/* Copyright (C) 2009 Kevin W. Hamlen
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 *
 * The latest version of this program can be obtained from
 * http://songs.sourceforge.net.
 */


/* Create a LaTeX scripture index file from a scripture index .dat file. */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#else
#  include "vsconfig.h"
#endif

#ifdef HAVE_STDLIB_H
#  include <stdlib.h>
#endif
#ifdef HAVE_STDIO_H
#  include <stdio.h>
#endif
#ifdef HAVE_STRING_H
#  include <string.h>
#else
#  ifdef HAVE_STRINGS_H
#    include <strings.h>
#  endif
#endif

#include "chars.h"
#include "songidx.h"
#include "fileio.h"

/* The following constant should be a large integer (but not greater than INT_MAX)
 * limiting the maximum number of verses in a single chapter of the bible.
 */
#define MAXVERSES 999

/* A BBOOK struct describes a book of the Bible, including:
 *   name: a \0-separated string of names (the first one is the name used when printing
 *         the scripture index)
 *   verses: an array of numbers giving the number of verses in each chapter
 *   aliases: the number of names in the name field
 *   chapters: the number of chapters in the book
 */
typedef struct
{
	WCHAR *name;
	int *verses;
	int aliases;
	int chapters;
}
BBOOK;

/* A VERSE struct refers to a verse in a book of the Bible.
 *   chapter: the integral chapter number of the verse (1 if the book has only one chapter)
 *   verse: the integral verse number
 */
typedef struct
{
	int chapter, verse;
}
VERSE;

/* A SONGLIST is a list of songs
 *   num: a string denoting the song number (e.g. "3" or "H10")
 *   link: a string denoting the hyperlink label for the song
 *   int: an integer key used to order songs when sorting
 *   next: next pointer
 */
typedef struct songliststruct
{
	WCHAR *num;
	WCHAR *link;
	int key;
	struct songliststruct *next;
}
SONGLIST;

/* A VERSELIST is the list of verses in a particular book of the Bible at which the
 * set of songs referencing that verse differs from the set of songs referencing
 * the previous verse in the book. Such a list allows us to sparsely represent the
 * set of songs referencing each verse in the book without having to create a distinct
 * list entry for each verse in the entire book. For example, if song "H1" references
 * verses 3:1-10, that would represented by a two-element list:
 *      [ {v={chapter=3, verse=1}, adds=[H1], drops=[]};
 *        {v={chapter=3, verse=10}, adds=[], drops=[H1]} ]
 * This is more reasonable than creating ten list items to refer to such a range.
 *   v: the verse at which the set of song references is changing
 *   adds: a list of songs that refer to this verse but not the previous one
 *   drops: a list of songs that refer to this verse but not the next one
 *   next: pointer to next verse at which the set of references changes
 */
typedef struct verseliststruct
{
	VERSE v;
	SONGLIST *adds, *drops;
	struct verseliststruct *next;
}
VERSELIST;

/* The bible global variable stores the array of bible books being used to generate
 * the scripture index. The numbooks variable stores the number of elements in the
 * bible array.
 */
BBOOK *bible = NULL;
int numbooks = 0;

/* free_bible()
 *   Free the bible array, set it to NULL, and set numbooks to 0.
 */
static void
free_bible()
{
	int i;

	if (!bible) return;
	for (i=0; i<numbooks; ++i)
	{
		if (bible[i].name) free(bible[i].name);
		if (bible[i].verses) free(bible[i].verses);
	}
	free(bible);
	bible = NULL;
	numbooks = 0;
}

/* free_songlist(<slist>)
 *   Free song list <slist>.
 */
static void
free_songlist(sl)
	SONGLIST *sl;
{
	SONGLIST *next;

	for (; sl; sl=next)
	{
		if (sl->num) free(sl->num);
		if (sl->link) free(sl->link);
		next = sl->next;
		free(sl);
	}
}

/* free_verselist(<vlist>)
 *    Free verse list <vlist>.
 */
static void
free_verselist(vl)
	VERSELIST *vl;
{
	VERSELIST *next;

	for (; vl; vl=next)
	{
		free_songlist(vl->adds);
		free_songlist(vl->drops);
		next = vl->next;
		free(vl);
	}
}

