json parser::parse_object(
const std::string& input, size_t& offset, std::error_code& error)
{
assert(!error);
json object = json(class_type::object);
offset++;
consume_white_space(input, offset, error);
if (input[offset] == '}')
{
offset++;
return object;
}
while (true)
{
json Key = parse_next(input, offset, error);
consume_white_space(input, offset, error);
if (input[offset] != ':')
{
error = std::make_error_code(std::errc::invalid_argument);
std::cerr << "Error: object: Expected colon, found '"
<< input[offset] << "'\n";
break;
}
offset++;
consume_white_space(input, offset, error);
json Value = parse_next(input, offset, error);
object[Key.to_string()] = Value;
consume_white_space(input, offset, error);
if (input[offset] == ',')
{
offset++;
continue;
}
else if (input[offset] == '}')
{
offset++;
break;
}
else
{
error = std::make_error_code(std::errc::invalid_argument);
std::cerr << "ERROR: object: Expected comma, found '"
<< input[offset] << "'\n";
break;
}
}
return object;
}
json parser::parse_next(
const std::string& input, size_t& offset, std::error_code& error)
{
char value;
consume_white_space(input, offset, error);
value = input[offset];
switch (value)
{
case '[': return parse_array(input, offset, error);
case '{': return parse_object(input, offset, error);
case '\"': return parse_string(input, offset, error);
case 't':
case 'f': return parse_bool(input, offset, error);
case 'n': return parse_null(input, offset, error);
default:
{
if ((value <= '9' && value >= '0') || value == '-')
{
return parse_number(input, offset, error);
}
}
}
// Error: Unknown starting character
error = std::make_error_code(std::errc::invalid_argument);
return json();
}
int read_calibration_from_file(const char *calibration_file,
struct calibration_data *accel,
struct calibration_data *magn,
struct calibration_data *gyro,
double *magnetic_declination_mrad)
{
#define STR_BUFFER_SIZE 128
int ret = 0;
FILE *stream;
int len;
char buffer[STR_BUFFER_SIZE];
stream = fopen(calibration_file, "r");
if (stream == NULL)
{
ret = -errno;
fprintf(stderr, "Error: cannot open %s\n", calibration_file);
return ret;
}
while (fgets(buffer, sizeof(buffer), stream) != NULL)
{
len = strlen(buffer);
// strip trailing '\n' if it exists
if (buffer[len-1] == '\n')
{
buffer[len-1] = 0;
len--;
}
else
{
// line is longer than our buffer, skip to the next line
continue;
}
if (buffer[0] != '#')
{
// find the '=' sign
char *equal = strstr(buffer, "=");
if (equal)
{
char *key = buffer;
char *value = equal+1;
*equal = 0;
consume_white_space(&key);
process_key_value(key, value, accel, magn, gyro, magnetic_declination_mrad);
}
}
}
fclose(stream);
return ret;
}
json parser::parse_array(
const std::string& input, size_t& offset, std::error_code& error)
{
json array = json(class_type::array);
uint32_t index = 0;
offset++;
consume_white_space(input, offset, error);
if (input[offset] == ']')
{
offset++;
return array;
}
while (true)
{
array[index++] = parse_next(input, offset, error);
consume_white_space(input, offset, error);
if (input[offset] == ',')
{
offset++; continue;
}
else if (input[offset] == ']')
{
offset++; break;
}
else
{
error = std::make_error_code(std::errc::invalid_argument);
std::cerr << "ERROR: array: Expected ',' or ']', found '"
<< input[offset] << "'\n";
return json(class_type::array);
}
}
return array;
}
