896 lines
28 KiB
Plaintext
896 lines
28 KiB
Plaintext
unit imjdcoefct;
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{ This file contains the coefficient buffer controller for decompression.
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This controller is the top level of the JPEG decompressor proper.
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The coefficient buffer lies between entropy decoding and inverse-DCT steps.
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In buffered-image mode, this controller is the interface between
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input-oriented processing and output-oriented processing.
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Also, the input side (only) is used when reading a file for transcoding. }
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{ Original: jdcoefct.c ; Copyright (C) 1994-1997, Thomas G. Lane. }
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interface
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{$I imjconfig.inc}
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uses
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imjmorecfg,
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imjinclude,
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imjdeferr,
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imjerror,
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imjutils,
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imjpeglib;
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{GLOBAL}
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procedure jinit_d_coef_controller (cinfo : j_decompress_ptr;
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need_full_buffer : boolean);
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implementation
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{ Block smoothing is only applicable for progressive JPEG, so: }
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{$ifndef D_PROGRESSIVE_SUPPORTED}
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{$undef BLOCK_SMOOTHING_SUPPORTED}
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{$endif}
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{ Private buffer controller object }
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{$ifdef BLOCK_SMOOTHING_SUPPORTED}
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const
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SAVED_COEFS = 6; { we save coef_bits[0..5] }
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type
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Latch = array[0..SAVED_COEFS-1] of int;
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Latch_ptr = ^Latch;
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{$endif}
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type
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my_coef_ptr = ^my_coef_controller;
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my_coef_controller = record
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pub : jpeg_d_coef_controller; { public fields }
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{ These variables keep track of the current location of the input side. }
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{ cinfo^.input_iMCU_row is also used for this. }
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MCU_ctr : JDIMENSION; { counts MCUs processed in current row }
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MCU_vert_offset : int; { counts MCU rows within iMCU row }
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MCU_rows_per_iMCU_row : int; { number of such rows needed }
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{ The output side's location is represented by cinfo^.output_iMCU_row. }
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{ In single-pass modes, it's sufficient to buffer just one MCU.
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We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
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and let the entropy decoder write into that workspace each time.
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(On 80x86, the workspace is FAR even though it's not really very big;
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this is to keep the module interfaces unchanged when a large coefficient
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buffer is necessary.)
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In multi-pass modes, this array points to the current MCU's blocks
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within the virtual arrays; it is used only by the input side. }
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MCU_buffer : array[0..D_MAX_BLOCKS_IN_MCU-1] of JBLOCKROW;
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{$ifdef D_MULTISCAN_FILES_SUPPORTED}
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{ In multi-pass modes, we need a virtual block array for each component. }
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whole_image : jvirt_barray_tbl;
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{$endif}
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{$ifdef BLOCK_SMOOTHING_SUPPORTED}
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{ When doing block smoothing, we latch coefficient Al values here }
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coef_bits_latch : Latch_Ptr;
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{$endif}
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end;
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{ Forward declarations }
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{METHODDEF}
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function decompress_onepass (cinfo : j_decompress_ptr;
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output_buf : JSAMPIMAGE) : int; forward;
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{$ifdef D_MULTISCAN_FILES_SUPPORTED}
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{METHODDEF}
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function decompress_data (cinfo : j_decompress_ptr;
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output_buf : JSAMPIMAGE) : int; forward;
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{$endif}
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{$ifdef BLOCK_SMOOTHING_SUPPORTED}
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{LOCAL}
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function smoothing_ok (cinfo : j_decompress_ptr) : boolean; forward;
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{METHODDEF}
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function decompress_smooth_data (cinfo : j_decompress_ptr;
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output_buf : JSAMPIMAGE) : int; forward;
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{$endif}
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{LOCAL}
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procedure start_iMCU_row (cinfo : j_decompress_ptr);
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{ Reset within-iMCU-row counters for a new row (input side) }
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var
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coef : my_coef_ptr;
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begin
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coef := my_coef_ptr (cinfo^.coef);
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{ In an interleaved scan, an MCU row is the same as an iMCU row.
