/*

 * jdsample.c

 *

 * This file was part of the Independent JPEG Group's software:

 * Copyright (C) 1991-1996, Thomas G. Lane.

 * libjpeg-turbo Modifications:

 * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB

 * Copyright (C) 2010, 2015-2016, D. R. Commander.

 * Copyright (C) 2014, MIPS Technologies, Inc., California.

 * Copyright (C) 2015, Google, Inc.

 * For conditions of distribution and use, see the accompanying README.ijg

 * file.

 *

 * This file contains upsampling routines.

 *

 * Upsampling input data is counted in "row groups".  A row group

 * is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size)

 * sample rows of each component.  Upsampling will normally produce

 * max_v_samp_factor pixel rows from each row group (but this could vary

 * if the upsampler is applying a scale factor of its own).

 *

 * An excellent reference for image resampling is

 *   Digital Image Warping, George Wolberg, 1990.

 *   Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.

 */

#include "jinclude.h"

#include "jdsample.h"

#include "jsimd.h"

#include "jpegcomp.h"

/*

 * Initialize for an upsampling pass.

 */

METHODDEF(void)

start_pass_upsample (j_decompress_ptr cinfo)

{

  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;

  /* Mark the conversion buffer empty */

  upsample->next_row_out = cinfo->max_v_samp_factor;

  /* Initialize total-height counter for detecting bottom of image */

  upsample->rows_to_go = cinfo->output_height;

}

/*

 * Control routine to do upsampling (and color conversion).

 *

 * In this version we upsample each component independently.

 * We upsample one row group into the conversion buffer, then apply

 * color conversion a row at a time.

 */

METHODDEF(void)

sep_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)

{

  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;

  int ci;

  jpeg_component_info *compptr;

  JDIMENSION num_rows;

  /* Fill the conversion buffer, if it's empty */

  if (upsample->next_row_out >= cinfo->max_v_samp_factor) {

    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

         ci++, compptr++) {

      /* Invoke per-component upsample method.  Notice we pass a POINTER

       * to color_buf[ci], so that fullsize_upsample can change it.

       */

      (*upsample->methods[ci]) (cinfo, compptr,

        input_buf[ci] + (*in_row_group_ctr * upsample->rowgroup_height[ci]),

        upsample->color_buf + ci);

    }

    upsample->next_row_out = 0;

  }

  /* Color-convert and emit rows */

  /* How many we have in the buffer: */

  num_rows = (JDIMENSION) (cinfo->max_v_samp_factor - upsample->next_row_out);

  /* Not more than the distance to the end of the image.  Need this test

   * in case the image height is not a multiple of max_v_samp_factor:

   */

  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;

  (*cinfo->cconvert->color_convert) (cinfo, upsample->color_buf,

                                     (JDIMENSION) upsample->next_row_out,

                                     output_buf + *out_row_ctr,

                                     (int) num_rows);

  /* Adjust counts */

  *out_row_ctr += num_rows;

  upsample->rows_to_go -= num_rows;

  upsample->next_row_out += num_rows;

  /* When the buffer is emptied, declare this input row group consumed */

  if (upsample->next_row_out >= cinfo->max_v_samp_factor)

    (*in_row_group_ctr)++;

}

/*

 * These are the routines invoked by sep_upsample to upsample pixel values

 * of a single component.  One row group is processed per call.

 */

/*

 * For full-size components, we just make color_buf[ci] point at the

 * input buffer, and thus avoid copying any data.  Note that this is

 * safe only because sep_upsample doesn't declare the input row group

 * "consumed" until we are done color converting and emitting it.

 */

METHODDEF(void)

fullsize_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

                   JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  *output_data_ptr = input_data;

}

/*

 * This is a no-op version used for "uninteresting" components.

 * These components will not be referenced by color conversion.

 */

METHODDEF(void)

noop_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

               JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  *output_data_ptr = NULL;      /* safety check */

}

/*

 * This version handles any integral sampling ratios.

 * This is not used for typical JPEG files, so it need not be fast.