/* freeidxarray(<array>,<len>)
 *   Free the array of verselists given by <array>. The array should have length <len>.
 */
static void
freeidxarray(idx,len)
	VERSELIST **idx;
	int len;
{
	int i;

	if (!idx) return;
	for (i=0; i<len; ++i) free_verselist(idx[i]);
	free(idx);
}

/* readbible(<filename>)
 *   Read bible data file <filename> into the bible array and set numbooks to the number of books read.
 *   Return 0 on error or 1 on success.
 */
static int
readbible(filename)
	const char *filename;
{
	FSTATE fs;
	int eof = 0;
	WCHAR buf[MAXLINELEN];
	int verses[MAXLINELEN/2+1];
	int arraysize, j;
	WCHAR *p1, *p2;

	if (!fileopen(&fs,filename)) return 0;

	bible = NULL;
	eof = 0;
	for (arraysize=numbooks=0; !eof; ++numbooks)
	{
		if (!filereadln(&fs,buf,&eof))
		{
			free_bible();
			return 0;
		}
		if (eof) break;
		if (*buf == wc_hash)
		{
			--numbooks;
			continue;
		}
		if (numbooks >= arraysize)
		{
			BBOOK *temp;
			arraysize *= 2;
			if (arraysize==0) arraysize=64;
			temp = (BBOOK *) realloc(bible,arraysize*sizeof(BBOOK));
			if (!temp)
			{
				fprintf(stderr, "songidx:%s:%d: too many bible books (out of memory)\n",
				        fs.filename, fs.lineno);
				free_bible();
				return 0;
			}
			bible = temp;
		}
		if ((bible[numbooks].name = (WCHAR *) calloc(ws_strlen(buf)+1,sizeof(WCHAR))) == NULL)
		{
			fprintf(stderr, "songidx:%s:%d: bible book name too large (out of memory)\n",
			        fs.filename, fs.lineno);
			fileclose(&fs);
			free_bible();
			return 0;
		}
		for(j=1, p1=buf, p2=bible[numbooks].name; *p1!=wc_null; ++p1, ++p2)
		{
			if (*p1 == wc_pipe)
			{
				++j;
				*p2=wc_null;
			}
			else *p2=*p1;
		}
		*p2 = wc_null;
		if (j == 0)
		{
			fprintf(stderr, "songidx:%s:%d: bible book has no name\n",
			        fs.filename, fs.lineno);
			free(bible[numbooks].name);
			fileclose(&fs);
			free_bible();
			return 0;
		}
		bible[numbooks].aliases = j;
		do
		{
			if (!filereadln(&fs,buf,&eof))
			{
				free_bible();
				return 0;
			}
			if (eof)
			{
				fprintf(stderr, "songidx:%s:%d: incomplete bible book entry (book title with no verses)\n",
				        fs.filename, fs.lineno);
				free_bible();
				return 0;
			}
		}
		while (*buf == wc_hash);
		for (j=0, p1=buf; *p1!=wc_null; ++j)
		{
			long v = ws_strtol(p1, &p1, 10);
			if ((v<=0) || (v>MAXVERSES))
			{
				fprintf(stderr, "songidx:%s:%d: illegal verse count for chapter %d\n",
				        fs.filename, fs.lineno, j+1);
				fileclose(&fs);
				free_bible();
				return 0;
			}
			verses[j] = (int) v;
		}
		if (j == 0)
		{
			fprintf(stderr, "songidx:%s:%d: book ", fs.filename, fs.lineno);
			ws_fputs(bible[numbooks].name, stderr);
			fprintf(stderr, " has no chapters\n");
			fileclose(&fs);
			free_bible();
			return 0;
		}
		bible[numbooks].chapters = j;
		if ((bible[numbooks].verses = (int *) calloc(j, sizeof(int))) == NULL)
		{
			fprintf(stderr, "songidx:%s:%d: too many verses (out of memory)\n",
			        fs.filename, fs.lineno);
			fileclose(&fs);
			free_bible();
			return 0;
		}
		for (j=0; j<bible[numbooks].chapters; ++j)
			bible[numbooks].verses[j] = verses[j];
	}

	fileclose(&fs);
	return 1;
}

/* ws_stricmp(<string1>,<string2>)
 *   Case-insensitive, wide-string comparison function. (Some standard C libs already have
 *   one of these, but not all do; for compatibility I have to write my own.)
 */
static int
ws_stricmp(p1,p2)
	const WCHAR *p1;
	const WCHAR *p2;
{
	for (;;)
	{
		int diff = wc_tolower(*p1) - wc_tolower(*p2);
		if (diff != 0) return diff;
		if (*p1 == wc_null) return 0;
		++p1; ++p2;
	}
}