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In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
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But at the bottom of the image, process only what's left. }
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if (cinfo^.comps_in_scan > 1) then
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begin
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coef^.MCU_rows_per_iMCU_row := 1;
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end
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else
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begin
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if (cinfo^.input_iMCU_row < (cinfo^.total_iMCU_rows-1)) then
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coef^.MCU_rows_per_iMCU_row := cinfo^.cur_comp_info[0]^.v_samp_factor
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else
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coef^.MCU_rows_per_iMCU_row := cinfo^.cur_comp_info[0]^.last_row_height;
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end;
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coef^.MCU_ctr := 0;
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coef^.MCU_vert_offset := 0;
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end;
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{ Initialize for an input processing pass. }
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{METHODDEF}
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procedure start_input_pass (cinfo : j_decompress_ptr);
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begin
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cinfo^.input_iMCU_row := 0;
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start_iMCU_row(cinfo);
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end;
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{ Initialize for an output processing pass. }
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{METHODDEF}
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procedure start_output_pass (cinfo : j_decompress_ptr);
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var
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coef : my_coef_ptr;
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begin
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{$ifdef BLOCK_SMOOTHING_SUPPORTED}
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coef := my_coef_ptr (cinfo^.coef);
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{ If multipass, check to see whether to use block smoothing on this pass }
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if (coef^.pub.coef_arrays <> NIL) then
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begin
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if (cinfo^.do_block_smoothing) and smoothing_ok(cinfo) then
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coef^.pub.decompress_data := decompress_smooth_data
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else
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coef^.pub.decompress_data := decompress_data;
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end;
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{$endif}
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cinfo^.output_iMCU_row := 0;
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end;
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{ Decompress and return some data in the single-pass case.
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Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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Input and output must run in lockstep since we have only a one-MCU buffer.
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Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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NB: output_buf contains a plane for each component in image,
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which we index according to the component's SOF position.}
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{METHODDEF}
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function decompress_onepass (cinfo : j_decompress_ptr;
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output_buf : JSAMPIMAGE) : int;
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var
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coef : my_coef_ptr;
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MCU_col_num : JDIMENSION; { index of current MCU within row }
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last_MCU_col : JDIMENSION;
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last_iMCU_row : JDIMENSION;
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blkn, ci, xindex, yindex, yoffset, useful_width : int;
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output_ptr : JSAMPARRAY;
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start_col, output_col : JDIMENSION;
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compptr : jpeg_component_info_ptr;
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inverse_DCT : inverse_DCT_method_ptr;
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begin
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coef := my_coef_ptr (cinfo^.coef);
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last_MCU_col := cinfo^.MCUs_per_row - 1;
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last_iMCU_row := cinfo^.total_iMCU_rows - 1;
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{ Loop to process as much as one whole iMCU row }
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for yoffset := coef^.MCU_vert_offset to pred(coef^.MCU_rows_per_iMCU_row) do
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begin
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for MCU_col_num := coef^.MCU_ctr to last_MCU_col do
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begin
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{ Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. }
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jzero_far( coef^.MCU_buffer[0],
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size_t (cinfo^.blocks_in_MCU * SIZEOF(JBLOCK)));
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if (not cinfo^.entropy^.decode_mcu (cinfo, coef^.MCU_buffer)) then
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begin
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{ Suspension forced; update state counters and exit }
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coef^.MCU_vert_offset := yoffset;
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coef^.MCU_ctr := MCU_col_num;
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decompress_onepass := JPEG_SUSPENDED;
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exit;
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end;
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{ Determine where data should go in output_buf and do the IDCT thing.
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We skip dummy blocks at the right and bottom edges (but blkn gets
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incremented past them!). Note the inner loop relies on having
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allocated the MCU_buffer[] blocks sequentially. }
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blkn := 0; { index of current DCT block within MCU }
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for ci := 0 to pred(cinfo^.comps_in_scan) do
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begin
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compptr := cinfo^.cur_comp_info[ci];
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{ Don't bother to IDCT an uninteresting component. }
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if (not compptr^.component_needed) then
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begin
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Inc(blkn, compptr^.MCU_blocks);
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continue;
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end;
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inverse_DCT := cinfo^.idct^.inverse_DCT[compptr^.component_index];
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if (MCU_col_num < last_MCU_col) then
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useful_width := compptr^.MCU_width
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else
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useful_width := compptr^.last_col_width;
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output_ptr := JSAMPARRAY(@ output_buf^[compptr^.component_index]^
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[yoffset * compptr^.DCT_scaled_size]);
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start_col := LongInt(MCU_col_num) * compptr^.MCU_sample_width;
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for yindex := 0 to pred(compptr^.MCU_height) do
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begin
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if (cinfo^.input_iMCU_row < last_iMCU_row) or
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(yoffset+yindex < compptr^.last_row_height) then
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begin
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output_col := start_col;
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for xindex := 0 to pred(useful_width) do
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begin
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inverse_DCT (cinfo, compptr,
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JCOEFPTR(coef^.MCU_buffer[blkn+xindex]),
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output_ptr, output_col);
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Inc(output_col, compptr^.DCT_scaled_size);
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end;
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end;
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Inc(blkn, compptr^.MCU_width);
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Inc(JSAMPROW_PTR(output_ptr), compptr^.DCT_scaled_size);
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end;
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end;
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end;
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{ Completed an MCU row, but perhaps not an iMCU row }
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coef^.MCU_ctr := 0;
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end;
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{ Completed the iMCU row, advance counters for next one }
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Inc(cinfo^.output_iMCU_row);
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Inc(cinfo^.input_iMCU_row);
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if (cinfo^.input_iMCU_row < cinfo^.total_iMCU_rows) then
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begin
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start_iMCU_row(cinfo);
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decompress_onepass := JPEG_ROW_COMPLETED;
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exit;
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end;
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{ Completed the scan }
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cinfo^.inputctl^.finish_input_pass (cinfo);
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decompress_onepass := JPEG_SCAN_COMPLETED;
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end;
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{ Dummy consume-input routine for single-pass operation. }
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{METHODDEF}
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function dummy_consume_data (cinfo : j_decompress_ptr) : int;
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begin
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dummy_consume_data := JPEG_SUSPENDED; { Always indicate nothing was done }
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end;
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{$ifdef D_MULTISCAN_FILES_SUPPORTED}
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{ Consume input data and store it in the full-image coefficient buffer.
