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
|
/*
* Copyright 2010 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/pdf/SkDeflate.h"
#include "include/core/SkData.h"
#include "include/private/base/SkMalloc.h"
#include "include/private/base/SkTo.h"
#include "src/core/SkTraceEvent.h"
#include "zlib.h"
#include <algorithm>
namespace {
// Different zlib implementations use different T.
// We've seen size_t and unsigned.
template <typename T> void* skia_alloc_func(void*, T items, T size) {
return sk_calloc_throw(SkToSizeT(items) * SkToSizeT(size));
}
void skia_free_func(void*, void* address) { sk_free(address); }
} // namespace
#define SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE 4096
#define SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE 4224 // 4096 + 128, usually big
// enough to always do a
// single loop.
// called by both write() and finalize()
static void do_deflate(int flush,
z_stream* zStream,
SkWStream* out,
unsigned char* inBuffer,
size_t inBufferSize) {
zStream->next_in = inBuffer;
zStream->avail_in = SkToInt(inBufferSize);
unsigned char outBuffer[SKDEFLATEWSTREAM_OUTPUT_BUFFER_SIZE];
SkDEBUGCODE(int returnValue;)
do {
zStream->next_out = outBuffer;
zStream->avail_out = sizeof(outBuffer);
SkDEBUGCODE(returnValue =) deflate(zStream, flush);
SkASSERT(!zStream->msg);
out->write(outBuffer, sizeof(outBuffer) - zStream->avail_out);
} while (zStream->avail_in || !zStream->avail_out);
SkASSERT(flush == Z_FINISH
? returnValue == Z_STREAM_END
: returnValue == Z_OK);
}
// Hide all zlib impl details.
struct SkDeflateWStream::Impl {
SkWStream* fOut;
unsigned char fInBuffer[SKDEFLATEWSTREAM_INPUT_BUFFER_SIZE];
size_t fInBufferIndex;
z_stream fZStream;
};
SkDeflateWStream::SkDeflateWStream(SkWStream* out,
int compressionLevel,
bool gzip)
: fImpl(std::make_unique<SkDeflateWStream::Impl>()) {
// There has existed at some point at least one zlib implementation which thought it was being
// clever by randomizing the compression level. This is actually not entirely incorrect, except
// for the no-compression level which should always be deterministically pass-through.
// Users should instead consider the zero compression level broken and handle it themselves.
SkASSERT(compressionLevel != 0);
fImpl->fOut = out;
fImpl->fInBufferIndex = 0;
if (!fImpl->fOut) {
return;
}
fImpl->fZStream.next_in = nullptr;
fImpl->fZStream.zalloc = &skia_alloc_func;
fImpl->fZStream.zfree = &skia_free_func;
fImpl->fZStream.opaque = nullptr;
SkASSERT(compressionLevel <= 9 && compressionLevel >= -1);
SkDEBUGCODE(int r =) deflateInit2(&fImpl->fZStream, compressionLevel,
Z_DEFLATED, gzip ? 0x1F : 0x0F,
8, Z_DEFAULT_STRATEGY);
SkASSERT(Z_OK == r);
}
SkDeflateWStream::~SkDeflateWStream() { this->finalize(); }
void SkDeflateWStream::finalize() {
TRACE_EVENT0("skia", TRACE_FUNC);
if (!fImpl->fOut) {
return;
}
do_deflate(Z_FINISH, &fImpl->fZStream, fImpl->fOut, fImpl->fInBuffer,
fImpl->fInBufferIndex);
(void)deflateEnd(&fImpl->fZStream);
fImpl->fOut = nullptr;
}
bool SkDeflateWStream::write(const void* void_buffer, size_t len) {
TRACE_EVENT0("skia", TRACE_FUNC);
if (!fImpl->fOut) {
return false;
}
const char* buffer = (const char*)void_buffer;
while (len > 0) {
size_t tocopy =
std::min(len, sizeof(fImpl->fInBuffer) - fImpl->fInBufferIndex);
memcpy(fImpl->fInBuffer + fImpl->fInBufferIndex, buffer, tocopy);
len -= tocopy;
buffer += tocopy;
fImpl->fInBufferIndex += tocopy;
SkASSERT(fImpl->fInBufferIndex <= sizeof(fImpl->fInBuffer));
// if the buffer isn't filled, don't call into zlib yet.
if (sizeof(fImpl->fInBuffer) == fImpl->fInBufferIndex) {
do_deflate(Z_NO_FLUSH, &fImpl->fZStream, fImpl->fOut,
fImpl->fInBuffer, fImpl->fInBufferIndex);
fImpl->fInBufferIndex = 0;
}
}
return true;
}
size_t SkDeflateWStream::bytesWritten() const {
return fImpl->fZStream.total_in + fImpl->fInBufferIndex;
}
|
