/* ----------------------------- MNI Header -----------------------------------
@NAME : acr_test_byte_ordering
@INPUT : afp
@OUTPUT : (none)
@RETURNS : status.
@DESCRIPTION: Tests input for byte ordering to use.
@METHOD :
@GLOBALS :
@CALLS :
@CREATED : November 10, 1993 (Peter Neelin)
@MODIFIED :
---------------------------------------------------------------------------- */
Acr_Status acr_test_byte_ordering(Acr_File *afp)
{
int ch, i, buflen;
unsigned char buffer[2*ACR_SIZEOF_SHORT+ACR_SIZEOF_LONG];
long data_length;
buflen = sizeof(buffer)/sizeof(buffer[0]);
/* Read in group id, element id and length of data, get length of data */
for (i=0; i < buflen; i++) {
ch = acr_getc(afp);
if (ch == EOF) {
if (i == 0)
return ACR_END_OF_INPUT;
else
return ACR_PROTOCOL_ERROR;
}
buffer[i] = ch;
}
/* Test data length (the first element should be a group length).
Try non-vax ordering first. */
(void) acr_set_vax_byte_ordering(FALSE);
acr_get_long(1, &buffer[4], &data_length);
/* If that doesn't work, set it to vax ordering. */
if (data_length != ACR_SIZEOF_LONG) {
(void) acr_set_vax_byte_ordering(TRUE);
acr_get_long(1, &buffer[4], &data_length);
}
/* Put the characters back */
for (i=buflen-1; i >=0; i--) {
if (acr_ungetc((int) buffer[i],afp) == EOF) {
return ACR_PROTOCOL_ERROR;
}
}
if (data_length != ACR_SIZEOF_LONG) {
return ACR_PROTOCOL_ERROR;
}
else {
return ACR_OK;
}
}
/* ----------------------------- MNI Header -----------------------------------
@NAME : acr_unget_buffer
@INPUT : afp
nbytes_to_unget
buffer
@OUTPUT : (none)
@RETURNS : Unget status.
@DESCRIPTION: Puts a buffer of data back into the input stream.
@METHOD :
@GLOBALS :
@CALLS :
@CREATED : February 12, 1997 (Peter Neelin)
@MODIFIED :
---------------------------------------------------------------------------- */
Acr_Status acr_unget_buffer(Acr_File *afp, unsigned char buffer[],
long nbytes_to_unget)
{
long i;
for (i=nbytes_to_unget-1; i >= 0; i--) {
if (acr_ungetc((int) buffer[i], afp) == EOF) {
break;
}
}
/* Return the status */
if (i >= 0) {
return ACR_IO_ERROR;
}
else {
return ACR_OK;
}
}
