int histGet(const int num, char * const str, const unsigned len)
{ char *p;
assert(str);
assert(len);
if(ctxtIsValid()
&& ctxtGet(0, CTXT_TAG_HISTORY, realNum(CTXT_TAG_HISTORY, num), &p) == 0) {
assert(p);
strncpy(str, p, len);
str[len - 1] = 0; /* Make sure the string is terminated */
free(p);
return 1;
}
return 0;
}
int ctxtPop(const Context_Tag tag, char ** const Xbuf)
{ ctxt_info_t *info;
char *buf;
ctxtCheckInfoTag(tag);
assert(Xbuf);
info = &CTXT_INFO_STRUCT(tag);
while(info->c_nummax > info->c_nummin)
switch(ctxtGet(1, tag, info->c_nummax--, &buf)) {
case 0: /* OK */
*Xbuf = buf;
return 1;
case 1: /* no such entry */
break; /* --> ifgnore silently */
case 2: /* out of memory */
error_out_of_memory();
return 0; /* will case "context empty" message */
}
/* Nothing in the stack ==> make sure it's consistent */
ctxtClear(tag);
return 0;
}
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;
}
}
