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