 * Nor, for that matter, is it particularly accurate: the algorithm is

 * simple replication of the input pixel onto the corresponding output

 * pixels.  The hi-falutin sampling literature refers to this as a

 * "box filter".  A box filter tends to introduce visible artifacts,

 * so if you are actually going to use 3:1 or 4:1 sampling ratios

 * you would be well advised to improve this code.

 */

METHODDEF(void)

int_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

              JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;

  JSAMPARRAY output_data = *output_data_ptr;

  register JSAMPROW inptr, outptr;

  register JSAMPLE invalue;

  register int h;

  JSAMPROW outend;

  int h_expand, v_expand;

  int inrow, outrow;

  h_expand = upsample->h_expand[compptr->component_index];

  v_expand = upsample->v_expand[compptr->component_index];

  inrow = outrow = 0;

  while (outrow < cinfo->max_v_samp_factor) {

    /* Generate one output row with proper horizontal expansion */

    inptr = input_data[inrow];

    outptr = output_data[outrow];

    outend = outptr + cinfo->output_width;

    while (outptr < outend) {

      invalue = *inptr++;       /* don't need GETJSAMPLE() here */

      for (h = h_expand; h > 0; h--) {

        *outptr++ = invalue;

      }

    }

    /* Generate any additional output rows by duplicating the first one */

    if (v_expand > 1) {

      jcopy_sample_rows(output_data, outrow, output_data, outrow+1,

                        v_expand-1, cinfo->output_width);

    }

    inrow++;

    outrow += v_expand;

  }

}

/*

 * Fast processing for the common case of 2:1 horizontal and 1:1 vertical.

 * It's still a box filter.

 */

METHODDEF(void)

h2v1_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

               JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  JSAMPARRAY output_data = *output_data_ptr;

  register JSAMPROW inptr, outptr;

  register JSAMPLE invalue;

  JSAMPROW outend;

  int inrow;

  for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {

    inptr = input_data[inrow];

    outptr = output_data[inrow];

    outend = outptr + cinfo->output_width;

    while (outptr < outend) {

      invalue = *inptr++;       /* don't need GETJSAMPLE() here */

      *outptr++ = invalue;

      *outptr++ = invalue;

    }

  }

}

/*

 * Fast processing for the common case of 2:1 horizontal and 2:1 vertical.

 * It's still a box filter.

 */

METHODDEF(void)

h2v2_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

               JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  JSAMPARRAY output_data = *output_data_ptr;

  register JSAMPROW inptr, outptr;

  register JSAMPLE invalue;

  JSAMPROW outend;

  int inrow, outrow;

  inrow = outrow = 0;

  while (outrow < cinfo->max_v_samp_factor) {

    inptr = input_data[inrow];

    outptr = output_data[outrow];

    outend = outptr + cinfo->output_width;

    while (outptr < outend) {

      invalue = *inptr++;       /* don't need GETJSAMPLE() here */

      *outptr++ = invalue;

      *outptr++ = invalue;

    }

    jcopy_sample_rows(output_data, outrow, output_data, outrow+1,

                      1, cinfo->output_width);

    inrow++;

    outrow += 2;

  }

}

/*

 * Fancy processing for the common case of 2:1 horizontal and 1:1 vertical.

 *

 * The upsampling algorithm is linear interpolation between pixel centers,

 * also known as a "triangle filter".  This is a good compromise between

 * speed and visual quality.  The centers of the output pixels are 1/4 and 3/4

 * of the way between input pixel centers.

 *

 * A note about the "bias" calculations: when rounding fractional values to

 * integer, we do not want to always round 0.5 up to the next integer.

 * If we did that, we'd introduce a noticeable bias towards larger values.

 * Instead, this code is arranged so that 0.5 will be rounded up or down at

 * alternate pixel locations (a simple ordered dither pattern).

