// Copyright (C) 2004-2022 Artifex Software, Inc.

//

// This file is part of MuPDF.

//

// MuPDF is free software: you can redistribute it and/or modify it under the

// terms of the GNU Affero General Public License as published by the Free

// Software Foundation, either version 3 of the License, or (at your option)

// any later version.

//

// MuPDF 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 Affero General Public License for more

// details.

//

// You should have received a copy of the GNU Affero General Public License

// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>

//

// Alternative licensing terms are available from the licensor.

// For commercial licensing, see <https://www.artifex.com/> or contact

// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,

// CA 94129, USA, for further information.

#include "mupdf/fitz.h"

#include <float.h>

fz_display_list *

fz_new_display_list_from_page(fz_context *ctx, fz_page *page)

{

  fz_display_list *list;

  fz_device *dev = NULL;

  fz_var(dev);

  list = fz_new_display_list(ctx, fz_bound_page(ctx, page));

  fz_try(ctx)

  {

    dev = fz_new_list_device(ctx, list);

    fz_run_page(ctx, page, dev, fz_identity, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_display_list(ctx, list);

    fz_rethrow(ctx);

  }

  return list;

}

fz_display_list *

fz_new_display_list_from_page_number(fz_context *ctx, fz_document *doc, int number)

{

  fz_page *page;

  fz_display_list *list = NULL;

  page = fz_load_page(ctx, doc, number);

  fz_try(ctx)

    list = fz_new_display_list_from_page(ctx, page);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return list;

}

fz_display_list *

fz_new_display_list_from_page_contents(fz_context *ctx, fz_page *page)

{

  fz_display_list *list;

  fz_device *dev = NULL;

  fz_var(dev);

  list = fz_new_display_list(ctx, fz_bound_page(ctx, page));

  fz_try(ctx)

  {

    dev = fz_new_list_device(ctx, list);

    fz_run_page_contents(ctx, page, dev, fz_identity, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_display_list(ctx, list);

    fz_rethrow(ctx);

  }

  return list;

}

fz_pixmap *

fz_new_pixmap_from_display_list(fz_context *ctx, fz_display_list *list, fz_matrix ctm, fz_colorspace *cs, int alpha)

{

  return fz_new_pixmap_from_display_list_with_separations(ctx, list, ctm, cs, NULL, alpha);

}

fz_pixmap *

fz_new_pixmap_from_display_list_with_separations(fz_context *ctx, fz_display_list *list, fz_matrix ctm, fz_colorspace *cs, fz_separations *seps, int alpha)

{

  fz_rect rect;

  fz_irect bbox;

  fz_pixmap *pix;

  rect = fz_bound_display_list(ctx, list);

  rect = fz_transform_rect(rect, ctm);

  bbox = fz_round_rect(rect);

  pix = fz_new_pixmap_with_bbox(ctx, cs, bbox, seps, alpha);

  if (alpha)

    fz_clear_pixmap(ctx, pix);

  else

    fz_clear_pixmap_with_value(ctx, pix, 0xFF);

  return fz_fill_pixmap_from_display_list(ctx, list, ctm, pix);

}

fz_pixmap *

fz_fill_pixmap_from_display_list(fz_context *ctx, fz_display_list *list, fz_matrix ctm, fz_pixmap *pix)

{

  fz_device *dev = NULL;

  fz_var(dev);

  fz_try(ctx)

  {

    dev = fz_new_draw_device(ctx, ctm, pix);

    fz_run_display_list(ctx, list, dev, fz_identity, fz_infinite_rect, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_pixmap(ctx, pix);

    fz_rethrow(ctx);

  }

  return pix;

}

fz_pixmap *

fz_new_pixmap_from_page_contents(fz_context *ctx, fz_page *page, fz_matrix ctm, fz_colorspace *cs, int alpha)

{

  return fz_new_pixmap_from_page_contents_with_separations(ctx, page, ctm, cs, NULL, alpha);

}

fz_pixmap *

fz_new_pixmap_from_page_contents_with_separations(fz_context *ctx, fz_page *page, fz_matrix ctm, fz_colorspace *cs, fz_separations *seps, int alpha)

