blob: 04b420c1db9801642614bf7466f98bd480b09896 (
plain) (
blame)
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
|
#pragma once
#include "input.h"
#include "output.h"
#include <util/system/yassert.h>
#include <util/generic/bitops.h>
/**
* @addtogroup Streams
* @{
*/
/**
* Proxy input stream that provides additional functions that make reading
* aligned data easier.
*/
class TAlignedInput: public IInputStream {
public:
TAlignedInput(IInputStream* s)
: Stream_(s)
, Position_(0)
{
}
/**
* Ensures alignment of the position in the input stream by skipping
* some input.
*
* @param alignment Alignment. Must be a power of 2.
*/
void Align(size_t alignment = sizeof(void*)) {
Y_ASSERT(IsPowerOf2(alignment));
if (Position_ & (alignment - 1)) {
size_t len = alignment - (Position_ & (alignment - 1));
do {
len -= DoSkip(len);
} while (len);
}
}
private:
size_t DoRead(void* ptr, size_t len) override;
size_t DoSkip(size_t len) override;
size_t DoReadTo(TString& st, char ch) override;
ui64 DoReadAll(IOutputStream& out) override;
private:
IInputStream* Stream_;
ui64 Position_;
};
/**
* Proxy output stream that provides additional functions that make writing
* aligned data easier.
*/
class TAlignedOutput: public IOutputStream {
public:
TAlignedOutput(IOutputStream* s)
: Stream_(s)
, Position_(0)
{
}
TAlignedOutput(TAlignedOutput&&) noexcept = default;
TAlignedOutput& operator=(TAlignedOutput&&) noexcept = default;
size_t GetCurrentOffset() const {
return Position_;
}
/**
* Ensures alignment of the position in the output stream by writing
* some data.
*
* @param alignment Alignment. Must be a power of 2.
*/
void Align(size_t alignment = sizeof(void*)) {
Y_ASSERT(IsPowerOf2(alignment));
static char unused[sizeof(void*) * 2];
Y_ASSERT(alignment <= sizeof(unused));
if (Position_ & (alignment - 1)) {
DoWrite(unused, alignment - (Position_ & (alignment - 1)));
}
}
private:
void DoWrite(const void* ptr, size_t len) override;
private:
IOutputStream* Stream_;
ui64 Position_;
};
/** @} */
|
