1File::RandomAccess(3) User Contributed Perl DocumentationFile::RandomAccess(3)
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NAME

6       File::RandomAccess - Random access reads of sequential file or scalar
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SYNOPSIS

9           use File::RandomAccess;
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11           $raf = new File::RandomAccess(\*FILE, $disableSeekTest);
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13           $raf = new File::RandomAccess(\$data);
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15           $err = $raf->Seek($pos);
16           $num = $raf->Read($buff, $bytes);
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DESCRIPTION

19       Allows random access to sequential file by buffering the file if
20       necessary.  Also allows access to data in memory to be accessed as if
21       it were a file.
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METHODS

24       new Creates a new RandomAccess object given a file reference or
25           reference to data in memory.
26
27               # Read from open file or pipe
28               $raf = new File::RandomAccess(\*FILE);
29
30               # Read from data in memory
31               $raf = new File::RandomAccess(\$data);
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33           Inputs:
34               0) Reference to RandomAccess object or RandomAccess class name.
35
36               1) File reference or scalar reference.
37
38               2) Flag set if file is already random access (disables
39               automatic SeekTest).
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41           Returns:
42               Reference to RandomAccess object.
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44       SeekTest
45           Performs test seek() on file to determine if buffering is
46           necessary.  If the seek() fails, then the file is buffered to allow
47           random access.  SeekTest() is automatically called from new unless
48           specified.
49
50               $result = $raf->SeekTest();
51
52           Inputs:
53               0) Reference to RandomAccess object.
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55           Returns:
56               1 if seek test passed (ie. no buffering required).
57
58           Notes:
59               Must be called before any other i/o.
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61       Tell
62           Get current position in file
63
64               $pos = $raf->Tell();
65
66           Inputs:
67               0) Reference to RandomAccess object.
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69           Returns:
70               Current position in file
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72       Seek
73           Seek to specified position in file.  When buffered, this doesn't
74           quite behave like seek() since it returns success even if you seek
75           outside the limits of the file.
76
77               $success = $raf->Seek($pos, 0);
78
79           Inputs:
80               0) Reference to RandomAccess object.
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82               1) Position.
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84               2) Whence (0=from start, 1=from cur pos, 2=from end).
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86           Returns:
87               1 on success, 0 otherwise
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89       Read
90           Read data from the file.
91
92               $num = $raf->Read($buff, 1024);
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94           Inputs:
95               0) Reference to RandomAccess object.
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97               1) Buffer.
98
99               2) Number of bytes to read.
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101           Returns:
102               Number of bytes actually read.
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104       ReadLine
105           Read a line from file (end of line is $/).
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107           Inputs:
108               0) Reference to RandomAccess object.
109
110               1) Buffer.
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112           Returns:
113               Number of bytes read.
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115       Slurp
116           Read whole file into buffer, without changing read pointer.
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118           Inputs:
119               0) Reference to RandomAccess object.
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121           Returns:
122               Nothing.
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124       BinMode
125           Set binary mode for file.
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127           Inputs:
128               0) Reference to RandomAccess object.
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130           Returns:
131               Nothing.
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133       Close
134           Close the file and free the buffer.
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136           Inputs:
137               0) Reference to RandomAccess object.
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139           Returns:
140               Nothing.
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OPTIONS

143       NoBuffer
144           Avoid buffering sequential files.
145
146               $raf->{NoBuffer} = 1;
147
148           When this option is set, old data is purged from the internal
149           buffer before a read operation on a sequential file.  In this mode,
150           memory requirements may be significantly reduced when reading
151           sequential files, but seeking backward is limited to within the
152           size of the internal buffer (which will be at least as large as the
153           last returned data block), and seeking relative to the end of file
154           is not allowed.
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AUTHOR

157       Copyright 2003-2019 Phil Harvey (phil at owl.phy.queensu.ca)
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159       This library is free software; you can redistribute it and/or modify it
160       under the same terms as Perl itself.
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SEE ALSO

163       Image::ExifTool(3pm)
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167perl v5.28.1                      2019-01-10             File::RandomAccess(3)