blob: 2cf36bacf1d9d2275c1dd974e99322e2bdde30eb (
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
|
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkJpegUtility.h"
#include "SkCodecPriv.h"
/*
* Initialize the source manager
*/
static void sk_init_source(j_decompress_ptr dinfo) {
skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
src->next_input_byte = (const JOCTET*) src->fBuffer;
src->bytes_in_buffer = 0;
}
/*
* Fill the input buffer from the stream
*/
static boolean sk_fill_input_buffer(j_decompress_ptr dinfo) {
skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
size_t bytes = src->fStream->read(src->fBuffer, skjpeg_source_mgr::kBufferSize);
// libjpeg is still happy with a less than full read, as long as the result is non-zero
if (bytes == 0) {
return false;
}
src->next_input_byte = (const JOCTET*) src->fBuffer;
src->bytes_in_buffer = bytes;
return true;
}
/*
* Skip a certain number of bytes in the stream
*/
static void sk_skip_input_data(j_decompress_ptr dinfo, long numBytes) {
skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
size_t bytes = (size_t) numBytes;
if (bytes > src->bytes_in_buffer) {
size_t bytesToSkip = bytes - src->bytes_in_buffer;
if (bytesToSkip != src->fStream->skip(bytesToSkip)) {
SkCodecPrintf("Failure to skip.\n");
dinfo->err->error_exit((j_common_ptr) dinfo);
return;
}
src->next_input_byte = (const JOCTET*) src->fBuffer;
src->bytes_in_buffer = 0;
} else {
src->next_input_byte += numBytes;
src->bytes_in_buffer -= numBytes;
}
}
/*
* We do not need to do anything to terminate our stream
*/
static void sk_term_source(j_decompress_ptr dinfo)
{
// The current implementation of SkJpegCodec does not call
// jpeg_finish_decompress(), so this function is never called.
// If we want to modify this function to do something, we also
// need to modify SkJpegCodec to call jpeg_finish_decompress().
}
/*
* Constructor for the source manager that we provide to libjpeg
* We provide skia implementations of all of the stream processing functions required by libjpeg
*/
skjpeg_source_mgr::skjpeg_source_mgr(SkStream* stream)
: fStream(stream)
{
init_source = sk_init_source;
fill_input_buffer = sk_fill_input_buffer;
skip_input_data = sk_skip_input_data;
resync_to_restart = jpeg_resync_to_restart;
term_source = sk_term_source;
}
/*
* Call longjmp to continue execution on an error
*/
void skjpeg_err_exit(j_common_ptr dinfo) {
// Simply return to Skia client code
// JpegDecoderMgr will take care of freeing memory
skjpeg_error_mgr* error = (skjpeg_error_mgr*) dinfo->err;
(*error->output_message) (dinfo);
longjmp(error->fJmpBuf, 1);
}
|