/* parseref(<string>,<book>,<verse>)
 *   Interpret <string> as a scripture reference, and store the NUMBER of the book of the Bible
 *   it refers to in <book>, and the chapter and verse that it refers to in <verse>. Return
 *   a pointer into <string> to the suffix of <string> that was not parsed.
 *   <book> and <verse> should hold the book and verse of the PREVIOUS scripture reference
 *   (if any) on entry to the function. If book or chapter information is missing, they will
 *   be drawn from this info. That way, successive calls can correctly parse a run-on
 *   string like "Philippians 3:1,5; 4:3", inferring that "5" refers to "Philippians 3" and
 *   "4:3" refers to "Philippians".
 *   If the parser encounters an error in processing the book name (e.g., a book name was
 *   specified but not recognized), <book> is set to numbooks. If no chapter or no verse is
 *   provided (e.g., the reference is just "Philippians" or "Philippians 3") then the
 *   chapter and/or verse fields of <verse> are set to -1.
 */
static WCHAR *
parseref(r,book,v)
	WCHAR *r;
	int *book;
	VERSE *v;
{
	WCHAR *p;
	WCHAR c;
	int i;
	const WCHAR *a;

	while (*r==wc_space) ++r;
	p = ws_strpbrk(r, ws_lit(",;-"));
	if (!p) p=r+ws_strlen(r);
	if (p>r) --p;
	while ((p>r) && (*p==wc_space)) --p;
	while ((p>r) && (wc_isdigit(*p) || (*p==wc_colon))) --p;
	if (p>r)
	{
		if (*p==wc_space)
		{
			*p++ = wc_null;
			for (*book=0; *book<numbooks; ++(*book))
			{
				for (i=0, a=bible[*book].name; i<bible[*book].aliases; ++i, a+=ws_strlen(a)+1)
					if (!ws_stricmp(r,a)) break;
				if (i<bible[*book].aliases) break;
			}
		}
		else
		{
			*book=numbooks;
		}
		r=p;
		v->chapter = v->verse = -1;
	}
	while (wc_isdigit(*p)) ++p;
	if (*p==wc_colon)
	{
		*p++ = wc_null;
		v->chapter = ws_strtol(r,NULL,10);
		r=p;
		while (wc_isdigit(*p)) ++p;
	}
	if (r==p) return NULL;
	c = *p;
	*p = wc_null;
	if ((v->chapter < 0)
	    && (*book>=0) && (*book<numbooks) && (bible[*book].chapters == 1))
	{
		/* Special case: This book only has one chapter. */
		v->chapter = 1;
	}
	if (v->chapter < 0)
		v->chapter = ws_strtol(r,NULL,10);
	else
		v->verse = ws_strtol(r,NULL,10);
	*p = c;
	while (*p==wc_space) ++p;
	if (*p && (*p!=wc_comma) && (*p!=wc_semicolon) && (*p!=wc_hyphen))
		return NULL;
	return p;
}

/* vlt(<v1>,<v2>)
 *   Return 1 if verse <v1> precedes <v2> and 0 otherwise.
 */
static int
vlt(v1,v2)
	const VERSE v1;
	const VERSE v2;
{
	return ((v1.chapter == v2.chapter) ? (v1.verse < v2.verse)
	                                   : (v1.chapter < v2.chapter));
}

/* vcpy(<vdest>,<vsrc>)
 *   Copy the data from verse <vsrc> into verse <vdest>.
 */
static void
vcpy(vdest,vsrc)
	VERSE *vdest;
	const VERSE vsrc;
{
	vdest->chapter = vsrc.chapter;
	vdest->verse = vsrc.verse;
}

/* getvcount(<book>,<chapter>)
 *   Return the number of verses in chapter <chapter> of book number <book> of the Bible.
 */
static int
getvcount(book,chapter)
	int book;
	int chapter;
{
	if ((book<0) || (book>=numbooks))
	{
		/* This should never happen. */
		fprintf(stderr, "songidx: Internal error (getvcount): Book %d out of range.\n", book);
		return 0;
	}
	if ((chapter<1) || (chapter > bible[book].chapters))
		return 0;
	return bible[book].verses[chapter-1];
}

