llvm-mirror/utils/Burg/lex.c

char rcsid_lex[] = "$Id$";

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include "b.h"
#include "fe.h"
#include "gram.tab.h"

static char buf[BUFSIZ];

static int yyline = 1;

typedef int (*ReadFn) ARGS((void));

static char *StrCopy ARGS((char *));
static int code_get ARGS((void));
static int simple_get ARGS((void));
static void ReadCharString ARGS((ReadFn, int));
static void ReadCodeBlock ARGS((void));
static void ReadOldComment ARGS((ReadFn));

static char *
StrCopy(s) char *s;
{
  char *t = (char *)zalloc(strlen(s) + 1);
  strcpy(t,s);
  return t;
}

static int
simple_get()
{
  int ch;
  if ((ch = getchar()) == '\n') {
    yyline++;
  }
  return ch;
}

static int
code_get()
{
  int ch;
  if ((ch = getchar()) == '\n') {
    yyline++;
  }
  if (ch != EOF) {
    fputc(ch, outfile);
  }
  return ch;
}

void
yypurge()
{
  while (code_get() != EOF) ;
}


static void
ReadCharString(rdfn, which) ReadFn rdfn; int which;
{
  int ch;
  int backslash = 0;
  int firstline = yyline;

  while ((ch = rdfn()) != EOF) {
    if (ch == which && !backslash) {
      return;
    }
    if (ch == '\\' && !backslash) {
      backslash = 1;
    } else {
      backslash = 0;
    }
  }
  yyerror1("Unexpected EOF in string on line ");
  fprintf(stderr, "%d\n", firstline);
  exit(1);
}

static void
ReadOldComment(rdfn) ReadFn rdfn;
{
  /* will not work for comments delimiter in string */

  int ch;
  int starred = 0;
  int firstline = yyline;

  while ((ch = rdfn()) != EOF) {
    if (ch == '*') {
      starred = 1;
    } else if (ch == '/' && starred) {
      return;
    } else {
      starred = 0;
    }
  }
  yyerror1("Unexpected EOF in comment on line ");
  fprintf(stderr, "%d\n", firstline);
  exit(1);
}

static void
ReadCodeBlock()
{
  int ch;
  int firstline = yyline;

  while ((ch = getchar()) != EOF) {
    if (ch == '%') {
      ch = getchar();
      if (ch != '}') {
        yyerror("bad %%");
      }
      return;
    }
    fputc(ch, outfile);
    if (ch == '\n') {
      yyline++;
    }
    if (ch == '"' || ch == '\'') {
      ReadCharString(code_get, ch);
    } else if (ch == '/') {
      ch = getchar();
      if (ch == '*') {
        fputc(ch, outfile);
        ReadOldComment(code_get);
        continue;
      } else {
        ungetc(ch, stdin);
      }
    }
  }
  yyerror1("Unclosed block of C code started on line ");
  fprintf(stderr, "%d\n", firstline);
  exit(1);
}

static int done;
void
yyfinished()
{
  done = 1;
}

int
yylex()
{
  int ch;
  char *ptr = buf;

  if (done) return 0;
  while ((ch = getchar()) != EOF) {
    switch (ch) {
    case ' ':
    case '\f':
    case '\t':
      continue;
    case '\n':
      yyline++;
      continue;
    case '(':
    case ')':
    case ',':
    case ':':
    case ';':
    case '=':
      return(ch);
    case '/':
      ch = getchar();
      if (ch == '*') {
        ReadOldComment(simple_get);
        continue;
      } else {
        ungetc(ch, stdin);
        yyerror("illegal char /");
        continue;
      }
    case '%':
      ch = getchar();
      switch (ch) {
      case '%':
        return (K_PPERCENT);
      case '{':
        ReadCodeBlock();
        continue;
      case 's':
      case 'g':
      case 't':
        do {
          if (ptr >= &buf[BUFSIZ]) {
            yyerror("ID too long");
            return(ERROR);
          } else {
            *ptr++ = ch;
          }
          ch = getchar();
        } while (isalpha(ch) || isdigit(ch) || ch == '_');
        ungetc(ch, stdin);
        *ptr = '\0';
        if (!strcmp(buf, "term")) return K_TERM;
        if (!strcmp(buf, "start")) return K_START;
        if (!strcmp(buf, "gram")) return K_GRAM;
        yyerror("illegal character after %%");
        continue;
      default:
        yyerror("illegal character after %%");
        continue;
      }
    default:
      if (isalpha(ch) ) {
        do {
          if (ptr >= &buf[BUFSIZ]) {
            yyerror("ID too long");
            return(ERROR);
          } else {
            *ptr++ = ch;
          }
          ch = getchar();
        } while (isalpha(ch) || isdigit(ch) || ch == '_');
        ungetc(ch, stdin);
        *ptr = '\0';
        yylval.y_string = StrCopy(buf);
        return(ID);
      }
      if (isdigit(ch)) {
        int val=0;
        do {
          val *= 10;
          val += (ch - '0');
          ch = getchar();
        } while (isdigit(ch));
        ungetc(ch, stdin);
        yylval.y_int = val;
        return(INT);
      }
      yyerror1("illegal char ");
      fprintf(stderr, "(\\%03o)\n", ch);
      exit(1);
    }
  }
  return(0);
}

void yyerror1(const char *str)
{
  fprintf(stderr, "line %d: %s", yyline, str);
}

void
yyerror(const char *str)
{
  yyerror1(str);
  fprintf(stderr, "\n");
  exit(1);
}