/* Copyright (C) 2002 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gdevpdtb.c,v 1.18.2.6 2004/12/15 23:25:36 igor Exp $ */
/* BaseFont implementation for pdfwrite */
#include "memory_.h"
#include "ctype_.h"
#include "string_.h"
#include "gx.h"
#include "gserrors.h"
#include "gsutil.h"		/* for bytes_compare */
#include "gxfcid.h"
#include "gxfcopy.h"
#include "gxfont.h"		/* for gxfont42.h */
#include "gxfont42.h"
#include "gdevpsf.h"
#include "gdevpdfx.h"
#include "gdevpdtb.h"
#include "gdevpdtf.h"

/*
 * Adobe's Distiller Parameters documentation for Acrobat Distiller 5
 * says that all fonts other than Type 1 are always subsetted; the
 * documentation for Distiller 4 says that fonts other than Type 1 and
 * TrueType are subsetted.  We do the latter, except that we always
 * subset large TrueType fonts.
 */
#define MAX_NO_SUBSET_GLYPHS 500	/* arbitrary */

/* ---------------- Definitions ---------------- */

struct pdf_base_font_s {
    /*
     * For the standard 14 fonts, copied == complete is a complete copy
     * of the font, and DO_SUBSET = NO.
     *
     * For fonts that MAY be subsetted, copied is a partial copy,
     * complete is a complete copy, and DO_SUBSET = UNKNOWN until
     * pdf_font_do_subset is called.
     *
     * For fonts that MUST be subsetted, copied == complete is a partial
     * copy, and DO_SUBSET = YES.
     */
    gs_font_base *copied;
    gs_font_base *complete;
    enum {
	DO_SUBSET_UNKNOWN = 0,
	DO_SUBSET_NO,
	DO_SUBSET_YES
    } do_subset;
    bool is_standard;
    /*
     * For CIDFonts, which are always subsetted, num_glyphs is CIDCount.
     * For optionally subsetted fonts, num_glyphs is the count of glyphs
     * in the font when originally copied.  Note that if the font is
     * downloaded incrementally, num_glyphs may be 0.
     */
    int num_glyphs;
    byte *CIDSet;		/* for CIDFonts */
    long FontFile_id;		/* non-0 iff the font is embedded */
    gs_string font_name;
    bool written;
};
BASIC_PTRS(pdf_base_font_ptrs) {
    GC_OBJ_ELT(pdf_base_font_t, copied),
    GC_OBJ_ELT(pdf_base_font_t, complete),
    GC_OBJ_ELT(pdf_base_font_t, CIDSet),
    GC_STRING_ELT(pdf_base_font_t, font_name)
};
gs_private_st_basic(st_pdf_base_font, pdf_base_font_t, "pdf_base_font_t",
		    pdf_base_font_ptrs, pdf_base_font_data);

/* ---------------- Private ---------------- */

#define SUBSET_PREFIX_SIZE 7	/* XXXXXX+ */

/*
 * Determine whether a font is a subset font by examining the name.
 */
bool
pdf_has_subset_prefix(const byte *str, uint size)
{
    int i;

    if (size < SUBSET_PREFIX_SIZE || str[SUBSET_PREFIX_SIZE - 1] != '+')
	return false;
    for (i = 0; i < SUBSET_PREFIX_SIZE - 1; ++i)
	if ((uint)(str[i] - 'A') >= 26)
	    return false;
    return true;
}

private ulong
hash(ulong v, int index, ushort w)
{
    return v * 3141592653u + w;
}

