/*
 * Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.
 *
 * This file is part of Jam - see jam.c for Copyright information.
 */

/*
 * pathvms.c - manipulate file names on VMS
 *
 * External routines:
 *
 *	path_parse() - split a file name into dir/base/suffix/member
 *	path_build() - build a filename given dir/base/suffix/member
 *	path_parent() - make a PATHNAME point to its parent dir
 *
 * File_parse() and path_build() just manipuate a string and a structure;
 * they do not make system calls.
 *
 * WARNING!  This file contains voodoo logic, as black magic is 
 * necessary for wrangling with VMS file name.  Woe be to people
 * who mess with this code.
 *
 * 02/09/95 (seiwald) - bungled R=[xxx] - was using directory length!
 * 05/03/96 (seiwald) - split from filevms.c
 * 11/04/02 (seiwald) - const-ing for string literals
 */

# include "jam.h"
# include "pathsys.h"

# ifdef OS_VMS

# define DEBUG

/*
 * path_parse() - split a file name into dir/base/suffix/member
 */

void
path_parse( 
	const char *file,
	PATHNAME *f )
{
	const char *p, *q;
	const char *end;
	
	memset( (char *)f, 0, sizeof( *f ) );

	/* Look for <grist> */

	if( file[0] == '<' && ( p = strchr( file, '>' ) ) )
	{
	    f->f_grist.ptr = file;
	    f->f_grist.len = p - file;
	    file = p + 1;
	}

	/* Look for dev:[dir] or dev: */

	if( ( p = strchr( file, ']' ) ) || ( p = strchr( file, ':' ) ) )
	{
	    f->f_dir.ptr = file;
	    f->f_dir.len = p + 1 - file;
	    file = p + 1;
	}

	end = file + strlen( file );

	/* Look for (member) */

	if( ( p = strchr( file, '(' ) ) && end[-1] == ')' )
	{
	    f->f_member.ptr = p + 1;
	    f->f_member.len = end - p - 2;
	    end = p;
	} 

	/* Look for .suffix */
	/* This would be memrchr() */

	p = 0;
	q = file;

	while( q = (char *)memchr( q, '.', end - q ) )
	    p = q++;

	if( p )
	{
	    f->f_suffix.ptr = p;
	    f->f_suffix.len = end - p;
	    end = p;
	}

	/* Leaves base */

	f->f_base.ptr = file;
	f->f_base.len = end - file;

	/* Is this a directory without a file spec? */

	f->parent = 0;
}

/*
 *	dir		mods		result
 *	---		---		------
 * Rerooting:
 *
 *	(none)		:R=dev:		dev:		
 *	devd:		:R=dev:		devd:
 *	devd:[dir]	:R=dev:		devd:[dir]
 *	[.dir]		:R=dev:		dev:[dir]	questionable
 *	[dir]		:R=dev:		dev:[dir]
 *
 *	(none)		:R=[rdir]	[rdir]		questionable
 *	devd:		:R=[rdir]	devd:
 *	devd:[dir]	:R=[rdir]	devd:[dir]
 *	[.dir]		:R=[rdir]	[rdir.dir]	questionable
 *	[dir]		:R=[rdir]	[rdir]
 *
 *	(none)		:R=dev:[root]	dev:[root]
 *	devd:		:R=dev:[root]	devd:
 *	devd:[dir]	:R=dev:[root]	devd:[dir]
 *	[.dir]		:R=dev:[root]	dev:[root.dir]
 *	[dir]		:R=dev:[root]	[dir]
 *
 * Climbing to parent:
 *
 */

# define DIR_EMPTY	0	/* empty string */
# define DIR_DEV	1	/* dev: */
# define DIR_DEVDIR	2	/* dev:[dir] */
# define DIR_DOTDIR	3	/* [.dir] */
# define DIR_DASHDIR	4	/* [-] or [-.dir] */
# define DIR_ABSDIR	5	/* [dir] */
# define DIR_ROOT	6	/* [000000] or dev:[000000] */

