/****************************************************************************
 *
 * ftsystem.c
 *
 *   Unix-specific FreeType low-level system interface (body).
 *
 * Copyright (C) 1996-2021 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */


#include <ft2build.h>
  /* we use our special ftconfig.h file, not the standard one */
#include FT_CONFIG_CONFIG_H
#include <freetype/internal/ftdebug.h>
#include <freetype/ftsystem.h>
#include <freetype/fterrors.h>
#include <freetype/fttypes.h>
#include <freetype/internal/ftstream.h>

  /* memory-mapping includes and definitions */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <sys/mman.h>
#ifndef MAP_FILE
#define MAP_FILE  0x00
#endif

#ifdef MUNMAP_USES_VOIDP
#define MUNMAP_ARG_CAST  void *
#else
#define MUNMAP_ARG_CAST  char *
#endif

#ifdef NEED_MUNMAP_DECL

#ifdef __cplusplus
  extern "C"
#else
  extern
#endif
  int
  munmap( char*  addr,
          int    len );

#define MUNMAP_ARG_CAST  char *

#endif /* NEED_DECLARATION_MUNMAP */


#include <sys/types.h>
#include <sys/stat.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>


  /**************************************************************************
   *
   *                      MEMORY MANAGEMENT INTERFACE
   *
   */


  /**************************************************************************
   *
   * It is not necessary to do any error checking for the
   * allocation-related functions.  This will be done by the higher level
   * routines like ft_mem_alloc() or ft_mem_realloc().
   *
   */


  /**************************************************************************
   *
   * @Function:
   *   ft_alloc
   *
   * @Description:
   *   The memory allocation function.
   *
   * @Input:
   *   memory ::
   *     A pointer to the memory object.
   *
   *   size ::
   *     The requested size in bytes.
   *
   * @Return:
   *   The address of newly allocated block.
   */
  FT_CALLBACK_DEF( void* )
  ft_alloc( FT_Memory  memory,
            long       size )
  {
    FT_UNUSED( memory );

    return malloc( size );
  }


  /**************************************************************************
   *
   * @Function:
   *   ft_realloc
   *
   * @Description:
   *   The memory reallocation function.
   *
   * @Input:
   *   memory ::
   *     A pointer to the memory object.
   *
   *   cur_size ::
   *     The current size of the allocated memory block.
   *
   *   new_size ::
   *     The newly requested size in bytes.
   *
   *   block ::
   *     The current address of the block in memory.
   *
   * @Return:
   *   The address of the reallocated memory block.
   */
  FT_CALLBACK_DEF( void* )
  ft_realloc( FT_Memory  memory,
              long       cur_size,
              long       new_size,
              void*      block )
  {
    FT_UNUSED( memory );
    FT_UNUSED( cur_size );

    return realloc( block, new_size );
  }


  /**************************************************************************
   *
   * @Function:
   *   ft_free
   *
   * @Description:
   *   The memory release function.
   *
   * @Input:
   *   memory ::
   *     A pointer to the memory object.
   *
   *   block ::
   *     The address of block in memory to be freed.
   */
  FT_CALLBACK_DEF( void )
  ft_free( FT_Memory  memory,
           void*      block )
  {
    FT_UNUSED( memory );

    free( block );
  }


  /**************************************************************************
   *
   *                    RESOURCE MANAGEMENT INTERFACE
   *
   */


  /**************************************************************************
   *
   * The macro FT_COMPONENT is used in trace mode.  It is an implicit
   * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
   * messages during execution.
   */
#undef  FT_COMPONENT
#define FT_COMPONENT  io

  /* We use the macro STREAM_FILE for convenience to extract the       */
  /* system-specific stream handle from a given FreeType stream object */
#define STREAM_FILE( stream )  ( (FILE*)stream->descriptor.pointer )


  /**************************************************************************
   *
   * @Function:
   *   ft_close_stream_by_munmap
   *
   * @Description:
   *   The function to close a stream which is opened by mmap.
   *
   * @Input:
   *   stream :: A pointer to the stream object.
   */
  FT_CALLBACK_DEF( void )
  ft_close_stream_by_munmap( FT_Stream  stream )
  {
    munmap( (MUNMAP_ARG_CAST)stream->descriptor.pointer, stream->size );

    stream->descriptor.pointer = NULL;
    stream->size               = 0;
    stream->base               = NULL;
  }


  /**************************************************************************
   *
   * @Function:
   *   ft_close_stream_by_free
   *
   * @Description:
   *   The function to close a stream which is created by ft_alloc.
   *
   * @Input:
   *   stream :: A pointer to the stream object.
   */
  FT_CALLBACK_DEF( void )
  ft_close_stream_by_free( FT_Stream  stream )
  {
    ft_free( stream->memory, stream->descriptor.pointer );

    stream->descriptor.pointer = NULL;
    stream->size               = 0;
    stream->base               = NULL;
  }


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( FT_Error )
  FT_Stream_Open( FT_Stream    stream,
                  const char*  filepathname )
  {
    int          file;
    struct stat  stat_buf;


    if ( !stream )
      return FT_THROW( Invalid_Stream_Handle );