/*
 * Add the XXXXXX+ prefix for a subset font.
 */
int
pdf_add_subset_prefix(const gx_device_pdf *pdev, gs_string *pstr, byte *used, int count)
{
    uint size = pstr->size;
    byte *data = gs_resize_string(pdev->pdf_memory, pstr->data, size,
				  size + SUBSET_PREFIX_SIZE,
				  "pdf_add_subset_prefix");
    int len = (count + 7) / 8;
    ulong v = 0;
    ushort t = 0;
    int i;

    if (data == 0)
	return_error(gs_error_VMerror);
    /* Hash the 'used' array. */
    for (i = 0; i < len; i += sizeof(ushort))
	v = hash(v, i, *(ushort *)(used + i));
    if (i < len) {
	i -= sizeof(ushort);
	memmove(&t, used + i, len - i);
	v = hash(v, i, *(ushort *)(used + i));
    }
    memmove(data + SUBSET_PREFIX_SIZE, data, size);
    for (i = 0; i < SUBSET_PREFIX_SIZE - 1; ++i, v /= 26)
	data[i] = 'A' + (v % 26);
    data[SUBSET_PREFIX_SIZE - 1] = '+';
    pstr->data = data;
    pstr->size = size + SUBSET_PREFIX_SIZE;
    return 0;
}

/* Begin writing FontFile* data. */
private int
pdf_begin_fontfile(gx_device_pdf *pdev, long FontFile_id,
		   const char *entries, long len1, pdf_data_writer_t *pdw)
{
    stream *s;

    pdf_open_separate(pdev, FontFile_id);
    s = pdev->strm;
    stream_puts(s, "<<");
    if (entries)
	stream_puts(pdev->strm, entries);
    if (len1 >= 0)
	pprintld1(pdev->strm, "/Length1 %ld", len1);
    return pdf_begin_data_stream(pdev, pdw, DATA_STREAM_BINARY | DATA_STREAM_ENCRYPT |
				 (pdev->CompressFonts ?
				  DATA_STREAM_COMPRESS : 0), FontFile_id);
}

/* Finish writing FontFile* data. */
private int
pdf_end_fontfile(gx_device_pdf *pdev, pdf_data_writer_t *pdw)
{
    return pdf_end_data(pdw);
}

/* ---------------- Public ---------------- */

/*
 * Allocate and initialize a base font structure, making the required
 * stable copy/ies of the gs_font.  Note that this removes any XXXXXX+
 * font name prefix from the copy.  If is_standard is true, the copy is
 * a complete one, and adding glyphs or Encoding entries is not allowed.
 */
int
pdf_base_font_alloc(gx_device_pdf *pdev, pdf_base_font_t **ppbfont,
		    gs_font_base *font, const gs_matrix *orig_matrix, 
		    bool is_standard, bool orig_name)
{
    gs_memory_t *mem = pdev->pdf_memory;
    gs_font *copied;
    gs_font *complete;
    pdf_base_font_t *pbfont =
	gs_alloc_struct(mem, pdf_base_font_t,
			&st_pdf_base_font, "pdf_base_font_alloc");
    const gs_font_name *pfname = pdf_choose_font_name((gs_font *)font, orig_name);
    gs_const_string font_name;
    char fnbuf[3 + sizeof(long) / 3 + 1]; /* .F#######\0 */
    int code;

