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ATParser.cpp
- Committer:
- mansiag
- Date:
- 2016-09-05
- Revision:
- 19:537f1380c44a
- Parent:
- 18:23f4573bcda2
File content as of revision 19:537f1380c44a:
/* 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 "mbed_debug.h" // 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(); } } // read/write handling with timeouts int ATParser::write(const char *data, int size) { int i = 0; for ( ; i < size; i++) { if (putc(data[i]) < 0) { return -1; } } return i; } int ATParser::read(char *data, int size) { int i = 0; for ( ; i < size; i++) { int c = getc(); if (c < 0) { return -1; } data[i] = c; } return i; } // printf/scanf handling int ATParser::vprintf(const char *format, va_list args) { if (vsprintf(_buffer, format, args) < 0) { return false; } int i = 0; for ( ; _buffer[i]; i++) { if (putc(_buffer[i]) < 0) { return -1; } } return i; } int ATParser::vscanf(const char *format, va_list args) { // Since format is const, we need to copy it into our buffer to // add the line's null terminator and clobber value-matches with asterisks. // // We just use the beginning of the buffer to avoid unnecessary allocations. int i = 0; int offset = 0; while (format[i]) { if (format[i] == '%' && format[i+1] != '%' && format[i+1] != '*') { _buffer[offset++] = '%'; _buffer[offset++] = '*'; i++; } else { _buffer[offset++] = format[i++]; } } // Scanf has very poor support for catching errors // fortunately, we can abuse the %n specifier to determine // if the entire string was matched. _buffer[offset++] = '%'; _buffer[offset++] = 'n'; _buffer[offset++] = 0; // To workaround scanf's lack of error reporting, we actually // make two passes. One checks the validity with the modified // format string that only stores the matched characters (%n). // The other reads in the actual matched values. // // We keep trying the match until we succeed or some other error // derails us. int j = 0; while (true) { // Ran out of space if (j+1 >= _buffer_size - offset) { return false; } // Recieve next character int c = getc(); if (c < 0) { return -1; } _buffer[offset + j++] = c; _buffer[offset + j] = 0; // Check for match int count = -1; sscanf(_buffer+offset, _buffer, &count); // We only succeed if all characters in the response are matched if (count == j) { // Store the found results vsscanf(_buffer+offset, format, args); return j; } } } // Command parsing with line handling bool ATParser::vsend(const char *command, va_list args) { // Create and send command if (vsprintf(_buffer, command, args) < 0) { return false; } for (int i = 0; _buffer[i]; i++) { if (putc(_buffer[i]) < 0) { return false; } } // Finish with CR "\r" //for (int i = 0; _delimiter[i]; i++) { if (putc(_delimiter[0]) < 0) { return false; } //} debug_if(dbg_on, "AT> %s\r\n", _buffer); return true; } bool ATParser::vrecv(const char *response, va_list args) { bool delim_recv = false; // Iterate through each line in the expected response while (response[0]) { // Since response is const, we need to copy it into our buffer to // add the line's null terminator and clobber value-matches with asterisks. // // We just use the beginning of the buffer to avoid unnecessary allocations. int i = 0; int offset = 0; while (response[i]) { if (memcmp(&response[i+1-_delim_size], _delimiter, _delim_size) == 0) { i++; break; } else if (response[i] == '%' && response[i+1] != '%' && response[i+1] != '*') { _buffer[offset++] = '%'; _buffer[offset++] = '*'; i++; } else { _buffer[offset++] = response[i++]; } } // Scanf has very poor support for catching errors // fortunately, we can abuse the %n specifier to determine // if the entire string was matched. _buffer[offset++] = '%'; _buffer[offset++] = 'n'; _buffer[offset++] = 0; // To workaround scanf's lack of error reporting, we actually // make two passes. One checks the validity with the modified // format string that only stores the matched characters (%n). // The other reads in the actual matched values. // // We keep trying the match until we succeed or some other error // derails us. int j = 0; while (true) { // Receive next character int c = getc(); if (c < 0) { return false; } _buffer[offset + j++] = c; _buffer[offset + j] = 0; // Check for match int count = -1; sscanf(_buffer+offset, _buffer, &count); // We only succeed if all characters in the response are matched if(count==j) { //check if last input is a number if (_buffer[offset-6]=='%' && _buffer[offset-5]=='*' && (_buffer[offset-4]=='x' || _buffer[offset-4]=='d' || _buffer[offset-4]=='u')) { //if the last char is a number, keep getting the next character till CR while(true) { int c = getc(); if (c < 0) { return false; } if(c==0xD) {//there is no next number so exit from condition c = getc();//get rid of the following '\n' delimiter delim_recv = true; break; } else { _buffer[offset + j++] = c; _buffer[offset + j] = 0; } } } debug_if(dbg_on, "AT= %s\r\n", _buffer+offset); // Reuse the front end of the buffer memcpy(_buffer, response, i); _buffer[i] = 0; // Store the found results vsscanf(_buffer+offset, _buffer, args); // Jump to next line and continue parsing response += i; // receive trailing delimiters for(int i=0; !delim_recv && i<_delim_size; i++) { c = getc(); if(c < 0) break; } break; } // Clear the buffer when we hit a newline or ran out of space // running out of space usually means we ran into binary data if (j+1 >= _buffer_size - offset || strcmp(&_buffer[offset + j-_delim_size], _delimiter) == 0) { debug_if(dbg_on, "AT< %s", _buffer+offset); j = 0; } } } return true; } // Mapping to vararg functions int ATParser::printf(const char *format, ...) { va_list args; va_start(args, format); int res = vprintf(format, args); va_end(args); return res; } int ATParser::scanf(const char *format, ...) { va_list args; va_start(args, format); int res = vscanf(format, args); va_end(args); return res; } bool ATParser::send(const char *command, ...) { va_list args; va_start(args, command); bool res = vsend(command, args); va_end(args); return res; } bool ATParser::recv(const char *response, ...) { va_list args; va_start(args, response); bool res = vrecv(response, args); va_end(args); return res; }