File content as of revision 10:9d4ec0359a5c:

#include "ArduinoSerial.h"

unsigned int ArduinoSerial::instance_counter = 0;
ArduinoSerial* ArduinoSerial::instance_reference[ARDUINOSERIAL_INSTANCE_MAX] = {0};

void ArduinoSerial::uart_irq_callback(void) {
    unsigned int index;
    for (index = 0; index < instance_counter; index++) {
        if (instance_reference[index] != NULL) {
            while(instance_reference[index]->readable()) {
                instance_reference[index]->write_char(instance_reference[index]->getc());
            }
        }
    }
}

ArduinoSerial::ArduinoSerial(PinName tx, PinName rx):Serial(tx, rx) {
    if (instance_counter < ARDUINOSERIAL_INSTANCE_MAX) {
        instance_reference[instance_counter++] = this;
        if (1 == instance_counter) {
            attach(&uart_irq_callback);
        }
    } else {
        printf("Create instance 0x%u failed: more instances created!\r\n");
    }
}
    
ArduinoSerial::~ArduinoSerial(void) {
    instance_counter--;
    if (0 == instance_counter) {
        attach(NULL);
    }
}
    
void ArduinoSerial::begin(int baud_rate) {
    baud(baud_rate);
    flush();
}
    
int ArduinoSerial::available(void) {
    return (unsigned int)(ARDUINOSERIAL_BUFFER_SIZE + rx_buffer.head - rx_buffer.tail) % ARDUINOSERIAL_BUFFER_SIZE;
}

/* 清空接收缓冲区的数据 */
void ArduinoSerial::flush(void)
{
    memset(&rx_buffer, 0, sizeof(rx_buffer));
}

char ArduinoSerial::read_char(void) {
    // if the head isn't ahead of the tail, we don't have any characters
    if (rx_buffer.head == rx_buffer.tail) {
        return (char)-1;
    } else {
        unsigned char c = rx_buffer.buffer[rx_buffer.tail];
        rx_buffer.tail = (unsigned int)(rx_buffer.tail + 1) % ARDUINOSERIAL_BUFFER_SIZE;
        return c;
    }
}

void ArduinoSerial::setTimeout(unsigned long millisecond) {
    find_timeout = millisecond;
}

/* 在超时之前, 如果在串口接收数据缓冲区中找到了定长字符串 str 就返回 true, 如果超时, 返回 false */
bool ArduinoSerial::find(const char *str) {
    bool ret = false;
    String data;
    char c;
    unsigned long i;
    
    for (i = 0; i < find_timeout; i++) {
        while(available() > 0) {
            c = read_char();
            data += c;
        }
        if (data.indexOf(String(str)) != -1) {
            ret = true;
            break;
        }
        delay(1);
    }
    
    return ret;
}

size_t ArduinoSerial::write(uint8_t data) {
    putc(data);
    return 1;
}

void ArduinoSerial::write_char(unsigned char c) {
    int i = (unsigned int)(rx_buffer.head + 1) % ARDUINOSERIAL_BUFFER_SIZE;

    // if we should be storing the received character into the location
    // just before the tail (meaning that the head would advance to the
    // current location of the tail), we're about to overflow the buffer
    // and so we don't write the character or advance the head.
    if (i != rx_buffer.tail) {
        rx_buffer.buffer[rx_buffer.head] = c;
        rx_buffer.head = i;
    }
}