/* font.c: define (more or less) format-independent font operations.

Copyright (C) 1992, 2011 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "config.h"

#include "tex-file.h"
#include "paths.h"
#include "c-ctype.h"

#include "filename.h"
#include "font.h"
#include "gf.h"
#include "list.h"
#include "pk.h"
#include "tfm.h"


/* We want to allow reading of multiple fonts, so we keep some
   information around for each font we read.  */

typedef struct
{
  bitmap_format_type bitmap_format;
  boolean bitmap_only;
  font_info_type info;
} internal_font_type;

/* The format of the bitmap file for this font.  */
#define INTERNAL_BITMAP_FORMAT(i)  ((i).bitmap_format)

/* If the font was opened with `get_bitmap_font', this field is true;
   if with `get_font', false.  */
#define INTERNAL_BITMAP_ONLY(i)  ((i).bitmap_only)

/* The filename for the bitmap font.  */
#define INTERNAL_BITMAP_NAME(i)  ((i).bitmap_name)

/* The fontwide information.  The parts of this that are found in the
   TFM file are garbage if INTERNAL_BITMAP_ONLY (I) is true.  */
#define INTERNAL_FONT_INFO(i)  ((i).info)


static void delete_internal_font (string filename);
static internal_font_type *find_internal_font (string font_name);
static void save_internal_font (string font_name, internal_font_type);

/* Starting with FONT_NAME as the base filename, e.g., `cmr10', we try
   various extensions to find a PK or GF file at resolution DPI.  This
   bitmap font defines the shapes of the characters.  */
   
bitmap_font_type
get_bitmap_font (string font_name, unsigned dpi)
{
  bitmap_font_type font;
  internal_font_type internal_f;
  internal_font_type *internal_font_ptr;
  string pk_name, gf_name;
  boolean found_pk = false, found_gf = false;

  /* If we are passed a null pointer or the empty string, it's got to be
     a mistake.  */
  assert (font_name && *font_name);

  /* If we already have the font saved, we just return it, thus (1) saving
     going out to the file system, and (2) causing multiple calls with
     the same FONT_NAME not to open more and more bitmap files.  */
  internal_font_ptr = find_internal_font (font_name); 
  if (internal_font_ptr != NULL)
    return FONT_BITMAP_FONT (INTERNAL_FONT_INFO (*internal_font_ptr));

  pk_name = find_pk_filename (font_name, dpi);
  if (pk_name != NULL)
    { /* Found the PK file, so unless something strange is happening
         (like the file being removed between the `find_path_filename'
         call and the `pk_open_input_file' call), we will be able to
         open it.  */
      found_pk = pk_open_input_file (pk_name);
      if (!found_pk)
        FATAL_PERROR (pk_name);
    }
  else if ((gf_name = find_gf_filename (font_name, dpi)) != NULL)
    {
      found_gf = gf_open_input_file (gf_name);
      if (!found_gf)
        {
          perror (gf_name);
          FATAL1 ("(I couldn't find the PK file `%s', either.)", pk_name);
        }
    }
  else
    FATAL2 ("%s.%d{gf,pk}: Nowhere in path", font_name, dpi);

    
  /* We've opened the files; get the information we need to return.  */
  if (found_pk)
    {
      pk_preamble_type preamble = pk_get_preamble (pk_name);

      BITMAP_FONT_DESIGN_SIZE (font)
        = fix_to_real (PK_DESIGN_SIZE (preamble));
      BITMAP_FONT_COMMENT (font) = PK_COMMENT (preamble);
      BITMAP_FONT_CHECKSUM (font) = PK_CHECKSUM (preamble);
      BITMAP_FONT_FILENAME (font) = pk_name;

      INTERNAL_BITMAP_FORMAT (internal_f) = pk_format;
    }
  else if (found_gf)
    {
      gf_postamble_type postamble = gf_get_postamble ();

