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#pike __REAL_VERSION__
#pragma strict_types
//! Alias for @[m_delete()]
constant delete=m_delete;
constant Iterator = __builtin.mapping_iterator;
//! A mapping look-alike that overrides (ie shadows) another @[parent] mapping.
//!
//! The class implements most of the usual mapping operations.
class ShadowedMapping(protected mapping|ShadowedMapping parent)
{
protected mapping shadow = ([]);
protected mapping joined;
protected mapping parent_copy;
protected int(0..1) modify_parent;
//! @decl void create(mapping|ShadowedMapping parent, @
//! mapping|void shadow, int(0..1)|void modify_parent)
//!
//! @param parent
//! Mapping to be shadowed.
//! @param shadow
//! Initial shadow of @[parent].
//! @param modify_parent
//! Modifications should be done to @[parent] rather than
//! to @[shadow]. If this is set, only entries that are
//! already present in @[shadow] can be modified by later
//! operations.
protected void create(mapping|void shadow, int(0..1)|void modify_parent)
{
if (shadow) this::shadow = shadow + ([]);
this::modify_parent = modify_parent;
}
// Updates the cached joined mapping if needed.
protected void update_joined()
{
if (!joined || !equal(parent, parent_copy)) {
joined = [mapping](parent + shadow);
parent_copy = [mapping](parent + ([]));
}
}
protected mixed `[](mixed ind)
{
mixed res = shadow[ind];
if (!undefinedp(res)) return res;
return parent[ind];
}
protected void `[]=(mixed ind, mixed val)
{
joined = 0;
if (modify_parent && !has_index(shadow, ind)) {
parent[ind] = val;
} else {
shadow[ind] = val;
}
}
protected mixed `->(string ind)
{
return `[](ind);
}
protected void `->=(string ind, mixed val)
{
`[]=(ind, val);
}
protected int(0..1) _equal(mixed other)
{
update_joined();
return equal(other, joined);
}
protected mixed _m_delete(mixed ind)
{
mixed res = m_delete(shadow, ind);
if (undefinedp(res))
res = m_delete(parent, ind);
else
joined = 0;
return res;
}
protected array(mixed) _indices()
{
update_joined();
return indices(joined);
}
protected array(mixed) _values()
{
update_joined();
return values(joined);
}
protected mixed `+(mixed ... args)
{
update_joined();
return predef::`+(joined, @args);
}
protected mixed ``+(mixed ... args)
{
update_joined();
return predef::`+(@args, joined);
}
protected mixed `-(mixed ... args)
{
update_joined();
return predef::`-(joined, @args);
}
protected mixed ``-(mixed ... args)
{
update_joined();
return predef::`-(@args, joined);
}
protected mixed `|(mixed ... args)
{
update_joined();
return predef::`|(joined, @args);
}
protected mixed ``|(mixed ... args)
{
update_joined();
return predef::`|(@args, joined);
}
protected mixed `&(mixed ... args)
{
update_joined();
return predef::`&(joined, @args);
}
protected mixed ``&(mixed ... args)
{
update_joined();
return predef::`&(@args, joined);
}
protected mixed `^(mixed ... args)
{
update_joined();
return predef::`^(joined, @args);
}
protected mixed ``^(mixed ... args)
{
update_joined();
return predef::`^(@args, joined);
}
protected mixed cast(string type)
{
update_joined();
switch(type) {
case "mapping": return joined + ([]);
case "array": return (array)joined;
}
return UNDEFINED;
}
protected mixed _search(mixed val)
{
update_joined();
return search(joined, val);
}
protected string _sprintf(int c)
{
update_joined();
return sprintf(sprintf("%%%c", c), joined);
}
}
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