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We read as much as one fully interleaved MCU row ("iMCU" row) per call,
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ie, v_samp_factor block rows for each component in the scan.
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Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.}
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{METHODDEF}
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function consume_data (cinfo : j_decompress_ptr) : int;
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var
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coef : my_coef_ptr;
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MCU_col_num : JDIMENSION; { index of current MCU within row }
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blkn, ci, xindex, yindex, yoffset : int;
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start_col : JDIMENSION;
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buffer : array[0..MAX_COMPS_IN_SCAN-1] of JBLOCKARRAY;
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buffer_ptr : JBLOCKROW;
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compptr : jpeg_component_info_ptr;
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begin
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coef := my_coef_ptr (cinfo^.coef);
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{ Align the virtual buffers for the components used in this scan. }
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for ci := 0 to pred(cinfo^.comps_in_scan) do
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begin
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compptr := cinfo^.cur_comp_info[ci];
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buffer[ci] := cinfo^.mem^.access_virt_barray
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(j_common_ptr (cinfo), coef^.whole_image[compptr^.component_index],
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LongInt(cinfo^.input_iMCU_row) * compptr^.v_samp_factor,
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JDIMENSION (compptr^.v_samp_factor), TRUE);
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{ Note: entropy decoder expects buffer to be zeroed,
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but this is handled automatically by the memory manager
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because we requested a pre-zeroed array. }
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end;
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{ Loop to process one whole iMCU row }
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for yoffset := coef^.MCU_vert_offset to pred(coef^.MCU_rows_per_iMCU_row) do
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begin
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for MCU_col_num := coef^.MCU_ctr to pred(cinfo^.MCUs_per_row) do
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begin
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{ Construct list of pointers to DCT blocks belonging to this MCU }
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blkn := 0; { index of current DCT block within MCU }
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for ci := 0 to pred(cinfo^.comps_in_scan) do
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begin
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compptr := cinfo^.cur_comp_info[ci];
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start_col := LongInt(MCU_col_num) * compptr^.MCU_width;
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for yindex := 0 to pred(compptr^.MCU_height) do
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begin
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buffer_ptr := JBLOCKROW(@ buffer[ci]^[yindex+yoffset]^[start_col]);
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for xindex := 0 to pred(compptr^.MCU_width) do
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begin
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coef^.MCU_buffer[blkn] := buffer_ptr;
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Inc(blkn);
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Inc(JBLOCK_PTR(buffer_ptr));
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end;
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end;
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end;
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{ Try to fetch the MCU. }
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if (not cinfo^.entropy^.decode_mcu (cinfo, coef^.MCU_buffer)) then
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begin
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{ Suspension forced; update state counters and exit }
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coef^.MCU_vert_offset := yoffset;
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coef^.MCU_ctr := MCU_col_num;
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consume_data := JPEG_SUSPENDED;
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exit;
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end;
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end;
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{ Completed an MCU row, but perhaps not an iMCU row }
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coef^.MCU_ctr := 0;
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end;
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{ Completed the iMCU row, advance counters for next one }
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Inc(cinfo^.input_iMCU_row);
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if (cinfo^.input_iMCU_row < cinfo^.total_iMCU_rows) then
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begin
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start_iMCU_row(cinfo);
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consume_data := JPEG_ROW_COMPLETED;
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exit;
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end;
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{ Completed the scan }
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cinfo^.inputctl^.finish_input_pass (cinfo);
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consume_data := JPEG_SCAN_COMPLETED;
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end;
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{ Decompress and return some data in the multi-pass case.
