jdmerge.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "mrpt_jpeglib.h"
#include <mrpt/utils/mrpt_macros.h>

#ifdef UPSAMPLE_MERGING_SUPPORTED

/* Private subobject */

typedef struct
{
        struct jpeg_upsampler pub; /* public fields */

        /* Pointer to routine to do actual upsampling/conversion of one row group */
        JMETHOD(
                void, upmethod, (j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
                                                 JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf));

        /* Private state for YCC->RGB conversion */
        int* Cr_r_tab; /* => table for Cr to R conversion */
        int* Cb_b_tab; /* => table for Cb to B conversion */
        INT32* Cr_g_tab; /* => table for Cr to G conversion */
        INT32* Cb_g_tab; /* => table for Cb to G conversion */

        /* For 2:1 vertical sampling, we produce two output rows at a time.
         * We need a "spare" row buffer to hold the second output row if the
         * application provides just a one-row buffer; we also use the spare
         * to discard the dummy last row if the image height is odd.
         */
        JSAMPROW spare_row;
        boolean spare_full; /* T if spare buffer is occupied */

        JDIMENSION out_row_width; /* samples per output row */
        JDIMENSION rows_to_go; /* counts rows remaining in image */
} my_upsampler;

typedef my_upsampler* my_upsample_ptr;

#define SCALEBITS 16 /* speediest right-shift on some machines */
#define ONE_HALF ((INT32)1 << (SCALEBITS - 1))
#define FIX(x) ((INT32)((x) * (1L << SCALEBITS) + 0.5))

/*
 * Initialize tables for YCC->RGB colorspace conversion.
 * This is taken directly from jdcolor.c; see that file for more info.
 */

LOCAL(void)
build_ycc_rgb_table(j_decompress_ptr cinfo)
{
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;
        int i;
        INT32 x;
        SHIFT_TEMPS

        upsample->Cr_r_tab = (int*)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, (MAXJSAMPLE + 1) * SIZEOF(int));
        upsample->Cb_b_tab = (int*)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, (MAXJSAMPLE + 1) * SIZEOF(int));
        upsample->Cr_g_tab = (INT32*)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, (MAXJSAMPLE + 1) * SIZEOF(INT32));
        upsample->Cb_g_tab = (INT32*)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, (MAXJSAMPLE + 1) * SIZEOF(INT32));

        for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++)
        {
                /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
                /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
                /* Cr=>R value is nearest int to 1.40200 * x */
                upsample->Cr_r_tab[i] =
                        (int)RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
                /* Cb=>B value is nearest int to 1.77200 * x */
                upsample->Cb_b_tab[i] =
                        (int)RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
                /* Cr=>G value is scaled-up -0.71414 * x */
                upsample->Cr_g_tab[i] = (-FIX(0.71414)) * x;
                /* Cb=>G value is scaled-up -0.34414 * x */
                /* We also add in ONE_HALF so that need not do it in inner loop */
                upsample->Cb_g_tab[i] = (-FIX(0.34414)) * x + ONE_HALF;
        }
}

/*
 * Initialize for an upsampling pass.
 */

METHODDEF(void)
start_pass_merged_upsample(j_decompress_ptr cinfo)
{
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;

        /* Mark the spare buffer empty */
        upsample->spare_full = FALSE;
        /* Initialize total-height counter for detecting bottom of image */
        upsample->rows_to_go = cinfo->output_height;
}

/*
 * Control routine to do upsampling (and color conversion).
 *
 * The control routine just handles the row buffering considerations.
 */

METHODDEF(void)
merged_2v_upsample(
        j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION* in_row_group_ctr,
        JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf,
        JDIMENSION* out_row_ctr, JDIMENSION out_rows_avail)
/* 2:1 vertical sampling case: may need a spare row. */
{
        MRPT_UNUSED_PARAM(in_row_group_ctr);
        MRPT_UNUSED_PARAM(in_row_groups_avail);
        MRPT_UNUSED_PARAM(out_rows_avail);
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;
        JSAMPROW work_ptrs[2];
        JDIMENSION num_rows; /* number of rows returned to caller */

        if (upsample->spare_full)
        {
                /* If we have a spare row saved from a previous cycle, just return it.
                 */
                jcopy_sample_rows(
                        &upsample->spare_row, 0, output_buf + *out_row_ctr, 0, 1,
                        upsample->out_row_width);
                num_rows = 1;
                upsample->spare_full = FALSE;
        }
        else
        {
                /* Figure number of rows to return to caller. */
                num_rows = 2;
                /* Not more than the distance to the end of the image. */
                if (num_rows > upsample->rows_to_go) num_rows = upsample->rows_to_go;
                /* And not more than what the client can accept: */
                out_rows_avail -= *out_row_ctr;
                if (num_rows > out_rows_avail) num_rows = out_rows_avail;
                /* Create output pointer array for upsampler. */
                work_ptrs[0] = output_buf[*out_row_ctr];
                if (num_rows > 1)
                {
                        work_ptrs[1] = output_buf[*out_row_ctr + 1];
                }
                else
                {
                        work_ptrs[1] = upsample->spare_row;
                        upsample->spare_full = TRUE;
                }
                /* Now do the upsampling. */
                (*upsample->upmethod)(cinfo, input_buf, *in_row_group_ctr, work_ptrs);
        }

