You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
503 lines
17 KiB
503 lines
17 KiB
unit imjdapimin;
|
|
|
|
{ This file contains application interface code for the decompression half
|
|
of the JPEG library. These are the "minimum" API routines that may be
|
|
needed in either the normal full-decompression case or the
|
|
transcoding-only case.
|
|
|
|
Most of the routines intended to be called directly by an application
|
|
are in this file or in jdapistd.c. But also see jcomapi.c for routines
|
|
shared by compression and decompression, and jdtrans.c for the transcoding
|
|
case. }
|
|
|
|
{ Original : jdapimin.c ; Copyright (C) 1994-1998, Thomas G. Lane. }
|
|
|
|
interface
|
|
|
|
{$I imjconfig.inc}
|
|
|
|
uses
|
|
imjmorecfg,
|
|
imjinclude,
|
|
imjdeferr,
|
|
imjerror,
|
|
imjpeglib,
|
|
imjmemmgr, imjdmarker, imjdinput, imjcomapi;
|
|
|
|
{ Nomssi }
|
|
procedure jpeg_create_decompress(cinfo : j_decompress_ptr);
|
|
|
|
{ Initialization of a JPEG decompression object.
|
|
The error manager must already be set up (in case memory manager fails). }
|
|
|
|
{GLOBAL}
|
|
procedure jpeg_CreateDecompress (cinfo : j_decompress_ptr;
|
|
version : int;
|
|
structsize : size_t);
|
|
|
|
{ Destruction of a JPEG decompression object }
|
|
|
|
{GLOBAL}
|
|
procedure jpeg_destroy_decompress (cinfo : j_decompress_ptr);
|
|
|
|
|
|
{ Decompression startup: read start of JPEG datastream to see what's there.
|
|
Need only initialize JPEG object and supply a data source before calling.
|
|
|
|
This routine will read as far as the first SOS marker (ie, actual start of
|
|
compressed data), and will save all tables and parameters in the JPEG
|
|
object. It will also initialize the decompression parameters to default
|
|
values, and finally return JPEG_HEADER_OK. On return, the application may
|
|
adjust the decompression parameters and then call jpeg_start_decompress.
|
|
(Or, if the application only wanted to determine the image parameters,
|
|
the data need not be decompressed. In that case, call jpeg_abort or
|
|
jpeg_destroy to release any temporary space.)
|
|
If an abbreviated (tables only) datastream is presented, the routine will
|
|
return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
|
|
re-use the JPEG object to read the abbreviated image datastream(s).
|
|
It is unnecessary (but OK) to call jpeg_abort in this case.
|
|
The JPEG_SUSPENDED return code only occurs if the data source module
|
|
requests suspension of the decompressor. In this case the application
|
|
should load more source data and then re-call jpeg_read_header to resume
|
|
processing.
|
|
If a non-suspending data source is used and require_image is TRUE, then the
|
|
return code need not be inspected since only JPEG_HEADER_OK is possible.
|
|
|
|
This routine is now just a front end to jpeg_consume_input, with some
|
|
extra error checking. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_read_header (cinfo : j_decompress_ptr;
|
|
require_image : boolean) : int;
|
|
|
|
{ Consume data in advance of what the decompressor requires.
|
|
This can be called at any time once the decompressor object has
|
|
been created and a data source has been set up.
|
|
|
|
This routine is essentially a state machine that handles a couple
|
|
of critical state-transition actions, namely initial setup and
|
|
transition from header scanning to ready-for-start_decompress.
|
|
All the actual input is done via the input controller's consume_input
|
|
method. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_consume_input (cinfo : j_decompress_ptr) : int;
|
|
|
|
{ Have we finished reading the input file? }
|
|
|
|
{GLOBAL}
|
|
function jpeg_input_complete (cinfo : j_decompress_ptr) : boolean;
|
|
|
|
{ Is there more than one scan? }
|
|
|
|
{GLOBAL}
|
|
function jpeg_has_multiple_scans (cinfo : j_decompress_ptr) : boolean;
|
|
|
|
|
|
{ Finish JPEG decompression.
|
|
|
|
This will normally just verify the file trailer and release temp storage.
|
|
|
|
Returns FALSE if suspended. The return value need be inspected only if
|
|
a suspending data source is used. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_finish_decompress (cinfo : j_decompress_ptr) : boolean;
|
|
|
|
implementation
|
|
|
|
procedure jpeg_create_decompress(cinfo : j_decompress_ptr);
|
|
begin
|
|
jpeg_CreateDecompress(cinfo, JPEG_LIB_VERSION,
|
|
size_t(sizeof(jpeg_decompress_struct)));
|
|
end;
|
|
|
|
{ Initialization of a JPEG decompression object.