      BITMAP_FONT_DESIGN_SIZE (font)
        = fix_to_real (GF_DESIGN_SIZE (postamble));
      BITMAP_FONT_COMMENT (font) = gf_get_preamble ();
      BITMAP_FONT_CHECKSUM (font) = GF_CHECKSUM (postamble);
      BITMAP_FONT_FILENAME (font) = gf_name;

      INTERNAL_BITMAP_FORMAT (internal_f) = gf_format;
    }
  else
    FATAL ("No bitmap file found, but I must have found one");

  FONT_BITMAP_FONT (INTERNAL_FONT_INFO (internal_f)) = font;
  INTERNAL_BITMAP_ONLY (internal_f) = true;

  save_internal_font (font_name, internal_f);

  return font;
}


/* Look for both a bitmap font named FONT_NAME, and for the TFM file
   FONT_NAME.tfm.  We call `get_bitmap_font' to find the bitmap font. 
   For the TFM file, we use the path in the environment variable
   TEXFONTS; if TEXFONTS isn't set, we use the default defined above.
   
   If FONT_NAME was previously opened with `get_bitmap_font', we give a
   fatal error.  */

font_info_type
get_font (string font_name, unsigned dpi)
{
  unsigned bitmap_checksum;
  font_info_type font;
  internal_font_type internal_f;
  internal_font_type *internal_font_ptr;
  unsigned tfm_checksum;
  string tfm_name;

  /* If we are passed a null pointer or the empty string, it's got to be
     a mistake.  */
  assert (font_name != NULL && *font_name);

  /* If we already have the font saved, we just return it, thus (1) saving
     going out to the file system, and (2) causing multiple calls with
     the same FONT_NAME not to open more and more bitmap files.  */
  internal_font_ptr = find_internal_font (font_name); 
  if (internal_font_ptr != NULL)
    if (INTERNAL_BITMAP_ONLY (*internal_font_ptr))
      FATAL1 ("get_font: `%s' was opened with get_bitmap_font", font_name);
    else
      return INTERNAL_FONT_INFO (*internal_font_ptr);

  /* If we don't have the font saved, we have to look for the TFM file.  */
  tfm_name = kpse_find_tfm (font_name);

  if (tfm_name == NULL)
    FATAL1 ("%s.tfm: Nowhere in path", font_name);

  if (!tfm_open_input_file (tfm_name))
    FATAL_PERROR (tfm_name);


  /* The TFM file is opened.  Save some global information.  */
  FONT_TFM_FONT (font) = tfm_get_global_info ();
  FONT_TFM_FILENAME (font) = tfm_name;
  
  /* Read the (we hope) corresponding bitmap file.  */
  FONT_BITMAP_FONT (font) = get_bitmap_font (font_name, dpi);
  
  /* We have found the bitmap font on the filesystem, so it should be in
     our internal list now.  We will overwrite it below.  */
  internal_font_ptr = find_internal_font (font_name);
  assert (internal_font_ptr != NULL);
  
  /* We've opened the files; now get the information we're supposed to
     return.  */

  /* Let's check the checksums.  */
  tfm_checksum = tfm_get_checksum ();
  bitmap_checksum = BITMAP_FONT_CHECKSUM (FONT_BITMAP_FONT (font));

  if (tfm_checksum != 0 && bitmap_checksum != 0 
      && tfm_checksum != bitmap_checksum)
    WARNING1 ("%s: TFM and bitmap checksums don't match", font_name);

