value: simplify list conversion code

There was really no reason to use ArrayLists here when the list length
is known ahead of time. This slightly shortens the code and should be
slightly more memory/stack efficient.
This commit is contained in:
torque 2023-11-23 17:54:14 -08:00
parent 39619e7d6b
commit 98eac68929
Signed by: torque
SSH Key Fingerprint: SHA256:nCrXefBNo6EbjNSQhv0nXmEg/VuNq3sMF5b8zETw3Tk

View File

@ -131,15 +131,18 @@ pub const Value = union(enum) {
}
},
.list, .inline_list => |lst| {
var result = try std.ArrayList(ptr.child).initCapacity(allocator, lst.items.len);
errdefer result.deinit();
for (lst.items) |item| {
result.appendAssumeCapacity(try item.convertTo(ptr.child, allocator, options));
const result = try allocator.alloc(ptr.child, lst.items.len + @intFromBool(ptr.sentinel != null));
for (result[0..lst.items.len], lst.items) |*res, item| {
res.* = try item.convertTo(ptr.child, allocator, options);
}
if (ptr.sentinel) |sent| {
return try result.toOwnedSliceSentinel(@as(*align(1) const ptr.child, @ptrCast(sent)).*);
if (comptime ptr.sentinel) |sentinel| {
const sval = @as(*align(1) const ptr.child, @ptrCast(sentinel)).*;
result[lst.items.len] = sval;
return result[0..lst.items.len :sval];
} else {
return try result.toOwnedSlice();
return result;
}
},
else => return error.BadValue,
@ -151,7 +154,7 @@ pub const Value = union(enum) {
result.* = try self.convertTo(ptr.child, allocator, options);
return result;
},
else => @compileError("Cannot deserialize into many-pointer or c-pointer " ++ @typeName(T)), // do not support many or C item pointers.
else => @compileError("Cannot deserialize into many-pointer or c-pointer " ++ @typeName(T)),
},
.Array => |arr| {
// TODO: There is ambiguity here because a document expecting a list
@ -168,14 +171,12 @@ pub const Value = union(enum) {
} else return error.BadValue;
},
.list, .inline_list => |lst| {
var storage = try std.ArrayList(arr.child).initCapacity(allocator, arr.len);
defer storage.deinit();
for (lst.items) |item| {
storage.appendAssumeCapacity(try item.convertTo(arr.child, allocator, options));
}
// this may result in a big stack allocation, which is not ideal
if (lst.items.len != arr.len) return error.BadValue;
var result: T = undefined;
@memcpy(&result, storage.items);
for (&result, lst.items) |*res, item| {
res.* = try item.convertTo(arr.child, allocator, options);
}
return result;
},
else => return error.BadValue,
@ -190,8 +191,8 @@ pub const Value = union(enum) {
.list, .inline_list => |list| {
if (list.items.len != stt.fields.len) return error.BadValue;
var result: T = undefined;
inline for (stt.fields, 0..) |field, idx| {
result[idx] = try list.items[idx].convertTo(field.type, allocator, options);
inline for (stt.fields, &result, list.items) |field, *res, item| {
res.* = try item.convertTo(field.type, allocator, options);
}
return result;
},