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 #include "char.h"
   8
   9 static const char *parse_escape(const char *p, unsigned *val, const char *end, int bits, struct position pos)
  10 {
  11         unsigned c = *p++;
  12         unsigned d;
  13         if (c != '\\') {
  14                 *val = c;
  15                 return p;
  16         }
  17
  18         c = *p++;
  19         switch (c) {
  20         case 'a': c = '\a'; break;
  21         case 'b': c = '\b'; break;
  22         case 't': c = '\t'; break;
  23         case 'n': c = '\n'; break;
  24         case 'v': c = '\v'; break;
  25         case 'f': c = '\f'; break;
  26         case 'r': c = '\r'; break;
  27         case 'e': c = '\e'; break;
  28         case 'x': {
  29                 unsigned mask = -(1U << (bits - 4));
  30                 for (c = 0; p < end; c = (c << 4) + d) {
  31                         d = hexval(*p);
  32                         if (d > 16)
  33                                 break;
  34                         p++;
  35                         if (c & mask) {
  36                                 warning(pos,
  37                                         "hex escape sequence out of range");
  38                                 mask = 0;
  39                         }
  40                 }
  41                 break;
  42         }
  43         case '0'...'7': {
  44                 if (p + 2 < end)
  45                         end = p + 2;
  46                 c -= '0';
  47                 while (p < end && (d = *p - '0') < 8) {
  48                         c = (c << 3) + d;
  49                         p++;
  50                 }
  51                 if ((c & 0400) && bits < 9)
  52                         warning(pos,
  53                                 "octal escape sequence out of range");
  54                 break;
  55         }
  56         default:        /* everything else is left as is */
  57                 break;
  58         }
  59         *val = c & ~((~0U << (bits - 1)) << 1);
  60         return p;
  61 }
  62
  63 void get_char_constant(struct token *token, unsigned long long *val)
  64 {
  65         const char *p = token->embedded, *end;
  66         unsigned v;
  67         int type = token_type(token);
  68         switch (type) {
  69         case TOKEN_CHAR:
  70         case TOKEN_WIDE_CHAR:
  71                 p = token->string->data;
  72                 end = p + token->string->length - 1;
  73                 break;
  74         case TOKEN_CHAR_EMBEDDED_0 ... TOKEN_CHAR_EMBEDDED_3:
  75                 end = p + type - TOKEN_CHAR;
  76                 break;
  77         default:
  78                 end = p + type - TOKEN_WIDE_CHAR;
  79         }
  80         p = parse_escape(p, &v, end,
  81                         type < TOKEN_WIDE_CHAR ? bits_in_char : 32, token->pos);
  82         if (p != end)
  83                 warning(token->pos,
  84                         "multi-character character constant");
  85         *val = v;
  86 }
  87
  88 struct token *get_string_constant(struct token *token, struct expression *expr)
  89 {
  90         struct string *string = token->string;
  91         struct token *next = token->next, *done = NULL;
  92         int stringtype = token_type(token);
  93         int is_wide = stringtype == TOKEN_WIDE_STRING;
  94         static char buffer[MAX_STRING];
  95         int len = 0;
  96         int bits;
  97         int esc_count = 0;
  98
  99         while (!done) {
 100                 switch (token_type(next)) {
 101                 case TOKEN_WIDE_STRING:
 102                         is_wide = 1;
 103                 case TOKEN_STRING:
 104                         next = next->next;
 105                         break;
 106                 default:
 107                         done = next;
 108                 }
 109         }
 110         bits = is_wide ? 32 : bits_in_char;
 111         while (token != done) {
 112                 unsigned v;
 113                 const char *p = token->string->data;
 114                 const char *end = p + token->string->length - 1;
 115                 while (p < end) {
 116                         if (*p == '\\')
 117                                 esc_count++;
 118                         p = parse_escape(p, &v, end, bits, token->pos);
 119                         if (len < MAX_STRING)
 120                                 buffer[len] = v;
 121                         len++;
 122                 }
 123                 token = token->next;
 124         }
 125         if (len > MAX_STRING) {
 126                 warning(token->pos, "trying to concatenate %d-character string (%d bytes max)", len, MAX_STRING);
 127                 len = MAX_STRING;
 128         }
 129
 130         if (esc_count || len >= string->length) {
 131                 if (string->immutable || len >= string->length) /* can't cannibalize */
 132                         string = __alloc_string(len+1);
 133                 string->length = len+1;
 134                 memcpy(string->data, buffer, len);
 135                 string->data[len] = '\0';
 136         }
 137         expr->string = string;
 138         expr->wide = is_wide;
 139         return token;
 140 }