/*
* Copyright (c) 2009-2011 Petri Lehtinen <petri@digip.org>
*
* Jansson is free software; you can redistribute it and/or modify
* it under the terms of the MIT license. See LICENSE for details.
*/
#define _GNU_SOURCE
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <jansson.h>
#include "jansson_private.h"
#include "strbuffer.h"
#include "utf.h"
#define STREAM_STATE_OK 0
#define STREAM_STATE_EOF -1
#define STREAM_STATE_ERROR -2
#define TOKEN_INVALID -1
#define TOKEN_EOF 0
#define TOKEN_STRING 256
#define TOKEN_INTEGER 257
#define TOKEN_REAL 258
#define TOKEN_TRUE 259
#define TOKEN_FALSE 260
#define TOKEN_NULL 261
/* Read one byte from stream, convert to unsigned char, then int, and
return. return EOF on end of file. This corresponds to the
behaviour of fgetc(). */
typedef int (*get_func)(void *data);
typedef struct {
get_func get;
void *data;
char buffer[5];
int buffer_pos;
int state;
int line;
int column, last_column;
size_t position;
} stream_t;
typedef struct {
stream_t stream;
strbuffer_t saved_text;
int token;
union {
char *string;
json_int_t integer;
double real;
} value;
} lex_t;
#define stream_to_lex(stream) container_of(stream, lex_t, stream)
/*** error reporting ***/
static void error_set(json_error_t *error, const lex_t *lex,
const char *msg, ...)
{
va_list ap;
char msg_text[JSON_ERROR_TEXT_LENGTH];
int line = -1, col = -1;
size_t pos = 0;
const char *result = msg_text;
if(!error)
return;
va_start(ap, msg);
vsnprintf(msg_text, JSON_ERROR_TEXT_LENGTH, msg, ap);
va_end(ap);
if(lex)
{
const char *saved_text = strbuffer_value(&lex->saved_text);
char msg_with_context[JSON_ERROR_TEXT_LENGTH];
line = lex->stream.line;
col = lex->stream.column;
pos = lex->stream.position;
if(saved_text && saved_text[0])
{
if(lex->saved_text.length <= 20) {
snprintf(msg_with_context, JSON_ERROR_TEXT_LENGTH,
"%s near '%s'", msg_text, saved_text);
result = msg_with_context;
}
}
else
{
if(lex->stream.state == STREAM_STATE_ERROR) {
/* No context for UTF-8 decoding errors */
result = msg_text;
}
else {
snprintf(msg_with_context, JSON_ERROR_TEXT_LENGTH,
"%s near end of file", msg_text);
result = msg_with_context;
}
}
}
jsonp_error_set(error, line, col, pos, "%s", result);
}
/*** lexical analyzer ***/
static void
stream_init(stream_t *stream, get_func get, void *data)
{
stream->get = get;
stream->data = data;
stream->buffer[0] = '\0';
stream->buffer_pos = 0;
stream->state = STREAM_STATE_OK;
stream->line = 1;
stream->column = 0;
stream->position = 0;
}
static int stream_get(stream_t *stream, json_error_t *error)
{
int c;
if(stream->state != STREAM_STATE_OK)
return stream->state;
if(!stream->buffer[stream->buffer_pos])
{
c = stream->get(stream->data);
if(c == EOF) {
stream->state = STREAM_STATE_EOF;
return STREAM_STATE_EOF;
}
stream->buffer[0] = c;
stream->buffer_pos = 0;
if(0x80 <= c && c <= 0xFF)
{
/* multi-byte UTF-8 sequence */
int i, count;
count = utf8_check_first(c);
if(!count)
goto out;
assert(count >= 2);
for(i = 1; i < count; i++)
stream->buffer[i] = stream->get(stream->data);
if(!utf8_check_full(stream->buffer, count, NULL))
goto out;
stream->buffer[count] = '\0';
}
else
stream->buffer[1] = '\0';
}
c = stream->buffer[stream->buffer_pos++];
stream->position++;
if(c == '\n') {
stream->line++;
stream->last_column = stream->column;
stream->column = 0;
}
else if(utf8_check_first(c)) {
