Date.c

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/*
 * Objectively: Ultra-lightweight object oriented framework for GNU C.
 * Copyright (C) 2014 Jay Dolan <jay@jaydolan.com>
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 *
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 *
 * 3. This notice may not be removed or altered from any source distribution.
 */
 
#include <assert.h>
 
#include "Date.h"
#include "Hash.h"
 
#define _Class _Date
 
#pragma mark - Object
 
static int hash(const Object *self) {
 
  Date *this = (Date *) self;
 
  int hash = HASH_SEED;
 
  hash = HashForInteger(hash, this->time.tv_sec);
  hash = HashForInteger(hash, this->time.tv_usec);
 
  return hash;
}
 
static bool isEqual(const Object *self, const Object *other) {
 
  if (super(Object, self, isEqual, other)) {
    return true;
  }
 
  if (other && $(other, isKindOfClass, _Date())) {
 
    const Date *this = (Date *) self;
    const Date *that = (Date *) other;
 
    return $(this, compareTo, that) == OrderSame;
  }
 
  return false;
}
 
#pragma mark - Date
 
static Order compareTo(const Date *self, const Date *other) {
 
  if (other) {
    const long seconds = self->time.tv_sec - other->time.tv_sec;
    if (seconds == 0) {
 
      const long microseconds = self->time.tv_usec - other->time.tv_usec;
      if (microseconds == 0) {
        return OrderSame;
      }
 
      return microseconds < 0 ? OrderAscending : OrderDescending;
    }
 
    return seconds < 0 ? OrderAscending : OrderDescending;
  }
 
  return OrderAscending;
}
 
static Date *date(void) {
 
  return $$(Date, dateWithTimeSinceNow, NULL);
}
 
static Date *dateWithTimeSinceNow(const Time *interval) {
 
  Date *date = $(alloc(Date), init);
  if (date) {
    if (interval) {
      date->time.tv_sec += interval->tv_sec;
      date->time.tv_usec += interval->tv_usec;
      if (date->time.tv_usec >= USEC_PER_SEC) {
        date->time.tv_sec++;
        date->time.tv_usec -= USEC_PER_SEC;
      } else if (date->time.tv_usec < 0) {
        date->time.tv_sec--;
        date->time.tv_usec += USEC_PER_SEC;
      }
    }
  }
 
  return date;
}
 
static Date *init(Date *self) {
  return $(self, initWithTime, NULL);
}
 
static Date *initWithTime(Date *self, const Time *time) {
 
  self = (Date *) super(Object, self, init);
  if (self) {
    if (time) {
      self->time = *time;
    } else {
      gettimeofday(&self->time, NULL);
    }
  }
 
  return self;
}
 
static Time timeSinceDate(const Date *self, const Date *date) {
 
  assert(date);
 
  return $(self, timeSinceTime, &date->time);
}
 
static Time timeSinceNow(const Date *self) {
 
  Date *date = $$(Date, date);
 
  Time time = $(self, timeSinceDate, date);
 
  release(date);
 
  return time;
}
 
static Time timeSinceTime(const Date *self, const Time *time) {
 
  Time delta = {
    .tv_sec = self->time.tv_sec - time->tv_sec,
    .tv_usec = self->time.tv_usec - time->tv_usec
  };
 
  if (delta.tv_usec < 0) {
    delta.tv_sec--;
    delta.tv_usec += USEC_PER_SEC;
  }
 
  return delta;
}
 
#pragma mark - Class lifecycle
 
static void initialize(Class *clazz) {
 
  ((ObjectInterface *) clazz->interface)->hash = hash;
  ((ObjectInterface *) clazz->interface)->isEqual = isEqual;
 
  ((DateInterface *) clazz->interface)->compareTo = compareTo;
  ((DateInterface *) clazz->interface)->date = date;
  ((DateInterface *) clazz->interface)->dateWithTimeSinceNow = dateWithTimeSinceNow;
  ((DateInterface *) clazz->interface)->init = init;
  ((DateInterface *) clazz->interface)->initWithTime = initWithTime;
  ((DateInterface *) clazz->interface)->timeSinceDate = timeSinceDate;
  ((DateInterface *) clazz->interface)->timeSinceNow = timeSinceNow;
  ((DateInterface *) clazz->interface)->timeSinceTime = timeSinceTime;
}
 
Class *_Date(void) {
  static Class *clazz;
  static Once once;
 
  do_once(&once, {
    clazz = _initialize(&(const ClassDef) {
      .name = "Date",
      .superclass = _Object(),
      .instanceSize = sizeof(Date),
      .interfaceOffset = offsetof(Date, interface),
      .interfaceSize = sizeof(DateInterface),
      .initialize = initialize,
    });
  });
 
  return clazz;
}
 
#undef _Class