    if (pbfont == 0)
	return_error(gs_error_VMerror);
    code = gs_copy_font((gs_font *)font, orig_matrix, mem, &copied);
    if (code < 0)
	goto fail;
    memset(pbfont, 0, sizeof(*pbfont));
    {
	/* 
	 * Adobe Technical Note # 5012 "The Type 42 Font Format Specification" says :
	 *
	 * There is a known bug in the TrueType rasterizer included in versions of the
	 * PostScript interpreter previous to version 2013. The problem is that the
	 * translation components of the FontMatrix, as used as an argument to the
	 * definefont or makefont operators, are ignored. Translation of user space is
	 * not affected by this bug.
	 *
	 * Besides that, we found that Adobe Acrobat Reader 4 and 5 ignore 
	 * FontMatrix.ty .
	 */
	copied->FontMatrix.tx = copied->FontMatrix.ty = 0;
    }
    switch (font->FontType) {
    case ft_encrypted:
    case ft_encrypted2:
	pbfont->do_subset = (is_standard ? DO_SUBSET_NO : DO_SUBSET_UNKNOWN);
	/* We will count the number of glyphs below. */
	pbfont->num_glyphs = -1;
	break;
    case ft_TrueType:
	pbfont->num_glyphs = ((gs_font_type42 *)font)->data.trueNumGlyphs;
	pbfont->do_subset =
	    (pbfont->num_glyphs <= MAX_NO_SUBSET_GLYPHS ?
	     DO_SUBSET_UNKNOWN : DO_SUBSET_YES);
	break;
    case ft_CID_encrypted:
	pbfont->num_glyphs = ((gs_font_cid0 *)font)->cidata.common.CIDCount;
	goto cid;
    case ft_CID_TrueType:
	pbfont->num_glyphs = ((gs_font_cid2 *)font)->cidata.common.CIDCount;
    cid:
	pbfont->do_subset = DO_SUBSET_YES;
	pbfont->CIDSet =
	    gs_alloc_bytes(mem, (pbfont->num_glyphs + 7) / 8,
			   "pdf_base_font_alloc(CIDSet)");
	if (pbfont->CIDSet == 0) {
	    code = gs_note_error(gs_error_VMerror);
	    goto fail;
	}
	memset(pbfont->CIDSet, 0, (pbfont->num_glyphs + 7) / 8);
	break;
    default:
	code = gs_note_error(gs_error_rangecheck);
	goto fail;
    }
    if (pbfont->do_subset != DO_SUBSET_YES) {
	/* The only possibly non-subsetted fonts are Type 1/2 and Type 42. */
	if (is_standard)
	    complete = copied, code = 0;
	else
	    code = gs_copy_font((gs_font *)font, &font->FontMatrix, mem, &complete);
	if (code >= 0)
	    code = gs_copy_font_complete((gs_font *)font, complete);
	if (pbfont->num_glyphs < 0) { /* Type 1 */
	    int index, count;
	    gs_glyph glyph;

	    for (index = 0, count = 0;
		 (font->procs.enumerate_glyph((gs_font *)font, &index,
					      GLYPH_SPACE_NAME, &glyph),
		  index != 0);
		 )
		++count;
	    pbfont->num_glyphs = count;
	}
    } else
	complete = copied;
    pbfont->copied = (gs_font_base *)copied;
    pbfont->complete = (gs_font_base *)complete;
    pbfont->is_standard = is_standard;
    if (pfname->size > 0) {
	font_name.data = pfname->chars;
	font_name.size = pfname->size;
	while (pdf_has_subset_prefix(font_name.data, font_name.size)) {
	    /* Strip off an existing subset prefix. */
	    font_name.data += SUBSET_PREFIX_SIZE;
	    font_name.size -= SUBSET_PREFIX_SIZE;
	}
    } else {
	sprintf(fnbuf, ".F%lx", (ulong)copied);
	font_name.data = (byte *)fnbuf;
	font_name.size = strlen(fnbuf);
    }
    pbfont->font_name.data =
	gs_alloc_string(mem, font_name.size, "pdf_base_font_alloc(font_name)");
    if (pbfont->font_name.data == 0)
	goto fail;
    memcpy(pbfont->font_name.data, font_name.data, font_name.size);
    pbfont->font_name.size = font_name.size;
    *ppbfont = pbfont;
    return 0;
 fail:
    gs_free_object(mem, pbfont, "pdf_base_font_alloc");
    return code;
}

/*
 * Return a reference to the name of a base font.  This name is guaranteed
 * not to have a XXXXXX+ prefix.  The client may change the name at will,
 * but must not add a XXXXXX+ prefix.
 */
gs_string *
pdf_base_font_name(pdf_base_font_t *pbfont)
{
    return &pbfont->font_name;
}

/*
 * Return the (copied, subset) font associated with a base font.
 * This procedure probably shouldn't exist....
 */
gs_font_base *
pdf_base_font_font(const pdf_base_font_t *pbfont, bool complete)
{
    return (complete ? pbfont->complete : pbfont->copied);
}

/*
 * Check for subset font.
 */
bool
pdf_base_font_is_subset(const pdf_base_font_t *pbfont)
{
    return pbfont->do_subset == DO_SUBSET_YES;
}

/*
 * Drop the copied complete font associated with a base font.
 */
void
pdf_base_font_drop_complete(pdf_base_font_t *pbfont)
{
    pbfont->complete = NULL;
}