|
|
The error manager must already be set up (in case memory manager fails). }
|
|
|
|
{GLOBAL}
|
|
procedure jpeg_CreateDecompress (cinfo : j_decompress_ptr;
|
|
version : int;
|
|
structsize : size_t);
|
|
var
|
|
i : int;
|
|
var
|
|
err : jpeg_error_mgr_ptr;
|
|
client_data : voidp;
|
|
begin
|
|
{ Guard against version mismatches between library and caller. }
|
|
cinfo^.mem := NIL; { so jpeg_destroy knows mem mgr not called }
|
|
if (version <> JPEG_LIB_VERSION) then
|
|
ERREXIT2(j_common_ptr(cinfo), JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
|
|
if (structsize <> SIZEOF(jpeg_decompress_struct)) then
|
|
ERREXIT2(j_common_ptr(cinfo), JERR_BAD_STRUCT_SIZE,
|
|
int(SIZEOF(jpeg_decompress_struct)), int(structsize));
|
|
|
|
{ For debugging purposes, we zero the whole master structure.
|
|
But the application has already set the err pointer, and may have set
|
|
client_data, so we have to save and restore those fields.
|
|
Note: if application hasn't set client_data, tools like Purify may
|
|
complain here. }
|
|
begin
|
|
err := cinfo^.err;
|
|
client_data := cinfo^.client_data; { ignore Purify complaint here }
|
|
MEMZERO(j_common_ptr(cinfo), SIZEOF(jpeg_decompress_struct));
|
|
cinfo^.err := err;
|
|
cinfo^.client_data := client_data;
|
|
end;
|
|
cinfo^.is_decompressor := TRUE;
|
|
|
|
{ Initialize a memory manager instance for this object }
|
|
jinit_memory_mgr(j_common_ptr(cinfo));
|
|
|
|
{ Zero out pointers to permanent structures. }
|
|
cinfo^.progress := NIL;
|
|
cinfo^.src := NIL;
|
|
|
|
for i := 0 to pred(NUM_QUANT_TBLS) do
|
|
cinfo^.quant_tbl_ptrs[i] := NIL;
|
|
|
|
for i := 0 to pred(NUM_HUFF_TBLS) do
|
|
begin
|
|
cinfo^.dc_huff_tbl_ptrs[i] := NIL;
|
|
cinfo^.ac_huff_tbl_ptrs[i] := NIL;
|
|
end;
|
|
|
|
{ Initialize marker processor so application can override methods
|
|
for COM, APPn markers before calling jpeg_read_header. }
|
|
cinfo^.marker_list := NIL;
|
|
jinit_marker_reader(cinfo);
|
|
|
|
{ And initialize the overall input controller. }
|
|
jinit_input_controller(cinfo);
|
|
|
|
{ OK, I'm ready }
|
|
cinfo^.global_state := DSTATE_START;
|
|
end;
|
|
|
|
|
|
{ Destruction of a JPEG decompression object }
|
|
|
|
{GLOBAL}
|
|
procedure jpeg_destroy_decompress (cinfo : j_decompress_ptr);
|
|
begin
|
|
jpeg_destroy(j_common_ptr(cinfo)); { use common routine }
|
|
end;
|
|
|
|
|
|
{ Abort processing of a JPEG decompression operation,
|
|
but don't destroy the object itself. }
|
|
|
|
{GLOBAL}
|
|
procedure jpeg_abort_decompress (cinfo : j_decompress_ptr);
|
|
begin
|
|
jpeg_abort(j_common_ptr(cinfo)); { use common routine }
|
|
end;
|
|
|
|
|
|
{ Set default decompression parameters. }
|
|
|
|
{LOCAL}
|
|
procedure default_decompress_parms (cinfo : j_decompress_ptr);
|
|
var
|
|
cid0 : int;
|
|
cid1 : int;
|
|
cid2 : int;
|
|
begin
|
|
{ Guess the input colorspace, and set output colorspace accordingly. }
|
|
{ (Wish JPEG committee had provided a real way to specify this...) }
|
|
{ Note application may override our guesses. }
|
|
case (cinfo^.num_components) of
|
|
1: begin