        /* Adjust counts */
        *out_row_ctr += num_rows;
        upsample->rows_to_go -= num_rows;
        /* When the buffer is emptied, declare this input row group consumed */
        if (!upsample->spare_full) (*in_row_group_ctr)++;
}

METHODDEF(void)
merged_1v_upsample(
        j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION* in_row_group_ctr,
        JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf,
        JDIMENSION* out_row_ctr, JDIMENSION out_rows_avail)
/* 1:1 vertical sampling case: much easier, never need a spare row. */
{
        MRPT_UNUSED_PARAM(in_row_groups_avail);
        MRPT_UNUSED_PARAM(out_rows_avail);
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;

        /* Just do the upsampling. */
        (*upsample->upmethod)(
                cinfo, input_buf, *in_row_group_ctr, output_buf + *out_row_ctr);
        /* Adjust counts */
        (*out_row_ctr)++;
        (*in_row_group_ctr)++;
}

/*
 * These are the routines invoked by the control routines to do
 * the actual upsampling/conversion.  One row group is processed per call.
 *
 * Note: since we may be writing directly into application-supplied buffers,
 * we have to be honest about the output width; we can't assume the buffer
 * has been rounded up to an even width.
 */

/*
 * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
 */

METHODDEF(void)
h2v1_merged_upsample(
        j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
        JSAMPARRAY output_buf)
{
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;
        int y, cred, cgreen, cblue;
        int cb, cr;
        JSAMPROW outptr;
        JSAMPROW inptr0, inptr1, inptr2;
        JDIMENSION col;
        /* copy these pointers into registers if possible */
        JSAMPLE* range_limit = cinfo->sample_range_limit;
        int* Crrtab = upsample->Cr_r_tab;
        int* Cbbtab = upsample->Cb_b_tab;
        INT32* Crgtab = upsample->Cr_g_tab;
        INT32* Cbgtab = upsample->Cb_g_tab;
        SHIFT_TEMPS

        inptr0 = input_buf[0][in_row_group_ctr];
        inptr1 = input_buf[1][in_row_group_ctr];
        inptr2 = input_buf[2][in_row_group_ctr];
        outptr = output_buf[0];
        /* Loop for each pair of output pixels */
        for (col = cinfo->output_width >> 1; col > 0; col--)
        {
                /* Do the chroma part of the calculation */
                cb = GETJSAMPLE(*inptr1++);
                cr = GETJSAMPLE(*inptr2++);
                cred = Crrtab[cr];
                cgreen = (int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
                cblue = Cbbtab[cb];
                /* Fetch 2 Y values and emit 2 pixels */
                y = GETJSAMPLE(*inptr0++);
                outptr[RGB_RED] = range_limit[y + cred];
                outptr[RGB_GREEN] = range_limit[y + cgreen];
                outptr[RGB_BLUE] = range_limit[y + cblue];
                outptr += RGB_PIXELSIZE;
                y = GETJSAMPLE(*inptr0++);
                outptr[RGB_RED] = range_limit[y + cred];
                outptr[RGB_GREEN] = range_limit[y + cgreen];
                outptr[RGB_BLUE] = range_limit[y + cblue];
                outptr += RGB_PIXELSIZE;
        }
        /* If image width is odd, do the last output column separately */
        if (cinfo->output_width & 1)
        {
                cb = GETJSAMPLE(*inptr1);
                cr = GETJSAMPLE(*inptr2);
                cred = Crrtab[cr];
                cgreen = (int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
                cblue = Cbbtab[cb];
                y = GETJSAMPLE(*inptr0);
                outptr[RGB_RED] = range_limit[y + cred];
                outptr[RGB_GREEN] = range_limit[y + cgreen];
                outptr[RGB_BLUE] = range_limit[y + cblue];
        }
}