/* vinc(<book>,<verse>)
 *   Return a reference to the verse immediately following <verse> in book number <book>
 *   of the Bible. The verse returned is static, so successive calls will overwrite it.
 *   If <verse> is the last verse in <book>, the return value will reference verse 1 of
 *   a non-existant chapter.
 */
static VERSE
vinc(book,v)
	int book;
	const VERSE v;
{
	static VERSE vret;
	int cnt;

	vret.chapter = v.chapter;
	vret.verse = v.verse + 1;
	cnt = getvcount(book, vret.chapter);
	if (cnt <= 0)
	{
		/* This should never happen. */
		fprintf(stderr, "songidx: Internal Error (vinc): Book ");
		ws_fputs(bible[book].name, stderr);
		fprintf(stderr, " has no chapter %d.\n", vret.chapter);
	}
	else if (vret.verse > cnt)
	{
		++vret.chapter;
		vret.verse = 1;
	}
	return vret;
}

/* vdec(<book>,<verse>)
 *   Return a reference to the verse immediately preceding <verse> in book number <book>
 *   of the Bible. The verse returned is static, so successive calls will overwrite it.
 *   If <verse> is the first verse in <book>, the return value will reference chapter
 *   -1 and an error message will be printed to stderr.
 */
static VERSE
vdec(book,v)
	int book;
	const VERSE v;
{
	static VERSE vret;
	vret.chapter = v.chapter;
	vret.verse = v.verse - 1;
	if (vret.verse < 1)
	{
		--vret.chapter;
		vret.verse = getvcount(book, vret.chapter);
		if (vret.verse <= 0)
		{
			/* This should never happen. */
			fprintf(stderr, "songidx: Internal Error (vdec): Book ");
			ws_fputs(bible[book].name, stderr);
			fprintf(stderr, " has no chapter %d.\n", vret.chapter);
			vret.verse = -1;
		}
	}
	return vret;
}

/* addref(<reflist>,<song>,<link>,<key>)
 *   Add a reference to song (<song>,<link>,<key>) to REFLIST <reflist>. <reflist> is
 *   assumed to be sorted by <key>. If a reference with the same <key> already exists,
 *   <reflist> is left unchanged. Both <song> and <link> are COPIED into the list.
 *   Return 1 on success or 0 on failure.
 */
static int
addref(sl,n,l,key)
	SONGLIST **sl;
	const WCHAR *n;
	const WCHAR *l;
	int key;
{
	SONGLIST *newsong;

	for (; *sl; sl=&((*sl)->next))
		if ((*sl)->key >= key) break;
	if (*sl && ((*sl)->key == key)) return 1;

	if ((newsong = (SONGLIST *) malloc(sizeof(SONGLIST))) == NULL)
	{
		fprintf(stderr, "songidx: too many scripture references (out of memory)\n");
		return 0;
	}
	newsong->num = newsong->link = NULL;
	if (((newsong->num = (WCHAR *) calloc(ws_strlen(n)+1, sizeof(WCHAR))) == NULL)
		|| ((newsong->link = (WCHAR *) calloc(ws_strlen(l)+1, sizeof(WCHAR))) == NULL))
	{
		fprintf(stderr, "songidx: too many scripture references (out of memory)\n");
		if (newsong->num) free(newsong->num);
		if (newsong->link) free(newsong->link);
		free(newsong);
		return 0;
	}
	ws_strcpy(newsong->num, n);
	ws_strcpy(newsong->link, l);
	newsong->key = key;
	newsong->next = *sl;
	*sl = newsong;
	return 1;
}

/* insertref(<type>,<verselist>,<verse>,<song>,<link>,<key>)
 *   If <type> is INSERT_ADD, then insert song (<song>,<link>,<key>) into the set of "adds" for
 *   verse <verse> in <verselist>. If <type> is INSERT_DROP, then insert the song into the set
 *   of "drops" for verse <verse>. In either case, create a new entry for <verse> in <verselist>
 *   if it doesn't already exist. Return 1 on success or 0 on failure.
 */
#define INSERT_ADD 1
#define INSERT_DROP 0

