Parser for AT commands and similar protocols
Dependencies: BufferedSerial
Dependents: ESP8266 Final_Project_2 Final_Project CHEN_Final_Project
Diff: ATParser.cpp
- Revision:
- 0:c741e144517c
- Child:
- 1:66a14afe650a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ATParser.cpp Wed Jul 15 22:39:25 2015 +0000 @@ -0,0 +1,136 @@ +/* Copyright (c) 2015 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * @section DESCRIPTION + * + * Parser for the AT command syntax + * + */ + +#include "ATParser.h" +#include <cstdarg> + +// This can be defined to assist in debugging +#define AT_ECHO 1 + + +// getc/putc handling with timeouts +int ATParser::_putc(char c) { + Timer timer; + timer.start(); + + while (true) { + if (_serial->writeable()) + return _serial->putc(c); + + if (timer.read_ms() > _timeout) + return -1; + } +} + +int ATParser::_getc() { + Timer timer; + timer.start(); + + while (true) { + if (_serial->readable()) + return _serial->getc(); + + if (timer.read_ms() > _timeout) + return -1; + } +} + +void ATParser::_flush() { + while (_serial->readable()) + _serial->getc(); +} + +// getline/putline handling with timeouts/bounds checking +bool ATParser::_putline(const char *line) { + for (int i = 0; line[i]; i++) { + if (_putc(line[i]) < 0) + return false; + } + + // Finish with newline + if (_putc('\r') < 0 || + _putc('\n') < 0) + return false; + +#ifdef AT_ECHO + printf("AT> %s\r\n", line); +#endif + + return true; +} + +bool ATParser::_getline(int size, char *line) { + for (int i = 0; i < size; i++) { + int c = _getc(); + + if (c < 0) + return false; + + // Finish if newline + if (c == '\r') { + if (_getc() != '\n') + return false; + + line[i] = 0; +#ifdef AT_ECHO + printf("AT< %s\r\n", line); +#endif + return true; + } + + line[i] = c; + } + + // Ran out of space + return false; +} + + +bool ATParser::command(const char *command, const char *response, ...) { + va_list args; + va_start(args, response); + + _flush(); + + // Create and send command + if (vsprintf(_buffer, command, args) < 0 || + !_putline(_buffer)) { + va_end(args); + return false; + } + + // Determine number of parameters + // this is needed for scanf's funky error signaling + int params = 0; + for (int i = 0; response[i]; i++) { + if (response[i] == '%' && response[i+1] != '%') + params++; + } + + // Recieve and parse response + if (!_getline(_buffer_size, _buffer) || + vsscanf(_buffer, response, args) < params) { + va_end(args); + return false; + } + + va_end(args); + return true; +}