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/*
* Copyright (c) 2012-2017 Chad Austin
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#pragma once
#include <assert.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <limits.h>
#include <algorithm>
#include <cstdio>
#include <limits>
#ifndef SAJSON_NO_STD_STRING
#include <string> // for convenient access to error messages and string values.
#endif
#if defined(__GNUC__) || defined(__clang__)
#define SAJSON_LIKELY(x) __builtin_expect(!!(x), 1)
#define SAJSON_UNLIKELY(x) __builtin_expect(!!(x), 0)
#define SAJSON_ALWAYS_INLINE __attribute__((always_inline))
#define SAJSON_UNREACHABLE() __builtin_unreachable()
#define SAJSON_snprintf snprintf
#elif defined(_MSC_VER)
#define SAJSON_LIKELY(x) x
#define SAJSON_UNLIKELY(x) x
#define SAJSON_ALWAYS_INLINE __forceinline
#define SAJSON_UNREACHABLE() __assume(0)
#if (_MSC_VER <= 1800)
#define SAJSON_snprintf _snprintf
#else
#define SAJSON_snprintf snprintf
#endif
#else
#define SAJSON_LIKELY(x) x
#define SAJSON_UNLIKELY(x) x
#define SAJSON_ALWAYS_INLINE inline
#define SAJSON_UNREACHABLE() assert(!"unreachable")
#define SAJSON_snprintf snprintf
#endif
/**
* sajson Public API
*/
namespace sajson {
/// Tag indicating a JSON value's type.
enum type: uint8_t {
TYPE_INTEGER = 0,
TYPE_DOUBLE = 1,
TYPE_NULL = 2,
TYPE_FALSE = 3,
TYPE_TRUE = 4,
TYPE_STRING = 5,
TYPE_ARRAY = 6,
TYPE_OBJECT = 7,
};
namespace internal {
static const size_t TYPE_BITS = 3;
static const size_t TYPE_MASK = (1 << TYPE_BITS) - 1;
static const size_t VALUE_MASK = size_t(-1) >> TYPE_BITS;
static const size_t ROOT_MARKER = VALUE_MASK;
inline type get_element_type(size_t s) {
return static_cast<type>(s & TYPE_MASK);
}
inline size_t get_element_value(size_t s) {
return s >> TYPE_BITS;
}
inline size_t make_element(type t, size_t value) {
//assert((value & ~VALUE_MASK) == 0);
//value &= VALUE_MASK;
return static_cast<size_t>(t) | (value << TYPE_BITS);
}
// This template utilizes the One Definition Rule to create global arrays in a header.
// This trick courtesy of Rich Geldreich's Purple JSON parser.
template<typename unused=void>
struct globals_struct {
static const unsigned char parse_flags[256];
};
typedef globals_struct<> globals;
// bit 0 (1) - set if: plain ASCII string character
// bit 1 (2) - set if: whitespace
// bit 4 (0x10) - set if: 0-9 e E .
template<typename unused>
const uint8_t globals_struct<unused>::parse_flags[256] = {
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 0, 2, 0, 0, // 0
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 1
3, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0x11,1, // 2
0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11, 0x11,0x11,1, 1, 1, 1, 1, 1, // 3
1, 1, 1, 1, 1, 0x11,1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 4
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, // 5
1, 1, 1, 1, 1, 0x11,1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 6
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 7
// 128-255
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0
};
inline bool is_plain_string_character(char c) {
//return c >= 0x20 && c <= 0x7f && c != 0x22 && c != 0x5c;
return (globals::parse_flags[static_cast<unsigned char>(c)] & 1) != 0;
}
inline bool is_whitespace(char c) {
//return c == '\r' || c == '\n' || c == '\t' || c == ' ';
return (globals::parse_flags[static_cast<unsigned char>(c)] & 2) != 0;
}
class allocated_buffer {
public:
allocated_buffer()
: memory(0)
{}
explicit allocated_buffer(size_t length) {
// throws std::bad_alloc upon allocation failure
void* buffer = operator new(sizeof(size_t) + length);
memory = static_cast<layout*>(buffer);
memory->refcount = 1;
}
allocated_buffer(const allocated_buffer& that)
: memory(that.memory)
{
incref();
}
allocated_buffer(allocated_buffer&& that)
: memory(that.memory)
{
that.memory = 0;
}
~allocated_buffer() {
decref();
}
allocated_buffer& operator=(const allocated_buffer& that) {
if (this != &that) {
decref();
memory = that.memory;
incref();
}
return *this;
}
allocated_buffer& operator=(allocated_buffer&& that) {
if (this != &that) {
decref();
memory = that.memory;
that.memory = 0;
}
return *this;
}
char* get_data() const {
return memory ? memory->data : 0;
}
private:
void incref() const {
if (memory) {
++(memory->refcount);
}
}
void decref() const {
if (memory && --(memory->refcount) == 0) {
operator delete(memory);
}
}
struct layout {
size_t refcount;
char data[];
};
layout* memory;
};
}
/// A simple type encoding a pointer to some memory and a length (in bytes).
/// Does not maintain any memory.
class string {
public:
string(const char* text_, size_t length)
: text(text_)
, _length(length)
{}
const char* data() const {
return text;
}
size_t length() const {
return _length;
}
#ifndef SAJSON_NO_STD_STRING
std::string as_string() const {
return std::string(text, text + _length);
}
#endif
private:
const char* const text;
const size_t _length;
string(); /*=delete*/
};
/// A convenient way to parse JSON from a string literal. The string ends
/// at its first NUL character.
class literal : public string {
public:
template <size_t sz>
explicit literal(const char (&text_)[sz])
: string(text_, sz - 1)
{
static_assert(sz > 0, "!");
}
};
/// A pointer to a mutable buffer, its size in bytes, and strong ownership of any
/// copied memory.
class mutable_string_view {
public:
/// Creates an empty, zero-sized view.
mutable_string_view()
: length_(0)
, data(0)
, buffer()
{}
/// Given a length in bytes and a pointer, constructs a view
/// that does not allocate a copy of the data or maintain its life.
/// The given pointer must stay valid for the duration of the parse and the
/// resulting \ref document's life.
mutable_string_view(size_t length, char* data_)
: length_(length)
, data(data_)
, buffer()
{}
/// Allocates a copy of the given \ref literal string and exposes a
/// mutable view into it. Throws std::bad_alloc if allocation fails.
mutable_string_view(const literal& s)
: length_(s.length())
, buffer(length_)
{
data = buffer.get_data();
memcpy(data, s.data(), length_);
}
/// Allocates a copy of the given \ref string and exposes a mutable view
/// into it. Throws std::bad_alloc if allocation fails.
mutable_string_view(const string& s)
: length_(s.length())
, buffer(length_)
{
data = buffer.get_data();
memcpy(data, s.data(), length_);
}
/// Copies a mutable_string_view. If any backing memory has been
/// allocated, its refcount is incremented - both views can safely
/// use the memory.
mutable_string_view(const mutable_string_view& that)
: length_(that.length_)
, data(that.data)
, buffer(that.buffer)
{}
/// Move constructor - neuters the old mutable_string_view.
mutable_string_view(mutable_string_view&& that)
: length_(that.length_)
, data(that.data)
, buffer(std::move(that.buffer))
{
that.length_ = 0;
that.data = 0;
}
mutable_string_view& operator=(mutable_string_view&& that) {
if (this != &that) {
length_ = that.length_;
data = that.data;
buffer = std::move(that.buffer);
that.length_ = 0;
that.data = 0;
}
return *this;
}
mutable_string_view& operator=(const mutable_string_view& that) {
if (this != &that) {
length_ = that.length_;
data = that.data;
buffer = that.buffer;
}
return *this;
}
size_t length() const {
return length_;
}
char* get_data() const {
return data;
}
private:
size_t length_;
char* data;
internal::allocated_buffer buffer; // may not be allocated
};
namespace internal {
struct object_key_record {
size_t key_start;
size_t key_end;
size_t value;
};
struct object_key_comparator {
object_key_comparator(const char* object_data)
: data(object_data)
{}
bool operator()(const object_key_record& lhs, const string& rhs) const {
const size_t lhs_length = lhs.key_end - lhs.key_start;
const size_t rhs_length = rhs.length();
if (lhs_length < rhs_length) {
return true;
} else if (lhs_length > rhs_length) {
return false;
}
return memcmp(data + lhs.key_start, rhs.data(), lhs_length) < 0;
}
bool operator()(const string& lhs, const object_key_record& rhs) const {
return !(*this)(rhs, lhs);
}
bool operator()(
const object_key_record& lhs,
const object_key_record& rhs
) {
const size_t lhs_length = lhs.key_end - lhs.key_start;
const size_t rhs_length = rhs.key_end - rhs.key_start;
if (lhs_length < rhs_length) {
return true;
} else if (lhs_length > rhs_length) {
return false;
}
return memcmp(
data + lhs.key_start,
data + rhs.key_start,
lhs_length
) < 0;
}
const char* data;
};
}
namespace integer_storage {
enum {
word_length = 1
};
inline int load(const size_t* location) {
int value;
memcpy(&value, location, sizeof(value));
return value;
}
inline void store(size_t* location, int value) {
// NOTE: Most modern compilers optimize away this constant-size
// memcpy into a single instruction. If any don't, and treat
// punning through a union as legal, they can be special-cased.