 */

METHODDEF(void)

h2v1_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  JSAMPARRAY output_data = *output_data_ptr;

  register JSAMPROW inptr, outptr;

  register int invalue;

  register JDIMENSION colctr;

  int inrow;

  for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {

    inptr = input_data[inrow];

    outptr = output_data[inrow];

    /* Special case for first column */

    invalue = GETJSAMPLE(*inptr++);

    *outptr++ = (JSAMPLE) invalue;

    *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(*inptr) + 2) >> 2);

    for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {

      /* General case: 3/4 * nearer pixel + 1/4 * further pixel */

      invalue = GETJSAMPLE(*inptr++) * 3;

      *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(inptr[-2]) + 1) >> 2);

      *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(*inptr) + 2) >> 2);

    }

    /* Special case for last column */

    invalue = GETJSAMPLE(*inptr);

    *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(inptr[-1]) + 1) >> 2);

    *outptr++ = (JSAMPLE) invalue;

  }

}

/*

 * Fancy processing for 1:1 horizontal and 2:1 vertical (4:4:0 subsampling).

 *

 * This is a less common case, but it can be encountered when losslessly

 * rotating/transposing a JPEG file that uses 4:2:2 chroma subsampling.

 */

METHODDEF(void)

h1v2_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  JSAMPARRAY output_data = *output_data_ptr;

  JSAMPROW inptr0, inptr1, outptr;

#if BITS_IN_JSAMPLE == 8

  int thiscolsum;

#else

  JLONG thiscolsum;

#endif

  JDIMENSION colctr;

  int inrow, outrow, v;

  inrow = outrow = 0;

  while (outrow < cinfo->max_v_samp_factor) {

    for (v = 0; v < 2; v++) {

      /* inptr0 points to nearest input row, inptr1 points to next nearest */

      inptr0 = input_data[inrow];

      if (v == 0)               /* next nearest is row above */

        inptr1 = input_data[inrow-1];

      else                      /* next nearest is row below */

        inptr1 = input_data[inrow+1];

      outptr = output_data[outrow++];

      for(colctr = 0; colctr < compptr->downsampled_width; colctr++) {

        thiscolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);

        *outptr++ = (JSAMPLE) ((thiscolsum + 1) >> 2);

      }

    }

    inrow++;

  }

}

/*

 * Fancy processing for the common case of 2:1 horizontal and 2:1 vertical.

 * Again a triangle filter; see comments for h2v1 case, above.

 *

 * It is OK for us to reference the adjacent input rows because we demanded

 * context from the main buffer controller (see initialization code).

 */

METHODDEF(void)

h2v2_fancy_upsample (j_decompress_ptr cinfo, jpeg_component_info *compptr,

                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)

{

  JSAMPARRAY output_data = *output_data_ptr;

  register JSAMPROW inptr0, inptr1, outptr;

#if BITS_IN_JSAMPLE == 8

  register int thiscolsum, lastcolsum, nextcolsum;

#else

  register JLONG thiscolsum, lastcolsum, nextcolsum;

#endif

  register JDIMENSION colctr;

  int inrow, outrow, v;

  inrow = outrow = 0;

  while (outrow < cinfo->max_v_samp_factor) {

    for (v = 0; v < 2; v++) {

      /* inptr0 points to nearest input row, inptr1 points to next nearest */

      inptr0 = input_data[inrow];

      if (v == 0)               /* next nearest is row above */

        inptr1 = input_data[inrow-1];

      else                      /* next nearest is row below */

        inptr1 = input_data[inrow+1];

      outptr = output_data[outrow++];

      /* Special case for first column */

      thiscolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);

      nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);

      *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 8) >> 4);

      *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);

      lastcolsum = thiscolsum; thiscolsum = nextcolsum;

      for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {

        /* General case: 3/4 * nearer pixel + 1/4 * further pixel in each */

        /* dimension, thus 9/16, 3/16, 3/16, 1/16 overall */

        nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);

        *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);

        *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);

        lastcolsum = thiscolsum; thiscolsum = nextcolsum;

      }

      /* Special case for last column */

      *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);

      *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 7) >> 4);

    }

    inrow++;

  }

}

/*

 * Module initialization routine for upsampling.