{

  fz_rect rect;

  fz_irect bbox;

  fz_pixmap *pix;

  fz_device *dev = NULL;

  fz_var(dev);

  rect = fz_bound_page(ctx, page);

  rect = fz_transform_rect(rect, ctm);

  bbox = fz_round_rect(rect);

  pix = fz_new_pixmap_with_bbox(ctx, cs, bbox, seps, alpha);

  if (alpha)

    fz_clear_pixmap(ctx, pix);

  else

    fz_clear_pixmap_with_value(ctx, pix, 0xFF);

  fz_try(ctx)

  {

    dev = fz_new_draw_device(ctx, ctm, pix);

    fz_run_page_contents(ctx, page, dev, fz_identity, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_pixmap(ctx, pix);

    fz_rethrow(ctx);

  }

  return pix;

}

fz_pixmap *

fz_new_pixmap_from_page(fz_context *ctx, fz_page *page, fz_matrix ctm, fz_colorspace *cs, int alpha)

{

  return fz_new_pixmap_from_page_with_separations(ctx, page, ctm, cs, NULL, alpha);

}

fz_pixmap *

fz_new_pixmap_from_page_with_separations(fz_context *ctx, fz_page *page, fz_matrix ctm, fz_colorspace *cs, fz_separations *seps, int alpha)

{

  fz_rect rect;

  fz_irect bbox;

  fz_pixmap *pix;

  fz_device *dev = NULL;

  fz_var(dev);

  rect = fz_bound_page(ctx, page);

  rect = fz_transform_rect(rect, ctm);

  bbox = fz_round_rect(rect);

  pix = fz_new_pixmap_with_bbox(ctx, cs, bbox, seps, alpha);

  fz_try(ctx)

  {

    if (alpha)

      fz_clear_pixmap(ctx, pix);

    else

      fz_clear_pixmap_with_value(ctx, pix, 0xFF);

    dev = fz_new_draw_device(ctx, ctm, pix);

    fz_run_page(ctx, page, dev, fz_identity, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_pixmap(ctx, pix);

    fz_rethrow(ctx);

  }

  return pix;

}

fz_pixmap *

fz_new_pixmap_from_page_number(fz_context *ctx, fz_document *doc, int number, fz_matrix ctm, fz_colorspace *cs, int alpha)

{

  return fz_new_pixmap_from_page_number_with_separations(ctx, doc, number, ctm, cs, NULL, alpha);

}

fz_pixmap *

fz_new_pixmap_from_page_number_with_separations(fz_context *ctx, fz_document *doc, int number, fz_matrix ctm, fz_colorspace *cs, fz_separations *seps, int alpha)

{

  fz_page *page;

  fz_pixmap *pix = NULL;

  page = fz_load_page(ctx, doc, number);

  fz_try(ctx)

    pix = fz_new_pixmap_from_page_with_separations(ctx, page, ctm, cs, seps, alpha);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return pix;

}

fz_stext_page *

fz_new_stext_page_from_display_list(fz_context *ctx, fz_display_list *list, const fz_stext_options *options)

{

  fz_stext_page *text;

  fz_device *dev = NULL;

  fz_var(dev);

  if (list == NULL)

    return NULL;

  text = fz_new_stext_page(ctx, fz_bound_display_list(ctx, list));

  fz_try(ctx)

  {

    dev = fz_new_stext_device(ctx, text, options);

    fz_run_display_list(ctx, list, dev, fz_identity, fz_infinite_rect, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_stext_page(ctx, text);

    fz_rethrow(ctx);

  }

  return text;

}

fz_stext_page *

fz_new_stext_page_from_page(fz_context *ctx, fz_page *page, const fz_stext_options *options)

{

  fz_stext_page *text;

  fz_device *dev = NULL;

  fz_var(dev);

  if (page == NULL)

    return NULL;

  text = fz_new_stext_page(ctx, fz_bound_page(ctx, page));

  fz_try(ctx)

  {

    dev = fz_new_stext_device(ctx, text, options);

    fz_run_page_contents(ctx, page, dev, fz_identity, NULL);

    fz_close_device(ctx, dev);

