;
 134         expr->wide = is_wide;
 135         return token;
 136 }