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                 warning(pos, "unknown escape sequence: '\\%c'", c);
  58                 break;
  59         case '\\':
  60         case '\'':
  61         case '"':
  62         case '?':
  63                 break;  /* those are legal, so no warnings */
  64         }
  65         *val = c & ~((~0U << (bits - 1)) << 1);
  66         return p;
  67 }
  68
  69 void get_char_constant(struct token *token, unsigned long long *val)
  70 {
  71         const char *p = token->embedded, *end;
  72         unsigned v;
  73         int type = token_type(token);
  74         switch (type) {
  75         case TOKEN_CHAR:
  76         case TOKEN_WIDE_CHAR:
  77                 p = token->string->data;
  78                 end = p + token->string->length - 1;
  79                 break;
  80         case TOKEN_CHAR_EMBEDDED_0 ... TOKEN_CHAR_EMBEDDED_3:
  81                 end = p + type - TOKEN_CHAR;
  82                 break;
  83         default:
  84                 end = p + type - TOKEN_WIDE_CHAR;
  85         }
  86         p = parse_escape(p, &v, end,
  87                         type < TOKEN_WIDE_CHAR ? bits_in_char : 32, token->pos);
  88         if (p != end)
  89                 warning(token->pos,
  90                         "multi-character character constant");
  91         *val = v;
  92 }
  93
  94 struct token *get_string_constant(struct token *token, struct expression *expr)
  95 {
  96         struct string *string = token->string;
  97         struct token *next = token->next, *done = NULL;
  98         int stringtype = token_type(token);
  99         int is_wide = stringtype == TOKEN_WIDE_STRING;
 100         static char buffer[MAX_STRING];
 101         int len = 0;
 102         int bits;
 103         int esc_count = 0;
 104
 105         while (!done) {
 106                 switch (token_type(next)) {
 107                 case TOKEN_WIDE_STRING:
 108                         is_wide = 1;
 109                 case TOKEN_STRING:
 110                         next = next->next;
 111                         break;
 112                 default:
 113                         done = next;
 114                 }
 115         }
 116         bits = is_wide ? 32 : bits_in_char;
 117         while (token != done) {
 118                 unsigned v;
 119                 const char *p = token->string->data;
 120                 const char *end = p + token->string->length - 1;
 121                 while (p < end) {
 122                         if (*p == '\\')
 123                                 esc_count++;
 124                         p = parse_escape(p, &v, end, bits, token->pos);
 125                         if (len < MAX_STRING)
 126                                 buffer[len] = v;
 127                         len++;
 128                 }
 129                 token = token->next;
 130         }
 131         if (len > MAX_STRING) {
 132                 warning(token->pos, "trying to concatenate %d-character string (%d bytes max)", len, MAX_STRING);
 133                 len = MAX_STRING;
 134         }
 135
 136         if (esc_count || len >= string->length) {
 137                 if (string->immutable || len >= string->length) /* can't cannibalize */
 138                         string = __alloc_string(len+1);
 139                 string->length = len+1;
 140                 memcpy(string->data, buffer, len);
 141                 string->data[len] = '\0';
 142         }
 143         expr->string = string;
 144         expr->wide = is_wide;
 145         return token;
 146 }