static int
insertref(type,vpp,v,n,l,key)
	char type;
	VERSELIST **vpp;
	const VERSE v;
	const WCHAR *n;
	const WCHAR *l;
	int key;
{
	for (;;)
	{
		if (!*vpp || vlt(v, (*vpp)->v))
		{
			VERSELIST *vnew = NULL;
			SONGLIST *sl = NULL;
			if (((vnew = (VERSELIST *) malloc(sizeof(VERSELIST))) == NULL)
				|| ((sl = (SONGLIST *) malloc(sizeof(SONGLIST))) == NULL))
			{
				fprintf(stderr, "songidx: too many scripture references (out of memory)\n");
				if (vnew) free(vnew);
				if (sl) free(sl);
				return 0;
			}
			sl->num = sl->link = NULL;
			if (((sl->num = (WCHAR *) calloc(ws_strlen(n)+1, sizeof(WCHAR))) == NULL)
				|| ((sl->link = (WCHAR *) calloc(ws_strlen(l)+1, sizeof(WCHAR))) == NULL))
			{
				fprintf(stderr, "songidx: too many scripture references (out of memory)\n");
				if (sl->num) free(sl->num);
				if (sl->link) free(sl->link);
				free(vnew);
				free(sl);
				return 0;
			}
			ws_strcpy(sl->num, n);
			ws_strcpy(sl->link, l);
			sl->key = key;
			sl->next = NULL;
			vcpy(&(vnew->v), v);
			if (type)
			{
				vnew->adds = sl;
				vnew->drops = NULL;
			}
			else
			{
				vnew->adds = NULL;
				vnew->drops = sl;
			}
			vnew->next = *vpp;
			*vpp = vnew;
			return 1;
	  	}
		else if (!vlt((*vpp)->v, v))
		{
			return addref(type ? &((*vpp)->adds) : &((*vpp)->drops), n, l, key);
		}
		vpp=&((*vpp)->next);
	}
}

/* addrefs(<dest>,<src>)
 *   Take the union of SONGLIST <dest> and SONGLIST <src>, storing the result in <dest>.
 *   Return 1 on success, or 0 on failure.
 */
static int
addrefs(dest,src)
	SONGLIST **dest;
	const SONGLIST *src;
{
	for (; src; src=src->next)
		if (!addref(dest, src->num, src->link, src->key)) return 0;
	return 1;
}

/* removerefs(<dest>,<src>)
 *   Take the set difference between SONGLIST <dest> and SONGLIST <src>, storing the
 *   result in <dest>.
 */
static void
removerefs(dest,src)
	SONGLIST **dest;
	const SONGLIST *src;
{
	SONGLIST **sl;

	for (; src; src=src->next)
	{
		for (sl=dest; *sl; sl=&((*sl)->next))
			if ((*sl)->key >= src->key) break;
		if (*sl && ((*sl)->key == src->key))
		{
			SONGLIST *temp = (*sl)->next;
			free((*sl)->num);
			free((*sl)->link);
			free(*sl);
			*sl = temp;
		}
  	}
}

/* slcmp(<slist1>,<slist2>)
 *   Compare SONGLIST's <slist1> and <slist2>, returning 1 if they are different
 *   and 0 if they are the same.
 */
static int
slcmp(s1,s2)
	const SONGLIST *s1;
	const SONGLIST *s2;
{
	for (; s1 && s2; s1=s1->next, s2=s2->next)
		if (s1->key != s2->key) return 1;
	return (s1 || s2);
}

/* print_vrange(<file>,<book>,<verse1>,<verse2>,<lastchapter>)
 *   Output LaTeX material to file handle <file> for verse range <verse1>-<verse2>
 *   of book number <book>. Depending on <lastchapter>, the outputted material
 *   might be the start of a new index entry or the continuation of a previous
 *   entry. If <lastchapter> is 0, start a new index entry. If <lastchapter> is >0,
 *   continue the previous entry and print the chapter of <verse1> only if it differs
 *   from <lastchapter>. If <lastchapter> is <0, continue the previous entry and
 *   always print the chapter number of <verse1>. Return 0 on success or -1 on failure.
 */
static int
print_vrange(f,book,v1,v2,lastchapter)
	FILE *f;
	int book;
	const VERSE v1;
	const VERSE v2;
	int lastchapter;
{
	if (ws_fputs(lastchapter ? ws_lit(",") : ws_lit("\\idxentry{"), f) < 0) return -1;
	if (v1.verse <= 0)
	{
		if (ws_fprintf1(f, lastchapter ? ws_lit("\\thinspace %d") : ws_lit("%d"), v1.chapter) < 0)
			return -1;
	}
	else if ((book>=0) && (book<numbooks) && (bible[book].chapters == 1))
	{
		/* This book has only one chapter. */
		if (ws_fprintf1(f, lastchapter ? ws_lit("\\thinspace %d") : ws_lit("%d"), v1.verse) < 0)
			return -1;
	}
	else if ((lastchapter<=0) || (lastchapter!=v1.chapter) || (v1.chapter!=v2.chapter))
	{
		if (ws_fprintf2(f, lastchapter ? ws_lit(" %d:%d") : ws_lit("%d:%d"), v1.chapter, v1.verse) < 0)
			return -1;
	}
	else
	{
		if (ws_fprintf1(f, lastchapter ? ws_lit("\\thinspace %d") : ws_lit("%d"), v1.verse) < 0)
			return -1;
	}