/*
 * Copy a glyph (presumably one that was just used) into a saved base
 * font.  Note that it is the client's responsibility to determine that
 * the source font is compatible with the target font.  (Normally they
 * will be the same.)
 */
int
pdf_base_font_copy_glyph(pdf_base_font_t *pbfont, gs_glyph glyph,
			 gs_font_base *font)
{
    int code =
	gs_copy_glyph_options((gs_font *)font, glyph,
			      (gs_font *)pbfont->copied,
			      (pbfont->is_standard ? COPY_GLYPH_NO_NEW : 0));

    if (code < 0)
	return code;
    if (pbfont->CIDSet != 0 &&
	(uint)(glyph - GS_MIN_CID_GLYPH) < pbfont->num_glyphs
	) {
	uint cid = glyph - GS_MIN_CID_GLYPH;

	pbfont->CIDSet[cid >> 3] |= 0x80 >> (cid & 7);
    }
    return 0;
}

/*
 * Determine whether a font should be subsetted.
 */
bool
pdf_do_subset_font(gx_device_pdf *pdev, pdf_base_font_t *pbfont, gs_id rid)
{
    gs_font_base *copied = pbfont->copied;

    /*
     * If the decision has not been made already, determine whether or not
     * to subset the font.
     */
    if (pbfont->do_subset == DO_SUBSET_UNKNOWN) {
	int max_pct = pdev->params.MaxSubsetPct;
	bool do_subset = pdev->params.SubsetFonts && max_pct > 0;

	if (do_subset && max_pct < 100) {
	    /* We want to subset iff used <= total * MaxSubsetPct / 100. */
	    do_subset = false;
	    if (max_pct > 0) {
		int max_subset_used = pbfont->num_glyphs * max_pct / 100;
		int used, index;
		gs_glyph ignore_glyph;

		do_subset = true;
		for (index = 0, used = 0;
		     (copied->procs.enumerate_glyph((gs_font *)copied,
						&index, GLYPH_SPACE_INDEX,
						&ignore_glyph), index != 0);
		     )
		    if (++used > max_subset_used) {
			do_subset = false;
			break;
		    }
	    }
	}
	pbfont->do_subset = (do_subset ? DO_SUBSET_YES : DO_SUBSET_NO);
    }
    return (pbfont->do_subset == DO_SUBSET_YES);
}

/*
 * Write the FontFile entry for an embedded font, /FontFile<n> # # R.
 */
int
pdf_write_FontFile_entry(gx_device_pdf *pdev, pdf_base_font_t *pbfont)
{
    stream *s = pdev->strm;
    const char *FontFile_key;

    switch (pbfont->copied->FontType) {
    case ft_TrueType:
    case ft_CID_TrueType:
	FontFile_key = "/FontFile2";
	break;
    default:			/* Type 1/2, CIDFontType 0 */
	FontFile_key = "/FontFile3";
    }
    if (pbfont->FontFile_id == 0)
	pbfont->FontFile_id = pdf_obj_ref(pdev);
    stream_puts(s, FontFile_key);
    pprintld1(s, " %ld 0 R", pbfont->FontFile_id);
    return 0;
}

/*
 * Adjust font name for Acrobat Reader 3.
 */
private int
pdf_adjust_font_name(gx_device_pdf *pdev, long id, pdf_base_font_t *pbfont)
{
    /*
     * In contradiction with previous version of pdfwrite,
     * this always adds a suffix. We don't check the original name
     * for uniquity bacause the layered architecture
     * (see gdevpdtx.h) doesn't provide an easy access for
     * related information.
     */
    int i;
    byte *chars = (byte *)pbfont->font_name.data; /* break 'const' */
    byte *data;
    uint size = pbfont->font_name.size;
    char suffix[sizeof(long) * 2 + 2];
    uint suffix_size;

