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Implement partial parsing support.
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This commit implements a consume method that takes a chunk of json, append it to
the current data and parses it.
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@canatella
canatella committed Dec 29, 2016
1 parent c77d73f commit 8711fc1
Showing 1 changed file with 158 additions and 113 deletions.
271 changes: 158 additions & 113 deletions json11.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -815,40 +815,71 @@ struct JsonParserPriv final {
void parse_object() {
assert(states.top() >= VALUE_OBJECT && states.top() <= OBJECT_VALUE);

values.push(map<string, Json>());
switch (states.top()) {
case VALUE_OBJECT:
values.push(map<string, Json>());
set_state(OBJECT_KEY_OR_END);
break;

set_state(OBJECT_KEY_OR_END);
char ch = get_next_token();
if (ch == '}') {
pop_state();
return;
}
case OBJECT_KEY_OR_END: {
char ch = get_next_token();

while (1) {
if (need_data)
return;
break;

if (ch == '}')
return pop_state();

if (ch != '"') {
values.pop();
return fail("expected '\"' in object, got " + esc(ch));
fail("expected '\"' in object, got " + esc(ch));
return;
}

set_state(OBJECT_KEY);
set_state(OBJECT_COLON);
push_state(VALUE_STRING);
parse_string();

break;
}
case OBJECT_COMMA_OR_END: {
char ch = get_next_token();

if (need_data)
break;

if (ch == '}') {
pop_state();
return;
}

string key = values.top().string_value();
values.pop();
if (ch != ',') {
values.pop();
fail("expected ',' or '}' in object, got " + esc(ch));
return;
}

set_state(OBJECT_KEY);

if (failed) {
break;
}
case OBJECT_KEY: {
char ch = get_next_token();

if (need_data)
break;

if (ch != '"') {
values.pop();
return values.push(Json());
return fail("expected '\"' in object, got " + esc(ch));
}

set_state(OBJECT_COLON);
ch = get_next_token();
push_state(VALUE_STRING);

break;
}
case OBJECT_COLON: {
char ch = get_next_token();
if (need_data)
return;

Expand All @@ -859,38 +890,23 @@ struct JsonParserPriv final {

set_state(OBJECT_VALUE);
push_state(EXPECT_VALUE);
parse_json();
if (need_data)
return;

break;
}
case OBJECT_VALUE: {
Json value = values.top();
values.pop();

if (failed) {
values.pop();
return values.push(Json());
}

string key = values.top().string_value();
values.pop();
map<string, Json> data = values.top().object_items();
data[std::move(key)] = value;
values.pop();
values.push(data);

set_state(OBJECT_COMMA_OR_END);
ch = get_next_token();
if (need_data)
return;

if (ch == '}') {
pop_state();
break;
}

if (ch != ',') {
values.pop();
return fail("expected ',' in object, got " + esc(ch));
}
ch = get_next_token();
break;
}
default:
assert(false);
}
}

Expand All @@ -901,59 +917,62 @@ struct JsonParserPriv final {
void parse_array() {
assert(states.top() >= VALUE_ARRAY && states.top() <= ARRAY_VALUE);

values.push(vector<Json>());
switch (states.top()) {
case VALUE_ARRAY:
values.push(vector<Json>());
set_state(ARRAY_VALUE_OR_END);
break;

set_state(ARRAY_VALUE_OR_END);
char ch = get_next_token();
case ARRAY_VALUE_OR_END: {
char ch = get_next_token();

if (ch == ']') {
pop_state();
return;
}

while (1) {
if (need_data)
return;

if (ch == ']')
return pop_state();

i--;

set_state(ARRAY_VALUE);
push_state(EXPECT_VALUE);

parse_json();
break;
}
case ARRAY_COMMA_OR_END: {
char ch = get_next_token();
if (need_data)
return;

