tok.c

   1 #include <ctype.h>
   2 #include <unistd.h>
   3 #include <string.h>
   4 #include "tok.h"
   5
   6 static char buf[BUFSIZE];
   7 static int len;
   8 static int cur;
   9 static char name[NAMELEN];
  10 static int next;
  11
  12 static struct {
  13         char *name;
  14         unsigned id;
  15 } kwds[] = {
  16         {"void", TOK_VOID},
  17         {"static", TOK_STATIC},
  18         {"return", TOK_RETURN},
  19         {"unsigned", TOK_UNSIGNED},
  20         {"signed", TOK_SIGNED},
  21         {"short", TOK_SHORT},
  22         {"long", TOK_LONG},
  23         {"int", TOK_INT},
  24         {"char", TOK_CHAR},
  25         {"struct", TOK_STRUCT},
  26         {"enum", TOK_ENUM},
  27         {"if", TOK_IF},
  28         {"else", TOK_ELSE},
  29         {"for", TOK_FOR},
  30         {"while", TOK_WHILE},
  31         {"do", TOK_DO},
  32         {"switch", TOK_SWITCH},
  33         {"case", TOK_CASE},
  34         {"sizeof", TOK_SIZEOF},
  35 };
  36
  37 static int id_char(int c)
  38 {
  39         return isalnum(c) || c == '_';
  40 }
  41
  42 int tok_get(void)
  43 {
  44         if (next != -1) {
  45                 int tok = next;
  46                 next = -1;
  47                 return tok;
  48         }
  49         while (cur < len && isspace(buf[cur]))
  50                 cur++;
  51         if (cur == len)
  52                 return TOK_EOF;
  53         if (isdigit(buf[cur])) {
  54                 char *s = name;
  55                 while (cur < len && isdigit(buf[cur]))
  56                         *s++ = buf[cur++];
  57                 *s = '\0';
  58                 return TOK_NUM;
  59         }
  60         if (id_char(buf[cur])) {
  61                 char *s = name;
  62                 int i;
  63                 while (cur < len && id_char(buf[cur]))
  64                         *s++ = buf[cur++];
  65                 *s = '\0';
  66                 for (i = 0; i < ARRAY_SIZE(kwds); i++)
  67                         if (!strcmp(kwds[i].name, name))
  68                                 return kwds[i].id;
  69                 return TOK_NAME;
  70         }
  71         if (strchr(";,{}()[]*=+-/", buf[cur]))
  72                 return buf[cur++];
  73         return -1;
  74 }
  75
  76 int tok_see(void)
  77 {
  78         if (next == -1)
  79                 next = tok_get();
  80         return next;
  81 }
  82
  83 void tok_init(int fd)
  84 {
  85         int n = 0;
  86         while ((n = read(fd, buf + len, sizeof(buf) - len)) > 0)
  87                 len += n;
  88         next = -1;
  89 }
  90
  91 char *tok_id(void)
  92 {
  93         return name;
  94 }