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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
include <config.h>
include <fio.h>
# FILBUF -- Fill the file buffer. Called by GETC, GETLINE, and READ when the
# i/o pointer no longer points into the file buffer. This happens when
# (1) there is no file buffer yet, (2) all the data in the buffer has been
# read, or (3) a SEEK has occurred.
int procedure filbuf (fd)
int fd #I input file
pointer bp, pb_sp
int maxch, nchars_read
int ffault()
errchk fmkbfs, ffault, filerr, syserr
include <fio.com>
define again_ 91
begin
fp = fiodes[fd]
if (fd <= 0 || fp == NULL) # verification
call syserr (SYS_FILENOTOPEN)
again_
if (and (FF_READ+FF_PUSHBACK, fflags[fd]) == 0) {
if (FTYPE(fp) == STRING_FILE || FTYPE(fp) == SPOOL_FILE)
return (EOF)
else
call filerr (FNAME(fp), SYS_FNOREADPERM)
}
# If filbuf was called at the end of a pushed back block of data,
# pop the old i/o pointers off the pushback stack and resume i/o
# at the point at which it was interrupted.
if (and (fflags[fd], FF_PUSHBACK) != 0) {
repeat {
pb_sp = FPBSP(fp)
iop[fd] = Memi[pb_sp]; pb_sp = pb_sp + 1
itop[fd] = Memi[pb_sp]; pb_sp = pb_sp + 1
bufptr[fd] = Memi[pb_sp]; pb_sp = pb_sp + 1
FPBIOP(fp) = Memi[pb_sp]; pb_sp = pb_sp + 1
FPBSP(fp) = pb_sp
# When the pb stack pointer reaches the top of the pushback
# buffer, all pushed back data has been read. Note that the
# stack pointer is a pointer to int while FPBTOP is a pointer
# to char.
if (pb_sp >= (FPBTOP(fp) - 1) / SZ_INT + 1)
fflags[fd] = fflags[fd] - FF_PUSHBACK
# If there was no data left when pushback occurred, then we
# aren't done yet.
nchars_read = itop[fd] - iop[fd]
if (nchars_read > 0)
return (nchars_read)
} until (and (fflags[fd], FF_PUSHBACK) == 0)
goto again_
}
# If we do not have a file buffer yet, allocate one.
bp = bufptr[fd]
if (bp == NULL) {
call fmkbfs (fd)
bp = bufptr[fd]
}
if (FTYPE(fp) == TEXT_FILE) {
# Get next line from text file, initialize pointers. In raw mode
# we only read one character at a time.
if (and (FF_RAW, fflags[fd]) == 0)
maxch = FBUFSIZE(fp)
else
maxch = 1
call zcall4 (ZGETTX(fp), FCHAN(fp), Memc[bp], maxch, nchars_read)
iop[fd] = bp
itop[fd] = max (bp, bp + nchars_read)
otop[fd] = bp
} else if (FNCHARS(fp) < 0) {
# Validate data in buffer without performing a physical read (used
# to attempt error recovery following a read error - see fseti).
nchars_read = -FNCHARS(fp)
iop[fd] = bp
itop[fd] = bp + nchars_read
otop[fd] = bp
} else {
# Fill buffer from binary file.
nchars_read = ffault (fd, LNOTE(fd), 0, FF_READ)
}
switch (nchars_read) {
case ERR:
call filerr (FNAME(fp), SYS_FREAD)
case 0:
return (EOF)
default:
return (nchars_read) # (or ERR)
}
end
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