static_assert(
sizeof(value) <= sizeof(*location),
"size_t must not be smaller than int");
memcpy(location, &value, sizeof(value));
}
}
namespace double_storage {
enum {
word_length = sizeof(double) / sizeof(size_t)
};
inline double load(const size_t* location) {
double value;
memcpy(&value, location, sizeof(double));
return value;
}
inline void store(size_t* location, double value) {
// NOTE: Most modern compilers optimize away this constant-size
// memcpy into a single instruction. If any don't, and treat
// punning through a union as legal, they can be special-cased.
memcpy(location, &value, sizeof(double));
}
}
/// Represents a JSON value. First, call get_type() to check its type,
/// which determines which methods are available.
///
/// Note that \ref value does not maintain any backing memory, only the
/// corresponding \ref document does. It is illegal to access a \ref value
/// after its \ref document has been destroyed.
class value {
public:
/// Returns the JSON value's \ref type.
type get_type() const {
return value_type;
}
/// Returns the length of the object or array.
/// Only legal if get_type() is TYPE_ARRAY or TYPE_OBJECT.
size_t get_length() const {
assert_type_2(TYPE_ARRAY, TYPE_OBJECT);
return payload[0];
}
/// Returns the nth element of an array. Calling with an out-of-bound
/// index is undefined behavior.
/// Only legal if get_type() is TYPE_ARRAY.
value get_array_element(size_t index) const {
using namespace internal;
assert_type(TYPE_ARRAY);
size_t element = payload[1 + index];
return value(get_element_type(element), payload + get_element_value(element), text);
}
/// Returns the nth key of an object. Calling with an out-of-bound
/// index is undefined behavior.
/// Only legal if get_type() is TYPE_OBJECT.
string get_object_key(size_t index) const {
assert_type(TYPE_OBJECT);
const size_t* s = payload + 1 + index * 3;
return string(text + s[0], s[1] - s[0]);
}
/// Returns the nth value of an object. Calling with an out-of-bound
/// index is undefined behavior. Only legal if get_type() is TYPE_OBJECT.
value get_object_value(size_t index) const {
using namespace internal;
assert_type(TYPE_OBJECT);
size_t element = payload[3 + index * 3];
return value(get_element_type(element), payload + get_element_value(element), text);
}
/// Given a string key, returns the value with that key or a null value
/// if the key is not found. Running time is O(lg N).
/// Only legal if get_type() is TYPE_OBJECT.
value get_value_of_key(const string& key) const {
assert_type(TYPE_OBJECT);
size_t i = find_object_key(key);
if (i < get_length()) {
return get_object_value(i);
} else {
return value(TYPE_NULL, 0, 0);
}
}
/// Given a string key, returns the index of the associated value if
/// one exists. Returns get_length() if there is no such key.
/// Note: sajson sorts object keys, so the running time is O(lg N).
/// Only legal if get_type() is TYPE_OBJECT
size_t find_object_key(const string& key) const {
using namespace internal;
assert_type(TYPE_OBJECT);
const object_key_record* start = reinterpret_cast<const object_key_record*>(payload + 1);
const object_key_record* end = start + get_length();
#ifdef SAJSON_UNSORTED_OBJECT_KEYS
for (const object_key_record* i = start; i != end; ++i)
#else
const object_key_record* i = std::lower_bound(start, end, key, object_key_comparator(text));
#endif
if (i != end
&& (i->key_end - i->key_start) == key.length()
&& memcmp(key.data(), text + i->key_start, key.length()) == 0) {
return i - start;
}
return get_length();
}
/// If a numeric value was parsed as a 32-bit integer, returns it.
/// Only legal if get_type() is TYPE_INTEGER.
int get_integer_value() const {
assert_type(TYPE_INTEGER);
return integer_storage::load(payload);
}
/// If a numeric value was parsed as a double, returns it.
/// Only legal if get_type() is TYPE_DOUBLE.
double get_double_value() const {
assert_type(TYPE_DOUBLE);
return double_storage::load(payload);
}
/// Returns a numeric value as a double-precision float.
/// Only legal if get_type() is TYPE_INTEGER or TYPE_DOUBLE.
double get_number_value() const {
assert_type_2(TYPE_INTEGER, TYPE_DOUBLE);
if (get_type() == TYPE_INTEGER) {
return get_integer_value();
} else {
return get_double_value();
}
}
/// Returns true and writes to the output argument if the numeric value
/// fits in a 53-bit integer. This is useful for timestamps and other
/// situations where integral values with greater than 32-bit precision
/// are used, as 64-bit values are not understood by all JSON
/// implementations or languages.
/// Returns false if the value is not an integer or not in range.
/// Only legal if get_type() is TYPE_INTEGER or TYPE_DOUBLE.
bool get_int53_value(int64_t* out) const {
// Make sure the output variable is always defined to avoid any
// possible situation like
// https://gist.github.com/chadaustin/2c249cb850619ddec05b23ca42cf7a18
*out = 0;
assert_type_2(TYPE_INTEGER, TYPE_DOUBLE);
if (get_type() == TYPE_INTEGER) {
*out = get_integer_value();
return true;
} else if (get_type() == TYPE_DOUBLE) {
double v = get_double_value();
if (v < -(1LL << 53) || v > (1LL << 53)) {
return false;
}
int64_t as_int = static_cast<int64_t>(v);
if (as_int != v) {
return false;
}
*out = as_int;
return true;
} else {
return false;
}
}
/// Returns the length of the string.
/// Only legal if get_type() is TYPE_STRING.
size_t get_string_length() const {
assert_type(TYPE_STRING);
return payload[1] - payload[0];
}
/// Returns a pointer to the beginning of a string value's data.
/// WARNING: Calling this function and using the return value as a
/// C-style string (that is, without also using get_string_length())
/// will cause the string to appear truncated if the string has
/// embedded NULs.
/// Only legal if get_type() is TYPE_STRING.
const char* as_cstring() const {
assert_type(TYPE_STRING);
return text + payload[0];
}
#ifndef SAJSON_NO_STD_STRING
/// Returns a string's value as a std::string.
/// Only legal if get_type() is TYPE_STRING.
std::string as_string() const {
assert_type(TYPE_STRING);
return std::string(text + payload[0], text + payload[1]);
}
#endif
/// \cond INTERNAL
const size_t* _internal_get_payload() const {
return payload;
}
/// \endcond
private:
explicit value(type value_type_, const size_t* payload_, const char* text_)
: value_type(value_type_)
, payload(payload_)
, text(text_)
{}
void assert_type(type expected) const {
assert(expected == get_type());
}
void assert_type_2(type e1, type e2) const {
assert(e1 == get_type() || e2 == get_type());
}
void assert_in_bounds(size_t i) const {
assert(i < get_length());
}
const type value_type;
const size_t* const payload;
const char* const text;
friend class document;
};
/// Error code indicating why parse failed.
