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<font color='#009900'>/*
* jcprepct.c
*
* Copyright (C) 1994-1996, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains the compression preprocessing controller.
* This controller manages the color conversion, downsampling,
* and edge expansion steps.
*
* Most of the complexity here is associated with buffering input rows
* as required by the downsampler. See the comments at the head of
* jcsample.c for the downsampler's needs.
*/</font>
<font color='#0000FF'>#define</font> JPEG_INTERNALS
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='jinclude.h.html'>jinclude.h</a>"
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='jpeglib.h.html'>jpeglib.h</a>"
<font color='#009900'>/* At present, jcsample.c can request context rows only for smoothing.
* In the future, we might also need context rows for CCIR601 sampling
* or other more-complex downsampling procedures. The code to support
* context rows should be compiled only if needed.
*/</font>
<font color='#0000FF'>#ifdef</font> INPUT_SMOOTHING_SUPPORTED
<font color='#0000FF'>#define</font> CONTEXT_ROWS_SUPPORTED
<font color='#0000FF'>#endif</font>
<font color='#009900'>/*
* For the simple (no-context-row) case, we just need to buffer one
* row group's worth of pixels for the downsampling step. At the bottom of
* the image, we pad to a full row group by replicating the last pixel row.
* The downsampler's last output row is then replicated if needed to pad
* out to a full iMCU row.
*
* When providing context rows, we must buffer three row groups' worth of
* pixels. Three row groups are physically allocated, but the row pointer
* arrays are made five row groups high, with the extra pointers above and
* below "wrapping around" to point to the last and first real row groups.
* This allows the downsampler to access the proper context rows.
* At the top and bottom of the image, we create dummy context rows by
* copying the first or last real pixel row. This copying could be avoided
* by pointer hacking as is done in jdmainct.c, but it doesn't seem worth the
* trouble on the compression side.
*/</font>
<font color='#009900'>/* Private buffer controller object */</font>
<font color='#0000FF'>typedef</font> <font color='#0000FF'>struct</font> <b>{</b>
<font color='#0000FF'>struct</font> jpeg_c_prep_controller pub; <font color='#009900'>/* public fields */</font>
<font color='#009900'>/* Downsampling input buffer. This buffer holds color-converted data
* until we have enough to do a downsample step.
*/</font>
JSAMPARRAY color_buf[MAX_COMPONENTS];
JDIMENSION rows_to_go; <font color='#009900'>/* counts rows remaining in source image */</font>
<font color='#0000FF'><u>int</u></font> next_buf_row; <font color='#009900'>/* index of next row to store in color_buf */</font>
<font color='#0000FF'>#ifdef</font> CONTEXT_ROWS_SUPPORTED <font color='#009900'>/* only needed for context case */</font>
<font color='#0000FF'><u>int</u></font> this_row_group; <font color='#009900'>/* starting row index of group to process */</font>
<font color='#0000FF'><u>int</u></font> next_buf_stop; <font color='#009900'>/* downsample when we reach this index */</font>
<font color='#0000FF'>#endif</font>
<b>}</b> my_prep_controller;
<font color='#0000FF'>typedef</font> my_prep_controller <font color='#5555FF'>*</font> my_prep_ptr;
<font color='#009900'>/*
* Initialize for a processing pass.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='start_pass_prep'></a>start_pass_prep</b> <font face='Lucida Console'>(</font>j_compress_ptr cinfo, J_BUF_MODE pass_mode<font face='Lucida Console'>)</font>
<b>{</b>
my_prep_ptr prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_prep_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>prep;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>pass_mode <font color='#5555FF'>!</font><font color='#5555FF'>=</font> JBUF_PASS_THRU<font face='Lucida Console'>)</font>
<font color='#BB00BB'>ERREXIT</font><font face='Lucida Console'>(</font>cinfo, JERR_BAD_BUFFER_MODE<font face='Lucida Console'>)</font>;
<font color='#009900'>/* Initialize total-height counter for detecting bottom of image */</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>image_height;
<font color='#009900'>/* Mark the conversion buffer empty */</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>#ifdef</font> CONTEXT_ROWS_SUPPORTED
<font color='#009900'>/* Preset additional state variables for context mode.
* These aren't used in non-context mode, so we needn't test which mode.