|
|
cinfo^.jpeg_color_space := JCS_GRAYSCALE;
|
|
cinfo^.out_color_space := JCS_GRAYSCALE;
|
|
end;
|
|
|
|
3: begin
|
|
if (cinfo^.saw_JFIF_marker) then
|
|
begin
|
|
cinfo^.jpeg_color_space := JCS_YCbCr; { JFIF implies YCbCr }
|
|
end
|
|
else
|
|
if (cinfo^.saw_Adobe_marker) then
|
|
begin
|
|
case (cinfo^.Adobe_transform) of
|
|
0: cinfo^.jpeg_color_space := JCS_RGB;
|
|
1: cinfo^.jpeg_color_space := JCS_YCbCr;
|
|
else
|
|
begin
|
|
WARNMS1(j_common_ptr(cinfo), JWRN_ADOBE_XFORM, cinfo^.Adobe_transform);
|
|
cinfo^.jpeg_color_space := JCS_YCbCr; { assume it's YCbCr }
|
|
end;
|
|
end;
|
|
end
|
|
else
|
|
begin
|
|
{ Saw no special markers, try to guess from the component IDs }
|
|
cid0 := cinfo^.comp_info^[0].component_id;
|
|
cid1 := cinfo^.comp_info^[1].component_id;
|
|
cid2 := cinfo^.comp_info^[2].component_id;
|
|
|
|
if (cid0 = 1) and (cid1 = 2) and (cid2 = 3) then
|
|
cinfo^.jpeg_color_space := JCS_YCbCr { assume JFIF w/out marker }
|
|
else
|
|
if (cid0 = 82) and (cid1 = 71) and (cid2 = 66) then
|
|
cinfo^.jpeg_color_space := JCS_RGB { ASCII 'R', 'G', 'B' }
|
|
else
|
|
begin
|
|
{$IFDEF DEBUG}
|
|
TRACEMS3(j_common_ptr(cinfo), 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
|
|
{$ENDIF}
|
|
cinfo^.jpeg_color_space := JCS_YCbCr; { assume it's YCbCr }
|
|
end;
|
|
end;
|
|
{ Always guess RGB is proper output colorspace. }
|
|
cinfo^.out_color_space := JCS_RGB;
|
|
end;
|
|
|
|
4: begin
|
|
if (cinfo^.saw_Adobe_marker) then
|
|
begin
|
|
case (cinfo^.Adobe_transform) of
|
|
0: cinfo^.jpeg_color_space := JCS_CMYK;
|
|
2: cinfo^.jpeg_color_space := JCS_YCCK;
|
|
else
|
|
begin
|
|
WARNMS1(j_common_ptr(cinfo), JWRN_ADOBE_XFORM, cinfo^.Adobe_transform);
|
|
cinfo^.jpeg_color_space := JCS_YCCK; { assume it's YCCK }
|
|
end;
|
|
end;
|
|
end
|
|
else
|
|
begin
|
|
{ No special markers, assume straight CMYK. }
|
|
cinfo^.jpeg_color_space := JCS_CMYK;
|
|
end;
|
|
cinfo^.out_color_space := JCS_CMYK;
|
|
end;
|
|
|
|
else
|
|
begin
|
|
cinfo^.jpeg_color_space := JCS_UNKNOWN;
|
|
cinfo^.out_color_space := JCS_UNKNOWN;
|
|
end;
|
|
end;
|
|
|
|
{ Set defaults for other decompression parameters. }
|
|
cinfo^.scale_num := 1; { 1:1 scaling }
|
|
cinfo^.scale_denom := 1;
|
|
cinfo^.output_gamma := 1.0;
|
|
cinfo^.buffered_image := FALSE;
|
|
cinfo^.raw_data_out := FALSE;
|
|
cinfo^.dct_method := JDCT_DEFAULT;
|
|
cinfo^.do_fancy_upsampling := TRUE;
|
|
cinfo^.do_block_smoothing := TRUE;
|
|
cinfo^.quantize_colors := FALSE;
|
|
{ We set these in case application only sets quantize_colors. }
|
|
cinfo^.dither_mode := JDITHER_FS;
|
|
{$ifdef QUANT_2PASS_SUPPORTED}
|
|
cinfo^.two_pass_quantize := TRUE;
|
|
{$else}
|
|
cinfo^.two_pass_quantize := FALSE;
|
|
{$endif}
|
|
cinfo^.desired_number_of_colors := 256;
|
|
cinfo^.colormap := NIL;
|
|
{ Initialize for no mode change in buffered-image mode. }
|
|
cinfo^.enable_1pass_quant := FALSE;
|
|
cinfo^.enable_external_quant := FALSE;
|
|
cinfo^.enable_2pass_quant := FALSE;
|
|
end;
|
|
|
|
|
|
{ Decompression startup: read start of JPEG datastream to see what's there.