/* track the Unicode character column, so increment only if
this is the first character of a UTF-8 sequence */
stream->column++;
}
return c;
out:
stream->state = STREAM_STATE_ERROR;
error_set(error, stream_to_lex(stream), "unable to decode byte 0x%x", c);
return STREAM_STATE_ERROR;
}
static void stream_unget(stream_t *stream, int c)
{
if(c == STREAM_STATE_EOF || c == STREAM_STATE_ERROR)
return;
stream->position--;
if(c == '\n') {
stream->line--;
stream->column = stream->last_column;
}
else if(utf8_check_first(c))
stream->column--;
assert(stream->buffer_pos > 0);
stream->buffer_pos--;
assert(stream->buffer[stream->buffer_pos] == c);
}
static int lex_get(lex_t *lex, json_error_t *error)
{
return stream_get(&lex->stream, error);
}
static void lex_save(lex_t *lex, int c)
{
strbuffer_append_byte(&lex->saved_text, c);
}
static int lex_get_save(lex_t *lex, json_error_t *error)
{
int c = stream_get(&lex->stream, error);
if(c != STREAM_STATE_EOF && c != STREAM_STATE_ERROR)
lex_save(lex, c);
return c;
}
static void lex_unget(lex_t *lex, int c)
{
stream_unget(&lex->stream, c);
}
static void lex_unget_unsave(lex_t *lex, int c)
{
if(c != STREAM_STATE_EOF && c != STREAM_STATE_ERROR) {
char d;
stream_unget(&lex->stream, c);
d = strbuffer_pop(&lex->saved_text);
assert(c == d);
}
}
static void lex_save_cached(lex_t *lex)
{
while(lex->stream.buffer[lex->stream.buffer_pos] != '\0')
{
lex_save(lex, lex->stream.buffer[lex->stream.buffer_pos]);
lex->stream.buffer_pos++;
lex->stream.position++;
}
}
/* assumes that str points to 'u' plus at least 4 valid hex digits */
static int32_t decode_unicode_escape(const char *str)
{
int i;
int32_t value = 0;
assert(str[0] == 'u');
for(i = 1; i <= 4; i++) {
char c = str[i];
value <<= 4;
if(isdigit(c))
value += c - '0';
else if(islower(c))
value += c - 'a' + 10;
else if(isupper(c))
value += c - 'A' + 10;
else
assert(0);
}
return value;
}
static void lex_scan_string(lex_t *lex, json_error_t *error)
{
int c;
const char *p;
char *t;
int i;
lex->value.string = NULL;
lex->token = TOKEN_INVALID;
c = lex_get_save(lex, error);
while(c != '"') {
if(c == STREAM_STATE_ERROR)
goto out;
else if(c == STREAM_STATE_EOF) {
error_set(error, lex, "premature end of input");
goto out;
}
else if(0 <= c && c <= 0x1F) {
/* control character */
lex_unget_unsave(lex, c);
if(c == '\n')
error_set(error, lex, "unexpected newline", c);
else
error_set(error, lex, "control character 0x%x", c);
goto out;
}
else if(c == '\\') {
c = lex_get_save(lex, error);
if(c == 'u') {
c = lex_get_save(lex, error);
for(i = 0; i < 4; i++) {
if(!isxdigit(c)) {
error_set(error, lex, "invalid escape");
goto out;
}
c = lex_get_save(lex, error);
}
}
else if(c == '"' || c == '\\' || c == '/' || c == 'b' ||
c == 'f' || c == 'n' || c == 'r' || c == 't')
c = lex_get_save(lex, error);
else {
error_set(error, lex, "invalid escape");
goto out;
}
}
else
c = lex_get_save(lex, error);
}
/* the actual value is at most of the same length as the source
string, because:
- shortcut escapes (e.g. "\t") (length 2) are converted to 1 byte
- a single \uXXXX escape (length 6) is converted to at most 3 bytes
- two \uXXXX escapes (length 12) forming an UTF-16 surrogate pair
are converted to 4 bytes
*/
lex->value.string = jsonp_malloc(lex->saved_text.length + 1);
if(!lex->value.string) {
/* this is not very nice, since TOKEN_INVALID is returned */