*/</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>this_row_group <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#009900'>/* Set next_buf_stop to stop after two row groups have been read in. */</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop <font color='#5555FF'>=</font> <font color='#979000'>2</font> <font color='#5555FF'>*</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<font color='#0000FF'>#endif</font>
<b>}</b>
<font color='#009900'>/*
* Expand an image vertically from height input_rows to height output_rows,
* by duplicating the bottom row.
*/</font>
<b><a name='LOCAL'></a>LOCAL</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='expand_bottom_edge'></a>expand_bottom_edge</b> <font face='Lucida Console'>(</font>JSAMPARRAY image_data, JDIMENSION num_cols,
<font color='#0000FF'><u>int</u></font> input_rows, <font color='#0000FF'><u>int</u></font> output_rows<font face='Lucida Console'>)</font>
<b>{</b>
<font color='#0000FF'>register</font> <font color='#0000FF'><u>int</u></font> row;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>row <font color='#5555FF'>=</font> input_rows; row <font color='#5555FF'><</font> output_rows; row<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#BB00BB'>jcopy_sample_rows</font><font face='Lucida Console'>(</font>image_data, input_rows<font color='#5555FF'>-</font><font color='#979000'>1</font>, image_data, row,
<font color='#979000'>1</font>, num_cols<font face='Lucida Console'>)</font>;
<b>}</b>
<b>}</b>
<font color='#009900'>/*
* Process some data in the simple no-context case.
*
* Preprocessor output data is counted in "row groups". A row group
* is defined to be v_samp_factor sample rows of each component.
* Downsampling will produce this much data from each max_v_samp_factor
* input rows.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='pre_process_data'></a>pre_process_data</b> <font face='Lucida Console'>(</font>j_compress_ptr cinfo,
JSAMPARRAY input_buf, JDIMENSION <font color='#5555FF'>*</font>in_row_ctr,
JDIMENSION in_rows_avail,
JSAMPIMAGE output_buf, JDIMENSION <font color='#5555FF'>*</font>out_row_group_ctr,
JDIMENSION out_row_groups_avail<font face='Lucida Console'>)</font>
<b>{</b>
my_prep_ptr prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_prep_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>prep;
<font color='#0000FF'><u>int</u></font> numrows, ci;
JDIMENSION inrows;
jpeg_component_info <font color='#5555FF'>*</font> compptr;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>in_row_ctr <font color='#5555FF'><</font> in_rows_avail <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
<font color='#5555FF'>*</font>out_row_group_ctr <font color='#5555FF'><</font> out_row_groups_avail<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Do color conversion to fill the conversion buffer. */</font>
inrows <font color='#5555FF'>=</font> in_rows_avail <font color='#5555FF'>-</font> <font color='#5555FF'>*</font>in_row_ctr;
numrows <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor <font color='#5555FF'>-</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row;
numrows <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font> <font color='#BB00BB'>MIN</font><font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> numrows, inrows<font face='Lucida Console'>)</font>;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>cconvert<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_convert<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo, input_buf <font color='#5555FF'>+</font> <font color='#5555FF'>*</font>in_row_ctr,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row,
numrows<font face='Lucida Console'>)</font>;
<font color='#5555FF'>*</font>in_row_ctr <font color='#5555FF'>+</font><font color='#5555FF'>=</font> numrows;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>+</font><font color='#5555FF'>=</font> numrows;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>-</font><font color='#5555FF'>=</font> numrows;
<font color='#009900'>/* If at bottom of image, pad to fill the conversion buffer. */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font> <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components; ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#BB00BB'>expand_bottom_edge</font><font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci], cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>image_width,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row, cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font>;
<b>}</b>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<b>}</b>
<font color='#009900'>/* If we've filled the conversion buffer, empty it. */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font> <b>{</b>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>downsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>downsample<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf, <font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font color='#979000'>0</font>,
output_buf, <font color='#5555FF'>*</font>out_row_group_ctr<font face='Lucida Console'>)</font>;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>out_row_group_ctr<font face='Lucida Console'>)</font><font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
<b>}</b>
<font color='#009900'>/* If at bottom of image, pad the output to a full iMCU height.
* Note we assume the caller is providing a one-iMCU-height output buffer!
