344 lines
11 KiB
Plaintext
344 lines
11 KiB
Plaintext
unit imjcmainct;
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{ This file contains the main buffer controller for compression.
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The main buffer lies between the pre-processor and the JPEG
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compressor proper; it holds downsampled data in the JPEG colorspace. }
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{ Original : jcmainct.c ; Copyright (C) 1994-1996, Thomas G. Lane. }
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interface
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{$I imjconfig.inc}
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{ Note: currently, there is no operating mode in which a full-image buffer
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is needed at this step. If there were, that mode could not be used with
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"raw data" input, since this module is bypassed in that case. However,
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we've left the code here for possible use in special applications. }
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{$undef FULL_MAIN_BUFFER_SUPPORTED}
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uses
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imjmorecfg,
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imjinclude,
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imjdeferr,
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imjerror,
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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imjutils,
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{$endif}
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imjpeglib;
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{ Initialize main buffer controller. }
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{GLOBAL}
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procedure jinit_c_main_controller (cinfo : j_compress_ptr;
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need_full_buffer : boolean);
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implementation
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{ Private buffer controller object }
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type
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my_main_ptr = ^my_main_controller;
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my_main_controller = record
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pub : jpeg_c_main_controller; { public fields }
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cur_iMCU_row : JDIMENSION; { number of current iMCU row }
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rowgroup_ctr : JDIMENSION; { counts row groups received in iMCU row }
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suspended : boolean; { remember if we suspended output }
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pass_mode : J_BUF_MODE; { current operating mode }
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{ If using just a strip buffer, this points to the entire set of buffers
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(we allocate one for each component). In the full-image case, this
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points to the currently accessible strips of the virtual arrays. }
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buffer : array[0..MAX_COMPONENTS-1] of JSAMPARRAY;
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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{ If using full-image storage, this array holds pointers to virtual-array
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control blocks for each component. Unused if not full-image storage. }
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whole_image : array[0..MAX_COMPONENTS-1] of jvirt_sarray_ptr;
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{$endif}
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end; {my_main_controller}
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{ Forward declarations }
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{METHODDEF}
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procedure process_data_simple_main(cinfo : j_compress_ptr;
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input_buf : JSAMPARRAY;
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var in_row_ctr: JDIMENSION;
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in_rows_avail : JDIMENSION); forward;
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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{METHODDEF}
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procedure process_data_buffer_main(cinfo : j_compress_ptr;
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input_buf : JSAMPARRAY;
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var in_row_ctr : JDIMENSION;
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in_rows_avail : JDIMENSION); forward;
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{$endif}
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{ Initialize for a processing pass. }
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{METHODDEF}
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procedure start_pass_main (cinfo : j_compress_ptr;
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pass_mode : J_BUF_MODE);
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var
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main : my_main_ptr;
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begin
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main := my_main_ptr (cinfo^.main);
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{ Do nothing in raw-data mode. }
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if (cinfo^.raw_data_in) then
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exit;
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main^.cur_iMCU_row := 0; { initialize counters }
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main^.rowgroup_ctr := 0;
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main^.suspended := FALSE;
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main^.pass_mode := pass_mode; { save mode for use by process_data }
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case (pass_mode) of
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JBUF_PASS_THRU:
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begin
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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if (main^.whole_image[0] <> NIL) then
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ERREXIT(j_common_ptr(cinfo), JERR_BAD_BUFFER_MODE);
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{$endif}
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main^.pub.process_data := process_data_simple_main;
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end;
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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JBUF_SAVE_SOURCE,
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JBUF_CRANK_DEST,
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JBUF_SAVE_AND_PASS:
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begin
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if (main^.whole_image[0] = NIL) then
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ERREXIT(j_common_ptr(cinfo), JERR_BAD_BUFFER_MODE);
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main^.pub.process_data := process_data_buffer_main;
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end;
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{$endif}
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else
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ERREXIT(j_common_ptr(cinfo), JERR_BAD_BUFFER_MODE);
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end;
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end;
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{ Process some data.
