source/texk/web2c/luatexdir/luazlib/gzip.lua

   1 --[[------------------------------------------------------------------------
   2 gzip.lua
   3 support code for zlib library version 1.2.1 - gzip extentions
   4 usage lua -lgzip ...
   5
   6 Author: Tiago Dionizio (tngd@mega.ist.utl.pt)
   7 $Id: gzip.lua,v 1.3 2004/07/22 19:11:55 tngd Exp $
   8 --]]------------------------------------------------------------------------
   9
  10
  11 --[[------------------------------------------------------------------------
  12
  13 After loading the module a table with the following interface should be
  14 available:
  15
  16 gzip.open(filename [, mode])
  17
  18     Opens a file name using "gzopen". Behaviour is identical to the description
  19     given in the zlib library. If mode is not given a default mode "rb" will be
  20     used. Mode is the same as interpreted by gzopen function, ie, it can
  21     include special modes such as characters 1 to 9 that will be treated as the
  22     compression level when opening a file for writing.
  23
  24     It returns a new file handle, or, in case of errors, nil plus an error
  25     message
  26
  27 gzip.lines(filename)
  28
  29     Same behaviour as io.lines in the io standard library provided by lua
  30     with the aditional feature of working with gzip files. If a normal text
  31     file is read it will read it normaly (normal gzopen behaviour).
  32
  33 gzip.close(file)
  34
  35     Same as file:close, use file:close instead.
  36
  37 file:flush()
  38
  39     This function takes no parameters and flushes all output to working file.
  40     The same as calling 'gzflush(file, Z_FINISH)' so writing to the file will
  41     most likely not work as expected. This is subject to change in the future
  42     if there is a strong reason for it to happen.
  43
  44 file:read(format1, ...)
  45     Reads the file file, according to the given formats, which specify what
  46     to read. For each format, the function returns a string with the characters
  47     read, or nil if it cannot read data with the specified format. When called
  48     without formats, it uses a default format that reads the entire next line
  49     (see below).
  50
  51     The available formats are
  52
  53         "*a"   reads the whole file, starting at the current position. On end of
  54                file, it returns the empty string.
  55         "*l"   reads the next line (skipping the end of line), returning nil on
  56                end of file. This is the default format.
  57         number reads a string with up to that number of characters, returning
  58                nil on end of file. If number is zero, it reads nothing and
  59                returns an empty string, or nil on end of file.
  60
  61     Unlink io.read, the "*n" format will not be available.
  62
  63
  64 file:lines()
  65
  66     Returns an iterator function that, each time it is called, returns a new
  67     line from the file. Therefore, the construction
  68        for line in file:lines() do ... end
  69    will iterate over all lines of the file. (Unlike gzip.lines, this function
  70    does not close the file when the loop ends.)
  71
  72 file:seek([whence] [, offset])
  73
  74     Sets and gets the file position, measured from the beginning of the file,
  75     to the position given by offset plus a base specified by the string whence,
  76     as follows:
  77
  78         "set" base is position 0 (beginning of the file);
  79         "cur" base is current position;
  80
  81     In case of success, function seek returns the final file position, measured in bytes from the beginning of the file. If this function fails, it returns nil, plus a string describing the error.
  82     The default value for whence is "cur", and for offset is 0. Therefore, the call file:seek() returns the current file position, without changing it; the call file:seek("set") sets the position to the beginning of the file (and returns 0); and the call file:seek("end") sets the position to the end of the file, and returns its size.
  83
  84     This function is subject to limitations imposed by gzseek function from
  85     zlib library, such as the inability to use "end" as the base for seeking
  86     and the inability to seek backwards when writing.
  87
  88 file:write(value1, ...)
  89
  90     Writes the value of each of its arguments to the filehandle file. The
  91     arguments must be strings or numbers. To write other values, use tostring
  92     or string.format before write
  93
  94 file:close()
  95
  96     Closes the file.
  97
  98 --]]------------------------------------------------------------------------
  99
 100 require("requirelib")
 101
 102 requirelib("lzlib", "luaopen_gzip", true)