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519 | -- SPDX-License-Identifier: Apache-2.0
--
-- Copyright (c) 2016 onox <denkpadje@gmail.com>
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
-- http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
with Ada.Characters.Handling;
with Ada.Characters.Latin_1;
with Ada.Strings.Bounded;
with Ada.Strings.Unbounded;
package body JSON.Types is
package SU renames Ada.Strings.Unbounded;
function "+" (Text : String) return SU.Unbounded_String
renames SU.To_Unbounded_String;
function "+" (Text : SU.Unbounded_String) return String
renames SU.To_String;
function Unescape (Text : String) return String is
-- Add 1 so that the length is always positive
package SB is new Ada.Strings.Bounded.Generic_Bounded_Length (Max => Text'Length + 1);
Value : SB.Bounded_String;
Escaped : Boolean := False;
use Ada.Characters.Latin_1;
begin
for C of Text loop
if Escaped then
case C is
when '"' | '\' | '/' =>
SB.Append (Value, C);
when 'b' =>
SB.Append (Value, BS);
when 'f' =>
SB.Append (Value, FF);
when 'n' =>
SB.Append (Value, LF);
when 'r' =>
SB.Append (Value, CR);
when 't' =>
SB.Append (Value, HT);
when others =>
raise Program_Error;
end case;
elsif C = '"' then
raise Program_Error;
elsif C /= '\' then
if Ada.Characters.Handling.Is_Control (C) then
raise Program_Error;
end if;
SB.Append (Value, C);
end if;
Escaped := not Escaped and C = '\';
end loop;
return SB.To_String (Value);
end Unescape;
-----------------------------------------------------------------------------
-- Memory allocator --
-----------------------------------------------------------------------------
function Create_Array
(Object : Memory_Allocator;
Depth : Positive) return Array_Offset is
begin
if Depth > Object.Maximum_Depth then
raise Constraint_Error with
"Maximum depth (" & Object.Maximum_Depth'Image & ") exceeded";
end if;
return Array_Offset (Object.Array_Levels (Depth).Length);
end Create_Array;
function Create_Object
(Object : Memory_Allocator;
Depth : Positive) return Array_Offset is
begin
if Depth > Object.Maximum_Depth then
raise Constraint_Error with
"Maximum depth (" & Object.Maximum_Depth'Image & ") exceeded";
end if;
return Array_Offset (Object.Object_Levels (Depth).Length);
end Create_Object;
-----------------------------------------------------------------------------
-- Constructors --
-----------------------------------------------------------------------------
function Create_String
(Stream : Streams.Stream_Ptr;
Offset, Length : Streams.AS.Stream_Element_Offset) return JSON_Value is
begin
return (Kind => String_Kind, Stream => Stream,
String_Offset => Offset, String_Length => Length);
end Create_String;
function Create_Integer (Value : Integer_Type) return JSON_Value is
begin
return (Kind => Integer_Kind, Integer_Value => Value);
end Create_Integer;
function Create_Float (Value : Float_Type) return JSON_Value is
begin
return (Kind => Float_Kind, Float_Value => Value);
end Create_Float;
function Create_Boolean (Value : Boolean) return JSON_Value is
begin
return (Kind => Boolean_Kind, Boolean_Value => Value);
end Create_Boolean;
function Create_Null return JSON_Value is
begin
return (Kind => Null_Kind);
end Create_Null;
function Create_Array
(Allocator : Memory_Allocator_Ptr;
Depth : Positive) return JSON_Value is
begin
return (Kind => Array_Kind,
Allocator => Allocator,
Depth => Depth,
Offset => Create_Array (Allocator.all, Depth),
Length => 0);
end Create_Array;
function Create_Object
(Allocator : Memory_Allocator_Ptr;
Depth : Positive) return JSON_Value is
begin
return (Kind => Object_Kind,
Allocator => Allocator,
Depth => Depth,
Offset => Create_Object (Allocator.all, Depth),
Length => 0);
end Create_Object;
-----------------------------------------------------------------------------
-- Value --
-----------------------------------------------------------------------------
function "=" (Left : String; Right : JSON_Value) return Boolean is
(if Right.Kind = String_Kind then
Right.Stream.Is_Equal_String (Right.String_Offset, Right.String_Length, Left)
else
False);
function Value (Object : JSON_Value) return String is
begin
if Object.Kind = String_Kind then
return Unescape (Object.Stream.Get_String
(Object.String_Offset, Object.String_Length));
else
raise Invalid_Type_Error with "Value not a string";
end if;
end Value;
function Value (Object : JSON_Value) return Boolean is
begin
if Object.Kind = Boolean_Kind then