goto out;
}
/* the target */
t = lex->value.string;
/* + 1 to skip the " */
p = strbuffer_value(&lex->saved_text) + 1;
while(*p != '"') {
if(*p == '\\') {
p++;
if(*p == 'u') {
char buffer[4];
int length;
int32_t value;
value = decode_unicode_escape(p);
p += 5;
if(0xD800 <= value && value <= 0xDBFF) {
/* surrogate pair */
if(*p == '\\' && *(p + 1) == 'u') {
int32_t value2 = decode_unicode_escape(++p);
p += 5;
if(0xDC00 <= value2 && value2 <= 0xDFFF) {
/* valid second surrogate */
value =
((value - 0xD800) << 10) +
(value2 - 0xDC00) +
0x10000;
}
else {
/* invalid second surrogate */
error_set(error, lex,
"invalid Unicode '\\u%04X\\u%04X'",
value, value2);
goto out;
}
}
else {
/* no second surrogate */
error_set(error, lex, "invalid Unicode '\\u%04X'",
value);
goto out;
}
}
else if(0xDC00 <= value && value <= 0xDFFF) {
error_set(error, lex, "invalid Unicode '\\u%04X'", value);
goto out;
}
else if(value == 0)
{
error_set(error, lex, "\\u0000 is not allowed");
goto out;
}
if(utf8_encode(value, buffer, &length))
assert(0);
memcpy(t, buffer, length);
t += length;
}
else {
switch(*p) {
case '"': case '\\': case '/':
*t = *p; break;
case 'b': *t = '\b'; break;
case 'f': *t = '\f'; break;
case 'n': *t = '\n'; break;
case 'r': *t = '\r'; break;
case 't': *t = '\t'; break;
default: assert(0);
}
t++;
p++;
}
}
else
*(t++) = *(p++);
}
*t = '\0';
lex->token = TOKEN_STRING;
return;
out:
jsonp_free(lex->value.string);
}
#if JSON_INTEGER_IS_LONG_LONG
#define json_strtoint strtoll
#else
#define json_strtoint strtol
#endif
static int lex_scan_number(lex_t *lex, int c, json_error_t *error)
{
const char *saved_text;
char *end;
double value;
lex->token = TOKEN_INVALID;
if(c == '-')
c = lex_get_save(lex, error);
if(c == '0') {
c = lex_get_save(lex, error);
if(isdigit(c)) {
lex_unget_unsave(lex, c);
goto out;
}
}
else if(isdigit(c)) {
c = lex_get_save(lex, error);
while(isdigit(c))
c = lex_get_save(lex, error);
}
else {
lex_unget_unsave(lex, c);
goto out;
}
if(c != '.' && c != 'E' && c != 'e') {
json_int_t value;
lex_unget_unsave(lex, c);
saved_text = strbuffer_value(&lex->saved_text);
errno = 0;
value = json_strtoint(saved_text, &end, 10);
if(errno == ERANGE) {
if(value < 0)
error_set(error, lex, "too big negative integer");
else
error_set(error, lex, "too big integer");
goto out;
}
assert(end == saved_text + lex->saved_text.length);
lex->token = TOKEN_INTEGER;
lex->value.integer = value;
return 0;
}
if(c == '.') {
c = lex_get(lex, error);
if(!isdigit(c)) {
lex_unget(lex, c);
goto out;
}
lex_save(lex, c);
c = lex_get_save(lex, error);
while(isdigit(c))
c = lex_get_save(lex, error);
}
if(c == 'E' || c == 'e') {
c = lex_get_save(lex, error);
if(c == '+' || c == '-')
c = lex_get_save(lex, error);
if(!isdigit(c)) {
lex_unget_unsave(lex, c);
goto out;
}
c = lex_get_save(lex, error);
while(isdigit(c))
c = lex_get_save(lex, error);
}
lex_unget_unsave(lex, c);
saved_text = strbuffer_value(&lex->saved_text);
errno = 0;
value = strtod(saved_text, &end);
assert(end == saved_text + lex->saved_text.length);
if(errno == ERANGE && value != 0) {
error_set(error, lex, "real number overflow");
goto out;
}
lex->token = TOKEN_REAL;
lex->value.real = value;
return 0;
out:
return -1;
}
static int lex_scan(lex_t *lex, json_error_t *error)
{
int c;
strbuffer_clear(&lex->saved_text);
if(lex->token == TOKEN_STRING) {