Json value = values.top();
values.pop();

if (failed) {
if (ch == ']') {
pop_state();
return;
}
if (ch != ',') {
values.pop();
return values.push(Json());
fail("expected ',' in list, got " + esc(ch));
return;
}

set_state(ARRAY_VALUE_OR_END);

break;
}
case ARRAY_VALUE: {
Json value = values.top();
values.pop();

vector<Json> data = values.top().array_items();
data.push_back(value);
values.pop();
values.push(data);

set_state(ARRAY_COMMA_OR_END);
ch = get_next_token();
if (need_data)
return;

if (ch == ']') {
pop_state();
break;
}

if (ch != ',') {
values.pop();
return fail("expected ',' in list, got " + esc(ch));
}

ch = get_next_token();
(void)ch;
break;
}
default:
assert(false);
}
}

Expand All @@ -974,42 +993,79 @@ struct JsonParserPriv final {

if (ch == '-' || (ch >= '0' && ch <= '9')) {
i--;
set_state(VALUE_NUMBER);
return parse_number();
return set_state(VALUE_NUMBER);
}

if (ch == 't') {
set_state(VALUE_TRUE);
return parse_true();
}
if (ch == 't')
return set_state(VALUE_TRUE);

if (ch == 'f') {
set_state(VALUE_FALSE);
return parse_false();
}
if (ch == 'f')
return set_state(VALUE_FALSE);

if (ch == 'n') {
set_state(VALUE_NULL);
return parse_null();
}
if (ch == 'n')
return set_state(VALUE_NULL);

if (ch == '"') {
set_state(VALUE_STRING);
return parse_string();
}
if (ch == '"')
return set_state(VALUE_STRING);

if (ch == '{') {
set_state(VALUE_OBJECT);
return parse_object();
}
if (ch == '{')
return set_state(VALUE_OBJECT);

if (ch == '[') {
set_state(VALUE_ARRAY);
return parse_array();
}
if (ch == '[')
return set_state(VALUE_ARRAY);

return fail("expected value, got " + esc(ch));
}

void consume(const std::string &in = std::string()) {
need_data = false;
str += in;

/* try to parse as much as possible */
while (!states.empty()) {
switch (states.top()) {
case EXPECT_VALUE:
parse_json();
break;
case VALUE_OBJECT:
case OBJECT_KEY_OR_END:
case OBJECT_COMMA_OR_END:
case OBJECT_KEY:
case OBJECT_COLON:
case OBJECT_VALUE:
parse_object();
break;
case VALUE_ARRAY:
case ARRAY_VALUE_OR_END:
case ARRAY_COMMA_OR_END:
case ARRAY_VALUE:
parse_array();
break;
case VALUE_STRING:
parse_string();
break;
case VALUE_NUMBER:
parse_number();
break;
case VALUE_TRUE:
parse_true();
break;
case VALUE_FALSE:
parse_false();
break;
case VALUE_NULL:
parse_null();
break;
case VALUE_COMMENT:
consume_comment();
break;
}

if (failed || need_data)
break;
}
}

};

JsonParser::JsonParser():
Expand All @@ -1024,21 +1080,20 @@ JsonParser::~JsonParser() {
}

void JsonParser::consume(const std::string &in) {
parser->str = in;
parser->eof = true;
parser->parse_json();
parser->consume(in);
}

Json JsonParser::json() const {
parser->eof = true;
parser->consume();
return parser->values.top();
}

Json Json::parse(const string &in, string &err, JsonParse strategy) {
JsonParserPriv parser { in, err, strategy };
assert(parser.states.size() == 1);

parser.eof = true;
parser.parse_json();
parser.consume();

// Check for any trailing garbage
parser.consume_garbage();
Expand All @@ -1047,12 +1102,6 @@ Json Json::parse(const string &in, string &err, JsonParse strategy) {
return Json();
}

if (parser.need_data) {
/* when doing full parsing, this is an error */
parser.failed = true;
parser.values.push(Json());
}

#ifndef NDEBUG
if (!parser.failed) {
assert(parser.values.size() == 1);
Expand All @@ -1072,11 +1121,7 @@ vector<Json> Json::parse_multi(const string &in,
parser_stop_pos = 0;
vector<Json> json_vec;
while (parser.i != in.size() && !parser.failed && !parser.need_data) {
parser.parse_json();
if (parser.need_data) {
parser.failed = true;
parser.values.push(Json());
}
parser.consume();
#ifndef NDEBUG
if (!parser.failed)
assert(parser.values.size() == 1);
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