summaryrefslogtreecommitdiff
path: root/lib/common/GetLine.cpp
blob: e6b26c8af2a0865817d84a75ea72565bdb255d4d (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
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
// --------------------------------------------------------------------------
//
// File
//		Name:    GetLine.cpp
//		Purpose: Common base class for line based file descriptor reading
//		Created: 2011/04/22
//
// --------------------------------------------------------------------------

#include "Box.h"

#include <sys/types.h>

#ifdef HAVE_UNISTD_H
	#include <unistd.h>
#endif

#include "GetLine.h"
#include "CommonException.h"

#include "MemLeakFindOn.h"

// utility whitespace function
inline bool iw(int c)
{
	return (c == ' ' || c == '\t' || c == '\v' || c == '\f'); // \r, \n are already excluded
}


// --------------------------------------------------------------------------
//
// Function
//		Name:    GetLine::GetLine(int)
//		Purpose: Constructor, taking file descriptor
//		Created: 2011/04/22
//
// --------------------------------------------------------------------------
GetLine::GetLine()
: mLineNumber(0),
  mBufferBegin(0),
  mBytesInBuffer(0),
  mPendingEOF(false),
  mEOF(false)
{ }

// --------------------------------------------------------------------------
//
// Function
//		Name:    GetLine::GetLineInternal(std::string &, bool, int)
//		Purpose: Gets a line from the file, returning it in rOutput.
//			 If Preprocess is true, leading and trailing
//			 whitespace is removed, and comments (after #)  are
//			 deleted. Returns true if a line is available now,
//			 false if retrying may get a line (eg timeout,
//			 signal), and exceptions if it's EOF.
//		Created: 2011/04/22
//
// --------------------------------------------------------------------------
bool GetLine::GetLineInternal(std::string &rOutput, bool Preprocess,
	int Timeout)
{
	// EOF?
	if(mEOF) {THROW_EXCEPTION(CommonException, GetLineEOF)}
	
	// Initialise string to stored into
	rOutput = mPendingString;
	mPendingString.erase();

	bool foundLineEnd = false;

	while(!foundLineEnd && !mEOF)
	{
		// Use any bytes left in the buffer
		while(mBufferBegin < mBytesInBuffer)
		{
			int c = mBuffer[mBufferBegin++];
			if(c == '\r')
			{
				// Ignore nasty Windows line ending extra chars
			}
			else if(c == '\n')
			{
				// Line end!
				foundLineEnd = true;
				break;
			}
			else
			{
				// Add to string
				rOutput += c;
			}
			
			// Implicit line ending at EOF
			if(mBufferBegin >= mBytesInBuffer && mPendingEOF)
			{
				foundLineEnd = true;
			}
		}
		
		// Check size
		if(rOutput.size() > GETLINE_MAX_LINE_SIZE)
		{
			THROW_EXCEPTION(CommonException, GetLineTooLarge)
		}
		
		// Read more in?
		if(!foundLineEnd && mBufferBegin >= mBytesInBuffer && !mPendingEOF)
		{
			int bytes = ReadMore(Timeout);
			
			// Error?
			if(bytes == -1)
			{
				THROW_EXCEPTION(CommonException, OSFileError)
			}
			
			// Adjust buffer info
			mBytesInBuffer = bytes;
			mBufferBegin = 0;
			
			// No data returned?
			if(bytes == 0 && IsStreamDataLeft())
			{
			       // store string away
			       mPendingString = rOutput;
			       // Return false;
			       return false;
			}
		}
		
		// EOF?
		if(mPendingEOF && mBufferBegin >= mBytesInBuffer)
		{
			// File is EOF, and now we've depleted the buffer completely, so tell caller as well.
			mEOF = true;
		}
	}

	if(Preprocess)
	{
		// Check for comment char, but char before must be whitespace
		// end points to a gap between characters, may equal start if
		// the string to be extracted has zero length, and indexes the
		// first character not in the string (== length, or a # mark
		// or whitespace)
		int end = 0;
		int size = rOutput.size();
		while(end < size)
		{
			if(rOutput[end] == '#' && (end == 0 || (iw(rOutput[end-1]))))
			{
				break;
			}
			end++;
		}
		
		// Remove whitespace
		int begin = 0;
		while(begin < size && iw(rOutput[begin]))
		{
			begin++;
		}

		while(end > begin && end <= size && iw(rOutput[end-1]))
		{
			end--;
		}
		
		// Return a sub string
		rOutput = rOutput.substr(begin, end - begin);
	}

	return true;
}