jsonp_free(lex->value.string);
lex->value.string = NULL;
}
c = lex_get(lex, error);
while(c == ' ' || c == '\t' || c == '\n' || c == '\r')
c = lex_get(lex, error);
if(c == STREAM_STATE_EOF) {
lex->token = TOKEN_EOF;
goto out;
}
if(c == STREAM_STATE_ERROR) {
lex->token = TOKEN_INVALID;
goto out;
}
lex_save(lex, c);
if(c == '{' || c == '}' || c == '[' || c == ']' || c == ':' || c == ',')
lex->token = c;
else if(c == '"')
lex_scan_string(lex, error);
else if(isdigit(c) || c == '-') {
if(lex_scan_number(lex, c, error))
goto out;
}
else if(isupper(c) || islower(c)) {
/* eat up the whole identifier for clearer error messages */
const char *saved_text;
c = lex_get_save(lex, error);
while(isupper(c) || islower(c))
c = lex_get_save(lex, error);
lex_unget_unsave(lex, c);
saved_text = strbuffer_value(&lex->saved_text);
if(strcmp(saved_text, "true") == 0)
lex->token = TOKEN_TRUE;
else if(strcmp(saved_text, "false") == 0)
lex->token = TOKEN_FALSE;
else if(strcmp(saved_text, "null") == 0)
lex->token = TOKEN_NULL;
else
lex->token = TOKEN_INVALID;
}
else {
/* save the rest of the input UTF-8 sequence to get an error
message of valid UTF-8 */
lex_save_cached(lex);
lex->token = TOKEN_INVALID;
}
out:
return lex->token;
}
static char *lex_steal_string(lex_t *lex)
{
char *result = NULL;
if(lex->token == TOKEN_STRING)
{
result = lex->value.string;
lex->value.string = NULL;
}
return result;
}
static int lex_init(lex_t *lex, get_func get, void *data)
{
stream_init(&lex->stream, get, data);
if(strbuffer_init(&lex->saved_text))
return -1;
lex->token = TOKEN_INVALID;
return 0;
}
static void lex_close(lex_t *lex)
{
if(lex->token == TOKEN_STRING)
jsonp_free(lex->value.string);
strbuffer_close(&lex->saved_text);
}
/*** parser ***/
static json_t *parse_value(lex_t *lex, size_t flags, json_error_t *error);
static json_t *parse_object(lex_t *lex, size_t flags, json_error_t *error)
{
json_t *object = json_object();
if(!object)
return NULL;
lex_scan(lex, error);
if(lex->token == '}')
return object;
while(1) {
char *key;
json_t *value;
if(lex->token != TOKEN_STRING) {
error_set(error, lex, "string or '}' expected");
goto error;
}
key = lex_steal_string(lex);
if(!key)
return NULL;
if(flags & JSON_REJECT_DUPLICATES) {
if(json_object_get(object, key)) {
jsonp_free(key);
error_set(error, lex, "duplicate object key");
goto error;
}
}
lex_scan(lex, error);
if(lex->token != ':') {
jsonp_free(key);
error_set(error, lex, "':' expected");
goto error;
}
lex_scan(lex, error);
value = parse_value(lex, flags, error);
if(!value) {
jsonp_free(key);
goto error;
}
if(json_object_set_nocheck(object, key, value)) {
jsonp_free(key);
json_decref(value);
goto error;
}
json_decref(value);
jsonp_free(key);
lex_scan(lex, error);
if(lex->token != ',')
break;
lex_scan(lex, error);
}
if(lex->token != '}') {
error_set(error, lex, "'}' expected");
goto error;
}
return object;
error:
json_decref(object);
return NULL;
}
static json_t *parse_array(lex_t *lex, size_t flags, json_error_t *error)
{
json_t *array = json_array();
if(!array)
return NULL;
lex_scan(lex, error);
if(lex->token == ']')
return array;
while(lex->token) {
json_t *elem = parse_value(lex, flags, error);
if(!elem)
goto error;
if(json_array_append(array, elem)) {
json_decref(elem);
goto error;
}
json_decref(elem);
lex_scan(lex, error);
if(lex->token != ',')
break;