  }

  fz_always(ctx)

  {

    fz_drop_device(ctx, dev);

  }

  fz_catch(ctx)

  {

    fz_drop_stext_page(ctx, text);

    fz_rethrow(ctx);

  }

  return text;

}

fz_stext_page *

fz_new_stext_page_from_page_number(fz_context *ctx, fz_document *doc, int number, const fz_stext_options *options)

{

  fz_page *page;

  fz_stext_page *text = NULL;

  page = fz_load_page(ctx, doc, number);

  fz_try(ctx)

    text = fz_new_stext_page_from_page(ctx, page, options);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return text;

}

fz_stext_page *

fz_new_stext_page_from_chapter_page_number(fz_context *ctx, fz_document *doc, int chapter, int number, const fz_stext_options *options)

{

  fz_page *page;

  fz_stext_page *text = NULL;

  page = fz_load_chapter_page(ctx, doc, chapter, number);

  fz_try(ctx)

    text = fz_new_stext_page_from_page(ctx, page, options);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return text;

}

int

fz_search_display_list(fz_context *ctx, fz_display_list *list, const char *needle, int *hit_mark, fz_quad *hit_bbox, int hit_max)

{

  fz_stext_page *text;

  int count = 0;

  text = fz_new_stext_page_from_display_list(ctx, list, NULL);

  fz_try(ctx)

    count = fz_search_stext_page(ctx, text, needle, hit_mark, hit_bbox, hit_max);

  fz_always(ctx)

    fz_drop_stext_page(ctx, text);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return count;

}

int

fz_search_page(fz_context *ctx, fz_page *page, const char *needle, int *hit_mark, fz_quad *hit_bbox, int hit_max)

{

  fz_stext_options opts = { FZ_STEXT_DEHYPHENATE };

  fz_stext_page *text;

  int count = 0;

  text = fz_new_stext_page_from_page(ctx, page, &opts);

  fz_try(ctx)

    count = fz_search_stext_page(ctx, text, needle, hit_mark, hit_bbox, hit_max);

  fz_always(ctx)

    fz_drop_stext_page(ctx, text);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return count;

}

int

fz_search_page_number(fz_context *ctx, fz_document *doc, int number, const char *needle, int *hit_mark, fz_quad *hit_bbox, int hit_max)

{

  fz_page *page;

  int count = 0;

  page = fz_load_page(ctx, doc, number);

  fz_try(ctx)

    count = fz_search_page(ctx, page, needle, hit_mark, hit_bbox, hit_max);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return count;

}

int

fz_search_chapter_page_number(fz_context *ctx, fz_document *doc, int chapter, int number, const char *needle, int *hit_mark, fz_quad *hit_bbox, int hit_max)

{

  fz_page *page;

  int count = 0;

  page = fz_load_chapter_page(ctx, doc, chapter, number);

  fz_try(ctx)

    count = fz_search_page(ctx, page, needle, hit_mark, hit_bbox, hit_max);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return count;

}

fz_buffer *

fz_new_buffer_from_stext_page(fz_context *ctx, fz_stext_page *page)

{

  fz_stext_block *block;

  fz_stext_line *line;

  fz_stext_char *ch;

  fz_buffer *buf;

  buf = fz_new_buffer(ctx, 256);

  fz_try(ctx)

  {

    for (block = page->first_block; block; block = block->next)

    {

      if (block->type == FZ_STEXT_BLOCK_TEXT)

      {

        for (line = block->u.t.first_line; line; line = line->next)

        {

          for (ch = line->first_char; ch; ch = ch->next)

            fz_append_rune(ctx, buf, ch->c);

          fz_append_byte(ctx, buf, '\n');

        }

        fz_append_byte(ctx, buf, '\n');

      }

    }

  }

  fz_catch(ctx)

  {

    fz_drop_buffer(ctx, buf);

    fz_rethrow(ctx);

  }

  return buf;

}

fz_buffer *

fz_new_buffer_from_display_list(fz_context *ctx, fz_display_list *list, const fz_stext_options *options)

