blob: bf6beb274ba8b7797f69fe26c7db71625a014a0f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/*
* jdcoefct.h
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1994-1997, Thomas G. Lane.
* libjpeg-turbo Modifications:
* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*/
#define JPEG_INTERNALS
#include "jpeglib.h"
/* Block smoothing is only applicable for progressive JPEG, so: */
#ifndef D_PROGRESSIVE_SUPPORTED
#undef BLOCK_SMOOTHING_SUPPORTED
#endif
/* Private buffer controller object */
typedef struct {
struct jpeg_d_coef_controller pub; /* public fields */
/* These variables keep track of the current location of the input side. */
/* cinfo->input_iMCU_row is also used for this. */
JDIMENSION MCU_ctr; /* counts MCUs processed in current row */
int MCU_vert_offset; /* counts MCU rows within iMCU row */
int MCU_rows_per_iMCU_row; /* number of such rows needed */
/* The output side's location is represented by cinfo->output_iMCU_row. */
/* In single-pass modes, it's sufficient to buffer just one MCU.
* We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
* and let the entropy decoder write into that workspace each time.
* In multi-pass modes, this array points to the current MCU's blocks
* within the virtual arrays; it is used only by the input side.
*/
JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU];
/* Temporary workspace for one MCU */
JCOEF *workspace;
#ifdef D_MULTISCAN_FILES_SUPPORTED
/* In multi-pass modes, we need a virtual block array for each component. */
jvirt_barray_ptr whole_image[MAX_COMPONENTS];
#endif
#ifdef BLOCK_SMOOTHING_SUPPORTED
/* When doing block smoothing, we latch coefficient Al values here */
int *coef_bits_latch;
#define SAVED_COEFS 6 /* we save coef_bits[0..5] */
#endif
} my_coef_controller;
typedef my_coef_controller *my_coef_ptr;
LOCAL(void)
start_iMCU_row (j_decompress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row (input side) */
{
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
/* In an interleaved scan, an MCU row is the same as an iMCU row.
* In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
* But at the bottom of the image, process only what's left.
*/
if (cinfo->comps_in_scan > 1) {
coef->MCU_rows_per_iMCU_row = 1;
} else {
if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1))
coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
else
coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
}
coef->MCU_ctr = 0;
coef->MCU_vert_offset = 0;
}
|