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Always attempts to emit one fully interleaved MCU row ("iMCU" row).
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Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
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NB: output_buf contains a plane for each component in image. }
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{METHODDEF}
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function decompress_data (cinfo : j_decompress_ptr;
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output_buf : JSAMPIMAGE) : int;
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var
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coef : my_coef_ptr;
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last_iMCU_row : JDIMENSION;
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block_num : JDIMENSION;
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ci, block_row, block_rows : int;
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buffer : JBLOCKARRAY;
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buffer_ptr : JBLOCKROW;
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output_ptr : JSAMPARRAY;
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output_col : JDIMENSION;
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compptr : jpeg_component_info_ptr;
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inverse_DCT : inverse_DCT_method_ptr;
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begin
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coef := my_coef_ptr (cinfo^.coef);
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last_iMCU_row := cinfo^.total_iMCU_rows - 1;
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{ Force some input to be done if we are getting ahead of the input. }
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while (cinfo^.input_scan_number < cinfo^.output_scan_number) or
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((cinfo^.input_scan_number = cinfo^.output_scan_number) and
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(LongInt(cinfo^.input_iMCU_row) <= cinfo^.output_iMCU_row)) do
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begin
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if (cinfo^.inputctl^.consume_input(cinfo) = JPEG_SUSPENDED) then
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begin
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decompress_data := JPEG_SUSPENDED;
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exit;
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end;
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end;
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{ OK, output from the virtual arrays. }
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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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{ Don't bother to IDCT an uninteresting component. }
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if (not compptr^.component_needed) then
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continue;
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{ Align the virtual buffer for this component. }
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buffer := cinfo^.mem^.access_virt_barray
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(j_common_ptr (cinfo), coef^.whole_image[ci],
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cinfo^.output_iMCU_row * compptr^.v_samp_factor,
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JDIMENSION (compptr^.v_samp_factor), FALSE);
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{ Count non-dummy DCT block rows in this iMCU row. }
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if (cinfo^.output_iMCU_row < LongInt(last_iMCU_row)) then
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block_rows := compptr^.v_samp_factor
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else
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begin
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{ NB: can't use last_row_height here; it is input-side-dependent! }
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block_rows := int(LongInt(compptr^.height_in_blocks) mod compptr^.v_samp_factor);
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if (block_rows = 0) then
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block_rows := compptr^.v_samp_factor;
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end;
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inverse_DCT := cinfo^.idct^.inverse_DCT[ci];
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output_ptr := output_buf^[ci];
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{ Loop over all DCT blocks to be processed. }
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for block_row := 0 to pred(block_rows) do
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begin
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buffer_ptr := buffer^[block_row];
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output_col := 0;
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for block_num := 0 to pred(compptr^.width_in_blocks) do
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begin
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inverse_DCT (cinfo, compptr, JCOEFPTR (buffer_ptr),
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output_ptr, output_col);
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Inc(JBLOCK_PTR(buffer_ptr));
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Inc(output_col, compptr^.DCT_scaled_size);
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end;
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Inc(JSAMPROW_PTR(output_ptr), compptr^.DCT_scaled_size);
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end;
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Inc(compptr);
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end;
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Inc(cinfo^.output_iMCU_row);
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if (cinfo^.output_iMCU_row < LongInt(cinfo^.total_iMCU_rows)) then
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begin
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decompress_data := JPEG_ROW_COMPLETED;
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exit;
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end;
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decompress_data := JPEG_SCAN_COMPLETED;
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end;
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{$endif} { D_MULTISCAN_FILES_SUPPORTED }
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{$ifdef BLOCK_SMOOTHING_SUPPORTED}
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{ This code applies interblock smoothing as described by section K.8
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of the JPEG standard: the first 5 AC coefficients are estimated from
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the DC values of a DCT block and its 8 neighboring blocks.
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We apply smoothing only for progressive JPEG decoding, and only if
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the coefficients it can estimate are not yet known to full precision. }
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{ Natural-order array positions of the first 5 zigzag-order coefficients }
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const
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Q01_POS = 1;
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Q10_POS = 8;
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|
Q20_POS = 16;
|
|
Q11_POS = 9;
|
|
Q02_POS = 2;
|
|
|
|
{ Determine whether block smoothing is applicable and safe.
