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