enum error {
ERROR_NO_ERROR,
ERROR_OUT_OF_MEMORY,
ERROR_UNEXPECTED_END,
ERROR_MISSING_ROOT_ELEMENT,
ERROR_BAD_ROOT,
ERROR_EXPECTED_COMMA,
ERROR_MISSING_OBJECT_KEY,
ERROR_EXPECTED_COLON,
ERROR_EXPECTED_END_OF_INPUT,
ERROR_UNEXPECTED_COMMA,
ERROR_EXPECTED_VALUE,
ERROR_EXPECTED_NULL,
ERROR_EXPECTED_FALSE,
ERROR_EXPECTED_TRUE,
ERROR_INVALID_NUMBER,
ERROR_MISSING_EXPONENT,
ERROR_ILLEGAL_CODEPOINT,
ERROR_INVALID_UNICODE_ESCAPE,
ERROR_UNEXPECTED_END_OF_UTF16,
ERROR_EXPECTED_U,
ERROR_INVALID_UTF16_TRAIL_SURROGATE,
ERROR_UNKNOWN_ESCAPE,
ERROR_INVALID_UTF8,
};
namespace internal {
class ownership {
public:
ownership() = delete;
ownership(const ownership&) = delete;
void operator=(const ownership&) = delete;
explicit ownership(size_t* p_)
: p(p_)
{}
ownership(ownership&& p_)
: p(p_.p) {
p_.p = 0;
}
~ownership() {
delete[] p;
}
bool is_valid() const {
return !!p;
}
private:
size_t* p;
};
inline const char* get_error_text(error error_code) {
switch (error_code) {
case ERROR_NO_ERROR: return "no error";
case ERROR_OUT_OF_MEMORY: return "out of memory";
case ERROR_UNEXPECTED_END: return "unexpected end of input";
case ERROR_MISSING_ROOT_ELEMENT: return "missing root element";
case ERROR_BAD_ROOT: return "document root must be object or array";
case ERROR_EXPECTED_COMMA: return "expected ,";
case ERROR_MISSING_OBJECT_KEY: return "missing object key";
case ERROR_EXPECTED_COLON: return "expected :";
case ERROR_EXPECTED_END_OF_INPUT: return "expected end of input";
case ERROR_UNEXPECTED_COMMA: return "unexpected comma";
case ERROR_EXPECTED_VALUE: return "expected value";
case ERROR_EXPECTED_NULL: return "expected 'null'";
case ERROR_EXPECTED_FALSE: return "expected 'false'";
case ERROR_EXPECTED_TRUE: return "expected 'true'";
case ERROR_INVALID_NUMBER: return "invalid number";
case ERROR_MISSING_EXPONENT: return "missing exponent";
case ERROR_ILLEGAL_CODEPOINT: return "illegal unprintable codepoint in string";
case ERROR_INVALID_UNICODE_ESCAPE: return "invalid character in unicode escape";
case ERROR_UNEXPECTED_END_OF_UTF16: return "unexpected end of input during UTF-16 surrogate pair";
case ERROR_EXPECTED_U: return "expected \\u";
case ERROR_INVALID_UTF16_TRAIL_SURROGATE: return "invalid UTF-16 trail surrogate";
case ERROR_UNKNOWN_ESCAPE: return "unknown escape";
case ERROR_INVALID_UTF8: return "invalid UTF-8";
}
SAJSON_UNREACHABLE();
}
}
/**
* Represents the result of a JSON parse: either is_valid() and the document
* contains a root value or parse error information is available.
*
* Note that the document holds a strong reference to any memory allocated:
* any mutable copy of the input text and any memory allocated for the
* AST data structure. Thus, the document must not be deallocated while any
* \ref value is in use.
*/
class document {
public:
document(document&& rhs)
: input(rhs.input)
, structure(std::move(rhs.structure))
, root_type(rhs.root_type)
, root(rhs.root)
, error_line(rhs.error_line)
, error_column(rhs.error_column)
, error_code(rhs.error_code)
, error_arg(rhs.error_arg)
{
// Yikes... but strcpy is okay here because formatted_error is
// guaranteed to be null-terminated.
strcpy(formatted_error_message, rhs.formatted_error_message);
// should rhs's fields be zeroed too?
}
/**
* Returns true if the document was parsed successfully.
* If true, call get_root() to access the document's root value.
* If false, call get_error_line(), get_error_column(), and
* get_error_message_as_cstring() to see why the parse failed.
*/
bool is_valid() const {
return root_type == TYPE_ARRAY || root_type == TYPE_OBJECT;
}
/// If is_valid(), returns the document's root \ref value.
value get_root() const {
return value(root_type, root, input.get_data());
}
/// If not is_valid(), returns the one-based line number where the parse failed.
size_t get_error_line() const {
return error_line;
}
/// If not is_valid(), returns the one-based column number where the parse failed.
size_t get_error_column() const {
return error_column;
}
#ifndef SAJSON_NO_STD_STRING
/// If not is_valid(), returns a std::string indicating why the parse failed.
std::string get_error_message_as_string() const {
return formatted_error_message;
}
#endif
/// If not is_valid(), returns a null-terminated C string indicating why the parse failed.
const char* get_error_message_as_cstring() const {
return formatted_error_message;
}
/// \cond INTERNAL
// WARNING: Internal function which is subject to change
error _internal_get_error_code() const {
return error_code;
}
// WARNING: Internal function which is subject to change
int _internal_get_error_argument() const {
return error_arg;
}
// WARNING: Internal function which is subject to change
const char* _internal_get_error_text() const {
return internal::get_error_text(error_code);
}
// WARNING: Internal function exposed only for high-performance language bindings.
type _internal_get_root_type() const {
return root_type;
}
// WARNING: Internal function exposed only for high-performance language bindings.
const size_t* _internal_get_root() const {
return root;
}
// WARNING: Internal function exposed only for high-performance language bindings.
const mutable_string_view& _internal_get_input() const {
return input;
}
/// \endcond
private:
document(const document&) = delete;
void operator=(const document&) = delete;
explicit document(const mutable_string_view& input_, internal::ownership&& structure_, type root_type_, const size_t* root_)
: input(input_)
, structure(std::move(structure_))
, root_type(root_type_)
, root(root_)
, error_line(0)
, error_column(0)
, error_code(ERROR_NO_ERROR)
, error_arg(0)
{
formatted_error_message[0] = 0;
}
explicit document(const mutable_string_view& input_, size_t error_line_, size_t error_column_, const error error_code_, int error_arg_)
: input(input_)
, structure(0)
, root_type(TYPE_NULL)
, root(0)
, error_line(error_line_)
, error_column(error_column_)
, error_code(error_code_)
, error_arg(error_arg_)
{
formatted_error_message[ERROR_BUFFER_LENGTH - 1] = 0;
int written = has_significant_error_arg()
? SAJSON_snprintf(formatted_error_message, ERROR_BUFFER_LENGTH - 1, "%s: %d", _internal_get_error_text(), error_arg)
: SAJSON_snprintf(formatted_error_message, ERROR_BUFFER_LENGTH - 1, "%s", _internal_get_error_text());
(void)written;
assert(written >= 0 && written < ERROR_BUFFER_LENGTH);
}
bool has_significant_error_arg() const {
return error_code == ERROR_ILLEGAL_CODEPOINT;
}
mutable_string_view input;
internal::ownership structure;
const type root_type;
const size_t* const root;
const size_t error_line;
const size_t error_column;
const error error_code;
const int error_arg;
enum { ERROR_BUFFER_LENGTH = 128 };
char formatted_error_message[ERROR_BUFFER_LENGTH];
template<typename AllocationStrategy, typename StringType>
friend document parse(const AllocationStrategy& strategy, const StringType& string);
template<typename Allocator>
friend class parser;
};
/// Allocation policy that allocates one large buffer guaranteed to hold the
/// resulting AST. This allocation policy is the fastest since it requires
/// no conditionals to see if more memory must be allocated.
class single_allocation {
public:
/// \cond INTERNAL
class stack_head {
public:
stack_head(stack_head&& other)
: stack_bottom(other.stack_bottom)
, stack_top(other.stack_top)
{}
bool push(size_t element) {
*stack_top++ = element;
return true;
}
size_t* reserve(size_t amount, bool* success) {
size_t* rv = stack_top;
stack_top += amount;
*success = true;
return rv;
}
// The compiler does not see the stack_head (stored in a local)
// and the allocator (stored as a field) have the same stack_bottom
// values, so it does a bit of redundant work.
// So there's a microoptimization available here: introduce a type
// "stack_mark" and make it polymorphic on the allocator. For
// single_allocation, it merely needs to be a single pointer.
void reset(size_t new_top) {
stack_top = stack_bottom + new_top;
}
size_t get_size() {
return stack_top - stack_bottom;
}
size_t* get_top() {
return stack_top;
}
size_t* get_pointer_from_offset(size_t offset) {
return stack_bottom + offset;
}
private:
stack_head() = delete;
stack_head(const stack_head&) = delete;
void operator=(const stack_head&) = delete;
explicit stack_head(size_t* base)
: stack_bottom(base)
, stack_top(base)
{}
size_t* const stack_bottom;
size_t* stack_top;
friend class single_allocation;
};
class allocator {
public:
allocator() = delete;
allocator(const allocator&) = delete;
void operator=(const allocator&) = delete;
explicit allocator(size_t* buffer, size_t input_size, bool should_deallocate_)
: structure(buffer)
, structure_end(buffer ? buffer + input_size : 0)
, write_cursor(structure_end)
, should_deallocate(should_deallocate_)
{}
explicit allocator(std::nullptr_t)
: structure(0)
, structure_end(0)
, write_cursor(0)
, should_deallocate(false)
{}
allocator(allocator&& other)
: structure(other.structure)
, structure_end(other.structure_end)
, write_cursor(other.write_cursor)
, should_deallocate(other.should_deallocate)
{
other.structure = 0;
other.structure_end = 0;
other.write_cursor = 0;
other.should_deallocate = false;
}
~allocator() {
if (should_deallocate) {
delete[] structure;
}
}
stack_head get_stack_head(bool* success) {
*success = true;
return stack_head(structure);
}
size_t get_write_offset() {
return structure_end - write_cursor;
}
size_t* get_write_pointer_of(size_t v) {
return structure_end - v;
}
size_t* reserve(size_t size, bool* success) {
*success = true;
write_cursor -= size;
return write_cursor;
}
size_t* get_ast_root() {
return write_cursor;
}
internal::ownership transfer_ownership() {
auto p = structure;
structure = 0;
structure_end = 0;
write_cursor = 0;
if (should_deallocate) {
return internal::ownership(p);
} else {
return internal::ownership(0);
}
}
private:
size_t* structure;
size_t* structure_end;
size_t* write_cursor;
bool should_deallocate;
};
/// \endcond
/// Allocate a single worst-case AST buffer with one word per byte in
/// the input document.
