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micropython/extmod/modjson.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2014-2019 Damien P. George
*
* 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.
*/
#include <stdio.h>
#include "py/objlist.h"
#include "py/objstringio.h"
#include "py/parsenum.h"
#include "py/runtime.h"
#include "py/stream.h"
#if MICROPY_PY_JSON
#if MICROPY_PY_JSON_SEPARATORS
enum {
DUMP_MODE_TO_STRING = 1,
DUMP_MODE_TO_STREAM = 2,
};
STATIC mp_obj_t mod_json_dump_helper(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args, unsigned int mode) {
enum { ARG_separators };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_separators, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - mode, pos_args + mode, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
mp_print_ext_t print_ext;
if (args[ARG_separators].u_obj == mp_const_none) {
print_ext.item_separator = ", ";
print_ext.key_separator = ": ";
} else {
mp_obj_t *items;
mp_obj_get_array_fixed_n(args[ARG_separators].u_obj, 2, &items);
print_ext.item_separator = mp_obj_str_get_str(items[0]);
print_ext.key_separator = mp_obj_str_get_str(items[1]);
}
if (mode == DUMP_MODE_TO_STRING) {
// dumps(obj)
vstr_t vstr;
vstr_init_print(&vstr, 8, &print_ext.base);
mp_obj_print_helper(&print_ext.base, pos_args[0], PRINT_JSON);
return mp_obj_new_str_from_utf8_vstr(&vstr);
} else {
// dump(obj, stream)
print_ext.base.data = MP_OBJ_TO_PTR(pos_args[1]);
print_ext.base.print_strn = mp_stream_write_adaptor;
mp_get_stream_raise(pos_args[1], MP_STREAM_OP_WRITE);
mp_obj_print_helper(&print_ext.base, pos_args[0], PRINT_JSON);
return mp_const_none;
}
}
STATIC mp_obj_t mod_json_dump(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
return mod_json_dump_helper(n_args, pos_args, kw_args, DUMP_MODE_TO_STREAM);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(mod_json_dump_obj, 2, mod_json_dump);
STATIC mp_obj_t mod_json_dumps(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
return mod_json_dump_helper(n_args, pos_args, kw_args, DUMP_MODE_TO_STRING);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(mod_json_dumps_obj, 1, mod_json_dumps);
#else
STATIC mp_obj_t mod_json_dump(mp_obj_t obj, mp_obj_t stream) {
mp_get_stream_raise(stream, MP_STREAM_OP_WRITE);
mp_print_t print = {MP_OBJ_TO_PTR(stream), mp_stream_write_adaptor};
mp_obj_print_helper(&print, obj, PRINT_JSON);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_json_dump_obj, mod_json_dump);
STATIC mp_obj_t mod_json_dumps(mp_obj_t obj) {
vstr_t vstr;
mp_print_t print;
vstr_init_print(&vstr, 8, &print);
mp_obj_print_helper(&print, obj, PRINT_JSON);
return mp_obj_new_str_from_utf8_vstr(&vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_json_dumps_obj, mod_json_dumps);
#endif
// The function below implements a simple non-recursive JSON parser.
//
// The JSON specification is at http://www.ietf.org/rfc/rfc4627.txt
// The parser here will parse any valid JSON and return the correct
// corresponding Python object. It allows through a superset of JSON, since
// it treats commas and colons as "whitespace", and doesn't care if
// brackets/braces are correctly paired. It will raise a ValueError if the
// input is outside it's specs.
//
// Most of the work is parsing the primitives (null, false, true, numbers,
// strings). It does 1 pass over the input stream. It tries to be fast and
// small in code size, while not using more RAM than necessary.
typedef struct _json_stream_t {
mp_obj_t stream_obj;
mp_uint_t (*read)(mp_obj_t obj, void *buf, mp_uint_t size, int *errcode);
int errcode;
byte cur;
} json_stream_t;
#define S_EOF (0) // null is not allowed in json stream so is ok as EOF marker
#define S_END(s) ((s).cur == S_EOF)
#define S_CUR(s) ((s).cur)
#define S_NEXT(s) (json_stream_next(&(s)))
STATIC byte json_stream_next(json_stream_t *s) {
mp_uint_t ret = s->read(s->stream_obj, &s->cur, 1, &s->errcode);
if (s->errcode != 0) {
mp_raise_OSError(s->errcode);
}
if (ret == 0) {
s->cur = S_EOF;
}
return s->cur;
}
STATIC mp_obj_t mod_json_load(mp_obj_t stream_obj) {
const mp_stream_p_t *stream_p = mp_get_stream_raise(stream_obj, MP_STREAM_OP_READ);
json_stream_t s = {stream_obj, stream_p->read, 0, 0};
vstr_t vstr;
vstr_init(&vstr, 8);
mp_obj_list_t stack; // we use a list as a simple stack for nested JSON
stack.len = 0;
stack.items = NULL;
mp_obj_t stack_top = MP_OBJ_NULL;