return Object.Boolean_Value;
else
raise Invalid_Type_Error with "Value not a boolean";
end if;
end Value;
function Value (Object : JSON_Value) return Integer_Type is
begin
if Object.Kind = Integer_Kind then
return Object.Integer_Value;
else
raise Invalid_Type_Error with "Value not a integer";
end if;
end Value;
function Value (Object : JSON_Value) return Float_Type is
begin
if Object.Kind = Float_Kind then
return Object.Float_Value;
elsif Object.Kind = Integer_Kind then
return Float_Type (Object.Integer_Value);
else
raise Invalid_Type_Error with "Value not a float";
end if;
end Value;
-----------------------------------------------------------------------------
function Length (Object : JSON_Value) return Natural is
begin
if Object.Kind in Array_Kind | Object_Kind then
return Object.Length;
else
raise Invalid_Type_Error with "Value not an object or array";
end if;
end Length;
function Contains (Object : JSON_Value; Key : String) return Boolean is
begin
if Object.Kind = Object_Kind then
for Index in 1 .. Object.Length loop
declare
Pair : Key_Value_Pair renames Object.Allocator.Object_Levels
(Object.Depth).Element (Object.Offset + Index);
begin
if Key = Pair.Key then
return True;
end if;
end;
end loop;
return False;
else
raise Invalid_Type_Error with "Value not an object";
end if;
end Contains;
function Get (Object : JSON_Value; Index : Positive) return JSON_Value is
begin
if Object.Kind = Array_Kind then
return Object.Allocator.Array_Levels (Object.Depth).Element
(Object.Offset + Index).Value;
else
raise Invalid_Type_Error with "Value not an array";
end if;
exception
when Constraint_Error =>
raise Constraint_Error with "JSON array has no element at index" & Index'Image;
end Get;
function Get (Object : JSON_Value; Key : String) return JSON_Value is
begin
if Object.Kind = Object_Kind then
for Index in 1 .. Object.Length loop
declare
Pair : constant Key_Value_Pair := Object.Allocator.Object_Levels
(Object.Depth).Element (Object.Offset + Index);
begin
if Key = Pair.Key then
return Pair.Element;
end if;
end;
end loop;
raise Constraint_Error with "JSON object has no key '" & Key & "'";
else
raise Invalid_Type_Error with "Value not an object";
end if;
end Get;
procedure Append (Object : in out JSON_Value; Value : JSON_Value) is
begin
if Object.Kind = Array_Kind then
declare
Length : constant Natural
:= Natural (Object.Allocator.Array_Levels (Object.Depth).Length);
begin
-- Assert that Object is the last array in a particular level
-- so that its elements form a continuous array
pragma Assert (Length = Object.Offset + Object.Length);
end;
Object.Allocator.Array_Levels (Object.Depth).Append
(Array_Value'(Kind => Value.Kind, Value => Value));
Object.Length := Object.Length + 1;
else
raise Invalid_Type_Error with "Value not an array";
end if;
end Append;
procedure Insert
(Object : in out JSON_Value;
Key : JSON_Value;
Value : JSON_Value;
Check_Duplicate_Keys : Boolean) is
begin
if Object.Kind = Object_Kind then
if Check_Duplicate_Keys and then Object.Contains (Key.Value) then
raise Constraint_Error with "JSON object already has key '" & Key.Value & "'";
end if;
declare
Length : constant Natural
:= Natural (Object.Allocator.Object_Levels (Object.Depth).Length);
begin
-- Assert that Object is the last object in a particular level
-- so that its key-value pairs form a continuous array
pragma Assert (Length = Object.Offset + Object.Length);
end;
pragma Assert (Key.Kind = String_Kind);
Object.Allocator.Object_Levels (Object.Depth).Append
(Key_Value_Pair'(Kind => Value.Kind, Key => Key, Element => Value));
Object.Length := Object.Length + 1;
else
raise Invalid_Type_Error with "Value not an object";
end if;
end Insert;
-----------------------------------------------------------------------------
function Constant_Reference (Object : JSON_Value; Index : Positive)
return JSON_Value renames Get;
function Constant_Reference (Object : JSON_Value; Key : String)
return JSON_Value renames Get;
function Constant_Reference (Object : aliased JSON_Value; Position : Cursor)
return JSON_Value is
begin
case Position.Kind is
when Array_Kind =>
return Object.Allocator.Array_Levels (Position.Data.Depth).Element
(Position.Data.Offset + Position.Index).Value;
when Object_Kind =>
return Object.Allocator.Object_Levels (Position.Data.Depth).Element
(Position.Data.Offset + Position.Index).Key;
end case;
end Constant_Reference;
function Has_Element (Position : Cursor) return Boolean is
