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rcsid[] and sccsid[] and copyright[] are essentially unmaintained (and
unmaintainable).  these days, people use source.  these id's do not provide
any benefit, and do hurt the small install media
(the 33,000 line diff is essentially mechanical)
ok with the idea millert, ok dms

/*	$OpenBSD: files.c,v 1.13 2009/10/27 23:59:43 deraadt Exp $	*/

/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Peter McIlroy.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "sort.h"
#include "fsort.h"

#include <string.h>

static int	seq(FILE *, DBT *, DBT *);

/*
 * this is the subroutine for file management for fsort().
 * It keeps the buffers for all temporary files.
 */
int
getnext(int binno, union f_handle infl0, int nfiles, RECHEADER *pos, u_char *end,
    struct field *dummy)
{
	int i;
	u_char *hp;
	static size_t nleft = 0;
	static int cnt = 0, flag = -1;
	static u_char maxb = 0;
	static FILE *fp;

	if (nleft == 0) {
		if (binno < 0)	/* reset files. */ {
			for (i = 0; i < nfiles; i++) {
				rewind(fstack[infl0.top + i].fp);
				fstack[infl0.top + i].max_o = 0;
			}
			flag = -1;
			nleft = cnt = 0;
			return (-1);
		}
		maxb = fstack[infl0.top].maxb;
		for (; nleft == 0; cnt++) {
			if (cnt >= nfiles) {
				cnt = 0;
				return (EOF);
			}
			fp = fstack[infl0.top + cnt].fp;
			fread(&nleft, sizeof(nleft), 1, fp);
			if (binno < maxb)
				fstack[infl0.top+cnt].max_o
					+= sizeof(nleft) + nleft;
			else if (binno == maxb) {
				if (binno != fstack[infl0.top].lastb) {
					fseek(fp, fstack[infl0.top+
						cnt].max_o, SEEK_SET);
					fread(&nleft, sizeof(nleft), 1, fp);
				}
				if (nleft == 0)
					fclose(fp);
			} else if (binno == maxb + 1) {		/* skip a bin */
				fseek(fp, nleft, SEEK_CUR);
				fread(&nleft, sizeof(nleft), 1, fp);
				flag = cnt;
			}
		}
	}
	if ((u_char *) pos > end - sizeof(TRECHEADER))
		return (BUFFEND);
	fread(pos, sizeof(TRECHEADER), 1, fp);
	if (end - pos->data < pos->length) {
		hp = ((u_char *)pos) + sizeof(TRECHEADER);
		for (i = sizeof(TRECHEADER); i ;  i--)
			ungetc(*--hp, fp);
		return (BUFFEND);
	}
	fread(pos->data, pos->length, 1, fp);
	nleft -= pos->length + sizeof(TRECHEADER);
	if (nleft == 0 && binno == fstack[infl0.top].maxb)
		fclose(fp);
	return (0);
}

/*
 * this is called when there is no special key. It's only called
 * in the first fsort pass.
 */
int
makeline(int flno, union f_handle filelist, int nfiles, RECHEADER *buffer,
    u_char *bufend, struct field *dummy2)
{
	static u_char *obufend;
	static size_t osz;
	char *pos;
	static int fileno = 0, overflow = 0;
	static FILE *fp = 0;
	int c;

	pos = (char *) buffer->data;
	if (overflow) {
		/*
		 * Buffer shortage is solved by either of two ways:
	 	 * * Flush previous buffered data and start using the 
		 *   buffer from start (see fsort())
		 * * realloc buffer and bump bufend
		 *
		 * The former is preferred, realloc is only done when
		 * there is exactly one item in buffer which does not fit.
		 */
		if (bufend == obufend)
			memmove(pos, bufend - osz, osz);
		pos+=osz;
		overflow = 0;
	}
	for (;;) {
		if (flno >= 0 && (fp = fstack[flno].fp) == NULL)
			return (EOF);
		else if (fp == 0) {
			if (fileno  >= nfiles)
				return (EOF);
			if (!(fp = fopen(filelist.names[fileno], "r")))
				err(2, "%s", filelist.names[fileno]);
			fileno++;
		}
		while ((pos < (char *)bufend) && ((c = getc(fp)) != EOF)) {
			if ((*pos++ = c) == REC_D) {
				buffer->offset = 0;
				buffer->length = pos - (char *) buffer->data;
				return (0);
			}
		}
		if (pos >= (char *)bufend) {
			if (buffer->data < bufend) {
				overflow = 1;
				obufend = bufend;
				osz = (pos - (char *)buffer->data);
			}
			return (BUFFEND);
		} else if (c == EOF) {
			if (buffer->data != (u_char *) pos) {
				*pos++ = REC_D;
				buffer->offset = 0;
				buffer->length = pos - (char *) buffer->data;
				return (0);
			}
			FCLOSE(fp);
			fp = 0;
			if (flno >= 0)
				fstack[flno].fp = 0;
		} else {
			warnx("line too long: ignoring %100s...", buffer->data);
			
