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     // No lock needed in the constructor
00030 }
00031 
00032 int RawSerial::getc() {
00033     lock();
00034     int ret = _base_getc();
00035     unlock();
00036     return ret;
00037 }
00038 
00039 int RawSerial::putc(int c) {
00040     lock();
00041     int ret = _base_putc(c);
00042     unlock();
00043     return ret;
00044 }
00045 
00046 int RawSerial::puts(const char *str) {
00047     lock();
00048     while (*str)
00049         putc(*str ++);
00050     unlock();
00051     return 0;
00052 }
00053 
00054 // Experimental support for printf in RawSerial. No Stream inheritance
00055 // means we can't call printf() directly, so we use sprintf() instead.
00056 // We only call malloc() for the sprintf() buffer if the buffer
00057 // length is above a certain threshold, otherwise we use just the stack.
00058 int RawSerial::printf(const char *format, ...) {
00059     lock();
00060     std::va_list arg;
00061     va_start(arg, format);
00062     // ARMCC microlib does not properly handle a size of 0.
00063     // As a workaround supply a dummy buffer with a size of 1.
00064     char dummy_buf[1];
00065     int len = vsnprintf(dummy_buf, sizeof(dummy_buf), format, arg);
00066     if (len < STRING_STACK_LIMIT) {
00067         char temp[STRING_STACK_LIMIT];
00068         vsprintf(temp, format, arg);
00069         puts(temp);
00070     } else {
00071         char *temp = new char[len + 1];
00072         vsprintf(temp, format, arg);
00073         puts(temp);
00074         delete[] temp;
00075     }
00076     va_end(arg);
00077     unlock();
00078     return len;
00079 }
00080 
00081 /** Acquire exclusive access to this serial port
00082  */
00083 void RawSerial::lock() {
00084     // No lock used - external synchronization required
00085 }
00086 
00087 /** Release exclusive access to this serial port
00088  */
00089 void RawSerial::unlock() {
00090     // No lock used - external synchronization required
00091 }
00092 
00093 } // namespace mbed
00094 
00095 #endif