	if (vlt(v1,v2))
	{
		if (v2.verse <= 0)
		{
			if (ws_fprintf1(f, ws_lit("--%d"), v2.chapter) < 0) return -1;
		}
		else if (v1.chapter!=v2.chapter)
		{
			if (ws_fprintf2(f, ws_lit("--%d:%d"), v2.chapter, v2.verse) < 0) return -1;
		}
		else
		{
			if (ws_fprintf1(f, ws_lit("--%d"), v2.verse) < 0) return -1;
		}
	}
	return 0;
}

/* print_reflist(<file>,<slist>)
 *   Output the list of song references given by <slist> to file handle <file>.
 *   Return 0 on success or -1 on failure.
 */
static int
print_reflist(f,sp)
	FILE *f;
	const SONGLIST *sp;
{
	char first;
	for (first=1; sp; sp=sp->next)
	{
		if (!first)
		{
			if (ws_fputs(ws_lit("\\\\"), f) < 0) return -1;
		}
		first = 0;
		if ((ws_fputs(ws_lit("\\hyperlink{"), f) < 0)
		    || (ws_fputs(sp->link, f) < 0)
		    || (ws_fputs(ws_lit("}{"), f) < 0)
		    || (ws_fputs(sp->num, f) < 0)
		    || (ws_fputs(ws_lit("}"), f) < 0))
			return -1;
	}
	return 0;
}

/* genscriptureindex(<fstate>,<outname>,<biblename>)
 *   Generate a LaTeX file named <outname> containing material suitable to typeset
 *   the scripture index data found in input file handle <file>. Input Bible data
 *   from an ascii file named <biblename>.
 *   Return 0 on success, 1 if there were warnings, and 2 if there was a fatal error.
 */
int
genscriptureindex(fs,outname,biblename)
	FSTATE *fs;
	const char *outname;
	const char *biblename;
{
	FILE *f;
	int eof = 0;
	VERSELIST **idx;
	int book, book2;
	WCHAR ref[MAXLINELEN], songnum[MAXLINELEN], linkname[MAXLINELEN];
	int songcount;
	WCHAR *p;
	VERSE v1, v2;
	char hadwarnings = 0;

	fprintf(stderr, "songidx: Parsing scripture index data file %s...\n", fs->filename);

	/* Read the bible data file into the bible array. */
	if (!readbible(biblename)) return 2;
	if ((idx = (VERSELIST **) calloc(numbooks, sizeof(VERSELIST *))) == NULL)
	{
		fprintf(stderr, "songidx: too many books of the bible (out of memory)\n");
		free_bible();
		return 2;
	}
	for (book=0; book<numbooks; ++book) idx[book] = NULL;

	/* Walk through the input file and construct a VERSELIST for each book
	 * of the Bible. Each VERSELIST represents the set of verses in that book
	 * referred to by songs in the song book.
	 */
	songcount = 0;
	book = -1;
	v1.chapter = -1;
	v1.verse = -1;
	for (;;)
	{
		/* Get the next song data record. */
		if (!filereadln(fs,ref,&eof))
		{
			freeidxarray(idx,numbooks);
			free_bible();
			return 2;
		}
		if (eof) break;
		if (!filereadln(fs,songnum,&eof) || eof || !filereadln(fs,linkname,&eof) || eof)
		{
			if (eof)
			{
				fprintf(stderr, "songidx:%s:%d: incomplete entry\n", fs->filename, fs->lineno);
				fileclose(fs);
			}
			freeidxarray(idx,numbooks);
			free_bible();
			return 2;
		}