single_allocation()
: has_existing_buffer(false)
, existing_buffer(0)
, existing_buffer_size(0)
{}
/// Write the AST into an existing buffer. Will fail with an out of
/// memory error if the buffer is not guaranteed to be big enough for
/// the document. The caller must guarantee the memory is valid for
/// the duration of the parse and the AST traversal.
single_allocation(size_t* existing_buffer_, size_t size_in_words)
: has_existing_buffer(true)
, existing_buffer(existing_buffer_)
, existing_buffer_size(size_in_words)
{}
/// Convenience wrapper for single_allocation(size_t*, size_t) that
/// automatically infers the length of a given array.
template<size_t N>
explicit single_allocation(size_t (&existing_buffer_)[N])
: single_allocation(existing_buffer_, N)
{}
/// \cond INTERNAL
allocator make_allocator(size_t input_document_size_in_bytes, bool* succeeded) const {
if (has_existing_buffer) {
if (existing_buffer_size < input_document_size_in_bytes) {
*succeeded = false;
return allocator(nullptr);
}
*succeeded = true;
return allocator(existing_buffer, input_document_size_in_bytes, false);
} else {
size_t* buffer = new(std::nothrow) size_t[input_document_size_in_bytes];
if (!buffer) {
*succeeded = false;
return allocator(nullptr);
}
*succeeded = true;
return allocator(buffer, input_document_size_in_bytes, true);
}
}
/// \endcond
private:
bool has_existing_buffer;
size_t* existing_buffer;
size_t existing_buffer_size;
};
/// Allocation policy that uses dynamically-growing buffers for both the
/// parse stack and the AST. This allocation policy minimizes peak memory
/// usage at the cost of some allocation and copying churn.
class dynamic_allocation {
public:
/// \cond INTERNAL
class stack_head {
public:
stack_head(stack_head&& other)
: stack_top(other.stack_top)
, stack_bottom(other.stack_bottom)
, stack_limit(other.stack_limit)
{
other.stack_top = 0;
other.stack_bottom = 0;
other.stack_limit = 0;
}
~stack_head() {
delete[] stack_bottom;
}
bool push(size_t element) {
if (can_grow(1)) {
*stack_top++ = element;
return true;
} else {
return false;
}
}
size_t* reserve(size_t amount, bool* success) {
if (can_grow(amount)) {
size_t* rv = stack_top;
stack_top += amount;
*success = true;
return rv;
} else {
*success = false;
return 0;
}
}
void reset(size_t new_top) {
stack_top = stack_bottom + new_top;
}
size_t get_size() {
return stack_top - stack_bottom;
}
size_t* get_top() {
return stack_top;
}
size_t* get_pointer_from_offset(size_t offset) {
return stack_bottom + offset;
}
private:
stack_head(const stack_head&) = delete;
void operator=(const stack_head&) = delete;
explicit stack_head(size_t initial_capacity, bool* success) {
assert(initial_capacity);
stack_bottom = new(std::nothrow) size_t[initial_capacity];
stack_top = stack_bottom;
if (stack_bottom) {
stack_limit = stack_bottom + initial_capacity;
} else {
stack_limit = 0;
}
*success = !!stack_bottom;
}
bool can_grow(size_t amount) {
if (SAJSON_LIKELY(amount <= static_cast<size_t>(stack_limit - stack_top))) {
return true;
}
size_t current_size = stack_top - stack_bottom;
size_t old_capacity = stack_limit - stack_bottom;
size_t new_capacity = old_capacity * 2;
while (new_capacity < amount + current_size) {
new_capacity *= 2;
}
size_t* new_stack = new(std::nothrow) size_t[new_capacity];
if (!new_stack) {
stack_top = 0;
stack_bottom = 0;
stack_limit = 0;
return false;
}
memcpy(new_stack, stack_bottom, current_size * sizeof(size_t));
delete[] stack_bottom;
stack_top = new_stack + current_size;
stack_bottom = new_stack;
stack_limit = stack_bottom + new_capacity;
return true;
}
size_t* stack_top; // stack grows up: stack_top >= stack_bottom
size_t* stack_bottom;
size_t* stack_limit;
friend class dynamic_allocation;
};
class allocator {
public:
allocator() = delete;
allocator(const allocator&) = delete;
void operator=(const allocator&) = delete;
explicit allocator(size_t* buffer_, size_t current_capacity, size_t initial_stack_capacity_)
: ast_buffer_bottom(buffer_)
, ast_buffer_top(buffer_ + current_capacity)
, ast_write_head(ast_buffer_top)
, initial_stack_capacity(initial_stack_capacity_)
{}
explicit allocator(std::nullptr_t)
: ast_buffer_bottom(0)
, ast_buffer_top(0)
, ast_write_head(0)
, initial_stack_capacity(0)
{}
allocator(allocator&& other)
: ast_buffer_bottom(other.ast_buffer_bottom)
, ast_buffer_top(other.ast_buffer_top)
, ast_write_head(other.ast_write_head)
, initial_stack_capacity(other.initial_stack_capacity)
{
other.ast_buffer_bottom = 0;
other.ast_buffer_top = 0;
other.ast_write_head = 0;
}
~allocator() {
delete[] ast_buffer_bottom;
}
stack_head get_stack_head(bool* success) {
return stack_head(initial_stack_capacity, success);
}
size_t get_write_offset() {
return ast_buffer_top - ast_write_head;
}
size_t* get_write_pointer_of(size_t v) {
return ast_buffer_top - v;
}
size_t* reserve(size_t size, bool* success) {
if (can_grow(size)) {
ast_write_head -= size;
*success = true;
return ast_write_head;
} else {
*success = false;
return 0;
}
}
size_t* get_ast_root() {
return ast_write_head;
}
internal::ownership transfer_ownership() {
auto p = ast_buffer_bottom;
ast_buffer_bottom = 0;
ast_buffer_top = 0;
ast_write_head = 0;
return internal::ownership(p);
}
private:
bool can_grow(size_t amount) {
if (SAJSON_LIKELY(amount <= static_cast<size_t>(ast_write_head - ast_buffer_bottom))) {
return true;
}
size_t current_capacity = ast_buffer_top - ast_buffer_bottom;
size_t current_size = ast_buffer_top - ast_write_head;
size_t new_capacity = current_capacity * 2;
while (new_capacity < amount + current_size) {
new_capacity *= 2;
}
size_t* old_buffer = ast_buffer_bottom;
size_t* new_buffer = new(std::nothrow) size_t[new_capacity];
if (!new_buffer) {
ast_buffer_bottom = 0;
ast_buffer_top = 0;
ast_write_head = 0;
return false;
}
size_t* old_write_head = ast_write_head;
ast_buffer_bottom = new_buffer;
ast_buffer_top = new_buffer + new_capacity;
ast_write_head = ast_buffer_top - current_size;
memcpy(ast_write_head, old_write_head, current_size * sizeof(size_t));
delete[] old_buffer;
return true;
}
size_t* ast_buffer_bottom; // base address of the ast buffer - it grows down
size_t* ast_buffer_top;
size_t* ast_write_head;
size_t initial_stack_capacity;
};
/// \endcond
/// Creates a dynamic_allocation policy with the given initial AST
/// and stack buffer sizes.