|
|
Need only initialize JPEG object and supply a data source before calling.
|
|
|
|
This routine will read as far as the first SOS marker (ie, actual start of
|
|
compressed data), and will save all tables and parameters in the JPEG
|
|
object. It will also initialize the decompression parameters to default
|
|
values, and finally return JPEG_HEADER_OK. On return, the application may
|
|
adjust the decompression parameters and then call jpeg_start_decompress.
|
|
(Or, if the application only wanted to determine the image parameters,
|
|
the data need not be decompressed. In that case, call jpeg_abort or
|
|
jpeg_destroy to release any temporary space.)
|
|
If an abbreviated (tables only) datastream is presented, the routine will
|
|
return JPEG_HEADER_TABLES_ONLY upon reaching EOI. The application may then
|
|
re-use the JPEG object to read the abbreviated image datastream(s).
|
|
It is unnecessary (but OK) to call jpeg_abort in this case.
|
|
The JPEG_SUSPENDED return code only occurs if the data source module
|
|
requests suspension of the decompressor. In this case the application
|
|
should load more source data and then re-call jpeg_read_header to resume
|
|
processing.
|
|
If a non-suspending data source is used and require_image is TRUE, then the
|
|
return code need not be inspected since only JPEG_HEADER_OK is possible.
|
|
|
|
This routine is now just a front end to jpeg_consume_input, with some
|
|
extra error checking. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_read_header (cinfo : j_decompress_ptr;
|
|
require_image : boolean) : int;
|
|
var
|
|
retcode : int;
|
|
begin
|
|
if (cinfo^.global_state <> DSTATE_START) and
|
|
(cinfo^.global_state <> DSTATE_INHEADER) then
|
|
ERREXIT1(j_common_ptr(cinfo), JERR_BAD_STATE, cinfo^.global_state);
|
|
|
|
retcode := jpeg_consume_input(cinfo);
|
|
|
|
case (retcode) of
|
|
JPEG_REACHED_SOS:
|
|
retcode := JPEG_HEADER_OK;
|
|
JPEG_REACHED_EOI:
|
|
begin
|
|
if (require_image) then { Complain if application wanted an image }
|
|
ERREXIT(j_common_ptr(cinfo), JERR_NO_IMAGE);
|
|
{ Reset to start state; it would be safer to require the application to
|
|
call jpeg_abort, but we can't change it now for compatibility reasons.
|
|
A side effect is to free any temporary memory (there shouldn't be any). }
|
|
|
|
jpeg_abort(j_common_ptr(cinfo)); { sets state := DSTATE_START }
|
|
retcode := JPEG_HEADER_TABLES_ONLY;
|
|
end;
|
|
JPEG_SUSPENDED: ; { no work }
|
|
end;
|
|
|
|
jpeg_read_header := retcode;
|
|
end;
|
|
|
|
|
|
{ Consume data in advance of what the decompressor requires.
|
|
This can be called at any time once the decompressor object has
|
|
been created and a data source has been set up.
|
|
|
|
This routine is essentially a state machine that handles a couple
|
|
of critical state-transition actions, namely initial setup and
|
|
transition from header scanning to ready-for-start_decompress.