/*
 * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
 */

METHODDEF(void)
h2v2_merged_upsample(
        j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
        JSAMPARRAY output_buf)
{
        my_upsample_ptr upsample = (my_upsample_ptr)cinfo->upsample;
        int y, cred, cgreen, cblue;
        int cb, cr;
        JSAMPROW outptr0, outptr1;
        JSAMPROW inptr00, inptr01, inptr1, inptr2;
        JDIMENSION col;
        /* copy these pointers into registers if possible */
        JSAMPLE* range_limit = cinfo->sample_range_limit;
        int* Crrtab = upsample->Cr_r_tab;
        int* Cbbtab = upsample->Cb_b_tab;
        INT32* Crgtab = upsample->Cr_g_tab;
        INT32* Cbgtab = upsample->Cb_g_tab;
        SHIFT_TEMPS

        inptr00 = input_buf[0][in_row_group_ctr * 2];
        inptr01 = input_buf[0][in_row_group_ctr * 2 + 1];
        inptr1 = input_buf[1][in_row_group_ctr];
        inptr2 = input_buf[2][in_row_group_ctr];
        outptr0 = output_buf[0];
        outptr1 = output_buf[1];
        /* Loop for each group of output pixels */
        for (col = cinfo->output_width >> 1; col > 0; col--)
        {
                /* Do the chroma part of the calculation */
                cb = GETJSAMPLE(*inptr1++);
                cr = GETJSAMPLE(*inptr2++);
                cred = Crrtab[cr];
                cgreen = (int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
                cblue = Cbbtab[cb];
                /* Fetch 4 Y values and emit 4 pixels */
                y = GETJSAMPLE(*inptr00++);
                outptr0[RGB_RED] = range_limit[y + cred];
                outptr0[RGB_GREEN] = range_limit[y + cgreen];
                outptr0[RGB_BLUE] = range_limit[y + cblue];
                outptr0 += RGB_PIXELSIZE;
                y = GETJSAMPLE(*inptr00++);
                outptr0[RGB_RED] = range_limit[y + cred];
                outptr0[RGB_GREEN] = range_limit[y + cgreen];
                outptr0[RGB_BLUE] = range_limit[y + cblue];
                outptr0 += RGB_PIXELSIZE;
                y = GETJSAMPLE(*inptr01++);
                outptr1[RGB_RED] = range_limit[y + cred];
                outptr1[RGB_GREEN] = range_limit[y + cgreen];
                outptr1[RGB_BLUE] = range_limit[y + cblue];
                outptr1 += RGB_PIXELSIZE;
                y = GETJSAMPLE(*inptr01++);
                outptr1[RGB_RED] = range_limit[y + cred];
                outptr1[RGB_GREEN] = range_limit[y + cgreen];
                outptr1[RGB_BLUE] = range_limit[y + cblue];
                outptr1 += RGB_PIXELSIZE;
        }
        /* If image width is odd, do the last output column separately */
        if (cinfo->output_width & 1)
        {
                cb = GETJSAMPLE(*inptr1);
                cr = GETJSAMPLE(*inptr2);
                cred = Crrtab[cr];
                cgreen = (int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
                cblue = Cbbtab[cb];
                y = GETJSAMPLE(*inptr00);
                outptr0[RGB_RED] = range_limit[y + cred];
                outptr0[RGB_GREEN] = range_limit[y + cgreen];
                outptr0[RGB_BLUE] = range_limit[y + cblue];
                y = GETJSAMPLE(*inptr01);
                outptr1[RGB_RED] = range_limit[y + cred];
                outptr1[RGB_GREEN] = range_limit[y + cgreen];
                outptr1[RGB_BLUE] = range_limit[y + cblue];
        }
}

/*
 * Module initialization routine for merged upsampling/color conversion.
 *
 * NB: this is called under the conditions determined by use_merged_upsample()
 * in jdmaster.c.  That routine MUST correspond to the actual capabilities
 * of this module; no safety checks are made here.
 */

GLOBAL(void)
jinit_merged_upsampler(j_decompress_ptr cinfo)
{
        my_upsample_ptr upsample;

        upsample = (my_upsample_ptr)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, SIZEOF(my_upsampler));
        cinfo->upsample = (struct jpeg_upsampler*)upsample;
        upsample->pub.start_pass = start_pass_merged_upsample;
        upsample->pub.need_context_rows = FALSE;

        upsample->out_row_width = cinfo->output_width * cinfo->out_color_components;

        if (cinfo->max_v_samp_factor == 2)
        {
                upsample->pub.upsample = merged_2v_upsample;
                upsample->upmethod = h2v2_merged_upsample;
                /* Allocate a spare row buffer */
                upsample->spare_row = (JSAMPROW)(*cinfo->mem->alloc_large)(
                        (j_common_ptr)cinfo, JPOOL_IMAGE,
                        (size_t)(upsample->out_row_width * SIZEOF(JSAMPLE)));
        }
        else
        {
                upsample->pub.upsample = merged_1v_upsample;
                upsample->upmethod = h2v1_merged_upsample;
                /* No spare row needed */
                upsample->spare_row = nullptr;
        }

        build_ycc_rgb_table(cinfo);
}

#endif /* UPSAMPLE_MERGING_SUPPORTED */