#include <stdio.h>
#include "tools.h"

/*
 * Match one pattern element, pointed at by pat, with the character at
 * **linp.  Return non-zero on match.  Otherwise, return 0.  *Linp is
 * advanced to skip over the matched character; it is not advanced on
 * failure.  The amount of advance is 0 for patterns that match null
 * strings, 1 otherwise.  "boln" should point at the position that will
 * match a BOL token.
 */
omatch(linp, pat, boln)
char	**linp;
TOKEN	*pat;
char	*boln;
{
	
	register int	advance;

	advance = -1;

	if (**linp)
	{
		switch (pat->tok)
		{
		case LITCHAR:
			if (**linp == pat->lchar)
				advance = 1;
			break;

		case BOL:
			if (*linp = boln)
				advance = 0;
			break;

		case ANY:
			if (**linp != '\n')
				advance = 1;
			break;

		case EOL:
			if (**linp == '\n')
				advance = 0;
			break;

		case CCL:
			if( testbit( **linp, pat->bitmap))
				advance = 1;
			break;

		case NCCL:
			if (!testbit (**linp, pat->bitmap))
				advance = 1;
			break;

		default:
			printf("omatch: can't happen\n");
		}
	}
	if (advance >= 0)
		*linp += advance;

	return (++advance);
}