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/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
*/
#define import_spp
#define import_libc
#define import_xnames
#define import_stdio
#define import_error
#define import_fset
#include <iraf.h>
/* C_READ -- FIO read from a file. Read up to maxbytes bytes from the stream
** fd into the buffer buf. If the device associated with file fd is a record
** structured device a single record is read, and the byte count will generally
** be less than the maximum. If the physical record was larger than maxbytes
** the remainder of the record is returned in successive reads. If the actual
** file is a text file FIO XCHARs are returned as C chars. If the actual file
** is a binary file no conversion is performed, and an integral number of XCHARs
** are read.
**
** For reasons of consistency with SPP usage, EOF is returned when end of file
** is reached (fread returns 0), and an error action is taken if a file read
** error occurs. We cannot return ERR when an error occurs since ERR and EOF
** have the same value in STDIO land. IFERR may be used to catch file read
** errors.
*/
int
c_read (
XINT fd, /* FIO file descriptor */
char *buf, /* output buffer */
int maxbytes /* max bytes to read */
)
{
XINT x_fd = fd;
int nchars_read;
if (c_fstati (fd, F_TYPE) == TEXT_FILE) {
register char *op = buf;
register int ch, n = maxbytes;
register FILE *fp = FDTOFP(fd);
while (--n >= 0 && (ch = getc(fp)) >= 0) {
*op++ = ch;
if (ch == '\n')
break;
}
if (ferror (fp))
c_erract (EA_ERROR);
if (!(nchars_read = op - buf))
nchars_read = XEOF;
} else {
XINT x_maxchars = maxbytes / sizeof(XCHAR);
XCHAR *bp = (XCHAR *)buf;
/* Verify that the pointer coercion char->XCHAR->char is legal,
* i.e., that the char pointer is aligned to an XCHAR word
* boundary if required on this machine.
*/
if (buf != (char *)bp)
c_error (1, "c_read: buffer not xchar aligned");
if ((nchars_read = READ (&x_fd, bp, &x_maxchars)) > 0)
nchars_read *= sizeof(XCHAR);
}
return (nchars_read == XEOF ? EOF : nchars_read);
}
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