dynamic_allocation(size_t initial_ast_capacity_ = 0, size_t initial_stack_capacity_ = 0)
: initial_ast_capacity(initial_ast_capacity_)
, initial_stack_capacity(initial_stack_capacity_)
{}
/// \cond INTERNAL
allocator make_allocator(size_t input_document_size_in_bytes, bool* succeeded) const {
size_t capacity = initial_ast_capacity;
if (!capacity) {
// TODO: guess based on input document size
capacity = 1024;
}
size_t* buffer = new(std::nothrow) size_t[capacity];
if (!buffer) {
*succeeded = false;
return allocator(nullptr);
}
size_t stack_capacity = initial_stack_capacity;
if (!stack_capacity) {
stack_capacity = 256;
}
*succeeded = true;
return allocator(buffer, capacity, stack_capacity);
}
/// \endcond
private:
size_t initial_ast_capacity;
size_t initial_stack_capacity;
};
/// Allocation policy that attempts to fit the parsed AST into an existing
/// memory buffer. This allocation policy is useful when using sajson in
/// a zero-allocation context or when there are constraints on the amount
// of memory that can be used.
class bounded_allocation {
public:
/// \cond INTERNAL
class allocator;
class stack_head {
public:
stack_head(stack_head&& other)
: source_allocator(other.source_allocator)
{
other.source_allocator = 0;
}
bool push(size_t element) {
if (SAJSON_LIKELY(source_allocator->can_grow(1))) {
*(source_allocator->stack_top)++ = element;
return true;
} else {
return false;
}
}
size_t* reserve(size_t amount, bool* success) {
if (SAJSON_LIKELY(source_allocator->can_grow(amount))) {
size_t* rv = source_allocator->stack_top;
source_allocator->stack_top += amount;
*success = true;
return rv;
} else {
*success = false;
return 0;
}
}
void reset(size_t new_top) {
source_allocator->stack_top = source_allocator->structure + new_top;
}
size_t get_size() {
return source_allocator->stack_top - source_allocator->structure;
}
size_t* get_top() {
return source_allocator->stack_top;
}
size_t* get_pointer_from_offset(size_t offset) {
return source_allocator->structure + offset;
}
private:
stack_head(const stack_head&) = delete;
void operator=(const stack_head&) = delete;
explicit stack_head(allocator* source_allocator_)
: source_allocator(source_allocator_)
{}
allocator* source_allocator;
friend class bounded_allocation;
};
class allocator {
public:
allocator() = delete;
allocator(const allocator&) = delete;
void operator=(const allocator&) = delete;
explicit allocator(size_t* existing_buffer, size_t existing_buffer_size)
: structure(existing_buffer)
, structure_end(existing_buffer + existing_buffer_size)
, write_cursor(structure_end)
, stack_top(structure)
{}
allocator(allocator&& other)
: structure(other.structure)
, structure_end(other.structure_end)
, write_cursor(other.write_cursor)
, stack_top(other.stack_top)
{
other.structure = 0;
other.structure_end = 0;
other.write_cursor = 0;
other.stack_top = 0;
}
stack_head get_stack_head(bool* success) {
*success = true;
return stack_head(this);
}
size_t get_write_offset() {
return structure_end - write_cursor;
}
size_t* get_write_pointer_of(size_t v) {
return structure_end - v;
}
size_t* reserve(size_t size, bool* success) {
if (can_grow(size)) {
write_cursor -= size;
*success = true;
return write_cursor;
} else {
*success = false;
return 0;
}
}
size_t* get_ast_root() {
return write_cursor;
}
internal::ownership transfer_ownership() {
structure = 0;
structure_end = 0;
write_cursor = 0;
return internal::ownership(0);
}
private:
bool can_grow(size_t amount) {
// invariant: stack_top <= write_cursor
// thus: write_cursor - stack_top is positive
return static_cast<size_t>(write_cursor - stack_top) >= amount;
}
size_t* structure;
size_t* structure_end;
size_t* write_cursor;
size_t* stack_top;
friend class bounded_allocation;
};
/// \endcond
/// Uses an existing buffer to hold the parsed AST, if it fits. The
/// specified buffer must not be deallocated until after the document
/// is parsed and the AST traversed.
bounded_allocation(size_t* existing_buffer_, size_t size_in_words)
: existing_buffer(existing_buffer_)
, existing_buffer_size(size_in_words)
{}
/// Convenience wrapper for bounded_allocation(size_t*, size) that
/// automatically infers the size of the given array.
template<size_t N>
explicit bounded_allocation(size_t (&existing_buffer_)[N])
: bounded_allocation(existing_buffer_, N)
{}
/// \cond INTERNAL
allocator make_allocator(size_t input_document_size_in_bytes, bool* succeeded) const {
*succeeded = true;
return allocator(existing_buffer, existing_buffer_size);
}
/// \endcond
private:
size_t* existing_buffer;
size_t existing_buffer_size;
};
// I thought about putting parser in the internal namespace but I don't
// want to indent it further...
/// \cond INTERNAL
template<typename Allocator>
class parser {
public:
parser(const mutable_string_view& msv, Allocator&& allocator_)
: input(msv)
, input_end(input.get_data() + input.length())
, allocator(std::move(allocator_))
, root_type(TYPE_NULL)
, error_line(0)
, error_column(0)
{}
document get_document() {
if (parse()) {
size_t* ast_root = allocator.get_ast_root();
return document(input, allocator.transfer_ownership(), root_type, ast_root);
} else {
return document(input, error_line, error_column, error_code, error_arg);
}
}
private:
struct error_result {
operator bool() const {
return false;
}
operator char*() const {
return 0;
}
};
bool at_eof(const char* p) {
return p == input_end;
}
char* skip_whitespace(char* p) {
// There is an opportunity to make better use of superscalar
// hardware here* but if someone cares about JSON parsing
// performance the first thing they do is minify, so prefer
// to optimize for code size here.
// * https://github.com/chadaustin/Web-Benchmarks/blob/master/json/third-party/pjson/pjson.h#L1873
for (;;) {
if (SAJSON_UNLIKELY(p == input_end)) {
return 0;
} else if (internal::is_whitespace(*p)) {
++p;
} else {
return p;
}
}
}
error_result oom(char* p) {
return make_error(p, ERROR_OUT_OF_MEMORY);
}
error_result unexpected_end() {
return make_error(0, ERROR_UNEXPECTED_END);
}
error_result unexpected_end(char* p) {
return make_error(p, ERROR_UNEXPECTED_END);
}
error_result make_error(char* p, error code, int arg = 0) {
if (!p) {
p = input_end;
}
error_line = 1;
error_column = 1;
char* c = input.get_data();
while (c < p) {
if (*c == '\r') {
if (c + 1 < p && c[1] == '\n') {
++error_line;
error_column = 1;
++c;
} else {
++error_line;
error_column = 1;
}
} else if (*c == '\n') {
++error_line;
error_column = 1;
} else {
// TODO: count UTF-8 characters
++error_column;
}
++c;
}
error_code = code;
error_arg = arg;
return error_result();
}
bool parse() {
using namespace internal;