*/</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font> <font color='#5555FF'>&</font><font color='#5555FF'>&</font>
<font color='#5555FF'>*</font>out_row_group_ctr <font color='#5555FF'><</font> out_row_groups_avail<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>, compptr <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>comp_info; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components;
ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font>, compptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
numrows <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>v_samp_factor <font color='#5555FF'>*</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>DCT_v_scaled_size<font face='Lucida Console'>)</font> <font color='#5555FF'>/</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>min_DCT_v_scaled_size;
<font color='#BB00BB'>expand_bottom_edge</font><font face='Lucida Console'>(</font>output_buf[ci],
compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>width_in_blocks <font color='#5555FF'>*</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>DCT_h_scaled_size,
<font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>out_row_group_ctr <font color='#5555FF'>*</font> numrows<font face='Lucida Console'>)</font>,
<font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>out_row_groups_avail <font color='#5555FF'>*</font> numrows<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
<b>}</b>
<font color='#5555FF'>*</font>out_row_group_ctr <font color='#5555FF'>=</font> out_row_groups_avail;
<font color='#0000FF'>break</font>; <font color='#009900'>/* can exit outer loop without test */</font>
<b>}</b>
<b>}</b>
<b>}</b>
<font color='#0000FF'>#ifdef</font> CONTEXT_ROWS_SUPPORTED
<font color='#009900'>/*
* Process some data in the context case.
*/</font>
<b><a name='METHODDEF'></a>METHODDEF</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='pre_process_context'></a>pre_process_context</b> <font face='Lucida Console'>(</font>j_compress_ptr cinfo,
JSAMPARRAY input_buf, JDIMENSION <font color='#5555FF'>*</font>in_row_ctr,
JDIMENSION in_rows_avail,
JSAMPIMAGE output_buf, JDIMENSION <font color='#5555FF'>*</font>out_row_group_ctr,
JDIMENSION out_row_groups_avail<font face='Lucida Console'>)</font>
<b>{</b>
my_prep_ptr prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_prep_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>prep;
<font color='#0000FF'><u>int</u></font> numrows, ci;
<font color='#0000FF'><u>int</u></font> buf_height <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor <font color='#5555FF'>*</font> <font color='#979000'>3</font>;
JDIMENSION inrows;
<font color='#0000FF'>while</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>out_row_group_ctr <font color='#5555FF'><</font> out_row_groups_avail<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>in_row_ctr <font color='#5555FF'><</font> in_rows_avail<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Do color conversion to fill the conversion buffer. */</font>
inrows <font color='#5555FF'>=</font> in_rows_avail <font color='#5555FF'>-</font> <font color='#5555FF'>*</font>in_row_ctr;
numrows <font color='#5555FF'>=</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop <font color='#5555FF'>-</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row;
numrows <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>int</u></font><font face='Lucida Console'>)</font> <font color='#BB00BB'>MIN</font><font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> numrows, inrows<font face='Lucida Console'>)</font>;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>cconvert<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_convert<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo, input_buf <font color='#5555FF'>+</font> <font color='#5555FF'>*</font>in_row_ctr,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row,
numrows<font face='Lucida Console'>)</font>;
<font color='#009900'>/* Pad at top of image, if first time through */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>=</font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>image_height<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components; ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'><u>int</u></font> row;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>row <font color='#5555FF'>=</font> <font color='#979000'>1</font>; row <font color='#5555FF'><</font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor; row<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#BB00BB'>jcopy_sample_rows</font><font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci], <font color='#979000'>0</font>,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci], <font color='#5555FF'>-</font>row,
<font color='#979000'>1</font>, cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>image_width<font face='Lucida Console'>)</font>;
<b>}</b>
<b>}</b>
<b>}</b>
<font color='#5555FF'>*</font>in_row_ctr <font color='#5555FF'>+</font><font color='#5555FF'>=</font> numrows;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>+</font><font color='#5555FF'>=</font> numrows;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>-</font><font color='#5555FF'>=</font> numrows;
<b>}</b> <font color='#0000FF'>else</font> <b>{</b>
<font color='#009900'>/* Return for more data, unless we are at the bottom of the image. */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>rows_to_go <font color='#5555FF'>!</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font>
<font color='#0000FF'>break</font>;
<font color='#009900'>/* When at bottom of image, pad to fill the conversion buffer. */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'><</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop<font face='Lucida Console'>)</font> <b>{</b>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components; ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#BB00BB'>expand_bottom_edge</font><font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci], cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>image_width,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row, prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop<font face='Lucida Console'>)</font>;
<b>}</b>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop;
<b>}</b>
<b>}</b>
<font color='#009900'>/* If we've gotten enough data, downsample a row group. */</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font><font color='#5555FF'>=</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop<font face='Lucida Console'>)</font> <b>{</b>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>downsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>downsample<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font>cinfo,
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>this_row_group,
output_buf, <font color='#5555FF'>*</font>out_row_group_ctr<font face='Lucida Console'>)</font>;
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>out_row_group_ctr<font face='Lucida Console'>)</font><font color='#5555FF'>+</font><font color='#5555FF'>+</font>;
<font color='#009900'>/* Advance pointers with wraparound as necessary. */</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>this_row_group <font color='#5555FF'>+</font><font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>this_row_group <font color='#5555FF'>></font><font color='#5555FF'>=</font> buf_height<font face='Lucida Console'>)</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>this_row_group <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>></font><font color='#5555FF'>=</font> buf_height<font face='Lucida Console'>)</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>=</font> <font color='#979000'>0</font>;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_stop <font color='#5555FF'>=</font> prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>next_buf_row <font color='#5555FF'>+</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<b>}</b>
<b>}</b>
<b>}</b>
<font color='#009900'>/*
* Create the wrapped-around downsampling input buffer needed for context mode.
