#include <stdio.h>
#include <osbind.h>
#include "bm.h"
#include "Extern.h"

static void loinit();
static int loread();

Execute(DescVec, NPats, TextFile, Buffer, inbufsiz)
register struct PattDesc *DescVec[];
/* pointers to status vectors for the different
	* patterns, including skip tables, position in buffer, etc. */
register int NPats; /* number of patterns */
register char Buffer[]; /* holds text from file */
register int TextFile; /* file to search */
{
	int NRead, /* number of chars read from file */
		NWanted, /* number of chars wanted */
		NAvail, /* number of chars actually read */
		BuffSize, /* number of chars in buffer */
		BuffPos, /* offset of first char in Buffer in TextFile */
		BuffEx, /* flag to indicate that buffer has been searched */
		ResSize,
		/* number of characters in the last, incomplete line */
		Found, /* flag indicates whether pattern found
		* completely and all matches printed */
		Valid; /* was the match "valid", i.e. if -x used,
		* did the whole line match? */
	char *BuffEnd; /* pointer to last char of last complete line */

	/* misc working variables */
	int i;

	/* initialize */
        loinit();
	ResSize = 0;
	Found = 0;
	BuffPos = 0;
	for (i=0; i < NPats; i++) {
		DescVec[i] -> Success = 0;
		DescVec[i] -> Start = Buffer;
	} /* for */
	/* now do the searching */
	do {
		/* first, read a bufferfull and set up the variables */
		NWanted = MAXBUFF - ResSize; NRead = 0;
		do {
			NAvail =
			   loread(TextFile,Buffer + ResSize + NRead, NWanted);
			if (NAvail == -1) {
				fprintf(stderr,
				  "bm: error reading from input file\n");
				exit(2);
			} /* if */
			NRead += NAvail; NWanted -= NAvail;
		} while (NAvail && NWanted);
		BuffEx = 0;
		BuffSize = ResSize + NRead;
		BuffEnd = Buffer + BuffSize - 1;
		/* locate the end of the last complete line */
		while (*BuffEnd != '\n' && BuffEnd >= Buffer)
			--BuffEnd;
		if (BuffEnd < Buffer)
			BuffEnd = Buffer + BuffSize - 1;
		while (!BuffEx) { /* work through one buffer full */
			BuffEx = 1; /* set it provisionally, then clear
			* it if we find the buffer non-empty */
			for (i=0; i< NPats; i++) {
				if (!DescVec[i]->Success)
				/* if the pattern  has not been found */
					DescVec[i]-> Success =
					Search(DescVec[i]->Pattern,
					DescVec[i]->PatLen, BuffEnd,
					DescVec[i]->Skip1, DescVec[i]->Skip2,
					DescVec[i]);
				if (DescVec[i]->Success){
				/* if a match occurred */
					BuffEx = 0;
					Valid = MatchFound(DescVec[i],BuffPos,
					Buffer, BuffEnd);
					Found |= Valid;
					if ((sFlag || lFlag) && Found)
						return(0);
				} /* if */
			} /* for */
		} /* while */
		if(NRead) {
			ResSize = MoveResidue(DescVec,NPats,Buffer,
			Buffer+BuffSize-1);
			BuffPos += BuffSize - ResSize;
		} /* if */
	} while (NRead);
	return(!Found);
} /* Execute */

static char *lobuf, *lopos;
static int lobread, loeof, lbsiz;

static void loinit()
{
    int newsiz;

    if (lobuf == (char *)0) {
        lbsiz = Malloc(-1);
        while (newsiz = lbsiz & (lbsiz-1)) {
            lbsiz = newsiz;
        }
        lobuf = (char *)Malloc(lbsiz);
        if (lobuf == (char *)-1) {
            fprintf(stderr,"bm: memory allocation failed\n");
            exit(1);
        }
    }
    lopos = lobuf;
    lobread = 0;
    loeof = 0;
}

static int loread(fd,pos,len)
int fd,len;
char *pos;
{
    int totalread = 0;
    register char *from, *to;
    register int toread;

    if (loeof) {
        return totalread;
    }
    for (;;) {
        if (lopos == lobuf + lobread) {
            if (lobread > 0 && lobread < lbsiz) {
                loeof = 1;
                return totalread;
            }
            lobread = read(fd,lobuf,lbsiz);
            if (lobread == 0) {
                loeof = 1;
                return totalread;
            }
            lopos = lobuf;
        }
        toread = (lobuf+lobread)-lopos;
        toread = min(toread,len);
        if (toread == 0) {
            return totalread;
        }
        len -= toread;
        totalread += toread;
        for (from = lopos, to = pos; toread-- != 0; ) {
            *to++ = *from++;
        }
        pos = to;
        lopos = from;
    }
}