/* ----------------------------- MNI Header -----------------------------------
@NAME : acr_read_one_element
@INPUT : afp - Acr_File pointer from which to read
@OUTPUT : group_id - ACR-NEMA group id
element_id - ACR-NEMA element id
data_length - length of data to follow
data_pointer - pointer to data. Space is allocated by this
routine. One additional byte is allocated and set to
zero so that the data can be treated as a string.
@RETURNS : Status.
@DESCRIPTION: Routine to read in one ACR-NEMA element.
@METHOD :
@GLOBALS :
@CALLS :
@CREATED : November 10, 1993 (Peter Neelin)
@MODIFIED :
---------------------------------------------------------------------------- */
Acr_Status acr_read_one_element(Acr_File *afp,
int *group_id, int *element_id,
long *data_length, char **data_pointer)
{
int ch, i, buflen;
unsigned char buffer[2*ACR_SIZEOF_SHORT+ACR_SIZEOF_LONG];
unsigned short grpid, elid;
size_t size_allocated;
buflen = sizeof(buffer)/sizeof(buffer[0]);
/* Read in group id, element id and 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;
}
acr_get_short(1, &buffer[0], &grpid);
*group_id = grpid;
acr_get_short(1, &buffer[2], &elid);
*element_id = elid;
acr_get_long(1, &buffer[4], data_length);
/* Allocate space for the data and null-terminate it */
size_allocated = *data_length + 1;
*data_pointer = MALLOC(size_allocated);
if (*data_pointer == NULL) {
*data_length = 0;
size_allocated = *data_length + 1;
*data_pointer = MALLOC(size_allocated);
}
(*data_pointer)[*data_length] = '\0';
/* Read in the data */
for (i=0; i < *data_length; i++) {
ch = acr_getc(afp);
if (ch == EOF) {
FREE(*data_pointer);
return ACR_PROTOCOL_ERROR;
}
(*data_pointer)[i] = ch;
}
return ACR_OK;
}
/* ----------------------------- MNI Header -----------------------------------
@NAME : acr_read_buffer
@INPUT : afp
nbytes_to_read
@OUTPUT : buffer
nbytes_read - if NULL, then this value is ignored, otherwise
the number of bytes actually read in is returned.
@RETURNS : Input status. If an error occurs on the first byte, then
ACR_END_OF_INPUT is returned, if an error occurs elsewhere,
then ACR_ABNORMAL_END_OF_INPUT is returned, otherwise ACR_OK
is returned.
@DESCRIPTION: Reads in a buffer of data and optionally returns the number
of bytes read
@METHOD :
@GLOBALS :
@CALLS :
@CREATED : February 12, 1997 (Peter Neelin)
@MODIFIED :
---------------------------------------------------------------------------- */
Acr_Status acr_read_buffer(Acr_File *afp, unsigned char buffer[],
long nbytes_to_read, long *nbytes_read)
{
long i;
int ch;
for (i=0; i < nbytes_to_read; i++) {
ch = acr_getc(afp);
if (ch == EOF) {
break;
}
buffer[i] = (unsigned char) ch;
}
/* Save the number of bytes read */
if (nbytes_read != NULL) {
*nbytes_read = i;
}
/* Return the status */
if (i >= nbytes_to_read) {
return ACR_OK;
}
else if (acr_get_io_watchpoint(afp) <= 0) {
return ACR_REACHED_WATCHPOINT;
}
else if (i == 0) {
return ACR_END_OF_INPUT;
}
else {
return ACR_ABNORMAL_END_OF_INPUT;
}
}
/* ----------------------------- MNI Header -----------------------------------
@NAME : acr_skip_input_data
@INPUT : afp
nbytes_to_skip
@OUTPUT : (none)
@RETURNS : Input status. If an error occurs on the first byte, then
ACR_END_OF_INPUT is returned, if an error occurs elsewhere,
then ACR_ABNORMAL_END_OF_INPUT is returned, otherwise ACR_OK
is returned.
@DESCRIPTION: Skips over input data.
@METHOD :
@GLOBALS :
@CALLS :
@CREATED : February 12, 1997 (Peter Neelin)
@MODIFIED :
---------------------------------------------------------------------------- */
Acr_Status acr_skip_input_data(Acr_File *afp, long nbytes_to_skip)
{
long i;
int ch;
for (i=0; i < nbytes_to_skip; i++) {
ch = acr_getc(afp);
if (ch == EOF) {
break;
}
}
/* Return the status */
if (i >= nbytes_to_skip) {
return ACR_OK;
}
else if (acr_get_io_watchpoint(afp) <= 0) {
return ACR_REACHED_WATCHPOINT;
}
else if (i == 0) {
return ACR_END_OF_INPUT;
}
else {
return ACR_ABNORMAL_END_OF_INPUT;
}
}
/* ----------------------------- 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;
}
}