(Position.Index <= Position.Data.Length);
overriding
function First (Object : Iterator) return Cursor is
begin
return (Kind => Object.Kind, Data => Object.Data, Index => 1);
end First;
overriding
function Next
(Object : Iterator;
Position : Cursor) return Cursor is
begin
return (Kind => Position.Kind, Data => Position.Data, Index => Position.Index + 1);
end Next;
function Iterate (Object : JSON_Value)
return Value_Iterator_Interfaces.Forward_Iterator'Class is
begin
if Object.Kind in Array_Kind | Object_Kind then
return Iterator'(Kind => Object.Kind, Data => Object);
else
raise Program_Error with "Can only iterate over an array or object";
end if;
end Iterate;
-----------------------------------------------------------------------------
-- Helpers --
-----------------------------------------------------------------------------
function Get_Array_Or_Empty
(Object : JSON_Value; Key : String) return JSON_Value is
begin
if Object.Contains (Key) then
return Object.Get (Key);
else
return
(Kind => Array_Kind,
Allocator => Object.Allocator,
Depth => Object.Allocator.Array_Levels'First,
Offset => 0,
Length => 0);
end if;
end Get_Array_Or_Empty;
function Get_Object_Or_Empty
(Object : JSON_Value; Key : String) return JSON_Value is
begin
if Object.Contains (Key) then
return Object.Get (Key);
else
return
(Kind => Object_Kind,
Allocator => Object.Allocator,
Depth => Object.Allocator.Object_Levels'First,
Offset => 0,
Length => 0);
end if;
end Get_Object_Or_Empty;
function Get
(Object : JSON_Value;
Key : String;
Default : Integer_Type) return JSON_Value is
begin
if Object.Contains (Key) then
return Object.Get (Key);
else
return Create_Integer (Default);
end if;
end Get;
function Get
(Object : JSON_Value;
Key : String;
Default : Float_Type) return JSON_Value is
begin
if Object.Contains (Key) then
return Object.Get (Key);
else
return Create_Float (Default);
end if;
end Get;
function Get
(Object : JSON_Value;
Key : String;
Default : Boolean) return JSON_Value is
begin
if Object.Contains (Key) then
return Object.Get (Key);
else
return Create_Boolean (Default);
end if;
end Get;
-----------------------------------------------------------------------------
-- Image -
-----------------------------------------------------------------------------
function Image_String (Object : JSON_Value) return String is
Text : String renames Object.Stream.Get_String
(Object.String_Offset, Object.String_Length);
begin
-- A string backed by a stream is always escaped. The tokenizer
-- will verify that the string does not contain unexpected characters
return '"' & Text & '"';
end Image_String;
function Image_Integer (Object : JSON_Value) return String is
Result : constant String := Integer_Type'Image (Object.Integer_Value);
begin
if Object.Integer_Value < 0 then
return Result;
else
return Result (2 .. Result'Last);
end if;
end Image_Integer;
function Image_Float (Object : JSON_Value) return String is
Result : constant String := Float_Type'Image (Object.Float_Value);
begin
if Object.Float_Value < 0.0 then
return Result;
else
return Result (2 .. Result'Last);
end if;
end Image_Float;
function Image_Boolean (Object : JSON_Value) return String is
(if Object.Boolean_Value then "true" else "false");
function Image_Array (Object : JSON_Value) return String is
Index : Natural := 0;
Result : SU.Unbounded_String := +"[";
begin
for Element of Object loop
Index := Index + 1;
if Index > 1 then
SU.Append (Result, ",");
end if;
SU.Append (Result, Element.Image);
end loop;
SU.Append (Result, "]");
return +Result;
end Image_Array;
function Image_Object (Object : JSON_Value) return String is
Index : Natural := 0;
Result : SU.Unbounded_String := +"{";
begin
for Key of Object loop
Index := Index + 1;
if Index > 1 then
SU.Append (Result, ',');
end if;
SU.Append (Result, '"' & Key.Value & '"');
SU.Append (Result, ':');
SU.Append (Result, Object.Get (Key.Value).Image);
end loop;
SU.Append (Result, '}');
return +Result;
end Image_Object;
function Image (Object : JSON_Value) return String is
begin
case Object.Kind is
when Array_Kind =>
return Image_Array (Object);
when Object_Kind =>
return Image_Object (Object);
when String_Kind =>
return Image_String (Object);
when Integer_Kind =>
return Image_Integer (Object);
when Float_Kind =>
return Image_Float (Object);
when Boolean_Kind =>
return Image_Boolean (Object);
when Null_Kind =>
return "null";
end case;
end Image;
end JSON.Types;
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