#define SUFFIX_CHAR '~'
    /*
     * If the name looks as though it has one of our unique suffixes,
     * remove the suffix.
     */
    for (i = size;
	 i > 0 && isxdigit(chars[i - 1]);
	 --i)
	DO_NOTHING;
    if (i < size && i > 0 && chars[i - 1] == SUFFIX_CHAR) {
	do {
	    --i;
	} while (i > 0 && chars[i - 1] == SUFFIX_CHAR);
	size = i + 1;
    }
    /* Create a unique name. */
    sprintf(suffix, "%c%lx", SUFFIX_CHAR, id);
    suffix_size = strlen(suffix);
    data = gs_resize_string(pdev->pdf_memory, chars, size,
				  size + suffix_size,
				  "pdf_adjust_font_name");
    if (data == 0)
	return_error(gs_error_VMerror);
    memcpy(data + size, (const byte *)suffix, suffix_size);
    pbfont->font_name.data = data;
    pbfont->font_name.size = size + suffix_size;
#undef SUFFIX_CHAR
    return 0;
}

/*
 * Write an embedded font.
 */
int
pdf_write_embedded_font(gx_device_pdf *pdev, pdf_base_font_t *pbfont,
			gs_int_rect *FontBBox, gs_id rid)
{
    bool do_subset = pdf_do_subset_font(pdev, pbfont, rid);
    gs_font_base *out_font =
	(do_subset || pbfont->complete == NULL ? pbfont->copied : pbfont->complete);
    long FontFile_id;
    gs_const_string fnstr;
    pdf_data_writer_t writer;
    int code;

    if (pbfont->written)
	return 0;		/* already written */
    if (pbfont->FontFile_id == 0)
	pbfont->FontFile_id = pdf_obj_ref(pdev);
    FontFile_id = pbfont->FontFile_id;
    if (pdev->CompatibilityLevel == 1.2 &&
	!do_subset && !pbfont->is_standard ) {
	/*
	 * Due to a bug in Acrobat Reader 3, we need to generate
	 * unique font names, except base 14 fonts being not embedded.
	 * To recognize base 14 fonts here we used the knowledge 
	 * that pbfont->is_standard is true for base 14 fonts only.
	 * Note that subsetted fonts already have an unique name
	 * due to subset prefix.
	 */
	 int code = pdf_adjust_font_name(pdev, FontFile_id, pbfont);
	 if (code < 0)
	    return code;
    }
    fnstr.data = pbfont->font_name.data;
    fnstr.size = pbfont->font_name.size;
    /* Now write the font (or subset). */
    switch (out_font->FontType) {

    case ft_composite:
	/* Nothing to embed -- the descendant fonts do it all. */
	code = 0;
	break;

    case ft_encrypted:
    case ft_encrypted2:
	code = copied_drop_extension_glyphs((gs_font *)out_font);
	if (code < 0)
	    return code;
	/*
	 * Since we only support PDF 1.2 and later, always write Type 1
	 * fonts as Type1C (Type 2).  Acrobat Reader apparently doesn't
	 * accept CFF fonts with Type 1 CharStrings, so we need to convert
	 * them.  Also remove lenIV, so Type 2 fonts will compress better.
	 */
#define TYPE2_OPTIONS (WRITE_TYPE2_NO_LENIV | WRITE_TYPE2_CHARSTRINGS)
	code = pdf_begin_fontfile(pdev, FontFile_id, "/Subtype/Type1C", -1L,
				  &writer);
	if (code < 0)
	    return code;
	code = psf_write_type2_font(writer.binary.strm,
				    (gs_font_type1 *)out_font,
				    TYPE2_OPTIONS |
			(pdev->CompatibilityLevel < 1.3 ? WRITE_TYPE2_AR3 : 0),
				    NULL, 0, &fnstr, FontBBox);
	goto finish;

    case ft_TrueType: {
	gs_font_type42 *const pfont = (gs_font_type42 *)out_font;
#define TRUETYPE_OPTIONS (WRITE_TRUETYPE_NAME | WRITE_TRUETYPE_HVMTX)
	/* Acrobat Reader 3 doesn't handle cmap format 6 correctly. */
	const int options = TRUETYPE_OPTIONS |
	    (pdev->CompatibilityLevel <= 1.2 ?
	     WRITE_TRUETYPE_NO_TRIMMED_TABLE : 0) |
	    /* Generate a cmap only for incrementally downloaded fonts
	       and for subsetted fonts. */
	    (pfont->data.numGlyphs != pfont->data.trueNumGlyphs || 
	     pbfont->do_subset == DO_SUBSET_YES ?
	     WRITE_TRUETYPE_CMAP : 0);
	stream poss;