*/</font>
<b><a name='LOCAL'></a>LOCAL</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='create_context_buffer'></a>create_context_buffer</b> <font face='Lucida Console'>(</font>j_compress_ptr cinfo<font face='Lucida Console'>)</font>
<b>{</b>
my_prep_ptr prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_prep_ptr<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>prep;
<font color='#0000FF'><u>int</u></font> rgroup_height <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor;
<font color='#0000FF'><u>int</u></font> ci, i;
jpeg_component_info <font color='#5555FF'>*</font> compptr;
JSAMPARRAY true_buffer, fake_buffer;
<font color='#009900'>/* Grab enough space for fake row pointers for all the components;
* we need five row groups' worth of pointers for each component.
*/</font>
fake_buffer <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>JSAMPARRAY<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_small<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font face='Lucida Console'>(</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components <font color='#5555FF'>*</font> <font color='#979000'>5</font> <font color='#5555FF'>*</font> rgroup_height<font face='Lucida Console'>)</font> <font color='#5555FF'>*</font>
<font color='#BB00BB'>SIZEOF</font><font face='Lucida Console'>(</font>JSAMPROW<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>, compptr <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>comp_info; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components;
ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font>, compptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Allocate the actual buffer space (3 row groups) for this component.
* We make the buffer wide enough to allow the downsampler to edge-expand
* horizontally within the buffer, if it so chooses.
*/</font>
true_buffer <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_sarray<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font color='#0000FF'><u>long</u></font><font face='Lucida Console'>)</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>width_in_blocks <font color='#5555FF'>*</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>min_DCT_h_scaled_size <font color='#5555FF'>*</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_h_samp_factor<font face='Lucida Console'>)</font> <font color='#5555FF'>/</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>h_samp_factor<font face='Lucida Console'>)</font>,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font color='#979000'>3</font> <font color='#5555FF'>*</font> rgroup_height<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
<font color='#009900'>/* Copy true buffer row pointers into the middle of the fake row array */</font>
<font color='#BB00BB'>MEMCOPY</font><font face='Lucida Console'>(</font>fake_buffer <font color='#5555FF'>+</font> rgroup_height, true_buffer,
<font color='#979000'>3</font> <font color='#5555FF'>*</font> rgroup_height <font color='#5555FF'>*</font> <font color='#BB00BB'>SIZEOF</font><font face='Lucida Console'>(</font>JSAMPROW<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
<font color='#009900'>/* Fill in the above and below wraparound pointers */</font>
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>i <font color='#5555FF'>=</font> <font color='#979000'>0</font>; i <font color='#5555FF'><</font> rgroup_height; i<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
fake_buffer[i] <font color='#5555FF'>=</font> true_buffer[<font color='#979000'>2</font> <font color='#5555FF'>*</font> rgroup_height <font color='#5555FF'>+</font> i];
fake_buffer[<font color='#979000'>4</font> <font color='#5555FF'>*</font> rgroup_height <font color='#5555FF'>+</font> i] <font color='#5555FF'>=</font> true_buffer[i];
<b>}</b>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci] <font color='#5555FF'>=</font> fake_buffer <font color='#5555FF'>+</font> rgroup_height;
fake_buffer <font color='#5555FF'>+</font><font color='#5555FF'>=</font> <font color='#979000'>5</font> <font color='#5555FF'>*</font> rgroup_height; <font color='#009900'>/* point to space for next component */</font>
<b>}</b>
<b>}</b>
<font color='#0000FF'>#endif</font> <font color='#009900'>/* CONTEXT_ROWS_SUPPORTED */</font>
<font color='#009900'>/*
* Initialize preprocessing controller.