  INTERNAL_FONT_INFO (internal_f) = font;
  INTERNAL_BITMAP_ONLY (internal_f) = false;
  INTERNAL_BITMAP_FORMAT (internal_f)
    = INTERNAL_BITMAP_FORMAT (*internal_font_ptr);
  save_internal_font (font_name, internal_f);

  return font;
}

/* Close the files we have opened, for tidiness.  */

void
close_font (string font_name)
{
  internal_font_type *f = find_internal_font (font_name);

  if (f == NULL)
    FATAL1 ("close_font: Font `%s' not open", font_name);
    
  switch (INTERNAL_BITMAP_FORMAT (*f))
    {
    case pk_format:
      {
        string pk_name
          = BITMAP_FONT_FILENAME (FONT_BITMAP_FONT (INTERNAL_FONT_INFO (*f)));
        pk_close_input_file (pk_name);
      }
      break;
    
    case gf_format:
      gf_close_input_file ();
      break;
    
    default:
      FATAL1 ("Impossible bitmap format (%d)", INTERNAL_BITMAP_FORMAT (*f));
    }

  if (!INTERNAL_BITMAP_ONLY (*f))
    tfm_close_input_file ();
  
  delete_internal_font (font_name);
}

/* Look for the character numbered CODE in the font FONT_NAME.  If it
   doesn't exist, return NULL.  Otherwise, fill in a `char_info_type'
   structure and return a pointer to it. 
   
   This merely calls the get-a-character routine in the appropriate
   library.  */

char_info_type *
get_char (string font_name, one_byte code)
{
  char_info_type *c;
  internal_font_type *f = find_internal_font (font_name);
  
  if (f == NULL)
    FATAL1 ("get_char: Font `%s' not open", font_name);

  switch (INTERNAL_BITMAP_FORMAT (*f))
    {
    case pk_format:
      {
        string pk_name
          = BITMAP_FONT_FILENAME (FONT_BITMAP_FONT (INTERNAL_FONT_INFO (*f)));
        pk_char_type *pk_char = pk_get_char (code, pk_name);
        if (pk_char == NULL) return NULL;
        
        c = XTALLOC1 (char_info_type);
        CHARCODE (*c) = PK_CHARCODE (*pk_char);
        CHAR_SET_WIDTH (*c) = PK_H_ESCAPEMENT (*pk_char);
        CHAR_TFM_WIDTH (*c) = PK_TFM_WIDTH (*pk_char);
        CHAR_BB (*c) = PK_CHAR_BB (*pk_char);
        CHAR_BITMAP (*c) = PK_BITMAP (*pk_char);
      }
      break;
    
    case gf_format:
      {
        gf_char_type *gf_char = gf_get_char (code);
        if (gf_char == NULL) return NULL;

        c = XTALLOC1 (char_info_type);
        CHARCODE (*c) = GF_CHARCODE (*gf_char);
        CHAR_SET_WIDTH (*c) = GF_H_ESCAPEMENT (*gf_char);
        CHAR_TFM_WIDTH (*c) = GF_TFM_WIDTH (*gf_char);
        CHAR_BB (*c) = GF_CHAR_BB (*gf_char);
        CHAR_BITMAP (*c) = GF_BITMAP (*gf_char);
      }
      break;
    
    default:
      FATAL1 ("Impossible bitmap format (%d)", INTERNAL_BITMAP_FORMAT (*f));
    }
  
  return c;
}

/* Look for the character numbered CODE in the font FONT_NAME.  If it
   doesn't exist, return NULL.  Otherwise, fill in a `raw_char_type'
   structure and return a pointer to it. 
   
   This merely calls the corresponding routine in the appropriate
   library.  */

raw_char_type *
get_raw_char (string font_name, one_byte code)
{
  raw_char_type *c;
  internal_font_type *f = find_internal_font (font_name);
  
  if (f == NULL)
    FATAL1 ("get_raw_char: Font `%s' not open", font_name);

  switch (INTERNAL_BITMAP_FORMAT (*f))
    {
    case pk_format:
      c = NULL;
      break;
    
    case gf_format:
      c = gf_get_raw_char (code);
      break;
      
    default:
      FATAL1 ("Impossible bitmap format (%d)", INTERNAL_BITMAP_FORMAT (*f));
    }
  
  if (c != NULL)
    RAW_CHAR_BITMAP_FORMAT (*c) = INTERNAL_BITMAP_FORMAT (*f);
  return c;
}


