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const std = @import("std");
const Value = @import("../value.zig").Value;
// Zig API
pub fn check(v: Value) bool {
return v.isPacked() and v.ptr.is_ptr;
}
pub fn assert(v: Value) void {
if (!check(v)) {
v.dump();
@panic("not a pointer");
}
}
// Foreign Pointers
pub fn checkForeign(v: Value) bool {
return check(v) and v.ptr.foreign;
}
pub fn assertForeign(v: Value) void {
if (!checkForeign(v)) {
v.dump();
@panic("not foreign pointer");
}
}
pub fn packForeign(int: u50) Value {
return .{ .fptr = .{int} };
}
pub fn unpackForeign(v: Value) u64 {
assertForeign(v);
return v.ptr.value.foreign;
}
// Zisp Pointers
pub fn checkZisp(v: Value) bool {
return check(v) and !v.ptr.foreign;
}
pub fn assertZisp(v: Value) void {
if (!checkZisp(v)) {
v.dump();
@panic("not zisp pointer");
}
}
pub fn checkWeak(v: Value) bool {
return checkZisp(v) and v.ptr.weak;
}
pub fn assertWeak(v: Value) void {
if (!checkWeak(v)) {
v.dump();
@panic("not weak zisp pointer");
}
}
pub fn checkNormal(v: Value) bool {
return checkZisp(v) and !v.ptr.weak;
}
pub fn assertNormal(v: Value) void {
if (!checkNormal(v)) {
v.dump();
@panic("not normal zisp pointer");
}
}
pub fn packZisp(ptr: *anyopaque, tag: Tag, weak: bool) Value {
return .{ .ptr = .{
.value = tagPtr(ptr, tag),
.weak = weak,
} };
}
pub fn pack(ptr: *anyopaque, tag: Tag) Value {
return packZisp(ptr, tag, false);
}
pub fn packWeak(ptr: *anyopaque, tag: Tag) Value {
return packZisp(ptr, tag, true);
}
// Unpacks weak as well; no need for a separate fn.
pub fn unpack(v: Value) PtrAndTag {
assertZisp(v);
return untagPtr(v.ptr.value);
}
// Weak pointers may be null.
pub fn isNull(v: Value) bool {
assertWeak(v);
const ptr, _ = untagPtr(v.ptr.value);
return @intFromPtr(ptr) == 0;
}
pub fn tagPtr(ptr: *anyopaque, tag: Tag) u49 {
const int: u64 = @intFromPtr(ptr);
const untagged: u49 = @truncate(int);
return untagged << 1 | @intFromEnum(tag);
}
pub const PtrAndTag = struct { *anyopaque, Tag };
pub fn untagPtr(tagged: u49) PtrAndTag {
const untagged: u49 = tagged >> 1 & 0xfffffffffff0;
const ptr: *anyopaque = @ptrFromInt(untagged);
const int: u4 = @truncate(tagged);
const tag: Tag = @enumFromInt(int);
return .{ ptr, tag };
}
pub const Tag = enum(u4) {
/// 0. Strings / Symbols
string,
/// 1. Bignums / Ratnums
number,
/// 2. Pairs ([2]Value)
pair,
/// 3. Vector, bytevector, etc.
array,
/// 4. Ordered hash table
table,
/// 5. String buffer
text,
/// 6. Class, interface, etc.
role,
/// 7. Instance, basically
actor,
/// 8. I/O Port
port,
/// 9. Procedure
proc,
/// 10. Continuation
cont,
/// Other
other = 15,
};
// Zisp API
pub fn predForeign(v: Value) Value {
return Value.boole.pack(checkForeign(v));
}
pub fn makeWeak(v: Value) Value {
assertNormal(v);
var copy = v;
copy.ptr.weak = true;
return copy;
}
pub fn predWeak(v: Value) Value {
const isWeak = checkWeak(v);
return Value.boole.pack(isWeak);
}
pub fn predWeakNull(v: Value) Value {
assertWeak(v);
return Value.boole.pack(v.ptr.weak);
}
pub fn getWeak(v: Value) Value {
assertWeak(v);
if (isNull(v)) {
return Value.boole.pack(false);
} else {
var copy = v;
copy.ptr.weak = false;
return copy;
}
}
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