*/</font>
<b><a name='GLOBAL'></a>GLOBAL</b><font face='Lucida Console'>(</font><font color='#0000FF'><u>void</u></font><font face='Lucida Console'>)</font>
<b><a name='jinit_c_prep_controller'></a>jinit_c_prep_controller</b> <font face='Lucida Console'>(</font>j_compress_ptr cinfo, boolean need_full_buffer<font face='Lucida Console'>)</font>
<b>{</b>
my_prep_ptr prep;
<font color='#0000FF'><u>int</u></font> ci;
jpeg_component_info <font color='#5555FF'>*</font> compptr;
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>need_full_buffer<font face='Lucida Console'>)</font> <font color='#009900'>/* safety check */</font>
<font color='#BB00BB'>ERREXIT</font><font face='Lucida Console'>(</font>cinfo, JERR_BAD_BUFFER_MODE<font face='Lucida Console'>)</font>;
prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font>my_prep_ptr<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_small<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font color='#BB00BB'>SIZEOF</font><font face='Lucida Console'>(</font>my_prep_controller<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>prep <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#0000FF'>struct</font> jpeg_c_prep_controller <font color='#5555FF'>*</font><font face='Lucida Console'>)</font> prep;
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.start_pass <font color='#5555FF'>=</font> start_pass_prep;
<font color='#009900'>/* Allocate the color conversion buffer.
* We make the buffer wide enough to allow the downsampler to edge-expand
* horizontally within the buffer, if it so chooses.
*/</font>
<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>downsample<font color='#5555FF'>-</font><font color='#5555FF'>></font>need_context_rows<font face='Lucida Console'>)</font> <b>{</b>
<font color='#009900'>/* Set up to provide context rows */</font>
<font color='#0000FF'>#ifdef</font> CONTEXT_ROWS_SUPPORTED
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.pre_process_data <font color='#5555FF'>=</font> pre_process_context;
<font color='#BB00BB'>create_context_buffer</font><font face='Lucida Console'>(</font>cinfo<font face='Lucida Console'>)</font>;
<font color='#0000FF'>#else</font>
<font color='#BB00BB'>ERREXIT</font><font face='Lucida Console'>(</font>cinfo, JERR_NOT_COMPILED<font face='Lucida Console'>)</font>;
<font color='#0000FF'>#endif</font>
<b>}</b> <font color='#0000FF'>else</font> <b>{</b>
<font color='#009900'>/* No context, just make it tall enough for one row group */</font>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>pub.pre_process_data <font color='#5555FF'>=</font> pre_process_data;
<font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>ci <font color='#5555FF'>=</font> <font color='#979000'>0</font>, compptr <font color='#5555FF'>=</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>comp_info; ci <font color='#5555FF'><</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>num_components;
ci<font color='#5555FF'>+</font><font color='#5555FF'>+</font>, compptr<font color='#5555FF'>+</font><font color='#5555FF'>+</font><font face='Lucida Console'>)</font> <b>{</b>
prep<font color='#5555FF'>-</font><font color='#5555FF'>></font>color_buf[ci] <font color='#5555FF'>=</font> <font face='Lucida Console'>(</font><font color='#5555FF'>*</font>cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>mem<font color='#5555FF'>-</font><font color='#5555FF'>></font>alloc_sarray<font face='Lucida Console'>)</font>
<font face='Lucida Console'>(</font><font face='Lucida Console'>(</font>j_common_ptr<font face='Lucida Console'>)</font> cinfo, JPOOL_IMAGE,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> <font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font face='Lucida Console'>(</font><font color='#0000FF'><u>long</u></font><font face='Lucida Console'>)</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>width_in_blocks <font color='#5555FF'>*</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>min_DCT_h_scaled_size <font color='#5555FF'>*</font>
cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_h_samp_factor<font face='Lucida Console'>)</font> <font color='#5555FF'>/</font> compptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>h_samp_factor<font face='Lucida Console'>)</font>,
<font face='Lucida Console'>(</font>JDIMENSION<font face='Lucida Console'>)</font> cinfo<font color='#5555FF'>-</font><font color='#5555FF'>></font>max_v_samp_factor<font face='Lucida Console'>)</font>;
<b>}</b>
<b>}</b>
<b>}</b>
</pre></body></html>