File content as of revision 0:f71232252dcf:

/**
 * =============================================================================
 * LS-Y201 device driver class (Version 0.0.1)
 * Reference documents: LinkSprite JPEG Color Camera Serial UART Interface
 *                      January 2010
 * =============================================================================
 * Copyright (c) 2010 Shinichiro Nakamura (CuBeatSystems)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * =============================================================================
 */

#include "mbed.h"
#include "SerialBuffered.h"

/**
 * Create a buffered serial class.
 *
 * @param tx A pin for transmit.
 * @param rx A pin for receive.
 */
SerialBuffered::SerialBuffered(PinName tx, PinName rx) : Serial(tx, rx) {
    indexContentStart = 0;
    indexContentEnd = 0;
    timeout = 1;
    attach(this, &SerialBuffered::handleInterrupt);
}

/**
 * Destroy.
 */
SerialBuffered::~SerialBuffered() {
}

/**
 * Set timeout for getc().
 *
 * @param ms milliseconds. (-1:Disable timeout)
 */
void SerialBuffered::setTimeout(int ms) {
    timeout = ms;
}

/**
 * Read requested bytes.
 *
 * @param bytes A pointer to a buffer.
 * @param requested Length.
 *
 * @return Readed byte length.
 */
size_t SerialBuffered::readBytes(uint8_t *bytes, size_t requested) {
    int i = 0;
    while (i < requested) {
        int c = getc();
        if (c < 0) {
            break;
        }
        bytes[i] = c;
        i++;
    }
    return i;
}

/**
 * Get a character.
 *
 * @return A character. (-1:timeout)
 */
int SerialBuffered::getc() {
    timer.reset();
    timer.start();
    while (indexContentStart == indexContentEnd) {
        wait_ms(1);
        if ((timeout > 0) && (timer.read_ms() > timeout)) {
            /*
             * Timeout occured.
             */
            // printf("Timeout occured.\n");
            return EOF;
        }
    }
    timer.stop();

    uint8_t result = buffer[indexContentStart++];
    indexContentStart =  indexContentStart % BUFFERSIZE;

    return result;
}

/**
 * Returns 1 if there is a character available to read, 0 otherwise.
 */
int SerialBuffered::readable() {
    return indexContentStart != indexContentEnd;
}

void SerialBuffered::handleInterrupt() {
    while (Serial::readable()) {
        if (indexContentStart == ((indexContentEnd + 1) % BUFFERSIZE)) {
            /*
             * Buffer overrun occured.
             */
            // printf("Buffer overrun occured.\n");
            Serial::getc();
        } else {
            buffer[indexContentEnd++] = Serial::getc();
            indexContentEnd = indexContentEnd % BUFFERSIZE;
        }
    }
}