{

  fz_stext_page *text;

  fz_buffer *buf = NULL;

  text = fz_new_stext_page_from_display_list(ctx, list, options);

  fz_try(ctx)

    buf = fz_new_buffer_from_stext_page(ctx, text);

  fz_always(ctx)

    fz_drop_stext_page(ctx, text);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return buf;

}

fz_buffer *

fz_new_buffer_from_page(fz_context *ctx, fz_page *page, const fz_stext_options *options)

{

  fz_stext_page *text;

  fz_buffer *buf = NULL;

  text = fz_new_stext_page_from_page(ctx, page, options);

  fz_try(ctx)

    buf = fz_new_buffer_from_stext_page(ctx, text);

  fz_always(ctx)

    fz_drop_stext_page(ctx, text);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return buf;

}

fz_buffer *

fz_new_buffer_from_page_number(fz_context *ctx, fz_document *doc, int number, const fz_stext_options *options)

{

  fz_page *page;

  fz_buffer *buf = NULL;

  page = fz_load_page(ctx, doc, number);

  fz_try(ctx)

    buf = fz_new_buffer_from_page(ctx, page, options);

  fz_always(ctx)

    fz_drop_page(ctx, page);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return buf;

}

void

fz_write_image_as_data_uri(fz_context *ctx, fz_output *out, fz_image *image)

{

  fz_compressed_buffer *cbuf;

  fz_buffer *buf;

  cbuf = fz_compressed_image_buffer(ctx, image);

  if (cbuf && cbuf->params.type == FZ_IMAGE_JPEG)

  {

    int type = fz_colorspace_type(ctx, image->colorspace);

    if (type == FZ_COLORSPACE_GRAY || type == FZ_COLORSPACE_RGB)

    {

      fz_write_string(ctx, out, "data:image/jpeg;base64,");

      fz_write_base64_buffer(ctx, out, cbuf->buffer, 1);

      return;

    }

  }

  if (cbuf && cbuf->params.type == FZ_IMAGE_PNG)

  {

    fz_write_string(ctx, out, "data:image/png;base64,");

    fz_write_base64_buffer(ctx, out, cbuf->buffer, 1);

    return;

  }

  buf = fz_new_buffer_from_image_as_png(ctx, image, fz_default_color_params);

  fz_try(ctx)

  {

    fz_write_string(ctx, out, "data:image/png;base64,");

    fz_write_base64_buffer(ctx, out, buf, 1);

  }

  fz_always(ctx)

    fz_drop_buffer(ctx, buf);

  fz_catch(ctx)

    fz_rethrow(ctx);

}

static uint32_t read16(const uint8_t *d, size_t *pos, size_t len, int order)

{

  size_t p = *pos;

  uint32_t v;

  if (p+1 >= len)

  {

    *pos = len;

    return 0;

  }

  if (order)

  {

    v = d[p++]<<8; /* BE */

    v |= d[p++];

  }

  else

  {

    v = d[p++]; /* LE */

    v |= d[p++]<<8;

  }

  *pos = p;

  return v;

}

static uint32_t read32(const uint8_t *d, size_t *pos, size_t len, int order)

{

  size_t p = *pos;

  uint32_t v;

  if (p+3 >= len)

  {

    *pos = len;

    return 0;

  }

  if (order)

  {

    v = d[p++]<<24; /* BE */

    v |= d[p++]<<16;

    v |= d[p++]<<8;

    v |= d[p++];

  }

  else

  {

    v = d[p++];

    v |= d[p++]<<8; /* LE */

    v |= d[p++]<<16;

    v |= d[p++]<<24;

  }

  *pos = p;

  return v;

}

static void write16(uint8_t *d, size_t *pos, size_t len, int order, uint32_t v)

{

  size_t p = *pos;

  if (p+1 >= len)

  {

    *pos = len;

    return;

  }

  if (order)

  {

    d[p++] = (v>>8);

    d[p++] = v;

  }

  else

  {

    d[p++] = v;

    d[p++] = (v>>8);

  }

  *pos = p;

