// Copyright (C) 2004-2021 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 <string.h>

/*

 * CMap parser

 */

static int

is_keyword(pdf_token tok, pdf_lexbuf *buf, const char *word)

{

  /* Ignore trailing garbage when matching keywords */

  return (tok == PDF_TOK_KEYWORD && !strncmp(buf->scratch, word, strlen(word)));

}

static void

skip_to_keyword(fz_context *ctx, fz_stream *file, pdf_lexbuf *buf, const char *end, const char *warn)

{

  fz_warn(ctx, "%s", warn);

  for (;;)

  {

    pdf_token tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, end))

      return;

    if (tok == PDF_TOK_ERROR)

      return;

    if (tok == PDF_TOK_EOF)

      return;

  }

}

static void

skip_to_token(fz_context *ctx, fz_stream *file, pdf_lexbuf *buf, pdf_token end, const char *warn)

{

  fz_warn(ctx, "%s", warn);

  for (;;)

  {

    pdf_token tok = pdf_lex(ctx, file, buf);

    if (tok == end)

      return;

    if (tok == PDF_TOK_ERROR)

      return;

    if (tok == PDF_TOK_EOF)

      return;

  }

}

static int

pdf_code_from_string(char *buf, size_t len)

{

  unsigned int a = 0;

  while (len--)

    a = (a << 8) | *(unsigned char *)buf++;

  return a;

}

static void

pdf_parse_cmap_name(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  tok = pdf_lex(ctx, file, buf);

  if (tok == PDF_TOK_NAME)

    fz_strlcpy(cmap->cmap_name, buf->scratch, sizeof(cmap->cmap_name));

  else

    fz_warn(ctx, "expected name after CMapName in cmap");

}

static void

pdf_parse_wmode(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  tok = pdf_lex(ctx, file, buf);

  if (tok == PDF_TOK_INT)

    pdf_set_cmap_wmode(ctx, cmap, buf->i);

  else

    fz_warn(ctx, "expected integer after WMode in cmap");

}

static void

pdf_parse_codespace_range(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  int lo, hi;

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, "endcodespacerange"))

      return;

    else if (tok == PDF_TOK_STRING)

    {

      lo = pdf_code_from_string(buf->scratch, buf->len);

      tok = pdf_lex(ctx, file, buf);

      if (tok == PDF_TOK_STRING)

      {

        hi = pdf_code_from_string(buf->scratch, buf->len);

        pdf_add_codespace(ctx, cmap, lo, hi, buf->len);

      }

      else

      {

        skip_to_keyword(ctx, file, buf, "endcodespacerange", "expected string or endcodespacerange");

        return;

      }

    }

    else

    {

      skip_to_keyword(ctx, file, buf, "endcodespacerange", "expected string or endcodespacerange");

      return;

    }

  }

}

static void

pdf_parse_cid_range(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  int lo, hi, dst;

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, "endcidrange"))

      return;

    else if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endcidrange", "expected string or endcidrange");

      return;

    }

    lo = pdf_code_from_string(buf->scratch, buf->len);

    tok = pdf_lex(ctx, file, buf);

    if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endcidrange", "expected string");

      return;

    }

    hi = pdf_code_from_string(buf->scratch, buf->len);

    tok = pdf_lex(ctx, file, buf);

    if (tok != PDF_TOK_INT)

    {

      skip_to_keyword(ctx, file, buf, "endcidrange", "expected integer");

      return;

    }

    dst = buf->i;

    pdf_map_range_to_range(ctx, cmap, lo, hi, dst);

  }

}

static void

pdf_parse_cid_char(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  int src, dst;

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, "endcidchar"))

      return;

    else if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endcidchar", "expected string or endcidchar");

      return;

    }

    src = pdf_code_from_string(buf->scratch, buf->len);

    tok = pdf_lex(ctx, file, buf);

    if (tok != PDF_TOK_INT)

    {

      skip_to_keyword(ctx, file, buf, "endcidchar", "expected integer");

      return;

    }

    dst = buf->i;

    pdf_map_range_to_range(ctx, cmap, src, src, dst);

  }

}

static void

pdf_parse_bf_range_array(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf, int lo, int hi)

{

  pdf_token tok;

  int dst[PDF_MRANGE_CAP];

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (tok == PDF_TOK_CLOSE_ARRAY)

      return;

    /* Note: does not handle [ /Name /Name ... ] */

    else if (tok != PDF_TOK_STRING)

    {

      skip_to_token(ctx, file, buf, PDF_TOK_CLOSE_ARRAY, "expected string or ]");

      return;

    }

    if (buf->len / 2)

    {

      size_t i;

      size_t len = fz_minz(buf->len / 2, nelem(dst));

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

        dst[i] = pdf_code_from_string(&buf->scratch[i * 2], 2);

      pdf_map_one_to_many(ctx, cmap, lo, dst, i);

    }

    lo ++;

  }

}

static void

pdf_parse_bf_range(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  int lo, hi, dst;

