SWAB

Section: Misc. Reference Manual Pages (3T)
Updated: December 16, 1991
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NAME

TIFFReverseBits, TIFFSwabShort, TIFFSwabLong, TIFFSwabArrayOfShort, TIFFSwabArrayOfLong - byte- and bit-swapping routines

SYNOPSIS

#include <tiffio.h>
const unsigned char* TIFFGetBitRevTable(int reversed);
void TIFFReverseBits(u_char* data, unsigned long nbytes)
void TIFFSwabShort(uint16* data)
void TIFFSwabLong(uint32* data)
void TIFFSwabArrayOfShort(uint16* data, unsigned long nshorts)
void TIFFSwabArrayOfLong(uint32* data, unsigned long nlongs)

DESCRIPTION

The following routines are used by the library to swap 16- and 32-bit data and to reverse the order of bits in bytes.

TIFFSwabShort and TIFFSwabLong swap the bytes in a single 16-bit and 32-bit item, respectively. TIFFSwabArrayOfShort and TIFFSwabArrayOfLong swap the bytes in an array of 16-bit and 32-bit items, respectively.

TIFFReverseBits replaces each byte in data with the equivalent bit-reversed value. This operation is done with a lookup table, TIFFBitRevTable which is declared public. A second table, TIFFNoBitRevTable is also declared public; it is a lookup table that can be used as an identity function; i.e. TIFFNoBitRevTable[n] == n.

DIAGNOSTICS

None.