		/* Add all scripture references for this song to the VERSELIST array */
		p = ref;
		while (*p != wc_null)
		{
			/* Parse the next reference. */
			p = parseref(p, &book, &v1);
			if (!p)
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Malformed scripture reference for song ",
					    fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, ". Ignoring it.\n");
				hadwarnings = 1;
				break;
			}
			if (book<0)
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Scripture reference for song ",
				        fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, " doesn't include a book name. Ignoring it.\n");
				hadwarnings = 1;
				break;
			}
			if (book>=numbooks)
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Scripture reference for song ",
				        fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, " references unknown book. Ignoring it.\n");
				hadwarnings = 1;
				break;
			}
			if (v1.chapter < 1)
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Scripture reference for song ",
				        fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, " has no chapter or verse. Ignoring it.\n");
				hadwarnings = 1;
				break;
			}
			/* Unless the reference ended in a "-", it consists of just one verse. */
			v2.chapter = v1.chapter;
			v2.verse = v1.verse;
			if (*p==wc_hyphen)
			{
 				/* This reference ended in a "-", which means it starts a range.
				 * Parse the next reference to find the range's end.
				 */
				book2 = book;
				p = parseref(++p, &book2, &v2);
				if (!p)
				{
					fprintf(stderr, "songidx:%s:%d: WARNING: Malformed scripture reference for song ",
					        fs->filename, fs->lineno);
					ws_fputs(songnum, stderr);
					fprintf(stderr, ". Ignoring it.\n");
					hadwarnings = 1;
					break;
				}
				if (book2!=book)
				{
					fprintf(stderr, "songidx:%s:%d: WARNING: Scripture reference for song ",
					        fs->filename, fs->lineno);
					ws_fputs(songnum, stderr);
					fprintf(stderr, " appears to span books! Ignoring it.\n");
					hadwarnings = 1;
					break;
				}
			}
			if (*p!=wc_null) ++p;
			/* If either the start or end references of the range were incomplete (e.g., the range
			 * was something like "Philippians 3", where the verse numbers are not explicit), try
			 * to fill in the missing information based on how many verses are in the chapter and
			 * how many chapters are in the book.
			 */
			if (v1.verse <= 0) v1.verse = 1;
			if (v2.verse <= 0)
			{
				v2.verse = getvcount(book,v2.chapter);
				if (v2.verse <= 0)
				{
					fprintf(stderr, "songidx:%s:%d: WARNING: Scripture reference for song ",
					        fs->filename, fs->lineno);
					ws_fputs(songnum, stderr);
					fprintf(stderr, " refers implicitly to chapter %d of ", v2.chapter);
					ws_fputs(bible[book].name, stderr);
					fprintf(stderr, ", which doesn't exist. Ignoring it.\n");
					hadwarnings = 1;
					break;
				}
			}
			if (v1.verse > getvcount(book,v1.chapter))
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Song ", fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, " references ");
				ws_fputs(bible[book].name, stderr);
				fprintf(stderr, " %d:%d, which doesn't exist! Ignoring it.\n", v1.chapter, v1.verse);
				hadwarnings = 1;
				break;
			}
			if (v2.verse > getvcount(book,v2.chapter))
			{
				fprintf(stderr, "songidx:%s:%d: WARNING: Song ", fs->filename, fs->lineno);
				ws_fputs(songnum, stderr);
				fprintf(stderr, " references ");
				ws_fputs(bible[book].name, stderr);
				fprintf(stderr, " %d:%d, which doesn't exist! Ignoring it.\n", v2.chapter, v2.verse);
				hadwarnings = 1;
				break;
			}

			/* Add the range to the SONGLIST array. */
			if (!insertref(INSERT_ADD, &(idx[book]), v1, songnum, linkname, songcount) ||
			    !insertref(INSERT_DROP, &(idx[book]), v2, songnum, linkname, songcount))
			{
				fileclose(fs);
				freeidxarray(idx,numbooks);
				free_bible();
				return 2;
			}
		}
		/* finished adding all refs for this song */
		++songcount;
	}
	/* finished adding all refs for all songs */
	fileclose(fs);

	/* Now create the index .sbx file */
	fprintf(stderr, "songidx: Generating scripture index TeX file %s...\n", outname);
	if (strcmp(outname,"-"))
	{
		if ((f = fopen(outname, "w")) == NULL)
		{
			fprintf(stderr, "songidx: Unable to open %s for writing.\n", outname);
			freeidxarray(idx,numbooks);
			free_bible();
			return 2;
		}
	}
	else
	{
		f = stdout;
		outname = "stdout";
	}