	code = copied_drop_extension_glyphs((gs_font *)out_font);
	if (code < 0)
	    return code;
	swrite_position_only(&poss);
	code = psf_write_truetype_font(&poss, pfont, options, NULL, 0, &fnstr);
	if (code < 0)
	    return code;
	code = pdf_begin_fontfile(pdev, FontFile_id, NULL, stell(&poss),
				  &writer);
	if (code < 0)
	    return code;
	code = psf_write_truetype_font(writer.binary.strm, pfont,
				       options, NULL, 0, &fnstr);
	goto finish;
    }

    case ft_CID_encrypted:
	code = pdf_begin_fontfile(pdev, FontFile_id, "/Subtype/CIDFontType0C",
				  -1L, &writer);
	if (code < 0)
	    return code;
	code = psf_write_cid0_font(writer.binary.strm,
				   (gs_font_cid0 *)out_font, TYPE2_OPTIONS,
				   NULL, 0, &fnstr);
	goto finish;

    case ft_CID_TrueType:
	/* CIDFontType 2 fonts don't use cmap, name, OS/2, or post. */
#define CID2_OPTIONS WRITE_TRUETYPE_HVMTX
	code = pdf_begin_fontfile(pdev, FontFile_id, NULL, -1L, &writer);
	if (code < 0)
	    return code;
	code = psf_write_cid2_font(writer.binary.strm,
				   (gs_font_cid2 *)out_font,
				   CID2_OPTIONS, NULL, 0, &fnstr);
    finish:
	if (code < 0) {
	    pdf_end_fontfile(pdev, &writer);
	    return code;
	}
	code = pdf_end_fontfile(pdev, &writer);
	break;

    default:
	code = gs_note_error(gs_error_rangecheck);
    }

    pbfont->written = true;
    return code;
}

/*
 * Write the CharSet for a subsetted font, as a PDF string.
 */
int
pdf_write_CharSet(gx_device_pdf *pdev, pdf_base_font_t *pbfont)
{
    stream *s = pdev->strm;
    gs_font_base *font = pbfont->copied;
    int index;
    gs_glyph glyph;

    stream_puts(s, "(");
    for (index = 0;
	 (font->procs.enumerate_glyph((gs_font *)font, &index,
				      GLYPH_SPACE_NAME, &glyph),
	  index != 0);
	 ) {
	gs_const_string gstr;
	int code = font->procs.glyph_name((gs_font *)font, glyph, &gstr);

	/* Don't include .notdef. */
	if (code >= 0 &&
	    bytes_compare(gstr.data, gstr.size, (const byte *)".notdef", 7)
	    )
	    pdf_put_name(pdev, gstr.data, gstr.size);
    }
    stream_puts(s, ")");
    return 0;
}

/*
 * Write the CIDSet object for a subsetted CIDFont.
 */
int
pdf_write_CIDSet(gx_device_pdf *pdev, pdf_base_font_t *pbfont,
		 long *pcidset_id)
{
    pdf_data_writer_t writer;
    long cidset_id = pdf_begin_separate(pdev);
    int code; 
    stream *s = pdev->strm;

    stream_puts(s, "<<");
    code = pdf_begin_data(pdev, &writer);
    if (code >= 0) {
	stream_write(writer.binary.strm, pbfont->CIDSet,
		     (pbfont->num_glyphs + 7) / 8);
	code = pdf_end_data(&writer);
	if (code >= 0) {
	    *pcidset_id = cidset_id;
	    return code;
	}
    }
    /* code < 0 */
    pdf_end_separate(pdev);
    return code;
}

/*
 * Check whether a base font is standard.
 */
bool
pdf_is_standard_font(pdf_base_font_t *bfont)
{   return bfont->is_standard;
}