			/* Consume the rest of the line from input */
			while((c = getc(fp)) != REC_D && c != EOF)
				;

			buffer->offset = 0;
			buffer->length = 0;

			return (BUFFEND);
		}
	}
}

/*
 * This generates keys. It's only called in the first fsort pass
 */
int
makekey(int flno, union f_handle filelist, int nfiles, RECHEADER *buffer,
    u_char *bufend, struct field *ftbl)
{
	static int fileno = 0;
	static FILE *dbdesc = 0;
	static DBT dbkey[1], line[1];
	static int overflow = 0;
	static int c;

	if (overflow) {
		overflow = enterkey(buffer, line, bufend - (u_char *)buffer,
									ftbl);
		if (overflow)
			return (BUFFEND);
		else
			return (0);
	}

	for (;;) {
		if (flno >= 0) {
			if (!(dbdesc = fstack[flno].fp))
				return (EOF);
		} else if (!dbdesc) {
			if (fileno  >= nfiles)
				return (EOF);
			dbdesc = fopen(filelist.names[fileno], "r");
			if (!dbdesc)
				err(2, "%s", filelist.names[fileno]);
			fileno++;
		}
		if (!(c = seq(dbdesc, line, dbkey))) {
			if ((signed)line->size > bufend - buffer->data) {
				overflow = 1;
			} else {
				overflow = enterkey(buffer, line,
				    bufend - (u_char *) buffer, ftbl);
			}
			if (overflow)
				return (BUFFEND);
			else
				return (0);
		}
		if (c == EOF) {
			FCLOSE(dbdesc);
			dbdesc = 0;
			if (flno >= 0)
				fstack[flno].fp = 0;
		} else {
			((char *) line->data)[60] = '\000';
			warnx("line too long: ignoring %.100s...",
			    (char *)line->data);
		}
	}
}

/*
 * get a key/line pair from fp
 */
static int
seq(FILE *fp, DBT *line, DBT *key)
{
	static char *buf, flag = 1;
	char *end, *pos;
	int c;

	if (flag) {
		flag = 0;
		buf = (char *) linebuf;
		line->data = buf;
	}
	pos = buf;
	end = buf + linebuf_size;
	while ((c = getc(fp)) != EOF) {
		if ((*pos++ = c) == REC_D) {
			line->size = pos - buf;
			return (0);
		}
		if (pos == end) {
			linebuf_size *= 2;
			linebuf = realloc(linebuf, linebuf_size);
			if (!linebuf)
				err(2, "realloc of linebuf to %lu bytes failed",
					(unsigned long)linebuf_size);
			end = linebuf + linebuf_size;
			pos = linebuf + (pos - buf);
			line->data = buf = (char *)linebuf;
			continue;
		}
	}
	if (pos != buf) {
		*pos++ = REC_D;
		line->size = pos - buf;
		return (0);
	} else
		return (EOF);
}

/*
 * write a key/line pair to a temporary file
 */
void
putrec(RECHEADER *rec, FILE *fp)
{
	EWRITE(rec, 1, rec->length + sizeof(TRECHEADER), fp);
}

/*
 * write a line to output
 */
void
putline(RECHEADER *rec, FILE *fp)
{
	EWRITE(rec->data+rec->offset, 1, rec->length - rec->offset, fp);
}

/*
 * get a record from a temporary file. (Used by merge sort.)
 */
int
geteasy(int flno, union f_handle filelist, int nfiles, RECHEADER *rec,
    u_char *end, struct field *dummy2)
{
	int i;
	FILE *fp;

	fp = fstack[flno].fp;
	if ((u_char *) rec > end - sizeof(TRECHEADER))
		return (BUFFEND);
	if (!fread(rec, 1, sizeof(TRECHEADER), fp)) {
		fclose(fp);
		fstack[flno].fp = 0;
		return (EOF);
	}
	if (end - rec->data < rec->length) {
		for (i = sizeof(TRECHEADER) - 1; i >= 0;  i--)
			ungetc(*((char *) rec + i), fp);
		return (BUFFEND);
	}
	fread(rec->data, rec->length, 1, fp);
	return (0);
}