NMEPluginCalendar.c

Go to the documentation of this file.

/* License: new BSD license (see NME.h) */

#include "NMEPluginCalendar.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

NMEErr NMEPluginCalendar(NMEConstText name, NMEInt nameLen,
        NMEConstText data, NMEInt dataLen,
        NMEContext *context,
        void *userData)
{
    char *endp;
    int year, month;
    int weekday;    // weekday of first day of month (0=monday)
    int m1, y1; // temp. values used to compute weekday
    int d, dmax;
    char str[16];
    static int const nd[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    (void)name;
    (void)nameLen;
    (void)userData;
    
    // read year and month in data
    year = strtol(data, &endp, 0);
    month = strtol(endp, NULL, 0);
    if (year < 0)
        year = 0;
    if (month < 1 || month > 12)
        month = 1;
    
    // find week day of 1st day of month
    m1 = (month - 14) / 12;
    y1 = year + 4800;
    weekday = (1461 * (y1 + m1) / 4 + 367 * (month - 2 - 12 * m1) / 12
                - 3 * ((y1 + m1 + 100) / 100) / 4 - 32074) % 7;
    // write calendar to dest: "\n|=Mon|=Tue...\n|||1|2|..."
    if (!NMEAddString("\n|=Mon|=Tue|=Wed|=Thu|=Fri|=Sat|=Sun\n", -1,
            '\0', context))
        return kNMEErrNotEnoughMemory;
    dmax = nd[month - 1];
    if (month == 2 && (year % 4 == 0 && year % 100 != 0 || year % 400 == 0))
        dmax = 29;
    for (d = 0; d < weekday; d++)
        if (!NMEAddString("|", 1, '\0', context))
            return kNMEErrNotEnoughMemory;
    for (d = 1; d <= dmax; d++)
    {
        sprintf(str, "|%d", d);
        if (!NMEAddString(str, -1, '\0', context))
            return kNMEErrNotEnoughMemory;
        if ((d + weekday) % 7 == 0)
            if (!NMEAddString("\n", 1, '\0', context))
                return kNMEErrNotEnoughMemory;
    }
    if (!NMEAddString("\n\n", 2, '\0', context))
        return kNMEErrNotEnoughMemory;
    
    return kNMEErrOk;
}