mlog.c

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/*
 * mlog.c
 *
 * Part of librfn (a general utility library from redfelineninja.org.uk)
 *
 * Copyright (C) 2015 Daniel Thompson <daniel@redfelineninja.org.uk> 
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 */

#include "librfn/mlog.h"

#include <stdint.h>

#include "librfn/string.h"
#include "librfn/util.h"

struct mlog_line {
        const char *fmt;
        uintptr_t arg[3];
};

struct mlog {
        struct mlog_line line[256];
        unsigned int head;
};

static struct mlog log;

void vmlog(const char *fmt, va_list ap)
{
        unsigned int head = log.head % lengthof(log.line);
        
        log.line[head].fmt = fmt;
        log.line[head].arg[0] = va_arg(ap, uintptr_t);
        log.line[head].arg[1] = va_arg(ap, uintptr_t);
        log.line[head].arg[2] = va_arg(ap, uintptr_t);

        log.head++;
        if (log.head >= 0x7fffffff)
                log.head -= lengthof(log.line);
}

void mlog(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        vmlog(fmt, ap);
        va_end(ap);
}

void vmlog_nice(const char *fmt, va_list ap)
{
        if (log.head < lengthof(log.line))
                vmlog(fmt, ap);
}

void mlog_nice(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        vmlog_nice(fmt, ap);
        va_end(ap);
}

void mlog_clear(void)
{
        log.head = 0;
}

static struct mlog_line *get_line(unsigned int n)
{
        if (n >= log.head || n >= lengthof(log.line))
                return NULL;

        /* if the buffer has wrapped adjust n by the wrap point */
        if (log.head >= lengthof(log.line))
                n += log.head;

        return &log.line[n % lengthof(log.line)];
}

void mlog_dump(FILE *f)
{
        struct mlog_line *line;

        for (int i=0; (line = get_line(i)); i++)
                fprintf(f, line->fmt, line->arg[0], line->arg[1], line->arg[2]);
}

char *mlog_get_line(int n)
{
        struct mlog_line *line = get_line(n);

        if (line)
                return strdup_printf(line->fmt, line->arg[0], line->arg[1],
                                     line->arg[2]);

        return NULL;
}