|
|
We also latch the current states of the coef_bits[] entries for the
|
|
AC coefficients; otherwise, if the input side of the decompressor
|
|
advances into a new scan, we might think the coefficients are known
|
|
more accurately than they really are. }
|
|
|
|
{LOCAL}
|
|
function smoothing_ok (cinfo : j_decompress_ptr) : boolean;
|
|
var
|
|
coef : my_coef_ptr;
|
|
smoothing_useful : boolean;
|
|
ci, coefi : int;
|
|
compptr : jpeg_component_info_ptr;
|
|
qtable : JQUANT_TBL_PTR;
|
|
coef_bits : coef_bits_ptr;
|
|
coef_bits_latch : Latch_Ptr;
|
|
begin
|
|
coef := my_coef_ptr (cinfo^.coef);
|
|
smoothing_useful := FALSE;
|
|
|
|
if (not cinfo^.progressive_mode) or (cinfo^.coef_bits = NIL) then
|
|
begin
|
|
smoothing_ok := FALSE;
|
|
exit;
|
|
end;
|
|
|
|
{ Allocate latch area if not already done }
|
|
if (coef^.coef_bits_latch = NIL) then
|
|
coef^.coef_bits_latch := Latch_Ptr(
|
|
cinfo^.mem^.alloc_small (j_common_ptr (cinfo), JPOOL_IMAGE,
|
|
cinfo^.num_components *
|
|
(SAVED_COEFS * SIZEOF(int))) );
|
|
coef_bits_latch := (coef^.coef_bits_latch);
|
|
|
|
compptr := jpeg_component_info_ptr(cinfo^.comp_info);
|
|
for ci := 0 to pred(cinfo^.num_components) do
|
|
begin
|
|
{ All components' quantization values must already be latched. }
|
|
qtable := compptr^.quant_table;
|
|
if (qtable = NIL) then
|
|
begin
|
|
smoothing_ok := FALSE;
|
|
exit;
|
|
end;
|
|
{ Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. }
|
|
if (qtable^.quantval[0] = 0) or
|
|
(qtable^.quantval[Q01_POS] = 0) or
|
|
(qtable^.quantval[Q10_POS] = 0) or
|
|
(qtable^.quantval[Q20_POS] = 0) or
|
|
(qtable^.quantval[Q11_POS] = 0) or
|
|
(qtable^.quantval[Q02_POS] = 0) then
|
|
begin
|
|
smoothing_ok := FALSE;
|
|
exit;
|
|
end;
|
|
{ DC values must be at least partly known for all components. }
|
|
coef_bits := @cinfo^.coef_bits^[ci]; { Nomssi }
|
|
if (coef_bits^[0] < 0) then
|
|
begin
|
|
smoothing_ok := FALSE;
|
|
exit;
|
|
end;
|
|
{ Block smoothing is helpful if some AC coefficients remain inaccurate. }
|
|
for coefi := 1 to 5 do
|
|
begin
|
|
coef_bits_latch^[coefi] := coef_bits^[coefi];
|
|
if (coef_bits^[coefi] <> 0) then
|
|
smoothing_useful := TRUE;
|
|
end;
|
|
Inc(coef_bits_latch {SAVED_COEFS});
|
|
Inc(compptr);
|
|
end;
|
|
|
|
smoothing_ok := smoothing_useful;
|
|
end;
|
|
|
|
|
|
{ Variant of decompress_data for use when doing block smoothing. }
|
|
|
|
{METHODDEF}
|
|
function decompress_smooth_data (cinfo : j_decompress_ptr;
|
|
output_buf : JSAMPIMAGE) : int;
|
|
var
|
|
coef : my_coef_ptr;
|
|
last_iMCU_row : JDIMENSION;
|
|
block_num, last_block_column : JDIMENSION;
|
|
ci, block_row, block_rows, access_rows : int;
|
|
buffer : JBLOCKARRAY;
|
|
buffer_ptr, prev_block_row, next_block_row : JBLOCKROW;
|
|
output_ptr : JSAMPARRAY;
|
|
output_col : JDIMENSION;
|
|
compptr : jpeg_component_info_ptr;
|
|
inverse_DCT : inverse_DCT_method_ptr;
|
|
first_row, last_row : boolean;
|
|
workspace : JBLOCK;
|
|
coef_bits : Latch_Ptr; { coef_bits_ptr; }
|
|
quanttbl : JQUANT_TBL_PTR;
|
|
Q00,Q01,Q02,Q10,Q11,Q20, num : INT32;
|
|
DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9 : int;
|
|
Al, pred : int;
|
|
var
|
|
delta : JDIMENSION;
|
|
begin
|
|
coef := my_coef_ptr (cinfo^.coef);
|
|
last_iMCU_row := cinfo^.total_iMCU_rows - 1;
|
|
|
|
