/*
 * Copyright (c) 2017 Richard Braun.
 *
 * 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 <stdarg.h>
#include <stdint.h>
#include <stdio.h>

#include "cpu.h"
#include "thread.h"
#include "uart.h"

#define PRINTF_BUFFER_SIZE 1024

/*
 * This implementation uses a global buffer in order to avoid allocating
 * from the stack, since stacks may be very small.
 */
static char printf_buffer[PRINTF_BUFFER_SIZE];

void
putchar(unsigned char c)
{
    uart_write(c);
}

int
getchar(void)
{
    uint8_t byte;
    int error;

    error = uart_read(&byte);
    return error ? EOF : byte;
}

int
printf(const char *format, ...)
{
    va_list ap;
    int length;

    va_start(ap, format);
    length = vprintf(format, ap);
    va_end(ap);

    return length;
}

int
vprintf(const char *format, va_list ap)
{
    uint32_t eflags;
    int length;

    thread_preempt_disable();
    eflags = cpu_intr_save();

    length = vsnprintf(printf_buffer, sizeof(printf_buffer), format, ap);

    for (const char *ptr = printf_buffer; *ptr != '\0'; ptr++) {
        uart_write((uint8_t)*ptr);
    }

    cpu_intr_restore(eflags);
    thread_preempt_enable();

    return length;
}