/* Copyright (C) 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id: gsfcmap.c $ */
/* CMap character decoding */
#include "gx.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gxfcmap.h"

/* CMap structure descriptors */
public_st_cmap();
public_st_code_map();
public_st_code_map_element();

/* Because code maps can be elements of arrays, */
/* their enum_ptrs procedure must never return 0 prematurely. */
private 
ENUM_PTRS_WITH(code_map_enum_ptrs, gx_code_map *pcmap) return 0;
ENUM_PTR(0, gx_code_map, cmap);
case 1:
switch (pcmap->type)
{
    case cmap_glyph:
	(*pcmap->cmap->mark_glyph)(pcmap->data.glyph,
				   pcmap->cmap->mark_glyph_data);
    default:
	ENUM_RETURN(0);
    case cmap_subtree:
	ENUM_RETURN_PTR(gx_code_map, data.subtree);
}
ENUM_PTRS_END
private RELOC_PTRS_WITH(code_map_reloc_ptrs, gx_code_map *pcmap);
switch (pcmap->type) {
    case cmap_subtree:
	RELOC_PTR(gx_code_map, data.subtree);
	break;
    default:
	;
}
RELOC_PTR(gx_code_map, cmap);
RELOC_PTRS_END

/* CIDSystemInfo structure descriptors */
private_st_cid_system_info();
public_st_cid_system_info_element();

/* ---------------- Procedures ---------------- */

/*
 * Decode a character from a string using a code map, updating the index.
 * Return 0 for a CID or name, N > 0 for a character code where N is the
 * number of bytes in the code, or an error.  In the case of a character
 * code, shift the bytes into *pchr.  For undefined characters, we set
 * *pglyph = gs_no_glyph and return 0.
 */
private int
code_map_decode_next(const gx_code_map * pcmap, const gs_const_string * str,
		     uint * pindex, uint * pfidx,
		     gs_char * pchr, gs_glyph * pglyph)
{
    const gx_code_map *map = pcmap;
    uint chr = 0;

    for (;;) {
	int result;

	if_debug1('J', "[J]cmap char = 0x%x: ", chr);
	switch ((gx_code_map_type) map->type) {
	    case cmap_char_code:
		if_debug0('J', "char code");
		*pglyph = (gs_glyph)map->data.ccode;
		result = map->num_bytes1 + 1;
leaf:		if (chr > map->last)
		    goto undef;
		if (map->add_offset)
		    *pglyph += chr - map->first;
		*pfidx = map->byte_data.font_index;
		if_debug3('J', " 0x%lx, fidx %u, result %d\n",
			  *pglyph, *pfidx, result);
		return result;
	    case cmap_glyph:
		if_debug0('J', "glyph");
		*pglyph = map->data.glyph;
		result = 0;
		goto leaf;
	    case cmap_subtree:
		if_debug0('J', "subtree\n");
		if (*pindex >= str->size)
		    return_error(gs_error_rangecheck);
		chr = str->data[(*pindex)++];
		if (chr >= map->data.subtree[0].first) {
		    /* Invariant: map[lo].first <= chr < map[hi].first. */
		    uint lo = 0, hi = map->byte_data.count1 + 1;

		    map = map->data.subtree;
		    while (lo + 1 < hi) {
			uint mid = (lo + hi) >> 1;

			if (chr >= map[mid].first)
			    lo = mid;
			else
			    hi = mid;
		    }
		    *pchr = (*pchr << 8) | chr;
		    map = &map[lo];
		    continue;
		}
undef:		if_debug0('J', " undef\n");
		*pchr = 0;
		*pglyph = gs_no_glyph;
		return 0;
	    default:		/* (can't happen) */
		if_debug0('J', "error!\n");
		return_error(gs_error_invalidfont);
	}
    }
}

/*
 * Decode a character from a string using a CMap.
 * Return like code_map_decode_next.
 */
int
gs_cmap_decode_next(const gs_cmap * pcmap, const gs_const_string * str,
		    uint * pindex, uint * pfidx,
		    gs_char * pchr, gs_glyph * pglyph)
{
    uint save_index = *pindex;
    int code;

    *pchr = 0;
    code =
	code_map_decode_next(&pcmap->def, str, pindex, pfidx, pchr, pglyph);
    if (code != 0 || *pglyph != gs_no_glyph)
	return code;
    /* This is an undefined character.  Use the notdef map. */
    {
	uint next_index = *pindex;

	*pindex = save_index;
	*pchr = 0;
	code =
	    code_map_decode_next(&pcmap->notdef, str, pindex, pfidx,
				 pchr, pglyph);
	*pindex = next_index;
    }
    return code;
}