{ Force some input to be done if we are getting ahead of the input. }
|
|
while (cinfo^.input_scan_number <= cinfo^.output_scan_number) and
|
|
(not cinfo^.inputctl^.eoi_reached) do
|
|
begin
|
|
if (cinfo^.input_scan_number = cinfo^.output_scan_number) then
|
|
begin
|
|
{ If input is working on current scan, we ordinarily want it to
|
|
have completed the current row. But if input scan is DC,
|
|
we want it to keep one row ahead so that next block row's DC
|
|
values are up to date. }
|
|
|
|
if (cinfo^.Ss = 0) then
|
|
delta := 1
|
|
else
|
|
delta := 0;
|
|
if (LongInt(cinfo^.input_iMCU_row) > cinfo^.output_iMCU_row+LongInt(delta)) then
|
|
break;
|
|
end;
|
|
if (cinfo^.inputctl^.consume_input(cinfo) = JPEG_SUSPENDED) then
|
|
begin
|
|
decompress_smooth_data := JPEG_SUSPENDED;
|
|
exit;
|
|
end;
|
|
end;
|
|
|
|
{ OK, output from the virtual arrays. }
|
|
compptr := jpeg_component_info_ptr(cinfo^.comp_info);
|
|
for ci := 0 to (cinfo^.num_components-1) do
|
|
begin
|
|
{ Don't bother to IDCT an uninteresting component. }
|
|
if (not compptr^.component_needed) then
|
|
continue;
|
|
{ Count non-dummy DCT block rows in this iMCU row. }
|
|
if (cinfo^.output_iMCU_row < LongInt(last_iMCU_row)) then
|
|
begin
|
|
block_rows := compptr^.v_samp_factor;
|
|
access_rows := block_rows * 2; { this and next iMCU row }
|
|
last_row := FALSE;
|
|
end
|
|
else
|
|
begin
|
|
{ NB: can't use last_row_height here; it is input-side-dependent! }
|
|
block_rows := int (compptr^.height_in_blocks) mod compptr^.v_samp_factor;
|
|
if (block_rows = 0) then
|
|
block_rows := compptr^.v_samp_factor;
|
|
access_rows := block_rows; { this iMCU row only }
|
|
last_row := TRUE;
|
|
end;
|
|
{ Align the virtual buffer for this component. }
|
|
if (cinfo^.output_iMCU_row > 0) then
|
|
begin
|
|
Inc(access_rows, compptr^.v_samp_factor); { prior iMCU row too }
|
|
buffer := cinfo^.mem^.access_virt_barray
|
|
(j_common_ptr (cinfo), coef^.whole_image[ci],
|
|
(cinfo^.output_iMCU_row - 1) * compptr^.v_samp_factor,
|
|
JDIMENSION (access_rows), FALSE);
|
|
Inc(JBLOCKROW_PTR(buffer), compptr^.v_samp_factor); { point to current iMCU row }
|
|
first_row := FALSE;
|
|
end
|
|
else
|
|
begin
|
|
buffer := cinfo^.mem^.access_virt_barray
|
|
(j_common_ptr (cinfo), coef^.whole_image[ci],
|
|
JDIMENSION (0), JDIMENSION (access_rows), FALSE);
|
|
first_row := TRUE;
|
|
end;
|
|
{ Fetch component-dependent info }
|
|
coef_bits := coef^.coef_bits_latch;
|
|
Inc(coef_bits, ci); { ci * SAVED_COEFS}
|
|
quanttbl := compptr^.quant_table;
|
|
Q00 := quanttbl^.quantval[0];
|
|
Q01 := quanttbl^.quantval[Q01_POS];
|
|
Q10 := quanttbl^.quantval[Q10_POS];
|
|
Q20 := quanttbl^.quantval[Q20_POS];
|
|
Q11 := quanttbl^.quantval[Q11_POS];
|
|
Q02 := quanttbl^.quantval[Q02_POS];
|
|
inverse_DCT := cinfo^.idct^.inverse_DCT[ci];
|
|
output_ptr := output_buf^[ci];
|
|
{ Loop over all DCT blocks to be processed. }
|
|
for block_row := 0 to (block_rows-1) do
|
|
begin
|
|
buffer_ptr := buffer^[block_row];
|
|
if (first_row) and (block_row = 0) then
|
|
prev_block_row := buffer_ptr
|
|
else
|
|
prev_block_row := buffer^[block_row-1];
|
|
if (last_row) and (block_row = block_rows-1) then
|
|
next_block_row := buffer_ptr
|
|
else
|
|
next_block_row := buffer^[block_row+1];
|
|
{ We fetch the surrounding DC values using a sliding-register approach.