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, "endbfrange"))

      return;

    else if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endbfrange", "expected string or endbfrange");

      return;

    }

    lo = pdf_code_from_string(buf->scratch, buf->len);

    tok = pdf_lex(ctx, file, buf);

    if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endbfrange", "expected string");

      return;

    }

    hi = pdf_code_from_string(buf->scratch, buf->len);

    if (lo < 0 || lo > 65535 || hi < 0 || hi > 65535 || lo > hi)

    {

      skip_to_keyword(ctx, file, buf, "endbfrange", "bfrange limits out of range");

      return;

    }

    tok = pdf_lex(ctx, file, buf);

    if (tok == PDF_TOK_STRING)

    {

      if (buf->len == 2)

      {

        dst = pdf_code_from_string(buf->scratch, buf->len);

        pdf_map_range_to_range(ctx, cmap, lo, hi, dst);

      }

      else

      {

        int dststr[PDF_MRANGE_CAP];

        size_t i;

        if (buf->len / 2)

        {

          size_t len = fz_minz(buf->len / 2, nelem(dststr));

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

            dststr[i] = pdf_code_from_string(&buf->scratch[i * 2], 2);

          while (lo <= hi)

          {

            pdf_map_one_to_many(ctx, cmap, lo, dststr, i);

            dststr[i-1] ++;

            lo ++;

          }

        }

      }

    }

    else if (tok == PDF_TOK_OPEN_ARRAY)

    {

      pdf_parse_bf_range_array(ctx, cmap, file, buf, lo, hi);

    }

    else

    {

      skip_to_keyword(ctx, file, buf, "endbfrange", "expected string or array or endbfrange");

      return;

    }

  }

}

static void

pdf_parse_bf_char(fz_context *ctx, pdf_cmap *cmap, fz_stream *file, pdf_lexbuf *buf)

{

  pdf_token tok;

  int dst[PDF_MRANGE_CAP];

  int src;

  while (1)

  {

    tok = pdf_lex(ctx, file, buf);

    if (is_keyword(tok, buf, "endbfchar"))

      return;

    else if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endbfchar", "expected string or endbfchar");

      return;

    }

    src = pdf_code_from_string(buf->scratch, buf->len);

    tok = pdf_lex(ctx, file, buf);

    /* Note: does not handle /dstName */

    if (tok != PDF_TOK_STRING)

    {

      skip_to_keyword(ctx, file, buf, "endbfchar", "expected string");

      return;

    }

    if (buf->len / 2)

    {

      size_t i;

      size_t len = fz_minz(buf->len / 2, nelem(dst));

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

        dst[i] = pdf_code_from_string(&buf->scratch[i * 2], 2);

      pdf_map_one_to_many(ctx, cmap, src, dst, i);

    }

  }

}

pdf_cmap *

pdf_load_cmap(fz_context *ctx, fz_stream *file)

{

  pdf_cmap *cmap;

  char key[64];

  pdf_lexbuf buf;

  pdf_token tok;

  pdf_lexbuf_init(ctx, &buf, PDF_LEXBUF_SMALL);

  cmap = pdf_new_cmap(ctx);

  strcpy(key, ".notdef");

  fz_try(ctx)

  {

    while (1)

    {

      tok = pdf_lex(ctx, file, &buf);

      if (tok == PDF_TOK_EOF)

        break;

      else if (tok == PDF_TOK_NAME)

      {

        if (!strcmp(buf.scratch, "CMapName"))

          pdf_parse_cmap_name(ctx, cmap, file, &buf);

        else if (!strcmp(buf.scratch, "WMode"))

          pdf_parse_wmode(ctx, cmap, file, &buf);

        else

          fz_strlcpy(key, buf.scratch, sizeof key);

      }

      else if (tok == PDF_TOK_KEYWORD)

      {

        if (is_keyword(tok, &buf, "endcmap"))

          break;

        else if (is_keyword(tok, &buf, "usecmap"))

          fz_strlcpy(cmap->usecmap_name, key, sizeof(cmap->usecmap_name));

        else if (is_keyword(tok, &buf, "begincodespacerange"))

          pdf_parse_codespace_range(ctx, cmap, file, &buf);

        else if (is_keyword(tok, &buf, "beginbfchar"))

          pdf_parse_bf_char(ctx, cmap, file, &buf);

        else if (is_keyword(tok, &buf, "begincidchar"))

          pdf_parse_cid_char(ctx, cmap, file, &buf);

        else if (is_keyword(tok, &buf, "beginbfrange"))

          pdf_parse_bf_range(ctx, cmap, file, &buf);

        else if (is_keyword(tok, &buf, "begincidrange"))

          pdf_parse_cid_range(ctx, cmap, file, &buf);

      }

      /* ignore everything else */

    }

    pdf_sort_cmap(ctx, cmap);

  }

  fz_always(ctx)

  {

    pdf_lexbuf_fin(ctx, &buf);

  }

  fz_catch(ctx)

  {

    pdf_drop_cmap(ctx, cmap);

    fz_rethrow(ctx);

  }

  return cmap;

}