// p points to the character currently being parsed
char* p = input.get_data();
bool success;
auto stack = allocator.get_stack_head(&success);
if (SAJSON_UNLIKELY(!success)) {
return oom(p);
}
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(!p)) {
return make_error(p, ERROR_MISSING_ROOT_ELEMENT);
}
// current_base is an offset to the first element of the current structure (object or array)
size_t current_base = stack.get_size();
type current_structure_type;
if (*p == '[') {
current_structure_type = TYPE_ARRAY;
bool s = stack.push(make_element(current_structure_type, ROOT_MARKER));
if (SAJSON_UNLIKELY(!s)) {
return oom(p);
}
goto array_close_or_element;
} else if (*p == '{') {
current_structure_type = TYPE_OBJECT;
bool s = stack.push(make_element(current_structure_type, ROOT_MARKER));
if (SAJSON_UNLIKELY(!s)) {
return oom(p);
}
goto object_close_or_element;
} else {
return make_error(p, ERROR_BAD_ROOT);
}
// BEGIN STATE MACHINE
size_t pop_element; // used as an argument into the `pop` routine
if (0) { // purely for structure
// ASSUMES: byte at p SHOULD be skipped
array_close_or_element:
p = skip_whitespace(p + 1);
if (SAJSON_UNLIKELY(!p)) {
return unexpected_end();
}
if (*p == ']') {
goto pop_array;
} else {
goto next_element;
}
SAJSON_UNREACHABLE();
// ASSUMES: byte at p SHOULD be skipped
object_close_or_element:
p = skip_whitespace(p + 1);
if (SAJSON_UNLIKELY(!p)) {
return unexpected_end();
}
if (*p == '}') {
goto pop_object;
} else {
goto object_key;
}
SAJSON_UNREACHABLE();
// ASSUMES: byte at p SHOULD NOT be skipped
structure_close_or_comma:
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(!p)) {
return unexpected_end();
}
if (current_structure_type == TYPE_ARRAY) {
if (*p == ']') {
goto pop_array;
} else {
if (SAJSON_UNLIKELY(*p != ',')) {
return make_error(p, ERROR_EXPECTED_COMMA);
}
++p;
goto next_element;
}
} else {
assert(current_structure_type == TYPE_OBJECT);
if (*p == '}') {
goto pop_object;
} else {
if (SAJSON_UNLIKELY(*p != ',')) {
return make_error(p, ERROR_EXPECTED_COMMA);
}
++p;
goto object_key;
}
}
SAJSON_UNREACHABLE();
// ASSUMES: *p == '}'
pop_object: {
++p;
size_t* base_ptr = stack.get_pointer_from_offset(current_base);
pop_element = *base_ptr;
if (SAJSON_UNLIKELY(!install_object(base_ptr + 1, stack.get_top()))) {
return oom(p);
}
goto pop;
}
// ASSUMES: *p == ']'
pop_array: {
++p;
size_t* base_ptr = stack.get_pointer_from_offset(current_base);
pop_element = *base_ptr;
if (SAJSON_UNLIKELY(!install_array(base_ptr + 1, stack.get_top()))) {
return oom(p);
}
goto pop;
}
// ASSUMES: byte at p SHOULD NOT be skipped
object_key: {
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(!p)) {
return unexpected_end();
}
if (SAJSON_UNLIKELY(*p != '"')) {
return make_error(p, ERROR_MISSING_OBJECT_KEY);
}
bool success_;
size_t* out = stack.reserve(2, &success_);
if (SAJSON_UNLIKELY(!success_)) {
return oom(p);
}
p = parse_string(p, out);
if (SAJSON_UNLIKELY(!p)) {
return false;
}
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(!p || *p != ':')) {
return make_error(p, ERROR_EXPECTED_COLON);
}
++p;
goto next_element;
}
// ASSUMES: byte at p SHOULD NOT be skipped
next_element:
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(!p)) {
return unexpected_end();
}
type value_type_result;
switch (*p) {
case 0:
return unexpected_end(p);
case 'n':
p = parse_null(p);
if (!p) {
return false;
}
value_type_result = TYPE_NULL;
break;
case 'f':
p = parse_false(p);
if (!p) {
return false;
}
value_type_result = TYPE_FALSE;
break;
case 't':
p = parse_true(p);
if (!p) {
return false;
}
value_type_result = TYPE_TRUE;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '-': {
auto result = parse_number(p);
p = result.first;
if (!p) {
return false;
}
value_type_result = result.second;
break;
}
case '"': {
bool success_;
size_t* string_tag = allocator.reserve(2, &success_);
if (SAJSON_UNLIKELY(!success_)) {
return oom(p);
}
p = parse_string(p, string_tag);
if (!p) {
return false;
}
value_type_result = TYPE_STRING;
break;
}
case '[': {
size_t previous_base = current_base;
current_base = stack.get_size();
bool s = stack.push(make_element(current_structure_type, previous_base));
if (SAJSON_UNLIKELY(!s)) {
return oom(p);
}
current_structure_type = TYPE_ARRAY;
goto array_close_or_element;
}
case '{': {
size_t previous_base = current_base;
current_base = stack.get_size();
bool s = stack.push(make_element(current_structure_type, previous_base));
if (SAJSON_UNLIKELY(!s)) {
return oom(p);
}
current_structure_type = TYPE_OBJECT;
goto object_close_or_element;
}
pop: {
size_t parent = get_element_value(pop_element);
if (parent == ROOT_MARKER) {
root_type = current_structure_type;
p = skip_whitespace(p);
if (SAJSON_UNLIKELY(p)) {
return make_error(p, ERROR_EXPECTED_END_OF_INPUT);
}
return true;
}
stack.reset(current_base);
current_base = parent;
value_type_result = current_structure_type;
current_structure_type = get_element_type(pop_element);
break;
}
case ',':
return make_error(p, ERROR_UNEXPECTED_COMMA);
default:
return make_error(p, ERROR_EXPECTED_VALUE);
}
bool s = stack.push(make_element(
value_type_result,
allocator.get_write_offset()));
if (SAJSON_UNLIKELY(!s)) {
return oom(p);
}
goto structure_close_or_comma;
}
SAJSON_UNREACHABLE();
}
bool has_remaining_characters(char* p, ptrdiff_t remaining) {
return input_end - p >= remaining;
}
char* parse_null(char* p) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 4))) {
make_error(p, ERROR_UNEXPECTED_END);
return 0;
}
char p1 = p[1];
char p2 = p[2];
char p3 = p[3];
if (SAJSON_UNLIKELY(p1 != 'u' || p2 != 'l' || p3 != 'l')) {
make_error(p, ERROR_EXPECTED_NULL);
return 0;
}
return p + 4;
}
char* parse_false(char* p) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 5))) {
return make_error(p, ERROR_UNEXPECTED_END);
}
char p1 = p[1];
char p2 = p[2];
char p3 = p[3];
char p4 = p[4];
if (SAJSON_UNLIKELY(p1 != 'a' || p2 != 'l' || p3 != 's' || p4 != 'e')) {
return make_error(p, ERROR_EXPECTED_FALSE);
}
return p + 5;
}
char* parse_true(char* p) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 4))) {
return make_error(p, ERROR_UNEXPECTED_END);
}
char p1 = p[1];
char p2 = p[2];
char p3 = p[3];
if (SAJSON_UNLIKELY(p1 != 'r' || p2 != 'u' || p3 != 'e')) {
return make_error(p, ERROR_EXPECTED_TRUE);
}
return p + 4;
}
static double pow10(int64_t exponent) {
if (SAJSON_UNLIKELY(exponent > 308)) {
return std::numeric_limits<double>::infinity();
} else if (SAJSON_UNLIKELY(exponent < -323)) {
return 0.0;
}
static const double constants[] = {
1e-323,1e-322,1e-321,1e-320,1e-319,1e-318,1e-317,1e-316,1e-315,1e-314,
1e-313,1e-312,1e-311,1e-310,1e-309,1e-308,1e-307,1e-306,1e-305,1e-304,
