src/lib/vampimg/JpegLib/imjcomapi.pas

   1 unit imjcomapi;
   2
   3 { This file contains application interface routines that are used for both
   4   compression and decompression. }
   5
   6 { Original: jcomapi.c;  Copyright (C) 1994-1997, Thomas G. Lane. }
   7
   8 interface
   9
  10 {$I imjconfig.inc}
  11
  12 uses
  13   imjmorecfg,
  14   imjinclude,
  15   imjpeglib;
  16
  17 { Abort processing of a JPEG compression or decompression operation,
  18   but don't destroy the object itself. }
  19
  20 {GLOBAL}
  21 procedure jpeg_abort (cinfo : j_common_ptr);
  22
  23
  24 { Destruction of a JPEG object. }
  25
  26 {GLOBAL}
  27 procedure jpeg_destroy (cinfo : j_common_ptr);
  28
  29 {GLOBAL}
  30 function jpeg_alloc_quant_table (cinfo : j_common_ptr) : JQUANT_TBL_PTR;
  31
  32 {GLOBAL}
  33 function jpeg_alloc_huff_table (cinfo : j_common_ptr) : JHUFF_TBL_PTR;
  34
  35 implementation
  36
  37 { Abort processing of a JPEG compression or decompression operation,
  38   but don't destroy the object itself.
  39
  40   For this, we merely clean up all the nonpermanent memory pools.
  41   Note that temp files (virtual arrays) are not allowed to belong to
  42   the permanent pool, so we will be able to close all temp files here.
  43   Closing a data source or destination, if necessary, is the application's
  44   responsibility. }
  45
  46
  47 {GLOBAL}
  48 procedure jpeg_abort (cinfo : j_common_ptr);
  49 var
  50   pool : int;
  51 begin
  52   { Do nothing if called on a not-initialized or destroyed JPEG object. }
  53   if (cinfo^.mem = NIL) then
  54     exit;
  55
  56   { Releasing pools in reverse order might help avoid fragmentation
  57     with some (brain-damaged) malloc libraries. }
  58
  59   for pool := JPOOL_NUMPOOLS-1 downto JPOOL_PERMANENT+1 do
  60   begin
  61     cinfo^.mem^.free_pool (cinfo, pool);
  62   end;
  63
  64   { Reset overall state for possible reuse of object }
  65   if (cinfo^.is_decompressor) then
  66   begin
  67     cinfo^.global_state := DSTATE_START;
  68     { Try to keep application from accessing now-deleted marker list.
  69       A bit kludgy to do it here, but this is the most central place. }
  70     j_decompress_ptr(cinfo)^.marker_list := NIL;
  71   end
  72   else
  73   begin
  74     cinfo^.global_state := CSTATE_START;
  75   end;
  76 end;
  77
  78
  79 { Destruction of a JPEG object.
  80
  81   Everything gets deallocated except the master jpeg_compress_struct itself
  82   and the error manager struct.  Both of these are supplied by the application
  83   and must be freed, if necessary, by the application.  (Often they are on
  84   the stack and so don't need to be freed anyway.)
  85   Closing a data source or destination, if necessary, is the application's
  86   responsibility. }
  87
  88
  89 {GLOBAL}
  90 procedure jpeg_destroy (cinfo : j_common_ptr);
  91 begin
  92   { We need only tell the memory manager to release everything. }
  93   { NB: mem pointer is NIL if memory mgr failed to initialize. }
  94   if (cinfo^.mem <> NIL) then
  95     cinfo^.mem^.self_destruct (cinfo);
  96   cinfo^.mem := NIL;           { be safe if jpeg_destroy is called twice }
  97   cinfo^.global_state := 0;    { mark it destroyed }
  98 end;
  99
 100
 101 { Convenience routines for allocating quantization and Huffman tables.
 102   (Would jutils.c be a more reasonable place to put these?) }
 103
 104
 105 {GLOBAL}
 106 function jpeg_alloc_quant_table (cinfo : j_common_ptr) : JQUANT_TBL_PTR;
 107 var
 108   tbl : JQUANT_TBL_PTR;
 109 begin
 110   tbl := JQUANT_TBL_PTR(
 111     cinfo^.mem^.alloc_small (cinfo, JPOOL_PERMANENT, SIZEOF(JQUANT_TBL))
 112                       );
 113   tbl^.sent_table := FALSE;   { make sure this is false in any new table }
 114   jpeg_alloc_quant_table := tbl;
 115 end;
 116
 117
 118 {GLOBAL}
 119 function jpeg_alloc_huff_table (cinfo : j_common_ptr) : JHUFF_TBL_PTR;
 120 var
 121   tbl : JHUFF_TBL_PTR;
 122 begin
 123   tbl := JHUFF_TBL_PTR(
 124     cinfo^.mem^.alloc_small (cinfo, JPOOL_PERMANENT, SIZEOF(JHUFF_TBL))
 125                      );
 126   tbl^.sent_table := FALSE;   { make sure this is false in any new table }
 127   jpeg_alloc_huff_table := tbl;
 128 end;
 129
 130 end.