lex_scan(lex, error);
}
if(lex->token != ']') {
error_set(error, lex, "']' expected");
goto error;
}
return array;
error:
json_decref(array);
return NULL;
}
static json_t *parse_value(lex_t *lex, size_t flags, json_error_t *error)
{
json_t *json;
switch(lex->token) {
case TOKEN_STRING: {
json = json_string_nocheck(lex->value.string);
break;
}
case TOKEN_INTEGER: {
json = json_integer(lex->value.integer);
break;
}
case TOKEN_REAL: {
json = json_real(lex->value.real);
break;
}
case TOKEN_TRUE:
json = json_true();
break;
case TOKEN_FALSE:
json = json_false();
break;
case TOKEN_NULL:
json = json_null();
break;
case '{':
json = parse_object(lex, flags, error);
break;
case '[':
json = parse_array(lex, flags, error);
break;
case TOKEN_INVALID:
error_set(error, lex, "invalid token");
return NULL;
default:
error_set(error, lex, "unexpected token");
return NULL;
}
if(!json)
return NULL;
return json;
}
static json_t *parse_json(lex_t *lex, size_t flags, json_error_t *error)
{
json_t *result;
lex_scan(lex, error);
if(lex->token != '[' && lex->token != '{') {
error_set(error, lex, "'[' or '{' expected");
return NULL;
}
result = parse_value(lex, flags, error);
if(!result)
return NULL;
if(!(flags & JSON_DISABLE_EOF_CHECK)) {
lex_scan(lex, error);
if(lex->token != TOKEN_EOF) {
error_set(error, lex, "end of file expected");
json_decref(result);
result = NULL;
}
}
return result;
}
typedef struct
{
const char *data;
int pos;
} string_data_t;
static int string_get(void *data)
{
char c;
string_data_t *stream = (string_data_t *)data;
c = stream->data[stream->pos];
if(c == '\0')
return EOF;
else
{
stream->pos++;
return (unsigned char)c;
}
}
json_t *json_loads(const char *string, size_t flags, json_error_t *error)
{
lex_t lex;
json_t *result;
string_data_t stream_data;
stream_data.data = string;
stream_data.pos = 0;
if(lex_init(&lex, string_get, (void *)&stream_data))
return NULL;
jsonp_error_init(error, "<string>");
result = parse_json(&lex, flags, error);
lex_close(&lex);
return result;
}
typedef struct
{
const char *data;
size_t len;
size_t pos;
} buffer_data_t;
static int buffer_get(void *data)
{
char c;
buffer_data_t *stream = data;
if(stream->pos >= stream->len)
return EOF;
c = stream->data[stream->pos];
stream->pos++;
return (unsigned char)c;
}
json_t *json_loadb(const char *buffer, size_t buflen, size_t flags, json_error_t *error)
{
lex_t lex;
json_t *result;
buffer_data_t stream_data;
stream_data.data = buffer;
stream_data.pos = 0;
stream_data.len = buflen;
if(lex_init(&lex, buffer_get, (void *)&stream_data))
return NULL;
jsonp_error_init(error, "<buffer>");
result = parse_json(&lex, flags, error);
lex_close(&lex);
return result;
}
json_t *json_loadf(FILE *input, size_t flags, json_error_t *error)
{
lex_t lex;
const char *source;
json_t *result;
if(lex_init(&lex, (get_func)fgetc, input))
return NULL;
if(input == stdin)
source = "<stdin>";
else
source = "<stream>";
jsonp_error_init(error, source);
result = parse_json(&lex, flags, error);
lex_close(&lex);
return result;
}
json_t *json_load_file(const char *path, size_t flags, json_error_t *error)
{
json_t *result;
FILE *fp;
jsonp_error_init(error, path);
fp = fopen(path, "r");
if(!fp)
{
error_set(error, NULL, "unable to open %s: %s",
path, strerror(errno));
return NULL;
}
result = json_loadf(fp, flags, error);
fclose(fp);
return result;
}
