/*
 * Copyright (c) 1995, 1996 Gunther Schadow.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include "pg_config.h"

IDENT("@(#) prefices.cc (Gunther Schadow) 12/19/96");

#include "Unit.h"
#include <string.h>

const int prefices::not_found = 12345;
const int prefices::best_fit  = -1;

const int maxpfx = 16;

prefices::prefix_s prefices::tab[maxpfx] =
{
  /*
   * THE FOLLOWING LINES MUST BE REVERSELY ALPHABETICALLY SORTED
   */

  {"u", 1, -6},
  {"t", 1, 12},
  {"pe",2, 15},
  {"p", 1,-12},
  {"n", 1, -9},
  {"ma",2,  6},
  {"m", 1, -3},
  {"k", 1,  3},
  {"h", 1,  2},
  {"g", 1,  9},
  {"f", 1,-15},
  {"ex",2, 18},
  {"da",2,  1},
  {"d", 1, -1},
  {"c", 1, -2},
  {"a", 1,-18}
};

/*
 * Lookup a key of exact length len, at the beginning of string s.
 * If successful return the exponent, and set r to the rootstring
 * after the prefix.
 */

int
prefices::lookup(const char *s, int l, const char **r)
{
  if(l == 0)
    {
      *r = s;
      return 0;
    }

  for(int i = 0; i < maxpfx; i++)
    {
      struct prefix_s entry = tab[i];
      
      if(s[0] == entry.name[0] && entry.len == l)
	{
	  if(strncmp(s, entry.name, l) == 0)
	    {
	      *r = s + l;
	      return entry.exponent;
	    }		  
	}
      else if(s[0] > entry.name[0])
	return not_found; // not found
    }

  return not_found;
}

/*
 * Lookup a key of maximum length len, at the beginning of string s.
 * If successful return the exponent, set l to the actual length of
 * the prefix and r to the rootstring after the prefix. If len is
 * best_fit at the beginning look for the best fit. 
 */

int
prefices::lookup(const char *s, int *l, const char **r)
{
  if(*l == 0)
    {
      *r = s;
      return 0;
    }

  int maxlen = *l;

  for(int i = 0; i < maxpfx; i++)
    {
      struct prefix_s entry = tab[i];
      
      if(s[0] == entry.name[0])
	{
	  if(maxlen == best_fit) maxlen = entry.len;
	  if(entry.len <= maxlen)
	    {
	      if(strncmp(s, entry.name, entry.len) == 0)
		{
		  *l = entry.len;
		  *r = s + entry.len;
		  return entry.exponent;
		}		  
	    }
	}
      else if(s[0] > entry.name[0])
	return not_found; // not found
    }

  return not_found;
}