1e-303,1e-302,1e-301,1e-300,1e-299,1e-298,1e-297,1e-296,1e-295,1e-294,
1e-293,1e-292,1e-291,1e-290,1e-289,1e-288,1e-287,1e-286,1e-285,1e-284,
1e-283,1e-282,1e-281,1e-280,1e-279,1e-278,1e-277,1e-276,1e-275,1e-274,
1e-273,1e-272,1e-271,1e-270,1e-269,1e-268,1e-267,1e-266,1e-265,1e-264,
1e-263,1e-262,1e-261,1e-260,1e-259,1e-258,1e-257,1e-256,1e-255,1e-254,
1e-253,1e-252,1e-251,1e-250,1e-249,1e-248,1e-247,1e-246,1e-245,1e-244,
1e-243,1e-242,1e-241,1e-240,1e-239,1e-238,1e-237,1e-236,1e-235,1e-234,
1e-233,1e-232,1e-231,1e-230,1e-229,1e-228,1e-227,1e-226,1e-225,1e-224,
1e-223,1e-222,1e-221,1e-220,1e-219,1e-218,1e-217,1e-216,1e-215,1e-214,
1e-213,1e-212,1e-211,1e-210,1e-209,1e-208,1e-207,1e-206,1e-205,1e-204,
1e-203,1e-202,1e-201,1e-200,1e-199,1e-198,1e-197,1e-196,1e-195,1e-194,
1e-193,1e-192,1e-191,1e-190,1e-189,1e-188,1e-187,1e-186,1e-185,1e-184,
1e-183,1e-182,1e-181,1e-180,1e-179,1e-178,1e-177,1e-176,1e-175,1e-174,
1e-173,1e-172,1e-171,1e-170,1e-169,1e-168,1e-167,1e-166,1e-165,1e-164,
1e-163,1e-162,1e-161,1e-160,1e-159,1e-158,1e-157,1e-156,1e-155,1e-154,
1e-153,1e-152,1e-151,1e-150,1e-149,1e-148,1e-147,1e-146,1e-145,1e-144,
1e-143,1e-142,1e-141,1e-140,1e-139,1e-138,1e-137,1e-136,1e-135,1e-134,
1e-133,1e-132,1e-131,1e-130,1e-129,1e-128,1e-127,1e-126,1e-125,1e-124,
1e-123,1e-122,1e-121,1e-120,1e-119,1e-118,1e-117,1e-116,1e-115,1e-114,
1e-113,1e-112,1e-111,1e-110,1e-109,1e-108,1e-107,1e-106,1e-105,1e-104,
1e-103,1e-102,1e-101,1e-100,1e-99,1e-98,1e-97,1e-96,1e-95,1e-94,1e-93,
1e-92,1e-91,1e-90,1e-89,1e-88,1e-87,1e-86,1e-85,1e-84,1e-83,1e-82,1e-81,
1e-80,1e-79,1e-78,1e-77,1e-76,1e-75,1e-74,1e-73,1e-72,1e-71,1e-70,1e-69,
1e-68,1e-67,1e-66,1e-65,1e-64,1e-63,1e-62,1e-61,1e-60,1e-59,1e-58,1e-57,
1e-56,1e-55,1e-54,1e-53,1e-52,1e-51,1e-50,1e-49,1e-48,1e-47,1e-46,1e-45,
1e-44,1e-43,1e-42,1e-41,1e-40,1e-39,1e-38,1e-37,1e-36,1e-35,1e-34,1e-33,
1e-32,1e-31,1e-30,1e-29,1e-28,1e-27,1e-26,1e-25,1e-24,1e-23,1e-22,1e-21,
1e-20,1e-19,1e-18,1e-17,1e-16,1e-15,1e-14,1e-13,1e-12,1e-11,1e-10,1e-9,
1e-8,1e-7,1e-6,1e-5,1e-4,1e-3,1e-2,1e-1,1e0,1e1,1e2,1e3,1e4,1e5,1e6,1e7,
1e8,1e9,1e10,1e11,1e12,1e13,1e14,1e15,1e16,1e17,1e18,1e19,1e20,1e21,
1e22,1e23,1e24,1e25,1e26,1e27,1e28,1e29,1e30,1e31,1e32,1e33,1e34,1e35,
1e36,1e37,1e38,1e39,1e40,1e41,1e42,1e43,1e44,1e45,1e46,1e47,1e48,1e49,
1e50,1e51,1e52,1e53,1e54,1e55,1e56,1e57,1e58,1e59,1e60,1e61,1e62,1e63,
1e64,1e65,1e66,1e67,1e68,1e69,1e70,1e71,1e72,1e73,1e74,1e75,1e76,1e77,
1e78,1e79,1e80,1e81,1e82,1e83,1e84,1e85,1e86,1e87,1e88,1e89,1e90,1e91,
1e92,1e93,1e94,1e95,1e96,1e97,1e98,1e99,1e100,1e101,1e102,1e103,1e104,
1e105,1e106,1e107,1e108,1e109,1e110,1e111,1e112,1e113,1e114,1e115,1e116,
1e117,1e118,1e119,1e120,1e121,1e122,1e123,1e124,1e125,1e126,1e127,1e128,
1e129,1e130,1e131,1e132,1e133,1e134,1e135,1e136,1e137,1e138,1e139,1e140,
1e141,1e142,1e143,1e144,1e145,1e146,1e147,1e148,1e149,1e150,1e151,1e152,
1e153,1e154,1e155,1e156,1e157,1e158,1e159,1e160,1e161,1e162,1e163,1e164,
1e165,1e166,1e167,1e168,1e169,1e170,1e171,1e172,1e173,1e174,1e175,1e176,
1e177,1e178,1e179,1e180,1e181,1e182,1e183,1e184,1e185,1e186,1e187,1e188,
1e189,1e190,1e191,1e192,1e193,1e194,1e195,1e196,1e197,1e198,1e199,1e200,
1e201,1e202,1e203,1e204,1e205,1e206,1e207,1e208,1e209,1e210,1e211,1e212,
1e213,1e214,1e215,1e216,1e217,1e218,1e219,1e220,1e221,1e222,1e223,1e224,
1e225,1e226,1e227,1e228,1e229,1e230,1e231,1e232,1e233,1e234,1e235,1e236,
1e237,1e238,1e239,1e240,1e241,1e242,1e243,1e244,1e245,1e246,1e247,1e248,
1e249,1e250,1e251,1e252,1e253,1e254,1e255,1e256,1e257,1e258,1e259,1e260,
1e261,1e262,1e263,1e264,1e265,1e266,1e267,1e268,1e269,1e270,1e271,1e272,
1e273,1e274,1e275,1e276,1e277,1e278,1e279,1e280,1e281,1e282,1e283,1e284,
1e285,1e286,1e287,1e288,1e289,1e290,1e291,1e292,1e293,1e294,1e295,1e296,
1e297,1e298,1e299,1e300,1e301,1e302,1e303,1e304,1e305,1e306,1e307,1e308
};
return constants[exponent + 323];
}
std::pair<char*, type> parse_number(char* p) {
bool negative = false;
if ('-' == *p) {
++p;
negative = true;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
}
bool try_double = false;
int i = 0;
double d = 0.0; // gcc complains that d might be used uninitialized which isn't true. appease the warning anyway.
if (*p == '0') {
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
} else {
unsigned char c = *p;
if (c < '0' || c > '9') {
return std::make_pair(make_error(p, ERROR_INVALID_NUMBER), TYPE_NULL);
}
do {
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
unsigned char digit = c - '0';
if (SAJSON_UNLIKELY(!try_double && i > INT_MAX / 10 - 9)) {
// TODO: could split this into two loops
try_double = true;
d = i;
}
if (SAJSON_UNLIKELY(try_double)) {
d = 10.0 * d + digit;
} else {
i = 10 * i + digit;
}
c = *p;
} while (c >= '0' && c <= '9');
}
int64_t exponent = 0;
if ('.' == *p) {
if (!try_double) {
try_double = true;
d = i;
}
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
char c = *p;
if (c < '0' || c > '9') {
return std::make_pair(make_error(p, ERROR_INVALID_NUMBER), TYPE_NULL);
}
do {
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
d = d * 10 + (c - '0');
// One option to avoid underflow would be to clamp
// to INT_MIN, but int64 subtraction is cheap and
// in the absurd case of parsing 2 GB of digits
// with an extremely high exponent, this will
// produce accurate results. Instead, we just
// leave exponent as int64_t and it will never
// underflow.
--exponent;
c = *p;
} while (c >= '0' && c <= '9');
}
char e = *p;
if ('e' == e || 'E' == e) {
if (!try_double) {
try_double = true;
d = i;
}
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
bool negativeExponent = false;
if ('-' == *p) {
negativeExponent = true;
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
} else if ('+' == *p) {
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
}
int exp = 0;
char c = *p;
if (SAJSON_UNLIKELY(c < '0' || c > '9')) {
return std::make_pair(make_error(p, ERROR_MISSING_EXPONENT), TYPE_NULL);
}
for (;;) {
// c guaranteed to be between '0' and '9', inclusive
unsigned char digit = c - '0';
if (exp > (INT_MAX - digit) / 10) {
// The exponent overflowed. Keep parsing, but
// it will definitely be out of range when
// pow10 is called.
exp = INT_MAX;
} else {
exp = 10 * exp + digit;
}
++p;
if (SAJSON_UNLIKELY(at_eof(p))) {
return std::make_pair(make_error(p, ERROR_UNEXPECTED_END), TYPE_NULL);
}
c = *p;
if (c < '0' || c > '9') {
break;
}
}
static_assert(-INT_MAX >= INT_MIN, "exp can be negated without loss or UB");
exponent += (negativeExponent ? -exp : exp);
}
if (exponent) {
assert(try_double);
// If d is zero but the exponent is huge, don't
// multiply zero by inf which gives nan.