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This routine handles the simple pass-through mode,
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where we have only a strip buffer. }
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{METHODDEF}
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procedure process_data_simple_main (cinfo : j_compress_ptr;
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input_buf : JSAMPARRAY;
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var in_row_ctr : JDIMENSION;
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in_rows_avail : JDIMENSION);
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var
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main : my_main_ptr;
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begin
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main := my_main_ptr (cinfo^.main);
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while (main^.cur_iMCU_row < cinfo^.total_iMCU_rows) do
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begin
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{ Read input data if we haven't filled the main buffer yet }
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if (main^.rowgroup_ctr < DCTSIZE) then
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cinfo^.prep^.pre_process_data (cinfo,
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input_buf,
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in_row_ctr,
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in_rows_avail,
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JSAMPIMAGE(@main^.buffer),
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main^.rowgroup_ctr,
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JDIMENSION(DCTSIZE));
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{ If we don't have a full iMCU row buffered, return to application for
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more data. Note that preprocessor will always pad to fill the iMCU row
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at the bottom of the image. }
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if (main^.rowgroup_ctr <> DCTSIZE) then
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exit;
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{ Send the completed row to the compressor }
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if (not cinfo^.coef^.compress_data (cinfo, JSAMPIMAGE(@main^.buffer))) then
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begin
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{ If compressor did not consume the whole row, then we must need to
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suspend processing and return to the application. In this situation
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we pretend we didn't yet consume the last input row; otherwise, if
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it happened to be the last row of the image, the application would
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think we were done. }
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if (not main^.suspended) then
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begin
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Dec(in_row_ctr);
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main^.suspended := TRUE;
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end;
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exit;
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end;
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{ We did finish the row. Undo our little suspension hack if a previous
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call suspended; then mark the main buffer empty. }
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if (main^.suspended) then
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begin
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Inc(in_row_ctr);
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main^.suspended := FALSE;
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end;
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main^.rowgroup_ctr := 0;
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Inc(main^.cur_iMCU_row);
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end;
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end;
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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{ Process some data.
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This routine handles all of the modes that use a full-size buffer. }
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{METHODDEF}
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procedure process_data_buffer_main (cinfo : j_compress_ptr;
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input_buf : JSAMPARRAY;
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var in_row_ctr : JDIMENSION;
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in_rows_avail : JDIMENSION);
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var
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main : my_main_ptr;
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ci : int;
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compptr : jpeg_component_info_ptr;
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writing : boolean;
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begin
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main := my_main_ptr (cinfo^.main);
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writing := (main^.pass_mode <> JBUF_CRANK_DEST);
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while (main^.cur_iMCU_row < cinfo^.total_iMCU_rows) do
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begin
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{ Realign the virtual buffers if at the start of an iMCU row. }
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if (main^.rowgroup_ctr = 0) then
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begin
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compptr := cinfo^.comp_info;
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for ci := 0 to pred(cinfo^.num_components) do
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begin
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main^.buffer[ci] := cinfo^.mem^.access_virt_sarray
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(j_common_ptr (cinfo), main^.whole_image[ci],
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main^.cur_iMCU_row * (compptr^.v_samp_factor * DCTSIZE),
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JDIMENSION (compptr^.v_samp_factor * DCTSIZE), writing);
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Inc(compptr);
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end;
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{ In a read pass, pretend we just read some source data. }
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if (not writing) then
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begin
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Inc(in_row_ctr, cinfo^.max_v_samp_factor * DCTSIZE);
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main^.rowgroup_ctr := DCTSIZE;
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end;
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end;
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{ If a write pass, read input data until the current iMCU row is full. }
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{ Note: preprocessor will pad if necessary to fill the last iMCU row. }
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if (writing) then
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begin
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cinfo^.prep^.pre_process_data (cinfo,
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input_buf, in_row_ctr, in_rows_avail,
