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bfac1972e25b40f849852ce3c10e0a8ad47f79d7
jansson/src/load.c
Petri Lehtinen bfac1972e2 Add a flags parameter to all decoding functions for future needs 
As of now, the parameter is unused, but may be needed in the future.
I'm adding it now so that in the future both API and ABI remain
backwards compatible as long as possible.

This is a backwards incompatible change.
2010-08-14 17:28:09 +03:00

889 lines
20 KiB
C
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/*
* Copyright (c) 2009, 2010 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 <stdarg.h>
#include <assert.h>
#include <jansson.h>
#include "jansson_private.h"
#include "strbuffer.h"
#include "utf.h"
#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, return EOF on end of file */
typedef int (*get_func)(void *data);
/* return non-zero if end of file has been reached */
typedef int (*eof_func)(void *data);
typedef struct {
get_func get;
eof_func eof;
void *data;
int stream_pos;
char buffer[5];
int buffer_pos;
} stream_t;
typedef struct {
stream_t stream;
strbuffer_t saved_text;
int token;
int line, column;
union {
char *string;
json_int_t integer;
double real;
} value;
} lex_t;
/*** error reporting ***/
static void error_init(json_error_t *error)
{
if(error)
{
error->text[0] = '\0';
error->line = -1;
}
}
static void error_set(json_error_t *error, const lex_t *lex,
const char *msg, ...)
{
va_list ap;
char text[JSON_ERROR_TEXT_LENGTH];
if(!error || error->text[0] != '\0') {
/* error already set */
return;
}
va_start(ap, msg);
vsnprintf(text, JSON_ERROR_TEXT_LENGTH, msg, ap);
va_end(ap);
if(lex)
{
const char *saved_text = strbuffer_value(&lex->saved_text);
error->line = lex->line;
if(saved_text && saved_text[0])
{
if(lex->saved_text.length <= 20) {
snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
"%s near '%s'", text, saved_text);
}
else
snprintf(error->text, JSON_ERROR_TEXT_LENGTH, "%s", text);
}
else
{
snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
"%s near end of file", text);
}
}
else
{
error->line = -1;
snprintf(error->text, JSON_ERROR_TEXT_LENGTH, "%s", text);
}
}
/*** lexical analyzer ***/
static void
stream_init(stream_t *stream, get_func get, eof_func eof, void *data)
{
stream->get = get;
stream->eof = eof;
stream->data = data;
stream->stream_pos = 0;
stream->buffer[0] = '\0';
stream->buffer_pos = 0;
}
static char stream_get(stream_t *stream, json_error_t *error)
{
char c;
if(!stream->buffer[stream->buffer_pos])
{
stream->buffer[0] = stream->get(stream->data);
stream->buffer_pos = 0;
c = stream->buffer[0];
if((unsigned char)c >= 0x80 && c != (char)EOF)
{
/* 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->stream_pos += count;
stream->buffer[count] = '\0';
}
else {
stream->buffer[1] = '\0';
stream->stream_pos++;
}
}
return stream->buffer[stream->buffer_pos++];
out:
error_set(error, NULL, "unable to decode byte 0x%x at position %d",
(unsigned char)c, stream->stream_pos);
stream->buffer[0] = EOF;
stream->buffer[1] = '\0';
stream->buffer_pos = 1;
return EOF;
}
static void stream_unget(stream_t *stream, char c)
{
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 int lex_eof(lex_t *lex)
{
return lex->stream.eof(lex->stream.data);
}
static void lex_save(lex_t *lex, char c)
{
strbuffer_append_byte(&lex->saved_text, c);
}
static int lex_get_save(lex_t *lex, json_error_t *error)
{
char c = stream_get(&lex->stream, error);
lex_save(lex, c);
return c;
}
static void lex_unget_unsave(lex_t *lex, char c)
{
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++;
}
}
/* 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)
{
char 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 == (char)EOF) {
lex_unget_unsave(lex, c);
if(lex_eof(lex))
error_set(error, lex, "premature end of input");
goto out;
}
else if((unsigned char)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)) {
lex_unget_unsave(lex, 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 {
lex_unget_unsave(lex, c);
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 = 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:
free(lex->value.string);
}
#ifdef JSON_INTEGER_IS_LONG_LONG
#define json_strtoint strtoll
#else
#define json_strtoint strtol
#endif
static int lex_scan_number(lex_t *lex, char 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))
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);
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)
{
char c;
strbuffer_clear(&lex->saved_text);
if(lex->token == TOKEN_STRING) {
free(lex->value.string);
lex->value.string = NULL;
}
c = lex_get(lex, error);
while(c == ' ' || c == '\t' || c == '\n' || c == '\r')
{
if(c == '\n')
lex->line++;
c = lex_get(lex, error);
}
if(c == (char)EOF) {
if(lex_eof(lex))
lex->token = TOKEN_EOF;
else
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, eof_func eof, void *data)
{
stream_init(&lex->stream, get, eof, data);
if(strbuffer_init(&lex->saved_text))
return -1;
lex->token = TOKEN_INVALID;
lex->line = 1;
return 0;
}
static void lex_close(lex_t *lex)
{
if(lex->token == TOKEN_STRING)
free(lex->value.string);
strbuffer_close(&lex->saved_text);
}
/*** parser ***/
static json_t *parse_value(lex_t *lex, json_error_t *error);
static json_t *parse_object(lex_t *lex, 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;
lex_scan(lex, error);
if(lex->token != ':') {
free(key);
error_set(error, lex, "':' expected");
goto error;
}
lex_scan(lex, error);
value = parse_value(lex, error);
if(!value) {
free(key);
goto error;
}
if(json_object_set_nocheck(object, key, value)) {
free(key);
json_decref(value);
goto error;
}
json_decref(value);
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, 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, 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, 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, error);
break;
case '[':
json = parse_array(lex, 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, json_error_t *error)
{
error_init(error);
lex_scan(lex, error);
if(lex->token != '[' && lex->token != '{') {
error_set(error, lex, "'[' or '{' expected");
return NULL;
}
return parse_value(lex, error);
}
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 c;
}
}
static int string_eof(void *data)
{
string_data_t *stream = (string_data_t *)data;
return (stream->data[stream->pos] == '\0');
}
json_t *json_loads(const char *string, size_t flags, json_error_t *error)
{
lex_t lex;
json_t *result;
(void)flags; /* unused */
string_data_t stream_data = {
.data = string,
.pos = 0
};
if(lex_init(&lex, string_get, string_eof, (void *)&stream_data))
return NULL;
result = parse_json(&lex, error);
if(!result)
goto out;
lex_scan(&lex, error);
if(lex.token != TOKEN_EOF) {
error_set(error, &lex, "end of file expected");
json_decref(result);
result = NULL;
}
out:
lex_close(&lex);
return result;
}
json_t *json_loadf(FILE *input, size_t flags, json_error_t *error)
{
lex_t lex;
json_t *result;
(void)flags; /* unused */
if(lex_init(&lex, (get_func)fgetc, (eof_func)feof, input))
return NULL;
result = parse_json(&lex, error);
if(!result)
goto out;
lex_scan(&lex, error);
if(lex.token != TOKEN_EOF) {
error_set(error, &lex, "end of file expected");
json_decref(result);
result = NULL;
}
out:
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;
error_init(error);
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;
}
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