|
|
Initialize all nine here so as to do the right thing on narrow pics.}
|
|
|
|
DC3 := int(prev_block_row^[0][0]);
|
|
DC2 := DC3;
|
|
DC1 := DC2;
|
|
DC6 := int(buffer_ptr^[0][0]);
|
|
DC5 := DC6;
|
|
DC4 := DC5;
|
|
DC9 := int(next_block_row^[0][0]);
|
|
DC8 := DC9;
|
|
DC7 := DC8 ;
|
|
output_col := 0;
|
|
last_block_column := compptr^.width_in_blocks - 1;
|
|
for block_num := 0 to last_block_column do
|
|
begin
|
|
{ Fetch current DCT block into workspace so we can modify it. }
|
|
jcopy_block_row(buffer_ptr, JBLOCKROW (@workspace), JDIMENSION(1));
|
|
{ Update DC values }
|
|
if (block_num < last_block_column) then
|
|
begin
|
|
DC3 := int (prev_block_row^[1][0]);
|
|
DC6 := int (buffer_ptr^[1][0]);
|
|
DC9 := int (next_block_row^[1][0]);
|
|
end;
|
|
{ Compute coefficient estimates per K.8.
|
|
An estimate is applied only if coefficient is still zero,
|
|
and is not known to be fully accurate. }
|
|
|
|
{ AC01 }
|
|
Al := coef_bits^[1];
|
|
if (Al <> 0) and (workspace[1] = 0) then
|
|
begin
|
|
num := 36 * Q00 * (DC4 - DC6);
|
|
if (num >= 0) then
|
|
begin
|
|
pred := int (((Q01 shl 7) + num) div (Q01 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
end
|
|
else
|
|
begin
|
|
pred := int (((Q01 shl 7) - num) div (Q01 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
pred := -pred;
|
|
end;
|
|
workspace[1] := JCOEF (pred);
|
|
end;
|
|
{ AC10 }
|
|
Al := coef_bits^[2];
|
|
if (Al <> 0) and (workspace[8] = 0) then
|
|
begin
|
|
num := 36 * Q00 * (DC2 - DC8);
|
|
if (num >= 0) then
|
|
begin
|
|
pred := int (((Q10 shl 7) + num) div (Q10 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
end
|
|
else
|
|
begin
|
|
pred := int (((Q10 shl 7) - num) div (Q10 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
pred := -pred;
|
|
end;
|
|
workspace[8] := JCOEF (pred);
|
|
end;
|
|
{ AC20 }
|
|
Al := coef_bits^[3];
|
|
if (Al <> 0) and (workspace[16] = 0) then
|
|
begin
|
|
num := 9 * Q00 * (DC2 + DC8 - 2*DC5);
|
|
if (num >= 0) then
|
|
begin
|
|
pred := int (((Q20 shl 7) + num) div (Q20 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
end
|
|
else
|
|
begin
|
|
pred := int (((Q20 shl 7) - num) div (Q20 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
pred := -pred;
|
|
end;
|
|
workspace[16] := JCOEF (pred);
|
|
end;
|
|
{ AC11 }
|
|
Al := coef_bits^[4];
|
|
if (Al <> 0) and (workspace[9] = 0) then
|
|
begin
|
|
num := 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
|
|
if (num >= 0) then
|
|
begin
|
|
pred := int (((Q11 shl 7) + num) div (Q11 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
end
|
|
else
|
|
begin
|
|
pred := int (((Q11 shl 7) - num) div (Q11 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
pred := -pred;
|
|
end;
|
|
workspace[9] := JCOEF (pred);
|
|
end;
|
|
{ AC02 }
|
|
Al := coef_bits^[5];
|
|
if (Al <> 0) and (workspace[2] = 0) then
|
|
begin
|
|
num := 9 * Q00 * (DC4 + DC6 - 2*DC5);
|
|
if (num >= 0) then
|
|
begin
|
|
pred := int (((Q02 shl 7) + num) div (Q02 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
end
|
|
else
|
|
begin
|
|
pred := int (((Q02 shl 7) - num) div (Q02 shl 8));
|
|
if (Al > 0) and (pred >= (1 shl Al)) then
|
|
pred := (1 shl Al)-1;
|
|
pred := -pred;
|
|
end;
|
|
workspace[2] := JCOEF (pred);
|
|
end;
|
|
{ OK, do the IDCT }
|
|
inverse_DCT (cinfo, compptr, JCOEFPTR (@workspace),