/* Free the information in the raw character RAW_CHAR, including the
   character itself.  */

void
free_raw_char (raw_char_type *raw_char)
{
  free (RAW_CHAR_BYTES (*raw_char));
  free (raw_char);
}

/* Print the character C to the file F, using ordinary characters.  */

void
print_char (FILE *f, char_info_type c)
{
  unsigned this_row, this_col;
  bitmap_type b = CHAR_BITMAP (c);

  fprintf (f, "Character 0x%x=%u", CHARCODE (c), CHARCODE (c));
  if (ISPRINT (CHARCODE (c)))
    fprintf (f, " (%c)", CHARCODE (c));
  
  fprintf (f, ":\n");
  
  fprintf (f, "   min/max col %d/%d, min/max row %d/%d, set width %d.\n", 
           CHAR_MIN_COL (c), CHAR_MAX_COL (c),
           CHAR_MIN_ROW (c), CHAR_MAX_ROW (c), CHAR_SET_WIDTH (c));
  
  /* We don't call `print_bitmap' because we want to print the Cartesian
     row number, as well as the bitmap row number.  */

  for (this_row = 0; this_row < BITMAP_HEIGHT (b); this_row++)
    {
      for (this_col = 0; this_col < BITMAP_WIDTH (b); this_col++)
        putc (BITMAP_PIXEL (b, this_row, this_col) ? '*' : ' ', f);
      
      fprintf (f, "%3d\t%u\n", CHAR_MAX_ROW (c) - this_row, this_row);
    }
}

/* We want to implement a typical key/value setup: here we are given the
   key (FONT_NAME) and the value (F).  We assign an index number to
   FONT_NAME, and store it and F in parallel lists.  If we are passed a
   FONT_NAME that is already in the list, we overwrite the old value.  */

static list_type font_name_list, internal_font_list;

static void
save_internal_font (string font_name, internal_font_type f)
{
  string *new_name;
  internal_font_type *new_font;
  static boolean first_call = true;
  
  if (first_call)
    { /* Have to construct our lists.  */
      font_name_list = list_init ();
      internal_font_list = list_init ();
      first_call = false;
    }

  new_font = find_internal_font (font_name);
  if (new_font == NULL)
    {
      /* Add another pointer to the end of the lists.  */
      new_name = LIST_TAPPEND (&font_name_list, string);
      new_font = LIST_TAPPEND (&internal_font_list, internal_font_type);

      /* Save the information.  */
      *new_name = xstrdup (font_name);
    }
  
  /* Either update the existing font, or save the new one.  */
  *new_font = f;
}


/* This routine returns the font information previously stored with
   FONT_NAME.  If FONT_NAME hasn't been saved, we return NULL.  */

static internal_font_type *
find_internal_font (string font_name)
{
  unsigned e;

  for (e = 0; e < LIST_SIZE (font_name_list); e++)
    if (STREQ (*(string *) LIST_ELT (font_name_list, e), font_name))
      return (internal_font_type *) LIST_ELT (internal_font_list, e);

  return NULL;
}


/* Remove FILENAME from `font_name_list', by setting the name in
   `font_name_list' to the empty string, so that the element is useless.
   (We don't have any actual memory to free.)  What a kludge.  */

static void
delete_internal_font (string filename)
{
  unsigned e;

  /* We can't use `find_internal_font', since we need to know the list
     element index, not just the internal font information.  */ 
  for (e = 0; e < LIST_SIZE (font_name_list); e++)
    if (STREQ (*(string *) LIST_ELT (font_name_list, e), filename))
      {
        string *name = LIST_ELT (font_name_list, e);
        internal_font_type *i
          = (internal_font_type *) LIST_ELT (internal_font_list, e);

        free (*name);
        *name = "";
        
        free (i);

        return;
      }

  FATAL1 ("The font `%s' hasn't been saved", filename);
}