static int scan (void * arg, word segm, word ofs) {
Context_Tag tag;
ctxt_info_t *info;
(void)arg;
assert(segm);
assert(ofs != (word)-1);
redo:
if((tag = peekb(segm, ofs), ctxtIsInfoTag(tag))) {
info = &CTXT_INFO_STRUCT(tag);
if(peekb(segm, ofs + 1) == '=' && peekb(segm, ofs + 4) == 0) {
/* status entry */
info->c_sizemax = peekw(segm, ofs + 2) & ~0x8001;
} else { /* normal entry */
char far *p = MK_FP(segm, ofs + 1);
unsigned num;
for(num = 0; isxdigit(*p); ++p) {
num <<= 8;
if(isdigit(*p))
num |= *p & 0xf;
else {
assert(islower(*p));
num |= *p - 'a' + 10;
}
}
if(*p == '=') {
info->c_sizecur += env_varlen(segm, ofs);
if(num < info->c_nummin)
info->c_nummin = num;
if(num > info->c_nummax)
info->c_nummax = num;
} else {
/* Invalid entry -> remove to make room for useful stuff */
env_subVarOffset(segm, ofs);
goto redo;
}
}
} else if(tag > ' ') { /* Alias */
CTXT_INFO(CTXT_TAG_ALIAS, sizecur) += env_varlen(segm ,ofs);
}
return 0; /* proceed */
}
word env_endOfVars(const word segm)
{ word offset;
DBG_ENTER("env_endOfVars", Suppl_env)
DBG_ARGUMENTS( ("env=%u", segm) )
chkMem
assert(segm != 0);
offset = 0; /* env starts always at location 0 */
while(peekb(segm, offset)) /* there is a variable */
offset += env_varlen(segm, offset);
DBG_RETURN_U( offset) /* This is the terminator byte */
}
void env_subVarOffset(word segm, word offset)
{ register unsigned moveStart;
DBG_ENTER("env_subVarOffset", Suppl_env)
DBG_ARGUMENTS( ("env=%u, ofs=%u", segm, offset) )
chkMem
assert(segm);
assert(offset < env_endOfVars(segm));
moveStart = offset + env_varlen(segm, offset);
_fmemmove(MK_FP(segm, offset), MK_FP(segm, moveStart),
env_firstFree(segm) - moveStart);
chkMem
DBG_EXIT
}
int chgCtxt(const Context_Tag tag, const char * const name, const char * const value)
{ word segm, ofs;
int newlen;
assert(name);
ctxtCheckInfoTag(tag);
segm = ctxtFromTag(tag);
assert(segm);
newlen = value? strlen(name) + strlen(value) + 2: 0;
if((ofs = env_findVar(segm, name)) != (word)-1)
newlen -= env_varlen(segm, ofs);
/* Make sure the context has enough room to add the value to */
if(newlen > 0) { /* contents size will grow */
ctxt_info_t *hinfo, *dinfo;
/* aliases may not exceed sizemax */
if(tag == CTXT_TAG_ALIAS) {
if(CTXT_INFO(CTXT_TAG_ALIAS, sizemax)
- CTXT_INFO(CTXT_TAG_ALIAS, sizecur) < newlen) {
error_alias_out_of_memory();
return E_NoMem;
}
}
/* Otherwise a removeable entry is removed;
those are:
oldest item of history
oldest item of dirstack */
hinfo = segm == ctxtFromTag(CTXT_TAG_HISTORY)
? &CTXT_INFO_STRUCT(CTXT_TAG_HISTORY): 0;
dinfo = segm == ctxtFromTag(CTXT_TAG_DIRSTACK)
? &CTXT_INFO_STRUCT(CTXT_TAG_DIRSTACK): 0;
while(env_freeCount(segm) < newlen) {
/* There are two structures that can shrink:
history & dirstack */
if(hinfo && (hinfo->c_sizecur <= hinfo->c_sizemax
/* inconsitency of redundant info */
|| hinfo->c_nummin >= hinfo->c_nummax))
/* in range -> ignore */
hinfo = 0;
if(dinfo && (dinfo->c_sizecur <= dinfo->c_sizemax
/* inconsitency of redundant info */
|| dinfo->c_nummin >= dinfo->c_nummax))
/* in range -> ignore */
dinfo = 0;
if(hinfo && dinfo) { /* Choose one */
if(weight(hinfo) < weight(dinfo))
ctxtGet(1, CTXT_TAG_DIRSTACK, ++dinfo->c_nummin, 0);
else
ctxtGet(1, CTXT_TAG_HISTORY, ++hinfo->c_nummin, 0);
} else if(dinfo)
ctxtGet(1, CTXT_TAG_DIRSTACK, ++dinfo->c_nummin, 0);
else if(hinfo)
ctxtGet(1, CTXT_TAG_HISTORY, ++hinfo->c_nummin, 0);
else { /* no space left */
error_context_out_of_memory();
return E_NoMem;
}
}
}
/* return values 1 and 3 are OK */
switch(env_change(segm, name, value)) {
case 2: /* variable to delete not found <-> no problem */
case 1: case 3: /* var replaced | deleted | inserted ==> OK */
CTXT_INFO(tag, sizecur) += newlen;
return 0;
case 0: /* Cannot insert */
dprintf(("chgCtxt(): out-of-mem shouldn't occure here!\n"));
error_context_out_of_memory();
return E_NoMem;
default:
return E_Syntax;
}
}
