blob: 2c9d250e36bbc4457d1a3c3ea438454a7f3fac4e (
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
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
/*
* The Python Imaging Library.
* $Id: PcxEncode.c 2134 2004-10-06 08:55:20Z fredrik $
*
* encoder for PCX data
*
* history:
* 99-02-07 fl created
*
* Copyright (c) Fredrik Lundh 1999.
* Copyright (c) Secret Labs AB 1999.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
enum { INIT, FETCH, ENCODE };
/* we're reusing "ystep" to store the last value */
#define LAST ystep
int
ImagingPcxEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
UINT8* ptr;
int this;
ptr = buf;
if (!state->state) {
/* sanity check */
if (state->xsize <= 0 || state->ysize <= 0) {
state->errcode = IMAGING_CODEC_END;
return 0;
}
state->bytes = (state->xsize*state->bits + 7) / 8;
state->state = FETCH;
}
for (;;)
switch (state->state) {
case FETCH:
/* get a line of data */
if (state->y >= state->ysize) {
state->errcode = IMAGING_CODEC_END;
return ptr - buf;
}
state->shuffle(state->buffer,
(UINT8*) im->image[state->y + state->yoff] +
state->xoff * im->pixelsize, state->xsize);
state->y++;
state->count = 1;
state->LAST = state->buffer[0];
state->x = 1;
state->state = ENCODE;
/* fall through */
case ENCODE:
/* compress this line */
/* when we arrive here, "count" contains the number of
bytes having the value of "LAST" that we've already
seen */
while (state->x < state->bytes) {
if (state->count == 63) {
/* this run is full; flush it */
if (bytes < 2)
return ptr - buf;
*ptr++ = 0xff;
*ptr++ = state->LAST;
bytes -= 2;
state->count = 0;
}
this = state->buffer[state->x];
if (this == state->LAST) {
/* extend the current run */
state->x++;
state->count++;
} else {
/* start a new run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1)
return ptr - buf;
*ptr++ = state->LAST;
bytes--;
} else {
if (state->count > 0) {
if (bytes < 2)
return ptr - buf;
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
}
}
state->LAST = this;
state->count = 1;
state->x++;
}
}
/* end of line; flush the current run */
if (state->count == 1 && (state->LAST < 0xc0)) {
if (bytes < 1)
return ptr - buf;
*ptr++ = state->LAST;
bytes--;
} else {
if (state->count > 0) {
if (bytes < 2)
return ptr - buf;
*ptr++ = 0xc0 | state->count;
*ptr++ = state->LAST;
bytes -= 2;
}
}
/* read next line */
state->state = FETCH;
break;
}
}
|
