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Use allocator backed array for json value decoder

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This commit is contained in:
Marc Tiehuis 2018-05-03 19:26:24 +12:00
parent f17472635e
commit ef3111be23
1 changed files with 39 additions and 43 deletions
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82
std/json.zig
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@ -1017,9 +1017,7 @@ const JsonParser = struct {
state: State,
copy_strings: bool,
// Stores parent nodes and un-combined Values.
// Worst case scenario we have nested key, values and so need two times the stack size.
stack: [2 * StreamingJsonParser.max_stack_size]Value,
stack_used: u16,
stack: ArrayList(Value),
const State = enum {
ObjectKey,
@ -1033,14 +1031,17 @@ const JsonParser = struct {
.allocator = allocator,
.state = State.Simple,
.copy_strings = copy_strings,
.stack = undefined,
.stack_used = 0,
.stack = ArrayList(Value).init(allocator),
};
}
pub fn deinit(p: &JsonParser) void {
p.stack.deinit();
}
pub fn reset(p: &JsonParser) void {
p.state = State.Simple;
p.stack_used = 0;
p.stack.shrink(0);
}
pub fn parse(p: &JsonParser, input: []const u8) !ValueTree {
@ -1079,11 +1080,11 @@ const JsonParser = struct {
return error.IncompleteJsonInput;
}
std.debug.assert(p.stack_used == 1);
std.debug.assert(p.stack.len == 1);
return ValueTree {
.arena = arena,
.root = p.stack[0],
.root = p.stack.at(0),
};
}
@ -1093,16 +1094,15 @@ const JsonParser = struct {
switch (p.state) {
State.ObjectKey => switch (token.id) {
Token.Id.ObjectEnd => {
if (p.stack_used == 1) {
if (p.stack.len == 1) {
return;
}
var value = p.stack[p.stack_used - 1];
p.stack_used -= 1;
var value = p.stack.pop();
try p.pushToParent(value);
},
Token.Id.String => {
p.pushStack(try p.parseString(allocator, token, input, i));
try p.stack.append(try p.parseString(allocator, token, input, i));
p.state = State.ObjectValue;
},
else => {
@ -1110,41 +1110,41 @@ const JsonParser = struct {
},
},
State.ObjectValue => {
var object = &p.stack[p.stack_used - 2].Object;
var key = p.stack[p.stack_used - 1].String;
var object = &p.stack.items[p.stack.len - 2].Object;
var key = p.stack.items[p.stack.len - 1].String;
switch (token.id) {
Token.Id.ObjectBegin => {
p.pushStack(Value { .Object = ObjectMap.init(allocator) });
try p.stack.append(Value { .Object = ObjectMap.init(allocator) });
p.state = State.ObjectKey;
},
Token.Id.ArrayBegin => {
p.pushStack(Value { .Array = ArrayList(Value).init(allocator) });
try p.stack.append(Value { .Array = ArrayList(Value).init(allocator) });
p.state = State.ArrayValue;
},
Token.Id.String => {
_ = try object.put(key, try p.parseString(allocator, token, input, i));
p.stack_used -= 1;
_ = p.stack.pop();
p.state = State.ObjectKey;
},
Token.Id.Number => {
_ = try object.put(key, try p.parseNumber(token, input, i));
p.stack_used -= 1;
_ = p.stack.pop();
p.state = State.ObjectKey;
},
Token.Id.True => {
_ = try object.put(key, Value { .Bool = true });
p.stack_used -= 1;
_ = p.stack.pop();
p.state = State.ObjectKey;
},
Token.Id.False => {
_ = try object.put(key, Value { .Bool = false });
p.stack_used -= 1;
_ = p.stack.pop();
p.state = State.ObjectKey;
},
Token.Id.Null => {
_ = try object.put(key, Value.Null);
p.stack_used -= 1;
_ = p.stack.pop();
p.state = State.ObjectKey;
},
else => {
@ -1153,24 +1153,23 @@ const JsonParser = struct {
}
},
State.ArrayValue => {
var array = &p.stack[p.stack_used - 1].Array;
var array = &p.stack.items[p.stack.len - 1].Array;
switch (token.id) {
Token.Id.ArrayEnd => {
if (p.stack_used == 1) {
if (p.stack.len == 1) {
return;
}
var value = p.stack[p.stack_used - 1];
p.stack_used -= 1;
var value = p.stack.pop();
try p.pushToParent(value);
},
Token.Id.ObjectBegin => {
p.pushStack(Value { .Object = ObjectMap.init(allocator) });
try p.stack.append(Value { .Object = ObjectMap.init(allocator) });
p.state = State.ObjectKey;
},
Token.Id.ArrayBegin => {
p.pushStack(Value { .Array = ArrayList(Value).init(allocator) });
try p.stack.append(Value { .Array = ArrayList(Value).init(allocator) });
p.state = State.ArrayValue;
},
Token.Id.String => {
@ -1195,27 +1194,27 @@ const JsonParser = struct {
},
State.Simple => switch (token.id) {
Token.Id.ObjectBegin => {
p.pushStack(Value { .Object = ObjectMap.init(allocator) });
try p.stack.append(Value { .Object = ObjectMap.init(allocator) });
p.state = State.ObjectKey;
},
Token.Id.ArrayBegin => {
p.pushStack(Value { .Array = ArrayList(Value).init(allocator) });
try p.stack.append(Value { .Array = ArrayList(Value).init(allocator) });
p.state = State.ArrayValue;
},
Token.Id.String => {
p.pushStack(try p.parseString(allocator, token, input, i));
try p.stack.append(try p.parseString(allocator, token, input, i));
},
Token.Id.Number => {
p.pushStack(try p.parseNumber(token, input, i));
try p.stack.append(try p.parseNumber(token, input, i));
},
Token.Id.True => {
p.pushStack(Value { .Bool = true });
try p.stack.append(Value { .Bool = true });
},
Token.Id.False => {
p.pushStack(Value { .Bool = false });
try p.stack.append(Value { .Bool = false });
},
Token.Id.Null => {
p.pushStack(Value.Null);
try p.stack.append(Value.Null);
},
Token.Id.ObjectEnd, Token.Id.ArrayEnd => {
unreachable;
@ -1225,12 +1224,12 @@ const JsonParser = struct {
}
fn pushToParent(p: &JsonParser, value: &const Value) !void {
switch (p.stack[p.stack_used - 1]) {
switch (p.stack.at(p.stack.len - 1)) {
// Object Parent -> [ ..., object, <key>, value ]
Value.String => |key| {
p.stack_used -= 1;
_ = p.stack.pop();
var object = &p.stack[p.stack_used - 1].Object;
var object = &p.stack.items[p.stack.len - 1].Object;
_ = try object.put(key, value);
p.state = State.ObjectKey;
},
@ -1245,11 +1244,6 @@ const JsonParser = struct {
}
}
fn pushStack(p: &JsonParser, value: &const Value) void {
p.stack[p.stack_used] = *value;
p.stack_used += 1;
}
fn parseString(p: &JsonParser, allocator: &Allocator, token: &const Token, input: []const u8, i: usize) !Value {
// TODO: We don't strictly have to copy values which do not contain any escape
// characters if flagged with the option.
@ -1270,6 +1264,7 @@ const debug = std.debug;
test "json parser dynamic" {
var p = JsonParser.init(std.debug.global_allocator, false);
defer p.deinit();
const s =
\\{
@ -1289,7 +1284,8 @@ test "json parser dynamic" {
;
var tree = try p.parse(s);
tree.deinit();
defer tree.deinit();
var root = tree.root;
var image = (??root.Object.get("Image")).value;