|
|
All the actual input is done via the input controller's consume_input
|
|
method. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_consume_input (cinfo : j_decompress_ptr) : int;
|
|
var
|
|
retcode : int;
|
|
begin
|
|
retcode := JPEG_SUSPENDED;
|
|
|
|
{ NB: every possible DSTATE value should be listed in this switch }
|
|
|
|
if (cinfo^.global_state) = DSTATE_START then
|
|
begin {work around the FALLTHROUGH}
|
|
{ Start-of-datastream actions: reset appropriate modules }
|
|
cinfo^.inputctl^.reset_input_controller (cinfo);
|
|
{ Initialize application's data source module }
|
|
cinfo^.src^.init_source (cinfo);
|
|
cinfo^.global_state := DSTATE_INHEADER;
|
|
end;
|
|
|
|
case (cinfo^.global_state) of
|
|
DSTATE_START,
|
|
DSTATE_INHEADER:
|
|
begin
|
|
retcode := cinfo^.inputctl^.consume_input (cinfo);
|
|
if (retcode = JPEG_REACHED_SOS) then
|
|
begin { Found SOS, prepare to decompress }
|
|
{ Set up default parameters based on header data }
|
|
default_decompress_parms(cinfo);
|
|
{ Set global state: ready for start_decompress }
|
|
cinfo^.global_state := DSTATE_READY;
|
|
end;
|
|
end;
|
|
DSTATE_READY:
|
|
{ Can't advance past first SOS until start_decompress is called }
|
|
retcode := JPEG_REACHED_SOS;
|
|
|
|
DSTATE_PRELOAD,
|
|
DSTATE_PRESCAN,
|
|
DSTATE_SCANNING,
|
|
DSTATE_RAW_OK,
|
|
DSTATE_BUFIMAGE,
|
|
DSTATE_BUFPOST,
|
|
DSTATE_STOPPING:
|
|
retcode := cinfo^.inputctl^.consume_input (cinfo);
|
|
else
|
|
ERREXIT1(j_common_ptr(cinfo), JERR_BAD_STATE, cinfo^.global_state);
|
|
end;
|
|
jpeg_consume_input := retcode;
|
|
end;
|
|
|
|
|
|
{ Have we finished reading the input file? }
|
|
|
|
{GLOBAL}
|
|
function jpeg_input_complete (cinfo : j_decompress_ptr) : boolean;
|
|
begin
|
|
{ Check for valid jpeg object }
|
|
if (cinfo^.global_state < DSTATE_START) or
|
|
(cinfo^.global_state > DSTATE_STOPPING) then
|
|
ERREXIT1(j_common_ptr(cinfo), JERR_BAD_STATE, cinfo^.global_state);
|
|
jpeg_input_complete := cinfo^.inputctl^.eoi_reached;
|
|
end;
|
|
|
|
|
|
{ Is there more than one scan? }
|
|
|
|
{GLOBAL}
|
|
function jpeg_has_multiple_scans (cinfo : j_decompress_ptr) : boolean;
|
|
begin
|
|
{ Only valid after jpeg_read_header completes }
|
|
if (cinfo^.global_state < DSTATE_READY) or
|
|
(cinfo^.global_state > DSTATE_STOPPING) then
|
|
ERREXIT1(j_common_ptr(cinfo), JERR_BAD_STATE, cinfo^.global_state);
|
|
jpeg_has_multiple_scans := cinfo^.inputctl^.has_multiple_scans;
|
|
end;
|
|
|
|
|
|
{ Finish JPEG decompression.
|
|
|
|
This will normally just verify the file trailer and release temp storage.
|
|
|
|
Returns FALSE if suspended. The return value need be inspected only if
|
|
a suspending data source is used. }
|
|
|
|
{GLOBAL}
|
|
function jpeg_finish_decompress (cinfo : j_decompress_ptr) : boolean;
|
|
begin
|
|
if ((cinfo^.global_state = DSTATE_SCANNING) or
|
|
(cinfo^.global_state = DSTATE_RAW_OK) and (not cinfo^.buffered_image)) then
|
|
begin
|
|
{ Terminate final pass of non-buffered mode }
|
|
if (cinfo^.output_scanline < cinfo^.output_height) then
|
|
ERREXIT(j_common_ptr(cinfo), JERR_TOO_LITTLE_DATA);
|
|
cinfo^.master^.finish_output_pass (cinfo);
|
|
cinfo^.global_state := DSTATE_STOPPING;
|
|
end
|
|
else
|
|
if (cinfo^.global_state = DSTATE_BUFIMAGE) then
|
|
begin
|
|
{ Finishing after a buffered-image operation }
|
|
cinfo^.global_state := DSTATE_STOPPING;
|
|
end
|
|
else
|
|
if (cinfo^.global_state <> DSTATE_STOPPING) then
|
|
begin
|
|
{ STOPPING := repeat call after a suspension, anything else is error }
|
|
ERREXIT1(j_common_ptr(cinfo), JERR_BAD_STATE, cinfo^.global_state);
|
|
end;
|
|
{ Read until EOI }
|
|
while (not cinfo^.inputctl^.eoi_reached) do
|
|
begin
|
|
if (cinfo^.inputctl^.consume_input (cinfo) = JPEG_SUSPENDED) then
|
|
begin
|
|
jpeg_finish_decompress := FALSE; { Suspend, come back later }
|
|
exit;
|
|
end;
|
|
end;
|
|
{ Do final cleanup }
|
|
cinfo^.src^.term_source (cinfo);
|
|
{ We can use jpeg_abort to release memory and reset global_state }
|
|
jpeg_abort(j_common_ptr(cinfo));
|
|
jpeg_finish_decompress := TRUE;
|
|
end;
|
|
|
|
end.
|