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
|
#ifndef moses_gzfile_buf_h
#define moses_gzfile_buf_h
#include <stdexcept>
#include <streambuf>
#include <zlib.h>
#include <cstring>
/** wrapper around gzip input stream. Unknown parentage
* @todo replace with boost version - output stream already uses it
*/
class gzfilebuf : public std::streambuf
{
public:
gzfilebuf(const char *filename) {
_gzf = gzopen(filename, "rb");
if (!_gzf)
throw std::runtime_error("Could not open " + std::string(filename) + ".");
setg (_buff+sizeof(int), // beginning of putback area
_buff+sizeof(int), // read position
_buff+sizeof(int)); // end position
}
~gzfilebuf() {
gzclose(_gzf);
}
protected:
virtual int_type overflow (int_type /* c */) {
throw;
}
// write multiple characters
virtual
std::streamsize xsputn (const char* /* s */,
std::streamsize /* num */) {
throw;
}
virtual std::streampos seekpos ( std::streampos /* sp */, std::ios_base::openmode /* which = std::ios_base::in | std::ios_base::out */ ) {
throw;
}
//read one character
virtual int_type underflow () {
// is read position before end of _buff?
if (gptr() < egptr()) {
return traits_type::to_int_type(*gptr());
}
/* process size of putback area
* - use number of characters read
* - but at most four
*/
unsigned int numPutback = gptr() - eback();
if (numPutback > sizeof(int)) {
numPutback = sizeof(int);
}
/* copy up to four characters previously read into
* the putback _buff (area of first four characters)
*/
std::memmove (_buff+(sizeof(int)-numPutback), gptr()-numPutback,
numPutback);
// read new characters
int num = gzread(_gzf, _buff+sizeof(int), _buffsize-sizeof(int));
if (num <= 0) {
// ERROR or EOF
return EOF;
}
// reset _buff pointers
setg (_buff+(sizeof(int)-numPutback), // beginning of putback area
_buff+sizeof(int), // read position
_buff+sizeof(int)+num); // end of buffer
// return next character
return traits_type::to_int_type(*gptr());
}
std::streamsize xsgetn (char* s,
std::streamsize num) {
return gzread(_gzf,s,num);
}
private:
gzFile _gzf;
static const unsigned int _buffsize = 1024;
char _buff[_buffsize];
};
#endif
|