# define G_DIR		0	/* take just dir */
# define G_ROOT		1	/* take just root */
# define G_VAD		2	/* root's dev: + [abs] */
# define G_DRD		3	/* root's dev:[dir] + [.rel] */
# define G_VRD		4	/* root's dev: + [.rel] made [abs] */
# define G_DDD		5	/* root's dev:[dir] + . + [dir] */

static int grid[7][7] = {

/* root/dir	EMPTY	DEV	DEVDIR	DOTDIR	DASH,	ABSDIR	ROOT */
/* EMPTY */	G_DIR,	G_DIR,	G_DIR,	G_DIR,	G_DIR,	G_DIR,	G_DIR,
/* DEV */	G_ROOT,	G_DIR,	G_DIR,	G_VRD,	G_VAD,	G_VAD,	G_VAD,
/* DEVDIR */	G_ROOT,	G_DIR,	G_DIR,	G_DRD,	G_VAD,	G_VAD,	G_VAD,
/* DOTDIR */	G_ROOT,	G_DIR,	G_DIR,	G_DRD,	G_DIR,	G_DIR,	G_DIR,
/* DASHDIR */	G_ROOT,	G_DIR,	G_DIR,	G_DRD,	G_DDD,	G_DIR,	G_DIR,
/* ABSDIR */	G_ROOT,	G_DIR,	G_DIR,	G_DRD,	G_DIR,	G_DIR,	G_DIR,
/* ROOT */	G_ROOT,	G_DIR,	G_DIR,	G_VRD,	G_DIR,	G_DIR,	G_DIR,

} ;

struct dirinf {
	int	flags;

	struct {
		char	*ptr;
		int	len;
	} dev, dir;
} ;

static char *
strnchr( 
	char	*buf,
	int	c,
	int	len )
{
	while( len-- )
	    if( *buf && *buf++ == c )
		return buf - 1;

	return 0;
}

static void
dir_flags( 
	const char *buf,
	int	len,
	struct dirinf *i )
{
	const char *p;

	if( !buf || !len )
	{
	    i->flags = DIR_EMPTY;
	    i->dev.ptr =
	    i->dir.ptr = 0;
	    i->dev.len =
	    i->dir.len = 0;
	}
	else if( p = strnchr( (char *)buf, ':', len ) )
	{
	    i->dev.ptr = (char *)buf;
	    i->dev.len = p + 1 - buf;
	    i->dir.ptr = (char *)buf + i->dev.len;
	    i->dir.len = len - i->dev.len;
	    i->flags = i->dir.len && *i->dir.ptr == '[' ? DIR_DEVDIR : DIR_DEV;
	}
	else
	{
	    i->dev.ptr = (char *)buf;
	    i->dev.len = 0;
	    i->dir.ptr = (char *)buf;
	    i->dir.len = len;

	    if( *buf == '[' && buf[1] == ']' )
		i->flags = DIR_EMPTY;
	    else if( *buf == '[' && buf[1] == '.' )
		i->flags = DIR_DOTDIR;
	    else if( *buf == '[' && buf[1] == '-' )
		i->flags = DIR_DASHDIR;
	    else
		i->flags = DIR_ABSDIR;
	}

	/* But if its rooted in any way */

	if( i->dir.len == 8 && !strncmp( i->dir.ptr, "[000000]", 8 ) )
	    i->flags = DIR_ROOT;
}

/*
 * path_build() - build a filename given dir/base/suffix/member
 */

void
path_build(
	PATHNAME *f,
	char	*file,
	int	binding )
{
	char *ofile = file;
	struct dirinf root, dir;
	int g;

	/* Start with the grist.  If the current grist isn't */
	/* surrounded by <>'s, add them. */

	if( f->f_grist.len )
	{
	    if( f->f_grist.ptr[0] != '<' ) *file++ = '<';
	    memcpy( file, f->f_grist.ptr, f->f_grist.len );
	    file += f->f_grist.len;
	    if( file[-1] != '>' ) *file++ = '>';
	}

	/* Get info on root and dir for combining. */

	dir_flags( f->f_root.ptr, f->f_root.len, &root );
	dir_flags( f->f_dir.ptr, f->f_dir.len, &dir );