#define TRYWRITE(x) \
	if (!(x)) \
	{ \
		fprintf(stderr, "songidx:%s: write error\n", outname); \
		if (f == stdout) fflush(f); else fclose(f); \
		freeidxarray(idx,numbooks); \
		free_bible(); \
		return 2; \
	}

	/* For each book of the Bible that has songs that reference it, go through its VERSELIST and
	 * generate a sequence of index entries. Wherever possible, compact adjacent entries that
	 * have identical SONGLISTS so that we never have two consecutive index entries with identical
	 * right-hand sides.
	 */
	for (book=0; book<numbooks; ++book)
		if (idx[book])
		{
			VERSE vrstart;
			VERSELIST *vp;
			SONGLIST *sl = NULL;
			int lastchapter; /* 0=none, -1=force printing of chapter */

			TRYWRITE((ws_fputs(ws_lit("\\begin{idxblock}{"), f) >=0)
			         && (ws_fputs(bible[book].name, f) >= 0)
			         && (ws_fputs(ws_lit("}\n"), f) >=0))
			lastchapter = 0;
			vcpy(&vrstart, idx[book]->v);
			for (vp=idx[book]; vp; vp=vp->next)
			{
				if (!addrefs(&sl, vp->adds))
				{
					fclose(f);
					freeidxarray(idx,numbooks);
					free_bible();
					return 2;
				}
				if (!slcmp(vp->drops, vp->next ? vp->next->adds : NULL))
				{
					/* Set of drops here equals set of adds next time. There's at least a
					 * chance that we can combine this item and the next one into a single
					 * index entry.
					 */
					if (vp->next && !vlt(vinc(book,vp->v), vp->next->v))
					{
						/* If the next item is adjacent to this one, do nothing. Just let the
						 * range in progress be extended. We'll output a single entry for all of
						 * these adjacent verses when we reach the end.
						 */
						continue;
					}
					else if (vp->next && !slcmp(sl, vp->drops))
					{
						/* Otherwise, if the next item is not adjacent but all refs are dropped
						 * here, then print a partial entry to be continued with a comma next
						 * time.
						 */
						TRYWRITE(print_vrange(f, book, vrstart, vp->v, lastchapter) >= 0)
						lastchapter = (vrstart.chapter != vp->v.chapter) ? -1 : vp->v.chapter;
						vcpy(&vrstart, vp->next->v);
						continue;
					}
				}
				if (vp->drops)
				{
					/* Some songs get dropped here, and either the next item is not adjacent
					 * to this one, or it's adjacent and the set of adds is not the same. In
					 * either case, that means the set of refs changes at this point, so we
					 * need to output a full entry (or finish the one in progress).
					 */
					TRYWRITE((print_vrange(f, book, vrstart, vp->v, lastchapter) >= 0)
							 && (ws_fputs(ws_lit("}{"), f) >= 0)
					         && (print_reflist(f, sl) >= 0)
					         && (ws_fputs(ws_lit("}\n"), f) >= 0))
					removerefs(&sl, vp->drops);
					lastchapter = 0;
					vcpy(&vrstart, (!sl && vp->next) ? vp->next->v : vinc(book,vp->v));
				}
				if (sl && vp->next && vp->next->adds && vlt(vrstart, vp->next->v))
				{
					/* There are verses between this item and the next which have refs, but
					 * the refs change at the beginning of the next item. Make an entry for
					 * the intermediate block of verses.
					 */
					VERSE vrend;
					vcpy(&vrend, vdec(book,vp->next->v));
					TRYWRITE((print_vrange(f, book, vrstart, vrend, lastchapter) >= 0)
					         && (ws_fputs(ws_lit("}{"), f) >= 0)
					         && (print_reflist(f, sl) >= 0)
					         && (ws_fputs(ws_lit("}\n"), f) >= 0))
					lastchapter = 0;
					vcpy(&vrstart, vp->next->v);
				}
			}
			if (sl)
			{
				fprintf(stderr, "songidx: scripture references in ");
				ws_fputs(bible[book].name, stderr);
				fprintf(stderr, " appear to extend past the end of the book! Aborting.\n");
				fclose(f);
				freeidxarray(idx,numbooks);
				free_bible();
				return 2;
			}
			TRYWRITE(ws_fputs(ws_lit("\\end{idxblock}\n"), f) >= 0)
		}

#undef TRYWRITE

	fclose(f);
	freeidxarray(idx,numbooks);
	free_bible();

	return hadwarnings;
}