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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
#include "fitz.h"
#include <jpeglib.h>
#include <setjmp.h>
typedef struct fz_dctd_s fz_dctd;
struct fz_dctd_s
{
fz_stream *chain;
int color_transform;
int init;
int stride;
unsigned char *scanline;
unsigned char *rp, *wp;
struct jpeg_decompress_struct cinfo;
struct jpeg_source_mgr srcmgr;
struct jpeg_error_mgr errmgr;
jmp_buf jb;
char msg[JMSG_LENGTH_MAX];
};
static void error_exit(j_common_ptr cinfo)
{
fz_dctd *state = cinfo->client_data;
cinfo->err->format_message(cinfo, state->msg);
longjmp(state->jb, 1);
}
static void init_source(j_decompress_ptr cinfo)
{
/* nothing to do */
}
static void term_source(j_decompress_ptr cinfo)
{
/* nothing to do */
}
static boolean fill_input_buffer(j_decompress_ptr cinfo)
{
struct jpeg_source_mgr *src = cinfo->src;
fz_dctd *state = cinfo->client_data;
fz_stream *chain = state->chain;
chain->rp = chain->wp;
fz_fill_buffer(chain);
src->next_input_byte = chain->rp;
src->bytes_in_buffer = chain->wp - chain->rp;
if (src->bytes_in_buffer == 0)
{
static unsigned char eoi[2] = { 0xFF, JPEG_EOI };
fz_warn("premature end of file in jpeg");
src->next_input_byte = eoi;
src->bytes_in_buffer = 2;
}
return 1;
}
static void skip_input_data(j_decompress_ptr cinfo, long num_bytes)
{
struct jpeg_source_mgr *src = cinfo->src;
if (num_bytes > 0)
{
while ((size_t)num_bytes > src->bytes_in_buffer)
{
num_bytes -= src->bytes_in_buffer;
(void) src->fill_input_buffer(cinfo);
}
src->next_input_byte += num_bytes;
src->bytes_in_buffer -= num_bytes;
}
}
static int
read_dctd(fz_stream *stm, unsigned char *buf, int len)
{
fz_dctd *state = stm->state;
j_decompress_ptr cinfo = &state->cinfo;
unsigned char *p = buf;
unsigned char *ep = buf + len;
if (setjmp(state->jb))
{
if (cinfo->src)
state->chain->rp = state->chain->wp - cinfo->src->bytes_in_buffer;
return fz_throw("jpeg error: %s", state->msg);
}
if (!state->init)
{
cinfo->client_data = state;
cinfo->err = &state->errmgr;
jpeg_std_error(cinfo->err);
cinfo->err->error_exit = error_exit;
jpeg_create_decompress(cinfo);
cinfo->src = &state->srcmgr;
cinfo->src->init_source = init_source;
cinfo->src->fill_input_buffer = fill_input_buffer;
cinfo->src->skip_input_data = skip_input_data;
cinfo->src->resync_to_restart = jpeg_resync_to_restart;
cinfo->src->term_source = term_source;
cinfo->src->next_input_byte = state->chain->rp;
cinfo->src->bytes_in_buffer = state->chain->wp - state->chain->rp;
jpeg_read_header(cinfo, 1);
/* speed up jpeg decoding a bit */
cinfo->dct_method = JDCT_FASTEST;
cinfo->do_fancy_upsampling = FALSE;
/* default value if ColorTransform is not set */
if (state->color_transform == -1)
{
if (state->cinfo.num_components == 3)
state->color_transform = 1;
else
state->color_transform = 0;
}
if (cinfo->saw_Adobe_marker)
state->color_transform = cinfo->Adobe_transform;
/* Guess the input colorspace, and set output colorspace accordingly */
switch (cinfo->num_components)
{
case 3:
if (state->color_transform)
cinfo->jpeg_color_space = JCS_YCbCr;
else
cinfo->jpeg_color_space = JCS_RGB;
break;
case 4:
if (state->color_transform)
cinfo->jpeg_color_space = JCS_YCCK;
else
cinfo->jpeg_color_space = JCS_CMYK;
break;
}
jpeg_start_decompress(cinfo);
state->stride = cinfo->output_width * cinfo->output_components;
state->scanline = fz_malloc(state->stride);
state->rp = state->scanline;
state->wp = state->scanline;
state->init = 1;
}
while (state->rp < state->wp && p < ep)
*p++ = *state->rp++;
while (p < ep)
{
if (cinfo->output_scanline == cinfo->output_height)
break;
if (p + state->stride <= ep)
{
jpeg_read_scanlines(cinfo, &p, 1);
p += state->stride;
}
else
{
jpeg_read_scanlines(cinfo, &state->scanline, 1);
state->rp = state->scanline;
state->wp = state->scanline + state->stride;
}
while (state->rp < state->wp && p < ep)
*p++ = *state->rp++;
}
return p - buf;
}
static void
close_dctd(fz_stream *stm)
{
fz_dctd *state = stm->state;
if (setjmp(state->jb))
{
state->chain->rp = state->chain->wp - state->cinfo.src->bytes_in_buffer;
fz_warn("jpeg error: %s", state->msg);
goto skip;
}
if (state->init)
jpeg_finish_decompress(&state->cinfo);
skip:
state->chain->rp = state->chain->wp - state->cinfo.src->bytes_in_buffer;
jpeg_destroy_decompress(&state->cinfo);
fz_free(state->scanline);
fz_close(state->chain);
fz_free(state);
}
fz_stream *
fz_open_dctd(fz_stream *chain, fz_obj *params)
{
fz_dctd *state;
fz_obj *obj;
state = fz_malloc(sizeof(fz_dctd));
memset(state, 0, sizeof(fz_dctd));
state->chain = chain;
state->color_transform = -1; /* unset */
state->init = 0;
obj = fz_dict_gets(params, "ColorTransform");
if (obj)
state->color_transform = fz_to_int(obj);
return fz_new_stream(state, read_dctd, close_dctd);
}
|