	/* Combine */

	switch( g = grid[ root.flags ][ dir.flags ] )
	{
	case G_DIR:	
		/* take dir */
		memcpy( file, f->f_dir.ptr, f->f_dir.len );
		file += f->f_dir.len;
		break;

	case G_ROOT:	
		/* take root */
		memcpy( file, f->f_root.ptr, f->f_root.len );
		file += f->f_root.len;
		break;

	case G_VAD:	
		/* root's dev + abs directory */
		memcpy( file, root.dev.ptr, root.dev.len );
		file += root.dev.len;
		memcpy( file, dir.dir.ptr, dir.dir.len );
		file += dir.dir.len;
		break;
		
	case G_DRD:	
	case G_DDD:
		/* root's dev:[dir] + rel directory */
		memcpy( file, f->f_root.ptr, f->f_root.len );
		file += f->f_root.len;

		/* sanity checks: root ends with ] */

		if( file[-1] == ']' )
		     --file;	

		/* Add . if separating two -'s */

		if( g == G_DDD )
		    *file++ = '.';

		/* skip [ of dir */
		memcpy( file, dir.dir.ptr + 1, dir.dir.len - 1 );
		file += dir.dir.len - 1;
		break;

	case G_VRD:	
		/* root's dev + rel directory made abs */
		memcpy( file, root.dev.ptr, root.dev.len );
		file += root.dev.len;
		*file++ = '[';
		/* skip [. of rel dir */
		memcpy( file, dir.dir.ptr + 2, dir.dir.len - 2 );
		file += dir.dir.len - 2;
		break;
	}

# ifdef DEBUG
	if( DEBUG_SEARCH && ( root.flags || dir.flags ) )
	{
		*file = 0;
		printf( "%d x %d = %d (%s)\n", root.flags, dir.flags,
			grid[ root.flags ][ dir.flags ], ofile );
	}
# endif 

	/* 
	 * Now do the special :P modifier when no file was present.
	 *	(none)		(none)
	 *	[dir1.dir2]	[dir1]
	 *	[dir]		[000000]
	 *	[.dir]		[]
	 *	[]		[]
	 */

	if( file[-1] == ']' && f->parent )
	{
	    while( file-- > ofile )
	    {
		if( *file == '.' )
		{
		    *file++ = ']';
		    break;
		}
		else if( *file == '-' )
		{
		    /* handle .- or - */
		    if( file > ofile && file[-1] == '.' )
		    	--file;
		    *file++ = ']';
		    break;
		}
		else if( *file == '[' )
		{
		    if( file[1] == ']' )
		    {
		    	file += 2;
		    }
		    else
		    {
			strcpy( file, "[000000]" );
			file += 8;
		    }
		    break;
		}
	    }
	}

	/* Now copy the file pieces. */

	if( f->f_base.len )
	{
	    memcpy( file, f->f_base.ptr, f->f_base.len );
	    file += f->f_base.len;
	}

	/* If there is no suffix, we append a "." onto all generated */
	/* names.  This keeps VMS from appending its own (wrong) idea */
	/* of what the suffix should be. */

	if( f->f_suffix.len )
	{
	    memcpy( file, f->f_suffix.ptr, f->f_suffix.len );
	    file += f->f_suffix.len;
	}
	else if( binding && f->f_base.len )
	{
	    *file++ = '.';
	}

	if( f->f_member.len )
	{
	    *file++ = '(';
	    memcpy( file, f->f_member.ptr, f->f_member.len );
	    file += f->f_member.len;
	    *file++ = ')';
	}
	*file = 0;

# ifdef DEBUG
	if( DEBUG_SEARCH )
	    printf("built %.*s + %.*s / %.*s suf %.*s mem %.*s -> %s\n", 
		    f->f_root.len, f->f_root.ptr,
		    f->f_dir.len, f->f_dir.ptr,
		    f->f_base.len, f->f_base.ptr,
		    f->f_suffix.len, f->f_suffix.ptr,
		    f->f_member.len, f->f_member.ptr,
		    ofile );
# endif
}

/*
 *	path_parent() - make a PATHNAME point to its parent dir
 */

void
path_parent( PATHNAME *f )
{
	if( f->f_base.len )
	{
	    f->f_base.ptr =
	    f->f_suffix.ptr =
	    f->f_member.ptr = "";

	    f->f_base.len =
	    f->f_suffix.len =
	    f->f_member.len = 0;
	}
	else
	{
	    f->parent = 1;
	}
}

# endif /* VMS */