 */

GLOBAL(void)

jinit_upsampler (j_decompress_ptr cinfo)

{

  my_upsample_ptr upsample;

  int ci;

  jpeg_component_info *compptr;

  boolean need_buffer, do_fancy;

  int h_in_group, v_in_group, h_out_group, v_out_group;

  if (!cinfo->master->jinit_upsampler_no_alloc) {

    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_upsample;

    upsample->pub.upsample = sep_upsample;

    upsample->pub.need_context_rows = FALSE; /* until we find out differently */

  } else

    upsample = (my_upsample_ptr) cinfo->upsample;

  if (cinfo->CCIR601_sampling)  /* this isn't supported */

    ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);

  /* jdmainct.c doesn't support context rows when min_DCT_scaled_size = 1,

   * so don't ask for it.

   */

  do_fancy = cinfo->do_fancy_upsampling && cinfo->_min_DCT_scaled_size > 1;

  /* Verify we can handle the sampling factors, select per-component methods,

   * and create storage as needed.

   */

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

       ci++, compptr++) {

    /* Compute size of an "input group" after IDCT scaling.  This many samples

     * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.

     */

    h_in_group = (compptr->h_samp_factor * compptr->_DCT_scaled_size) /

                 cinfo->_min_DCT_scaled_size;

    v_in_group = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /

                 cinfo->_min_DCT_scaled_size;

    h_out_group = cinfo->max_h_samp_factor;

    v_out_group = cinfo->max_v_samp_factor;

    upsample->rowgroup_height[ci] = v_in_group; /* save for use later */

    need_buffer = TRUE;

    if (! compptr->component_needed) {

      /* Don't bother to upsample an uninteresting component. */

      upsample->methods[ci] = noop_upsample;

      need_buffer = FALSE;

    } else if (h_in_group == h_out_group && v_in_group == v_out_group) {

      /* Fullsize components can be processed without any work. */

      upsample->methods[ci] = fullsize_upsample;

      need_buffer = FALSE;

    } else if (h_in_group * 2 == h_out_group &&

               v_in_group == v_out_group) {

      /* Special cases for 2h1v upsampling */

      if (do_fancy && compptr->downsampled_width > 2) {

        if (jsimd_can_h2v1_fancy_upsample())

          upsample->methods[ci] = jsimd_h2v1_fancy_upsample;

        else

          upsample->methods[ci] = h2v1_fancy_upsample;

      } else {

        if (jsimd_can_h2v1_upsample())

          upsample->methods[ci] = jsimd_h2v1_upsample;

        else

          upsample->methods[ci] = h2v1_upsample;

      }

    } else if (h_in_group == h_out_group &&

               v_in_group * 2 == v_out_group && do_fancy) {

      /* Non-fancy upsampling is handled by the generic method */

      upsample->methods[ci] = h1v2_fancy_upsample;

      upsample->pub.need_context_rows = TRUE;

    } else if (h_in_group * 2 == h_out_group &&

               v_in_group * 2 == v_out_group) {

      /* Special cases for 2h2v upsampling */

      if (do_fancy && compptr->downsampled_width > 2) {

        if (jsimd_can_h2v2_fancy_upsample())

          upsample->methods[ci] = jsimd_h2v2_fancy_upsample;

        else

          upsample->methods[ci] = h2v2_fancy_upsample;

        upsample->pub.need_context_rows = TRUE;

      } else {

        if (jsimd_can_h2v2_upsample())

          upsample->methods[ci] = jsimd_h2v2_upsample;

        else

          upsample->methods[ci] = h2v2_upsample;

      }

    } else if ((h_out_group % h_in_group) == 0 &&

               (v_out_group % v_in_group) == 0) {

      /* Generic integral-factors upsampling method */

#if defined(__mips__)

      if (jsimd_can_int_upsample())

        upsample->methods[ci] = jsimd_int_upsample;

      else

#endif

        upsample->methods[ci] = int_upsample;

      upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);

      upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);

    } else

      ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);

    if (need_buffer && !cinfo->master->jinit_upsampler_no_alloc) {

      upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)

        ((j_common_ptr) cinfo, JPOOL_IMAGE,

         (JDIMENSION) jround_up((long) cinfo->output_width,

                                (long) cinfo->max_h_samp_factor),

         (JDIMENSION) cinfo->max_v_samp_factor);

    }

  }

}