|
|
output_ptr, output_col);
|
|
{ Advance for next column }
|
|
DC1 := DC2; DC2 := DC3;
|
|
DC4 := DC5; DC5 := DC6;
|
|
DC7 := DC8; DC8 := DC9;
|
|
Inc(JBLOCK_PTR(buffer_ptr));
|
|
Inc(JBLOCK_PTR(prev_block_row));
|
|
Inc(JBLOCK_PTR(next_block_row));
|
|
Inc(output_col, compptr^.DCT_scaled_size);
|
|
end;
|
|
Inc(JSAMPROW_PTR(output_ptr), compptr^.DCT_scaled_size);
|
|
end;
|
|
Inc(compptr);
|
|
end;
|
|
|
|
Inc(cinfo^.output_iMCU_row);
|
|
if (cinfo^.output_iMCU_row < LongInt(cinfo^.total_iMCU_rows)) then
|
|
begin
|
|
decompress_smooth_data := JPEG_ROW_COMPLETED;
|
|
exit;
|
|
end;
|
|
decompress_smooth_data := JPEG_SCAN_COMPLETED;
|
|
end;
|
|
|
|
{$endif} { BLOCK_SMOOTHING_SUPPORTED }
|
|
|
|
|
|
{ Initialize coefficient buffer controller. }
|
|
|
|
{GLOBAL}
|
|
procedure jinit_d_coef_controller (cinfo : j_decompress_ptr;
|
|
need_full_buffer : boolean);
|
|
var
|
|
coef : my_coef_ptr;
|
|
{$ifdef D_MULTISCAN_FILES_SUPPORTED}
|
|
var
|
|
ci, access_rows : int;
|
|
compptr : jpeg_component_info_ptr;
|
|
{$endif}
|
|
var
|
|
buffer : JBLOCK_PTR;
|
|
i : int;
|
|
begin
|
|
coef := my_coef_ptr(
|
|
cinfo^.mem^.alloc_small (j_common_ptr (cinfo), JPOOL_IMAGE,
|
|
SIZEOF(my_coef_controller)) );
|
|
cinfo^.coef := jpeg_d_coef_controller_ptr(coef);
|
|
coef^.pub.start_input_pass := start_input_pass;
|
|
coef^.pub.start_output_pass := start_output_pass;
|
|
{$ifdef BLOCK_SMOOTHING_SUPPORTED}
|
|
coef^.coef_bits_latch := NIL;
|
|
{$endif}
|
|
|
|
{ Create the coefficient buffer. }
|
|
if (need_full_buffer) then
|
|
begin
|
|
{$ifdef D_MULTISCAN_FILES_SUPPORTED}
|
|
{ Allocate a full-image virtual array for each component, }
|
|
{ padded to a multiple of samp_factor DCT blocks in each direction. }
|
|
{ Note we ask for a pre-zeroed array. }
|
|
|
|
compptr := jpeg_component_info_ptr(cinfo^.comp_info);
|
|
for ci := 0 to pred(cinfo^.num_components) do
|
|
begin
|
|
access_rows := compptr^.v_samp_factor;
|
|
{$ifdef BLOCK_SMOOTHING_SUPPORTED}
|
|
{ If block smoothing could be used, need a bigger window }
|
|
if (cinfo^.progressive_mode) then
|
|
access_rows := access_rows * 3;
|
|
{$endif}
|
|
coef^.whole_image[ci] := cinfo^.mem^.request_virt_barray
|
|
(j_common_ptr (cinfo), JPOOL_IMAGE, TRUE,
|
|
JDIMENSION (jround_up( long(compptr^.width_in_blocks),
|
|
long(compptr^.h_samp_factor) )),
|
|
JDIMENSION (jround_up( long(compptr^.height_in_blocks),
|
|
long(compptr^.v_samp_factor) )),
|
|
JDIMENSION (access_rows));
|
|
Inc(compptr);
|
|
end;
|
|
coef^.pub.consume_data := consume_data;
|
|
coef^.pub.decompress_data := decompress_data;
|
|
coef^.pub.coef_arrays := @(coef^.whole_image);
|
|
{ link to virtual arrays }
|
|
{$else}
|
|
ERREXIT(j_common_ptr(cinfo), JERR_NOT_COMPILED);
|
|
{$endif}
|
|
end
|
|
else
|
|
begin
|
|
{ We only need a single-MCU buffer. }
|
|
buffer := JBLOCK_PTR (
|
|
cinfo^.mem^.alloc_large (j_common_ptr (cinfo), JPOOL_IMAGE,
|
|
D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)) );
|
|
for i := 0 to pred(D_MAX_BLOCKS_IN_MCU) do
|
|
begin
|
|
coef^.MCU_buffer[i] := JBLOCKROW(buffer);
|
|
Inc(buffer);
|
|
end;
|
|
coef^.pub.consume_data := dummy_consume_data;
|
|
coef^.pub.decompress_data := decompress_onepass;
|
|
coef^.pub.coef_arrays := NIL; { flag for no virtual arrays }
|
|
end;
|
|
end;
|
|
|
|
end.
|