const mp_obj_type_t *stack_top_type = NULL;
mp_obj_t stack_key = MP_OBJ_NULL;
S_NEXT(s);
for (;;) {
cont:
if (S_END(s)) {
break;
}
mp_obj_t next = MP_OBJ_NULL;
bool enter = false;
byte cur = S_CUR(s);
S_NEXT(s);
switch (cur) {
case ',':
case ':':
case ' ':
case '\t':
case '\n':
case '\r':
goto cont;
case 'n':
if (S_CUR(s) == 'u' && S_NEXT(s) == 'l' && S_NEXT(s) == 'l') {
S_NEXT(s);
next = mp_const_none;
} else {
goto fail;
}
break;
case 'f':
if (S_CUR(s) == 'a' && S_NEXT(s) == 'l' && S_NEXT(s) == 's' && S_NEXT(s) == 'e') {
S_NEXT(s);
next = mp_const_false;
} else {
goto fail;
}
break;
case 't':
if (S_CUR(s) == 'r' && S_NEXT(s) == 'u' && S_NEXT(s) == 'e') {
S_NEXT(s);
next = mp_const_true;
} else {
goto fail;
}
break;
case '"':
vstr_reset(&vstr);
for (; !S_END(s) && S_CUR(s) != '"';) {
byte c = S_CUR(s);
if (c == '\\') {
c = S_NEXT(s);
switch (c) {
case 'b':
c = 0x08;
break;
case 'f':
c = 0x0c;
break;
case 'n':
c = 0x0a;
break;
case 'r':
c = 0x0d;
break;
case 't':
c = 0x09;
break;
case 'u': {
mp_uint_t num = 0;
for (int i = 0; i < 4; i++) {
c = (S_NEXT(s) | 0x20) - '0';
if (c > 9) {
c -= ('a' - ('9' + 1));
}
num = (num << 4) | c;
}
vstr_add_char(&vstr, num);
goto str_cont;
}
}
}
vstr_add_byte(&vstr, c);
str_cont:
S_NEXT(s);
}
if (S_END(s)) {
goto fail;
}
S_NEXT(s);
next = mp_obj_new_str(vstr.buf, vstr.len);
break;
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9': {
bool flt = false;
vstr_reset(&vstr);
for (;;) {
vstr_add_byte(&vstr, cur);
cur = S_CUR(s);
if (cur == '.' || cur == 'E' || cur == 'e') {
flt = true;
} else if (cur == '+' || cur == '-' || unichar_isdigit(cur)) {
// pass
} else {
break;
}
S_NEXT(s);
}
if (flt) {
next = mp_parse_num_float(vstr.buf, vstr.len, false, NULL);
} else {
next = mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
}
break;
}
case '[':
next = mp_obj_new_list(0, NULL);
enter = true;
break;
case '{':
next = mp_obj_new_dict(0);
enter = true;
break;
case '}':
case ']': {
if (stack_top == MP_OBJ_NULL) {
// no object at all
goto fail;
}
if (stack.len == 0) {
// finished; compound object
goto success;
}
stack.len -= 1;
stack_top = stack.items[stack.len];
stack_top_type = mp_obj_get_type(stack_top);
goto cont;
}
default:
goto fail;
}
if (stack_top == MP_OBJ_NULL) {
stack_top = next;
stack_top_type = mp_obj_get_type(stack_top);
if (!enter) {
// finished; single primitive only
goto success;
}
} else {
// append to list or dict
if (stack_top_type == &mp_type_list) {
mp_obj_list_append(stack_top, next);
} else {
if (stack_key == MP_OBJ_NULL) {
stack_key = next;
if (enter) {
goto fail;
}
} else {
mp_obj_dict_store(stack_top, stack_key, next);
stack_key = MP_OBJ_NULL;
}
}
if (enter) {
if (stack.items == NULL) {
mp_obj_list_init(&stack, 1);
stack.items[0] = stack_top;
} else {
mp_obj_list_append(MP_OBJ_FROM_PTR(&stack), stack_top);
}
stack_top = next;
stack_top_type = mp_obj_get_type(stack_top);
}
}
}
success:
// eat trailing whitespace
while (unichar_isspace(S_CUR(s))) {
S_NEXT(s);
}
if (!S_END(s)) {
// unexpected chars
goto fail;
}
if (stack_top == MP_OBJ_NULL || stack.len != 0) {
// not exactly 1 object
goto fail;
}
vstr_clear(&vstr);
return stack_top;
fail:
mp_raise_ValueError(MP_ERROR_TEXT("syntax error in JSON"));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_json_load_obj, mod_json_load);
STATIC mp_obj_t mod_json_loads(mp_obj_t obj) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(obj, &bufinfo, MP_BUFFER_READ);
vstr_t vstr = {bufinfo.len, bufinfo.len, (char *)bufinfo.buf, true};
mp_obj_stringio_t sio = {{&mp_type_stringio}, &vstr, 0, MP_OBJ_NULL};
return mod_json_load(MP_OBJ_FROM_PTR(&sio));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_json_loads_obj, mod_json_loads);
STATIC const mp_rom_map_elem_t mp_module_json_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_json) },
{ MP_ROM_QSTR(MP_QSTR_dump), MP_ROM_PTR(&mod_json_dump_obj) },
{ MP_ROM_QSTR(MP_QSTR_dumps), MP_ROM_PTR(&mod_json_dumps_obj) },
{ MP_ROM_QSTR(MP_QSTR_load), MP_ROM_PTR(&mod_json_load_obj) },
{ MP_ROM_QSTR(MP_QSTR_loads), MP_ROM_PTR(&mod_json_loads_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_json_globals, mp_module_json_globals_table);
const mp_obj_module_t mp_module_json = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t *)&mp_module_json_globals,
};
MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_json, mp_module_json);
#endif // MICROPY_PY_JSON
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