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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
include <mach.h>
include <knet.h>
include "fmio.h"
# FMIO_READHEADER -- Read the header of a FMIO datafile and set up the FMIO
# runtime descriptor.
procedure fmio_readheader (fm)
pointer fm #I FMIO descriptor
pointer sp, buf, dh, pti, pt, ft, ip, op
int offset, buflen, npti, p1, p2, d1, d2, b_off1, b_off2, i
int status, chan, nbytes, nwords, maxpages, szbpage
errchk syserrs, calloc, malloc, realloc
long clktime()
begin
call smark (sp)
call salloc (dh, LEN_DHSTRUCT, TY_STRUCT)
chan = FM_CHAN(fm)
# Make a guess at the size of buffer needed to hold the header.
buflen = DEF_DFHDRLEN
call malloc (buf, buflen, TY_STRUCT)
# Read the full datafile header area into BUF.
repeat {
# Get the raw data.
nbytes = buflen * (SZ_STRUCT * SZB_CHAR)
call zardbf (chan, Memi[buf], nbytes, 1)
call zawtbf (chan, status)
if (status == ERR)
call syserrs (SYS_FMRERR, FM_DFNAME(fm))
# Extract the datafile header struct.
call miiupk32 (Memi[buf], Memi[dh], LEN_DHSTRUCT, TY_STRUCT)
if (DH_MAGIC(dh) != FMIO_MAGIC)
call syserrs (SYS_FMBADMAGIC, FM_DFNAME(fm))
# Repeat if the full header was not read.
if (DH_DATASTART(dh)-1 > nbytes) {
buflen = DH_DATASTART(dh)-1 / (SZ_STRUCT * SZB_CHAR)
call realloc (buf, buflen, TY_STRUCT)
} else if (status < DH_DATASTART(dh)-1) {
call syserrs (SYS_FMTRUNC, FM_DFNAME(fm))
} else
break
}
# Compute region of file in buffer.
b_off1 = 1
b_off2 = b_off1 + buflen * SZ_STRUCT * SZB_CHAR
# Copy general header fields.
FM_DFVERSION(fm) = DH_DFVERSION(dh)
FM_SZBPAGE(fm) = DH_SZBPAGE(dh)
FM_NLFILES(fm) = DH_NLFILES(dh)
FM_DATASTART(fm) = DH_DATASTART(dh)
FM_LSYNCTIME(fm) = clktime(0)
FM_DHMODIFIED(fm) = NO
# Initialize buffer sizes.
szbpage = FM_SZBPAGE(fm)
call fmio_setbuf (fm)
if (FM_SZBPAGE(fm) != szbpage)
call syserrs (SYS_FMBLKCHSZ, FM_DFNAME(fm))
# Initialize the file table.
call calloc (ft, (FM_NLFILES(fm) + 1) * LEN_FTE, TY_STRUCT)
FM_FTOFF(fm) = DH_FTOFF(dh)
FM_FTLASTNF(fm) = DH_FTLASTNF(dh)
FM_FTABLE(fm) = ft
ip = buf + FM_FTOFF(fm) - 1
call miiupk32 (Memi[ip], Memi[ip],
(FM_NLFILES(fm) + 1) * LEN_FTEX, TY_INT)
do i = 0, FM_NLFILES(fm) {
op = ft + i * LEN_FTE
LF_FSIZE(op) = FT_FSIZE(ip)
LF_FLAGS(op) = FT_FLAGS(ip)
ip = ip + LEN_FTEX
}
# Read the page table index.
FM_PTIOFF(fm) = DH_PTIOFF(dh)
FM_PTILEN(fm) = DH_PTILEN(dh)
FM_PTINPTI(fm) = DH_PTINPTI(dh)
ip = buf + FM_PTIOFF(fm) - 1
call malloc (pti, FM_PTILEN(fm), TY_INT)
call miiupk32 (Memi[ip], Memi[pti], FM_PTILEN(fm), TY_INT)
FM_PTINDEX(fm) = pti
# Now read the page table itself, stored in the data pages.
FM_PTLEN(fm) = DH_PTLEN(dh)
FM_PTNPTE(fm) = DH_PTNPTE(dh)
FM_PTLUPTE(fm) = DH_PTNPTE(dh)
call malloc (pt, FM_PTLEN(fm), TY_SHORT)
FM_PTABLE(fm) = pt
maxpages = FM_MAXBUFSIZE(fm) / FM_SZBPAGE(fm)
if (maxpages <= 0)
maxpages = DEF_BIGBUFNP
op = pt
npti = FM_PTINPTI(fm)
for (p1=1; p1 <= npti; p1=p2) {
# Get a contiguous range of page table pages.
d1 = Memi[pti+p1-1]
for (p2=p1+1; p2 <= npti; p2=p2+1) {
d2 = Memi[pti+p2-1]
if (d2-d1 != p2-p1 || p2-p1 >= maxpages)
break
}
# Read in the pages.
nbytes = (p2 - p1) * FM_SZBPAGE(fm)
nwords = nbytes / (SZB_CHAR * SZ_SHORT)
offset = (d1-1) * FM_SZBPAGE(fm) + FM_DATASTART(fm)
# Check to see if data is in BUF before reading datafile.
if (offset >= b_off1 && (offset+nbytes) <= b_off2)
call bytmov (Memi[buf], offset, Mems[op], 1, nbytes)
else {
call zardbf (chan, Mems[op], nbytes, offset)
call zawtbf (chan, status)
if (status < nbytes)
call syserrs (SYS_FMTRUNC, FM_DFNAME(fm))
}
op = op + nwords
}
# Swap the data.
if (BYTE_SWAP2 == YES)
call bswap2 (Mems[pt], 1, Mems[pt], 1, npti * FM_SZBPAGE(fm))
call mfree (buf, TY_STRUCT)
call sfree (sp)
end
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