lex.c

   1 #include <stdio.h>
   2 #include <ctype.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5 #include <stdarg.h>
   6
   7 #include "cond.tab.h"
   8 #include "umpf.h"
   9 #define KLEN 10
  10
  11 struct keys {
  12         char* keywords;
  13         enum yytokentype keytoks;
  14 };
  15
  16 static struct keys kwds[] =
  17         {       {"copy", KW_COPY},
  18                 {"else", KW_ELSE},
  19                 {"if", KW_IF},
  20                 {"mail", KW_MAIL},
  21                 {"pipe", KW_PIPE},
  22                 {"discard", KW_DISCARD},
  23                 {"filter", KW_FILTER}
  24         };
  25
  26 void
  27 read_conf(char* filename)
  28 {
  29         conf = fopen(filename, "r");
  30
  31         if (! conf)
  32                 die("read_conf: %m");
  33 }
  34
  35 void __attribute__ ((noreturn))
  36 die(char* msg, ...)
  37 {
  38         va_list args;
  39
  40         va_start(args, msg);
  41         vfprintf(stderr, msg, args);
  42         fputc('\n', stderr);
  43         va_end(args);
  44         exit(1);
  45 }
  46
  47 void*
  48 xmalloc(size_t size)
  49 {
  50         void* ret;
  51
  52         if (!(ret = malloc(size)))
  53                 die("Low memory");
  54
  55         return ret;
  56 }
  57
  58 void*
  59 xrealloc(void* buf, size_t size)
  60 {
  61         buf = realloc(buf, size);
  62
  63         if (!buf)
  64                 die("Low memory");
  65
  66         return buf;
  67 }
  68
  69 static void __attribute__ ((noreturn))
  70 parse_err(char* msg, ...)
  71 {
  72         va_list args;
  73
  74         va_start(args, msg);
  75         fprintf(stderr, "Line %d: ", line);
  76         vfprintf(stderr, msg, args);
  77         fputc('\n', stderr);
  78         va_end(args);
  79         exit(1);
  80 }
  81
  82 char*
  83 xstrdup(const char* s)
  84 {
  85         void* ret;
  86
  87         if (!(ret = strdup(s)))
  88                 die("Low memory");
  89
  90         return ret;
  91 }
  92
  93 static char*
  94 get_string_out(int delim)
  95 {
  96         int last = delim;
  97         int i = 0;
  98         int c;
  99         char buf[BUFSIZE];
 100
 101         while ((c = getc(conf)) != delim || last == '\\'){
 102                 if (last=='\\' && c != delim)
 103                         buf[i-1] = c;
 104                 else {
 105                         buf[i] = c;
 106                         i++;
 107                 }
 108                 last = c;
 109                 if (i >= BUFSIZE-1)
 110                         parse_err("Too long string, max allowed length is %d",BUFSIZE-1);
 111         }
 112         buf[i] = '\0';
 113
 114         return xstrdup(buf);
 115 }
 116
 117 static int
 118 is_var_id(int c)
 119 {
 120         return  (c >= '0' && c <= '9' ) ||
 121                 (c >= 'a' && c <= 'z') ||
 122                 (c >= 'A' && c <= 'Z') ||
 123                 c == '_' ||
 124                 c == '-';
 125 }
 126
 127 static int
 128 is_alpha(int c)
 129 {
 130         return (c >= 'a' && c <= 'z') ||
 131                 (c >= 'A' && c <= 'Z');
 132 }
 133
 134 int
 135 yylex(void)
 136 {
 137         int c;
 138
 139         while ((c = getc(conf)) == ' ' || c == '\t' || c =='\n'){
 140                 if (c == '\n')
 141                         line++;
 142         }
 143
 144         if (c == EOF)
 145                 return 0;
 146
 147         int d = getc(conf);
 148         if (d >= 0) {
 149                 switch (CC(c,d)) {
 150                 case CC('!','='): yylval.n = CC('!','='); return NEQ;
 151                 case CC('!','~'): yylval.n = CC('!','='); return NRE;
 152                 case CC('<','='): yylval.n = CC('<','='); return LE;
 153                 case CC('>','='): yylval.n = CC('>','='); return GE;
 154                 case CC('=','='): yylval.n = CC('=','='); return EQ;
 155                 case CC('~','~'): yylval.n = CC('~','~'); return RE;
 156                 case CC('-','>'): yylval.n = CC('-','>'); return ARROW;
 157                 }
 158                 ungetc(d,conf);
 159         }
 160
 161         switch (c) {
 162                 case '!':
 163                 case '(':
 164                 case ')':
 165                 case '-':
 166                 case '+':
 167                 case '*':
 168                 case '/':
 169                 case '{':
 170                 case '}':
 171                 case '<':
 172                 case '>':
 173                 case '=':
 174                 case ';':
 175                 case '.':
 176                 case '|':
 177                 case '&':
 178                 case '^':
 179                         yylval.n = c;
 180                         return c;
 181
 182                 case '"':
 183                 case '\'':
 184                         yylval.str = get_string_out(c);
 185                         return CONST;
 186         }
 187
 188         if (c >= '0' && c <= '9'){
 189                 ungetc(c,conf);
 190                 int i = 0;
 191                 char buf[BUFSIZE];
 192
 193                 while ((c = getc(conf))>= '0' && c<= '9'){
 194                         buf[i] = c;
 195                         i++;
 196                         if (i >= BUFSIZE-1)
 197                                 parse_err("Too long number");
 198                 }
 199                 ungetc(c,conf);
 200                 buf[i] = 0;
 201                 yylval.str = xstrdup(buf);
 202
 203                 return CONST;
 204         }
 205
 206         if (c == '$'){
 207                 int i = 0;
 208                 char buf[BUFSIZE];
 209
 210                 while (is_var_id(c = getc(conf))){
 211                         buf[i]=c;
 212                         i++;
 213                         if (i >= BUFSIZE-1)
 214                                 parse_err("Too long identifier, max allowed length is %d",BUFSIZE-1);
 215                 }
 216                 ungetc(c,conf);
 217                 buf[i] = 0;
 218                 yylval.str = xstrdup(buf);
 219
 220                 return VAR;
 221         }
 222
 223         if (is_alpha(c)){
 224                 char buf[KLEN];
 225                 int n, i = 0;
 226
 227                 ungetc(c,conf);
 228                 while (is_alpha(c = getc(conf))){
 229                         buf[i++] = c;
 230                         if (i >= KLEN)
 231                                 parse_err("Keyword too long");
 232                 }
 233                 buf[i] = 0;
 234                 ungetc(c,conf);
 235
 236                 n = (sizeof(kwds)/sizeof(struct keys));
 237                 for (i = 0; i < n; i++){
 238                         if (!strcmp(buf,kwds[i].keywords))
 239                                 return kwds[i].keytoks;
 240                 }
 241
 242                 parse_err("Unknown keyword %s", buf);
 243         }
 244
 245         parse_err("Unknown character %c", c);
 246 }