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JSAMPIMAGE(@main^.buffer),
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main^.rowgroup_ctr,
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JDIMENSION (DCTSIZE));
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{ Return to application if we need more data to fill the iMCU row. }
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if (main^.rowgroup_ctr < DCTSIZE) then
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exit;
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end;
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{ Emit data, unless this is a sink-only pass. }
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if (main^.pass_mode <> JBUF_SAVE_SOURCE) then
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begin
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if (not cinfo^.coef^.compress_data (cinfo,
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JSAMPIMAGE(@main^.buffer))) then
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begin
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{ If compressor did not consume the whole row, then we must need to
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suspend processing and return to the application. In this situation
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we pretend we didn't yet consume the last input row; otherwise, if
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it happened to be the last row of the image, the application would
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think we were done. }
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if (not main^.suspended) then
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begin
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Dec(in_row_ctr);
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main^.suspended := TRUE;
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end;
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exit;
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end;
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{ We did finish the row. Undo our little suspension hack if a previous
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call suspended; then mark the main buffer empty. }
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if (main^.suspended) then
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begin
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Inc(in_row_ctr);
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main^.suspended := FALSE;
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end;
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end;
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{ If get here, we are done with this iMCU row. Mark buffer empty. }
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main^.rowgroup_ctr := 0;
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Inc(main^.cur_iMCU_row);
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end;
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end;
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{$endif} { FULL_MAIN_BUFFER_SUPPORTED }
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{ Initialize main buffer controller. }
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{GLOBAL}
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procedure jinit_c_main_controller (cinfo : j_compress_ptr;
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need_full_buffer : boolean);
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var
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main : my_main_ptr;
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ci : int;
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compptr : jpeg_component_info_ptr;
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begin
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main := my_main_ptr(
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cinfo^.mem^.alloc_small (j_common_ptr(cinfo), JPOOL_IMAGE,
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SIZEOF(my_main_controller)) );
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cinfo^.main := jpeg_c_main_controller_ptr(main);
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main^.pub.start_pass := start_pass_main;
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{ We don't need to create a buffer in raw-data mode. }
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if (cinfo^.raw_data_in) then
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exit;
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{ Create the buffer. It holds downsampled data, so each component
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may be of a different size. }
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if (need_full_buffer) then
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begin
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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{ Allocate a full-image virtual array for each component }
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{ Note we pad the bottom to a multiple of the iMCU height }
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compptr := cinfo^.comp_info;
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for ci := 0 to pred(cinfo^.num_components) do
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begin
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main^.whole_image[ci] := cinfo^.mem^.request_virt_sarray
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(j_common_ptr(cinfo), JPOOL_IMAGE, FALSE,
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compptr^.width_in_blocks * DCTSIZE,
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JDIMENSION (jround_up( long (compptr^.height_in_blocks),
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long (compptr^.v_samp_factor)) * DCTSIZE),
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JDIMENSION (compptr^.v_samp_factor * DCTSIZE));
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Inc(compptr);
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end;
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{$else}
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ERREXIT(j_common_ptr(cinfo), JERR_BAD_BUFFER_MODE);
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{$endif}
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end
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else
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begin
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{$ifdef FULL_MAIN_BUFFER_SUPPORTED}
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main^.whole_image[0] := NIL; { flag for no virtual arrays }
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{$endif}
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{ Allocate a strip buffer for each component }
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compptr := jpeg_component_info_ptr(cinfo^.comp_info);
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for ci := 0 to pred(cinfo^.num_components) do
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begin
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main^.buffer[ci] := cinfo^.mem^.alloc_sarray
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(j_common_ptr(cinfo), JPOOL_IMAGE,
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compptr^.width_in_blocks * DCTSIZE,
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JDIMENSION (compptr^.v_samp_factor * DCTSIZE));
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Inc(compptr);
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end;
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end;
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end;
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end.
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