    /* open the file */
    file = open( filepathname, O_RDONLY );
    if ( file < 0 )
    {
      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not open `%s'\n", filepathname ));
      return FT_THROW( Cannot_Open_Resource );
    }

    /* Here we ensure that a "fork" will _not_ duplicate   */
    /* our opened input streams on Unix.  This is critical */
    /* since it avoids some (possible) access control      */
    /* issues and cleans up the kernel file table a bit.   */
    /*                                                     */
#ifdef F_SETFD
#ifdef FD_CLOEXEC
    (void)fcntl( file, F_SETFD, FD_CLOEXEC );
#else
    (void)fcntl( file, F_SETFD, 1 );
#endif /* FD_CLOEXEC */
#endif /* F_SETFD */

    if ( fstat( file, &stat_buf ) < 0 )
    {
      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not `fstat' file `%s'\n", filepathname ));
      goto Fail_Map;
    }

    /* XXX: TODO -- real 64bit platform support                        */
    /*                                                                 */
    /* `stream->size' is typedef'd to unsigned long (in `ftsystem.h'); */
    /* `stat_buf.st_size', however, is usually typedef'd to off_t      */
    /* (in sys/stat.h).                                                */
    /* On some platforms, the former is 32bit and the latter is 64bit. */
    /* To avoid overflow caused by fonts in huge files larger than     */
    /* 2GB, do a test.  Temporary fix proposed by Sean McBride.        */
    /*                                                                 */
    if ( stat_buf.st_size > LONG_MAX )
    {
      FT_ERROR(( "FT_Stream_Open: file is too big\n" ));
      goto Fail_Map;
    }
    else if ( stat_buf.st_size == 0 )
    {
      FT_ERROR(( "FT_Stream_Open: zero-length file\n" ));
      goto Fail_Map;
    }

    /* This cast potentially truncates a 64bit to 32bit! */
    stream->size = (unsigned long)stat_buf.st_size;
    stream->pos  = 0;
    stream->base = (unsigned char *)mmap( NULL,
                                          stream->size,
                                          PROT_READ,
                                          MAP_FILE | MAP_PRIVATE,
                                          file,
                                          0 );

    if ( stream->base != MAP_FAILED )
      stream->close = ft_close_stream_by_munmap;
    else
    {
      ssize_t  total_read_count;


      FT_ERROR(( "FT_Stream_Open:" ));
      FT_ERROR(( " could not `mmap' file `%s'\n", filepathname ));

      stream->base = (unsigned char*)ft_alloc( stream->memory, stream->size );

      if ( !stream->base )
      {
        FT_ERROR(( "FT_Stream_Open:" ));
        FT_ERROR(( " could not `alloc' memory\n" ));
        goto Fail_Map;
      }

      total_read_count = 0;
      do
      {
        ssize_t  read_count;


        read_count = read( file,
                           stream->base + total_read_count,
                           stream->size - total_read_count );

        if ( read_count <= 0 )
        {
          if ( read_count == -1 && errno == EINTR )
            continue;

          FT_ERROR(( "FT_Stream_Open:" ));
          FT_ERROR(( " error while `read'ing file `%s'\n", filepathname ));
          goto Fail_Read;
        }

        total_read_count += read_count;

      } while ( (unsigned long)total_read_count != stream->size );

      stream->close = ft_close_stream_by_free;
    }

    close( file );

    stream->descriptor.pointer = stream->base;
    stream->pathname.pointer   = (char*)filepathname;

    stream->read = NULL;

    FT_TRACE1(( "FT_Stream_Open:" ));
    FT_TRACE1(( " opened `%s' (%ld bytes) successfully\n",
                filepathname, stream->size ));

    return FT_Err_Ok;

  Fail_Read:
    ft_free( stream->memory, stream->base );

  Fail_Map:
    close( file );

    stream->base = NULL;
    stream->size = 0;
    stream->pos  = 0;

    return FT_THROW( Cannot_Open_Stream );
  }


#ifdef FT_DEBUG_MEMORY

  extern FT_Int
  ft_mem_debug_init( FT_Memory  memory );

  extern void
  ft_mem_debug_done( FT_Memory  memory );

#endif


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( FT_Memory )
  FT_New_Memory( void )
  {
    FT_Memory  memory;


    memory = (FT_Memory)malloc( sizeof ( *memory ) );
    if ( memory )
    {
      memory->user    = NULL;
      memory->alloc   = ft_alloc;
      memory->realloc = ft_realloc;
      memory->free    = ft_free;
#ifdef FT_DEBUG_MEMORY
      ft_mem_debug_init( memory );
#endif
    }

    return memory;
  }


  /* documentation is in ftobjs.h */

  FT_BASE_DEF( void )
  FT_Done_Memory( FT_Memory  memory )
  {
#ifdef FT_DEBUG_MEMORY
    ft_mem_debug_done( memory );
#endif
    memory->free( memory, memory );
  }


/* END */
