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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
include <error.h>
# MFREE -- Free a previously allocated buffer. If the buffer has already been
# returned (NULL pointer), ignore the request. Once the buffer has been
# returned, the old pointer value is of not useful (and invalid), so set it
# to NULL.
procedure mfree (ptr, dtype)
pointer ptr
int dtype
pointer bp
int fwa, gc_type, status, lwl
char emsg[SZ_LINE]
int mgtfwa(), coerce(), mgc_gettype()
errchk mgtfwa
include "nmemio.com"
begin
# Check for NULL or already-freed pointers. We only invoke an error
# rather than sys_panic to allow for recovery.
if (ptr < 0) {
call merror ("Attempt to free already freed pointer")
return
}
if (mdebug > 0 && ptr == NULL) {
call merror ("Attempt to free NULL pointer")
return
}
if (mcollect > 0) {
gc_type = mgc_gettype (ptr)
if ((gc_type != NULL && gc_type != dtype) && in_task > 0) {
call merror ("Attempt to free pointer of wrong type")
dtype = gc_type
}
}
if (ptr != NULL) {
fwa = mgtfwa (ptr, dtype)
bp = coerce (ptr, dtype, TY_INT)
if (mwatch > 0) {
# Check the lower sentinal value. Any serious underflow
# would have corrupted the fwa and been detected above in
# mgtfwa(), we really only use this to check for 0/1 indexing
# problems that write before the start od the data.
if (Memi[bp-1] != lsentinal) {
call aclrc (emsg, SZ_LINE)
call sprintf (emsg, SZ_LINE,
"Pointer underflow: addr=0x%x nelem=%d type=%s\n")
call pargi (ptr)
call pargi (Memi[bp-2])
call ptype (dtype)
if (mreport > 0)
call eprintf (emsg)
call merror (emsg)
}
# Check the upper sentinal value. Note that the setinal is
# aligned to the INT boundary so depending on the type we
# might still allow a slight overrun.
lwl = Memi[bp-4]
if (Memi[lwl] != usentinal) {
call aclrc (emsg, SZ_LINE)
call sprintf (emsg, SZ_LINE,
"Pointer overflow: addr=0x%x nelem=%d type=%s\n")
call pargi (ptr)
call pargi (Memi[bp-2])
call ptype (dtype)
if (mreport > 0)
call eprintf (emsg)
call merror (emsg)
}
}
call zmfree (fwa, status)
if (status == ERR)
call sys_panic (SYS_MCORRUPTED, "Memory has been corrupted")
# Negate the pointer so we can detect another attempt to free it.
if (mcollect > 0 && in_task > 0)
call mgc_update (ptr)
if (mcollect >= 0)
nfree = nfree + 1
ptr = - ptr
ptr = NULL
}
end
# PTYPE -- Convert a pointer type code t its string equivalent.
procedure ptype (dtype)
int dtype
begin
switch (dtype) {
case TY_BOOL: call pargstr ("TY_BOOL")
case TY_CHAR: call pargstr ("TY_CHAR")
case TY_SHORT: call pargstr ("TY_SHORT")
case TY_INT: call pargstr ("TY_INT")
case TY_LONG: call pargstr ("TY_LONG")
case TY_REAL: call pargstr ("TY_REAL")
case TY_DOUBLE: call pargstr ("TY_DOUBLE")
case TY_COMPLEX: call pargstr ("TY_COMPLEX")
case TY_STRUCT: call pargstr ("TY_STRUCT")
case TY_POINTER: call pargstr ("TY_POINTER")
}
end
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