jdmerge.cpp File Reference

#include "jinclude.h"
#include "jpeglib.h"

Include dependency graph for jdmerge.cpp:

Classes
struct	my_upsampler

Macros
#define	JPEG_INTERNALS
#define	SCALEBITS   16 /* speediest right-shift on some machines */
#define	ONE_HALF   ((int32_t) 1 << (SCALEBITS-1))
#define	FIX(x)   ((int32_t) ((x) * (1L<<SCALEBITS) + 0.5))

Typedefs
typedef my_upsampler *	my_upsample_ptr

Functions
static void	build_ycc_rgb_table (j_decompress_ptr cinfo)
static void	start_pass_merged_upsample (j_decompress_ptr cinfo)
static 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)
static 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)
static void	h2v1_merged_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf)
static void	h2v2_merged_upsample (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr, JSAMPARRAY output_buf)
void	jinit_merged_upsampler (j_decompress_ptr cinfo)

Macro Definition Documentation

#define JPEG_INTERNALS

#define SCALEBITS   16 /* speediest right-shift on some machines */

#define ONE_HALF   ((int32_t) 1 << (SCALEBITS-1))

#define FIX

(

x

)

((int32_t) ((x) * (1L<<SCALEBITS) + 0.5))

Typedef Documentation

typedef my_upsampler* my_upsample_ptr

Function Documentation

static void build_ycc_rgb_table ( j_decompress_ptr  cinfo )

static

{
  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
  int i;
  int32_t 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_t *)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                (MAXJSAMPLE+1) * SIZEOF(int32_t));
  upsample->Cb_g_tab = (int32_t *)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
                (MAXJSAMPLE+1) * SIZEOF(int32_t));

  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;
  }
}

static void start_pass_merged_upsample ( j_decompress_ptr  cinfo )

static

{
  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;
}

static 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  )

static

{
  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)++;
}

static 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  )

static

{
  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)++;
}

static void h2v1_merged_upsample ( j_decompress_ptr  cinfo, JSAMPIMAGE  input_buf, JDIMENSION  in_row_group_ctr, JSAMPARRAY  output_buf  )

static

{
  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
  register int y, cred, cgreen, cblue;
  int cb, cr;
  register JSAMPROW outptr;
  JSAMPROW inptr0, inptr1, inptr2;
  JDIMENSION col;
  /* copy these pointers into registers if possible */
  register JSAMPLE * range_limit = cinfo->sample_range_limit;
  int * Crrtab = upsample->Cr_r_tab;
  int * Cbbtab = upsample->Cb_b_tab;
  int32_t * Crgtab = upsample->Cr_g_tab;
  int32_t * 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];
  }
}

static void h2v2_merged_upsample ( j_decompress_ptr  cinfo, JSAMPIMAGE  input_buf, JDIMENSION  in_row_group_ctr, JSAMPARRAY  output_buf  )

static

{
  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
  register int y, cred, cgreen, cblue;
  int cb, cr;
  register JSAMPROW outptr0, outptr1;
  JSAMPROW inptr00, inptr01, inptr1, inptr2;
  JDIMENSION col;
  /* copy these pointers into registers if possible */
  register JSAMPLE * range_limit = cinfo->sample_range_limit;
  int * Crrtab = upsample->Cr_r_tab;
  int * Cbbtab = upsample->Cb_b_tab;
  int32_t * Crgtab = upsample->Cr_g_tab;
  int32_t * 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];
  }
}

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 = NULL;
  }

  build_ycc_rgb_table(cinfo);
}