1/*
2 * jdsample.h
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1996, Thomas G. Lane.
6 * For conditions of distribution and use, see the accompanying README.ijg
7 * file.
8 */
9
10#define JPEG_INTERNALS
11#include "jpeglib.h"
12
13
14/* Pointer to routine to upsample a single component */
15typedef void (*upsample1_ptr) (j_decompress_ptr cinfo,
16                               jpeg_component_info *compptr,
17                               JSAMPARRAY input_data,
18                               JSAMPARRAY *output_data_ptr);
19
20/* Private subobject */
21
22typedef struct {
23  struct jpeg_upsampler pub;    /* public fields */
24
25  /* Color conversion buffer.  When using separate upsampling and color
26   * conversion steps, this buffer holds one upsampled row group until it
27   * has been color converted and output.
28   * Note: we do not allocate any storage for component(s) which are full-size,
29   * ie do not need rescaling.  The corresponding entry of color_buf[] is
30   * simply set to point to the input data array, thereby avoiding copying.
31   */
32  JSAMPARRAY color_buf[MAX_COMPONENTS];
33
34  /* Per-component upsampling method pointers */
35  upsample1_ptr methods[MAX_COMPONENTS];
36
37  int next_row_out;             /* counts rows emitted from color_buf */
38  JDIMENSION rows_to_go;        /* counts rows remaining in image */
39
40  /* Height of an input row group for each component. */
41  int rowgroup_height[MAX_COMPONENTS];
42
43  /* These arrays save pixel expansion factors so that int_expand need not
44   * recompute them each time.  They are unused for other upsampling methods.
45   */
46  UINT8 h_expand[MAX_COMPONENTS];
47  UINT8 v_expand[MAX_COMPONENTS];
48} my_upsampler;
49
50typedef my_upsampler *my_upsample_ptr;
51