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151 lines
2.7 KiB
C
151 lines
2.7 KiB
C
/***************************************************************************
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* gswap.c:
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*
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* Functions for generalized, in-pace byte swapping between LSBF and
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* MSBF byte orders.
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*
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* Some standard integer types are needed, namely uint8_t and
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* uint32_t, (these are normally declared by including inttypes.h or
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* stdint.h). Each function expects it's input to be a void pointer
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* to a quantity of the appropriate size.
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*
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* There are two versions of most routines, one that works on
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* quantities regardless of alignment (gswapX) and one that works on
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* memory aligned quantities (gswapXa). The memory aligned versions
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* (gswapXa) are much faster than the other versions (gswapX), but the
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* memory *must* be aligned.
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*
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* Written by Chad Trabant,
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* IRIS Data Management Center
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*
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* Version: 2010.006
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***************************************************************************/
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#include "lmplatform.h"
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/* Swap routines that work on any (aligned or not) quantities */
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void
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ms_gswap2 ( void *data2 )
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{
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uint8_t temp;
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union
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{
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uint8_t c[2];
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} dat;
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memcpy( &dat, data2, 2 );
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temp = dat.c[0];
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dat.c[0] = dat.c[1];
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dat.c[1] = temp;
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memcpy( data2, &dat, 2 );
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}
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void
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ms_gswap3 ( void *data3 )
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{
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uint8_t temp;
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union
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{
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uint8_t c[3];
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} dat;
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memcpy( &dat, data3, 3 );
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temp = dat.c[0];
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dat.c[0] = dat.c[2];
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dat.c[2] = temp;
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memcpy( data3, &dat, 3 );
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}
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void
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ms_gswap4 ( void *data4 )
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{
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uint8_t temp;
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union {
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uint8_t c[4];
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} dat;
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memcpy( &dat, data4, 4 );
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temp = dat.c[0];
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dat.c[0] = dat.c[3];
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dat.c[3] = temp;
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temp = dat.c[1];
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dat.c[1] = dat.c[2];
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dat.c[2] = temp;
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memcpy( data4, &dat, 4 );
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}
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void
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ms_gswap8 ( void *data8 )
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{
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uint8_t temp;
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union
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{
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uint8_t c[8];
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} dat;
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memcpy( &dat, data8, 8 );
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temp = dat.c[0];
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dat.c[0] = dat.c[7];
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dat.c[7] = temp;
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temp = dat.c[1];
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dat.c[1] = dat.c[6];
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dat.c[6] = temp;
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temp = dat.c[2];
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dat.c[2] = dat.c[5];
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dat.c[5] = temp;
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temp = dat.c[3];
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dat.c[3] = dat.c[4];
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dat.c[4] = temp;
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memcpy( data8, &dat, 8 );
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}
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/* Swap routines that work on memory aligned quantities */
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void
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ms_gswap2a ( void *data2 )
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{
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uint16_t *data = data2;
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*data=(((*data>>8)&0xff) | ((*data&0xff)<<8));
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}
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void
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ms_gswap4a ( void *data4 )
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{
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uint32_t *data = data4;
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*data=(((*data>>24)&0xff) | ((*data&0xff)<<24) |
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((*data>>8)&0xff00) | ((*data&0xff00)<<8));
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}
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void
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ms_gswap8a ( void *data8 )
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{
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uint32_t *data4 = data8;
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uint32_t h0, h1;
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h0 = data4[0];
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h0 = (((h0>>24)&0xff) | ((h0&0xff)<<24) |
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((h0>>8)&0xff00) | ((h0&0xff00)<<8));
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h1 = data4[1];
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h1 = (((h1>>24)&0xff) | ((h1&0xff)<<24) |
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((h1>>8)&0xff00) | ((h1&0xff00)<<8));
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data4[0] = h1;
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data4[1] = h0;
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}
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