}

static void write32( uint8_t *d, size_t *pos, size_t len, int order, uint32_t v)

{

  size_t p = *pos;

  if (p+3 >= len)

  {

    *pos = len;

    return;

  }

  if (order)

  {

    d[p++] = (v>>24);

    d[p++] = (v>>16);

    d[p++] = (v>>8);

    d[p++] = v;

  }

  else

  {

    d[p++] = v;

    d[p++] = (v>>8);

    d[p++] = (v>>16);

    d[p++] = (v>>24);

  }

  *pos = p;

}

fz_buffer *

fz_sanitize_jpeg_buffer(fz_context *ctx, fz_buffer *in)

{

  fz_buffer *out = fz_clone_buffer(ctx, in);

  size_t len = out->len;

  size_t pos = 0;

  uint8_t *d = out->data;

  /* We need at least 4 data bytes. */

  while (pos+4 < len)

  {

    uint8_t m;

    /* We should be on a marker. If not, inch forwards until we are. */

    if (d[pos++] != 0xff)

      continue;

    m = d[pos++];

    if (m == 0xDA)

      break; /* Start Of Scan. All our rewriting happens before this. */

    if (m == 0xE1)

    {

      uint8_t order;

      uint32_t tmp;

      size_t body_start;

      /* APP1 tag. This is where the EXIF data lives. */

      /* Read and discard the marker length. We're not continuing after this anyway. */

      (void)read16(d, &pos, len, 0);

      tmp = read32(d, &pos, len, 0);

      if (tmp != 0x66697845) /* Exif */

        break; /* Not exif - nothing to rewrite. */

      tmp = read16(d, &pos, len, 0);

      if (tmp != 0) /* Terminator + Pad */

        break; /* Not exif - nothing to rewrite. */

      /* Now we're at the APP1 Body. */

      body_start = pos;

      tmp = read16(d, &pos, len, 0);

      if (tmp == 0x4949)

        order = 0; /* LE */

      else if (tmp == 0x4d4d)

        order = 1; /* BE */

      else

        break; /* Bad TIFF type. Bale. */

      tmp = read16(d, &pos, len, order);

      if (tmp != 0x002a) /* 42 */

        break; /* Bad version field.  Bale. */

      do

      {

        uint32_t i, n;

        tmp = read32(d, &pos, len, order);

        pos = body_start + tmp;

        if (tmp == 0 || pos >= len)

          break;

        n = read16(d, &pos, len, order);

        for (i = 0; i < n; i++)

        {

          if (read16(d, &pos, len, order) == 0x112)

          {

            /* Orientation tag! */

            write16(d, &pos, len, order, 3); /* 3 = short */

            write32(d, &pos, len, order, 1); /* Count = 1 */

            write16(d, &pos, len, order, 1); /* Value = 1 */

            write16(d, &pos, len, order, 0); /* padding */

            i = n;

            pos = len; /* Done! */

          }

          else

            pos += 10;

        }

      }

      while (pos+4 < len);

      break;

    }

    else if (m >= 0xD0 && m <= 0xD7)

    {

      /* RSTm - no length code. But we shouldn't hit this! */

    }

    else if (m == 0x01)

    {

      /* TEM - temporary private use in arithmetic coding - shouldn't hit this either. */

    }

    else if (m == 0xD8)

    {

      /* SOI - start of image. */

    }

    else if (m == 0x01)

    {

      /* EOI - end of image. */

    }

    else

    {

      /* All other markers have a length. */

      size_t marker_len = d[pos]*256 + d[pos+1];

      pos += marker_len; /* The 2 length bytes are included in the marker_len */

    }

  }

  return out;

}

void

fz_append_image_as_data_uri(fz_context *ctx, fz_buffer *out, fz_image *image)

{

  fz_compressed_buffer *cbuf;

  fz_buffer *buf;

  cbuf = fz_compressed_image_buffer(ctx, image);

  if (cbuf && cbuf->params.type == FZ_IMAGE_JPEG)

  {

    int type = fz_colorspace_type(ctx, image->colorspace);

    if (type == FZ_COLORSPACE_GRAY || type == FZ_COLORSPACE_RGB)

