src/tiff/man/TIFFswab.3tiff

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  25 .if n .po 0
  26 .TH SWAB 3TIFF "November 04, 2004" "libtiff"
  27 .SH NAME
  28 TIFFGetBitRevTable, TIFFReverseBits, TIFFSwabShort, TIFFSwabLong,
  29 TIFFSwabArrayOfShort, TIFFSwabArrayOfLong \- byte- and bit-swapping routines
  30 .SH SYNOPSIS
  31 .B "#include <tiffio.h>"
  32 .sp
  33 .BI "const unsigned char* TIFFGetBitRevTable(int " reversed ")"
  34 .br
  35 .BI "void TIFFReverseBits(u_char *" data ", unsigned long " nbytes ")"
  36 .br
  37 .BI "void TIFFSwabShort(uint16 *" data ")"
  38 .br
  39 .BI "void TIFFSwabLong(uint32 *" data ")"
  40 .br
  41 .BI "void TIFFSwabArrayOfShort(uint16 *" data ", unsigned long " nshorts ")"
  42 .br
  43 .BI "void TIFFSwabArrayOfLong(uint32 *" data ", unsigned long " nlongs ")"
  44 .SH DESCRIPTION
  45 The following routines are used by the library to swap
  46 16- and 32-bit data and to reverse the order of bits in bytes.
  47 .PP
  48 .IR TIFFSwabShort
  49 and
  50 .IR TIFFSwabLong
  51 swap the bytes in a single 16-bit and 32-bit item, respectively.
  52 .IR TIFFSwabArrayOfShort
  53 and
  54 .IR TIFFSwabArrayOfLong
  55 swap the bytes in an array of 16-bit and 32-bit items, respectively.
  56 .PP
  57 .IR TIFFReverseBits
  58 replaces each byte in
  59 .I data
  60 with the equivalent bit-reversed value. This operation is performed with a
  61 lookup table, which is returned using the
  62 .IR TIFFGetBitRevTable
  63 function.
  64 .I reversed
  65 parameter specifies which table should be returned. Supply
  66 .I 1
  67 if you want bit reversal table. Supply
  68 .I 0
  69 to get the table that do not reverse bit values. It is a lookup table that can
  70 be used as an
  71 .IR "identity function" ;
  72 i.e.
  73 .IR "TIFFNoBitRevTable[n] == n" .
  74 .SH DIAGNOSTICS
  75 None.
  76 .SH "SEE ALSO"
  77 .BR libtiff (3TIFF)
  78 .PP
  79 Libtiff library home page:
  80 .BR http://www.remotesensing.org/libtiff/