RawSerial.cpp

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #include "drivers/RawSerial.h"
00017 #include "platform/mbed_wait_api.h"
00018 #include <stdio.h>
00019 #include <cstdarg>
00020 
00021 
00022 #if DEVICE_SERIAL
00023 
00024 #define STRING_STACK_LIMIT    120
00025 
00026 namespace mbed {
00027 
00028 RawSerial::RawSerial(PinName tx, PinName rx, int baud) : SerialBase(tx, rx, baud)
00029 {
00030     // No lock needed in the constructor
00031 }
00032 
00033 int RawSerial::getc()
00034 {
00035     lock();
00036     int ret = _base_getc();
00037     unlock();
00038     return ret;
00039 }
00040 
00041 int RawSerial::putc(int c)
00042 {
00043     lock();
00044     int ret = _base_putc(c);
00045     unlock();
00046     return ret;
00047 }
00048 
00049 int RawSerial::puts(const char *str)
00050 {
00051     lock();
00052     while (*str) {
00053         putc(*str ++);
00054     }
00055     unlock();
00056     return 0;
00057 }
00058 
00059 // Experimental support for printf in RawSerial. No Stream inheritance
00060 // means we can't call printf() directly, so we use sprintf() instead.
00061 // We only call malloc() for the sprintf() buffer if the buffer
00062 // length is above a certain threshold, otherwise we use just the stack.
00063 int RawSerial::printf(const char *format, ...)
00064 {
00065     lock();
00066     std::va_list arg;
00067     va_start(arg, format);
00068     // ARMCC microlib does not properly handle a size of 0.
00069     // As a workaround supply a dummy buffer with a size of 1.
00070     char dummy_buf[1];
00071     int len = vsnprintf(dummy_buf, sizeof(dummy_buf), format, arg);
00072     if (len < STRING_STACK_LIMIT) {
00073         char temp[STRING_STACK_LIMIT];
00074         vsprintf(temp, format, arg);
00075         puts(temp);
00076     } else {
00077         char *temp = new char[len + 1];
00078         vsprintf(temp, format, arg);
00079         puts(temp);
00080         delete[] temp;
00081     }
00082     va_end(arg);
00083     unlock();
00084     return len;
00085 }
00086 
00087 /** Acquire exclusive access to this serial port
00088  */
00089 void RawSerial::lock()
00090 {
00091     // No lock used - external synchronization required
00092 }
00093 
00094 /** Release exclusive access to this serial port
00095  */
00096 void RawSerial::unlock()
00097 {
00098     // No lock used - external synchronization required
00099 }
00100 
00101 } // namespace mbed
00102 
00103 #endif