    {

      fz_buffer *new_buf = fz_sanitize_jpeg_buffer(ctx, cbuf->buffer);

      fz_append_string(ctx, out, "data:image/jpeg;base64,");

      fz_try(ctx)

        fz_append_base64_buffer(ctx, out, new_buf, 1);

      fz_always(ctx)

        fz_drop_buffer(ctx, new_buf);

      fz_catch(ctx)

        fz_rethrow(ctx);

      return;

    }

  }

  if (cbuf && cbuf->params.type == FZ_IMAGE_PNG)

  {

    fz_append_string(ctx, out, "data:image/png;base64,");

    fz_append_base64_buffer(ctx, out, cbuf->buffer, 1);

    return;

  }

  buf = fz_new_buffer_from_image_as_png(ctx, image, fz_default_color_params);

  fz_try(ctx)

  {

    fz_append_string(ctx, out, "data:image/png;base64,");

    fz_append_base64_buffer(ctx, out, buf, 1);

  }

  fz_always(ctx)

    fz_drop_buffer(ctx, buf);

  fz_catch(ctx)

    fz_rethrow(ctx);

}

void

fz_write_pixmap_as_data_uri(fz_context *ctx, fz_output *out, fz_pixmap *pixmap)

{

  fz_buffer *buf = fz_new_buffer_from_pixmap_as_png(ctx, pixmap, fz_default_color_params);

  fz_try(ctx)

  {

    fz_write_string(ctx, out, "data:image/png;base64,");

    fz_write_base64_buffer(ctx, out, buf, 1);

  }

  fz_always(ctx)

    fz_drop_buffer(ctx, buf);

  fz_catch(ctx)

    fz_rethrow(ctx);

}

void

fz_append_pixmap_as_data_uri(fz_context *ctx, fz_buffer *out, fz_pixmap *pixmap)

{

  fz_buffer *buf = fz_new_buffer_from_pixmap_as_png(ctx, pixmap, fz_default_color_params);

  fz_try(ctx)

  {

    fz_append_string(ctx, out, "data:image/png;base64,");

    fz_append_base64_buffer(ctx, out, buf, 1);

  }

  fz_always(ctx)

    fz_drop_buffer(ctx, buf);

  fz_catch(ctx)

    fz_rethrow(ctx);

}

fz_document *

fz_new_xhtml_document_from_document(fz_context *ctx, fz_document *old_doc, const fz_stext_options *opts)

{

  fz_stext_options default_opts = { FZ_STEXT_PRESERVE_IMAGES | FZ_STEXT_DEHYPHENATE };

  fz_document *new_doc;

  fz_buffer *buf = NULL;

  fz_output *out = NULL;

  fz_stream *stm = NULL;

  fz_stext_page *text = NULL;

  int i;

  fz_var(buf);

  fz_var(out);

  fz_var(stm);

  fz_var(text);

  if (!opts)

    opts = &default_opts;

  fz_try(ctx)

  {

    buf = fz_new_buffer(ctx, 8192);

    out = fz_new_output_with_buffer(ctx, buf);

    fz_print_stext_header_as_xhtml(ctx, out);

    for (i = 0; i < fz_count_pages(ctx, old_doc); ++i)

    {

      text = fz_new_stext_page_from_page_number(ctx, old_doc, i, opts);

      fz_print_stext_page_as_xhtml(ctx, out, text, i+1);

      fz_drop_stext_page(ctx, text);

      text = NULL;

    }

    fz_print_stext_trailer_as_xhtml(ctx, out);

    fz_close_output(ctx, out);

    fz_terminate_buffer(ctx, buf);

    stm = fz_open_buffer(ctx, buf);

    new_doc = fz_open_document_with_stream(ctx, "application/xhtml+xml", stm);

  }

  fz_always(ctx)

  {

    fz_drop_stream(ctx, stm);

    fz_drop_buffer(ctx, buf);

    fz_drop_output(ctx, out);

    fz_drop_stext_page(ctx, text);

  }

  fz_catch(ctx)

    fz_rethrow(ctx);

  return new_doc;

}