if (d != 0.0) {
d *= pow10(exponent);
}
}
if (negative) {
if (try_double) {
d = -d;
} else {
i = -i;
}
}
if (try_double) {
bool success;
size_t* out = allocator.reserve(double_storage::word_length, &success);
if (SAJSON_UNLIKELY(!success)) {
return std::make_pair(oom(p), TYPE_NULL);
}
double_storage::store(out, d);
return std::make_pair(p, TYPE_DOUBLE);
} else {
bool success;
size_t* out = allocator.reserve(integer_storage::word_length, &success);
if (SAJSON_UNLIKELY(!success)) {
return std::make_pair(oom(p), TYPE_NULL);
}
integer_storage::store(out, i);
return std::make_pair(p, TYPE_INTEGER);
}
}
bool install_array(size_t* array_base, size_t* array_end) {
using namespace sajson::internal;
const size_t length = array_end - array_base;
bool success;
size_t* const new_base = allocator.reserve(length + 1, &success);
if (SAJSON_UNLIKELY(!success)) {
return false;
}
size_t* out = new_base + length + 1;
size_t* const structure_end = allocator.get_write_pointer_of(0);
while (array_end > array_base) {
size_t element = *--array_end;
type element_type = get_element_type(element);
size_t element_value = get_element_value(element);
size_t* element_ptr = structure_end - element_value;
*--out = make_element(element_type, element_ptr - new_base);
}
*--out = length;
return true;
}
bool install_object(size_t* object_base, size_t* object_end) {
using namespace internal;
assert((object_end - object_base) % 3 == 0);
const size_t length_times_3 = object_end - object_base;
#ifndef SAJSON_UNSORTED_OBJECT_KEYS
std::sort(
reinterpret_cast<object_key_record*>(object_base),
reinterpret_cast<object_key_record*>(object_end),
object_key_comparator(input.get_data()));
#endif
bool success;
size_t* const new_base = allocator.reserve(length_times_3 + 1, &success);
if (SAJSON_UNLIKELY(!success)) {
return false;
}
size_t* out = new_base + length_times_3 + 1;
size_t* const structure_end = allocator.get_write_pointer_of(0);
while (object_end > object_base) {
size_t element = *--object_end;
type element_type = get_element_type(element);
size_t element_value = get_element_value(element);
size_t* element_ptr = structure_end - element_value;
*--out = make_element(element_type, element_ptr - new_base);
*--out = *--object_end;
*--out = *--object_end;
}
*--out = length_times_3 / 3;
return true;
}
char* parse_string(char* p, size_t* tag) {
using namespace internal;
++p; // "
size_t start = p - input.get_data();
char* input_end_local = input_end;
while (input_end_local - p >= 4) {
if (!is_plain_string_character(p[0])) { goto found; }
if (!is_plain_string_character(p[1])) { p += 1; goto found; }
if (!is_plain_string_character(p[2])) { p += 2; goto found; }
if (!is_plain_string_character(p[3])) { p += 3; goto found; }
p += 4;
}
for (;;) {
if (SAJSON_UNLIKELY(p >= input_end_local)) {
return make_error(p, ERROR_UNEXPECTED_END);
}
if (!is_plain_string_character(*p)) {
break;
}
++p;
}
found:
if (SAJSON_LIKELY(*p == '"')) {
tag[0] = start;
tag[1] = p - input.get_data();
*p = '\0';
return p + 1;
}
if (*p >= 0 && *p < 0x20) {
return make_error(p, ERROR_ILLEGAL_CODEPOINT, static_cast<int>(*p));
} else {
// backslash or >0x7f
return parse_string_slow(p, tag, start);
}
}
char* read_hex(char* p, unsigned& u) {
unsigned v = 0;
int i = 4;
while (i--) {
unsigned char c = *p++;
if (c >= '0' && c <= '9') {
c -= '0';
} else if (c >= 'a' && c <= 'f') {
c = c - 'a' + 10;
} else if (c >= 'A' && c <= 'F') {
c = c - 'A' + 10;
} else {
return make_error(p, ERROR_INVALID_UNICODE_ESCAPE);
}
v = (v << 4) + c;
}
u = v;
return p;
}
void write_utf8(unsigned codepoint, char*& end) {
if (codepoint < 0x80) {
*end++ = codepoint;
} else if (codepoint < 0x800) {
*end++ = 0xC0 | (codepoint >> 6);
*end++ = 0x80 | (codepoint & 0x3F);
} else if (codepoint < 0x10000) {
*end++ = 0xE0 | (codepoint >> 12);
*end++ = 0x80 | ((codepoint >> 6) & 0x3F);
*end++ = 0x80 | (codepoint & 0x3F);
} else {
assert(codepoint < 0x200000);
*end++ = 0xF0 | (codepoint >> 18);
*end++ = 0x80 | ((codepoint >> 12) & 0x3F);
*end++ = 0x80 | ((codepoint >> 6) & 0x3F);
*end++ = 0x80 | (codepoint & 0x3F);
}
}
char* parse_string_slow(char* p, size_t* tag, size_t start) {
char* end = p;
char* input_end_local = input_end;
for (;;) {
if (SAJSON_UNLIKELY(p >= input_end_local)) {
return make_error(p, ERROR_UNEXPECTED_END);
}
if (SAJSON_UNLIKELY(*p >= 0 && *p < 0x20)) {
return make_error(p, ERROR_ILLEGAL_CODEPOINT, static_cast<int>(*p));
}
switch (*p) {
case '"':
tag[0] = start;
tag[1] = end - input.get_data();
*end = '\0';
return p + 1;
case '\\':
++p;
if (SAJSON_UNLIKELY(p >= input_end_local)) {
return make_error(p, ERROR_UNEXPECTED_END);
}
char replacement;
switch (*p) {
case '"': replacement = '"'; goto replace;
case '\\': replacement = '\\'; goto replace;
case '/': replacement = '/'; goto replace;
case 'b': replacement = '\b'; goto replace;
case 'f': replacement = '\f'; goto replace;
case 'n': replacement = '\n'; goto replace;
case 'r': replacement = '\r'; goto replace;
case 't': replacement = '\t'; goto replace;
replace:
*end++ = replacement;
++p;
break;
case 'u': {
++p;
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 4))) {
return make_error(p, ERROR_UNEXPECTED_END);
}
unsigned u = 0; // gcc's complaining that this could be used uninitialized. wrong.
p = read_hex(p, u);
if (!p) {
return 0;
}
if (u >= 0xD800 && u <= 0xDBFF) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 6))) {
return make_error(p, ERROR_UNEXPECTED_END_OF_UTF16);
}
char p0 = p[0];
char p1 = p[1];
if (p0 != '\\' || p1 != 'u') {
return make_error(p, ERROR_EXPECTED_U);
}
p += 2;
unsigned v = 0; // gcc's complaining that this could be used uninitialized. wrong.
p = read_hex(p, v);
if (!p) {
return p;
}
if (v < 0xDC00 || v > 0xDFFF) {
return make_error(p, ERROR_INVALID_UTF16_TRAIL_SURROGATE);
}
u = 0x10000 + (((u - 0xD800) << 10) | (v - 0xDC00));
}
write_utf8(u, end);
break;
}
default:
return make_error(p, ERROR_UNKNOWN_ESCAPE);
}
break;
default:
// validate UTF-8
unsigned char c0 = p[0];
if (c0 < 128) {
*end++ = *p++;
} else if (c0 < 224) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 2))) {
return unexpected_end(p);
}
unsigned char c1 = p[1];
if (c1 < 128 || c1 >= 192) {
return make_error(p + 1, ERROR_INVALID_UTF8);
}
end[0] = c0;
end[1] = c1;
end += 2;
p += 2;
} else if (c0 < 240) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 3))) {
return unexpected_end(p);
}
unsigned char c1 = p[1];
if (c1 < 128 || c1 >= 192) {
return make_error(p + 1, ERROR_INVALID_UTF8);
}
unsigned char c2 = p[2];
if (c2 < 128 || c2 >= 192) {
return make_error(p + 2, ERROR_INVALID_UTF8);
}
end[0] = c0;
end[1] = c1;
end[2] = c2;
end += 3;
p += 3;
} else if (c0 < 248) {
if (SAJSON_UNLIKELY(!has_remaining_characters(p, 4))) {
return unexpected_end(p);
}
unsigned char c1 = p[1];
if (c1 < 128 || c1 >= 192) {
return make_error(p + 1, ERROR_INVALID_UTF8);
}
unsigned char c2 = p[2];
if (c2 < 128 || c2 >= 192) {
return make_error(p + 2, ERROR_INVALID_UTF8);
}
unsigned char c3 = p[3];
if (c3 < 128 || c3 >= 192) {
return make_error(p + 3, ERROR_INVALID_UTF8);
}
end[0] = c0;
end[1] = c1;
end[2] = c2;
end[3] = c3;
end += 4;
p += 4;
} else {
return make_error(p, ERROR_INVALID_UTF8);
}
break;
}
}
}
mutable_string_view input;
char* const input_end;
Allocator allocator;
type root_type;
size_t error_line;
size_t error_column;
error error_code;
int error_arg; // optional argument for the error
};
/// \endcond
/**
* Parses a string of JSON bytes into a \ref document, given an allocation
* strategy instance. Any kind of string type is valid as long as a
* mutable_string_view can be constructed from it.
*
* Valid allocation strategies are \ref single_allocation,
* \ref dynamic_allocation, and \ref bounded_allocation.
*
* A \ref document is returned whether or not the parse succeeds: success
* state is available by calling document::is_valid().
*/
template<typename AllocationStrategy, typename StringType>
document parse(const AllocationStrategy& strategy, const StringType& string) {
mutable_string_view input(string);
bool success;
auto allocator = strategy.make_allocator(input.length(), &success);
if (!success) {
return document(input, 1, 1, ERROR_OUT_OF_MEMORY, 0);
}
return parser<typename AllocationStrategy::allocator>(
input,
std::move(allocator)
).get_document();
}
}