// Copyright (C) 2004-2025 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 "mupdf/pdf.h"

#include <zlib.h> /* for crc32 */

#include <string.h>

static void pdf_drop_obj_as_void(fz_context *ctx, void *obj)

{

  pdf_drop_obj(ctx, obj);

}

/* We do need to come up with an effective way to see what is already in the

 * file to avoid adding to what is already there. This is avoided for pdfwrite

 * as we check as we add each font. For adding text to an existing file though

 * it may be more problematic. */

pdf_obj *

pdf_find_font_resource(fz_context *ctx, pdf_document *doc, int type, int encoding, fz_font *item, pdf_font_resource_key *key)

{

  pdf_obj *res;

  if (!doc->resources.fonts)

    doc->resources.fonts = fz_new_hash_table(ctx, 4096, sizeof(*key), -1, pdf_drop_obj_as_void);

  memset(key, 0, sizeof(*key));

  fz_font_digest(ctx, item, key->digest);

  key->type = type;

  key->encoding = encoding;

  key->local_xref = doc->local_xref_nesting > 0;

  res = fz_hash_find(ctx, doc->resources.fonts, (void *)key);

  if (res)

    pdf_keep_obj(ctx, res);

  return res;

}

pdf_obj *

pdf_find_colorspace_resource(fz_context *ctx, pdf_document *doc, fz_colorspace *item, pdf_colorspace_resource_key *key)

{

  pdf_obj *res;

  if (!doc->resources.colorspaces)

    doc->resources.colorspaces = fz_new_hash_table(ctx, 4096, sizeof(*key), -1, pdf_drop_obj_as_void);

  memset(key, 0, sizeof(*key));

  fz_colorspace_digest(ctx, item, key->digest);

  key->local_xref = doc->local_xref_nesting > 0;

  res = fz_hash_find(ctx, doc->resources.colorspaces, (void *)key);

  if (res)

    pdf_keep_obj(ctx, res);

  return res;

}

pdf_obj *

pdf_find_image_resource(fz_context *ctx, pdf_document *doc, fz_image *item, pdf_image_resource_key *key)

{

  pdf_obj *res;

  if (!doc->resources.images)

    doc->resources.images = fz_new_hash_table(ctx, 4096, sizeof(*key), -1, pdf_drop_obj_as_void);

  memset(key, 0, sizeof(*key));

  key->w = item->w;

  key->h = item->h;

  key->n = item->n;

  key->bpc = item->bpc;

  key->imagemask = item->imagemask;

  key->use_colorkey = item->use_colorkey;

  key->use_decode = item->use_decode;

  key->decode = crc32(0, (unsigned char *)item->decode, 2 * item->n * sizeof(float));

  key->decode = crc32(key->decode, (unsigned char *)item->colorkey, 2 * item->n * sizeof(int));

  if (item->mask)

    fz_image_digest(ctx, item->mask, key->mask);

  fz_image_digest(ctx, item, key->digest);

  key->local_xref = doc->local_xref_nesting > 0;

  res = fz_hash_find(ctx, doc->resources.images, (void *)key);

  if (res)

    pdf_keep_obj(ctx, res);

  return res;

}

pdf_obj *

pdf_insert_font_resource(fz_context *ctx, pdf_document *doc, pdf_font_resource_key *key, pdf_obj *obj)

{

  pdf_obj *res = fz_hash_insert(ctx, doc->resources.fonts, (void *)key, obj);

  if (res)

    fz_warn(ctx, "warning: font resource already present");

  else

    res = pdf_keep_obj(ctx, obj);

  return pdf_keep_obj(ctx, res);

}

pdf_obj *

pdf_insert_colorspace_resource(fz_context *ctx, pdf_document *doc, pdf_colorspace_resource_key *key, pdf_obj *obj)

{

  pdf_obj *res = fz_hash_insert(ctx, doc->resources.colorspaces, (void *)key, obj);

  if (res)

    fz_warn(ctx, "warning: colorspace resource already present");

  else

    res = pdf_keep_obj(ctx, obj);

  return pdf_keep_obj(ctx, res);

}

pdf_obj *

pdf_insert_image_resource(fz_context *ctx, pdf_document *doc, pdf_image_resource_key *key, pdf_obj *obj)

{

  pdf_obj *res = fz_hash_insert(ctx, doc->resources.images, (void *)key, obj);

  if (res)

    fz_warn(ctx, "warning: image resource already present");

  else

    res = pdf_keep_obj(ctx, obj);

  return pdf_keep_obj(ctx, res);

}

static int purge_local_font_resource(fz_context *ctx, void *state, void *key_, int keylen, void *val)

{

  pdf_font_resource_key *key = key_;

  if (key->local_xref)

  {

    pdf_drop_obj(ctx, val);

    return 1;

  }

  return 0;

}

static int purge_local_colorspace_resource(fz_context *ctx, void *state, void *key_, int keylen, void *val)

{

  pdf_colorspace_resource_key *key = key_;

  if (key->local_xref)

  {

    pdf_drop_obj(ctx, val);

    return 1;

  }

  return 0;

}

static int purge_local_image_resource(fz_context *ctx, void *state, void *key_, int keylen, void *val)

{

  pdf_image_resource_key *key = key_;

  if (key->local_xref)

  {

    pdf_drop_obj(ctx, val);

    return 1;

  }

  return 0;

}

void

pdf_purge_local_resources(fz_context *ctx, pdf_document *doc)

{

  if (doc->resources.fonts)

    fz_hash_filter(ctx, doc->resources.fonts, NULL, purge_local_font_resource);

  if (doc->resources.colorspaces)

    fz_hash_filter(ctx, doc->resources.colorspaces, NULL, purge_local_colorspace_resource);

  if (doc->resources.images)

    fz_hash_filter(ctx, doc->resources.images, NULL, purge_local_image_resource);

}

void

pdf_drop_resource_tables(fz_context *ctx, pdf_document *doc)

{

  if (doc)

  {

    fz_drop_hash_table(ctx, doc->resources.colorspaces);

    fz_drop_hash_table(ctx, doc->resources.fonts);

    fz_drop_hash_table(ctx, doc->resources.images);

  }

}