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sort.h

Overview

sort.h is an implementation a ton of sorting algorithms in C with a user-defined type, that is defined at include time.

This means you don't have to pay the function call overhead of using standard library routine.

You get the choice of many extra sorting routines as well, including:

  • Shell sort
  • Binary insertion sort
  • Heap sort
  • Quick sort
  • Merge sort
  • Bubble sort (ugh)
  • Tim sort

If you don't know which one to use, you should probably use Tim sort.

Usage

To use this library, you need to do three things:

  • #define SORT_TYPE to be the type of the elements of the array you want to sort.
  • #define SORT_NAME to be a unique name that will be prepended to all the routines, i.e., #define SORT_NAME mine would give you routines named mine_heap_sort, and so forth.
  • #include "sort.h". Make sure that sort.h is in your include path, obviously.

Then, enjoy using the sorting routines.

See demo.c for example usage.

If you are going to use your own custom type, you must redefine SORT_CMP(x, y) with your comparison function, so that it returns a value less than zero if x < y, equal to zero if x == y, and greater than 0 if x > y.

The default just uses the builtin <, ==, and > operators:

#define SORT_CMP(x, y) ((x) < (y) ? -1 : ((x) == (y) ? 0 : 1))

It is often just fine to just subtract the arguments as well (though this can cause some stability problems with floating-point types):

#define SORT_CMP(x, y) ((x) - (y))

Speed of routines

The speed of each routine is highly dependent on your computer and the structure of your data.

If your data has a lot of, like partially sorted sequences, then Tim sort will beat the pants off of anything else.

In general, Tim sort is probably the best sorting algorithm in this library, even for random data.

Tim sort is not as good if memory movement is many orders of magnitude more expensive than comparisons (like, many more than for normal int and double). If so, then quick sort is probably your routine. On the other hand, Tim sort does extremely well if the comparison operator is very expensive, since it strives hard to minimize comparisons.

Here is the output of demo.c, which will give you the timings for a run of 10,000 things on my old Mac Pro (2006-era 2.66 GHz Xeons, 64-bit) on OS X 10.6:

Running tests
quick sort time: 740.20 us per iteration
bubble sort time: 183914.60 us per iteration
merge sort time: 954.20 us per iteration
binary insertion sort time: 20472.70 us per iteration
heap sort time: 994.50 us per iteration
shell sort time: 1170.30 us per iteration
tim sort time: 708.50 us per iteration

Author

Christopher Swenson (chris@caswenson.com)

References

  • Wikipedia
  • timsort.txt (under doc/)

License

All code in this repository, unless otherwise specified, is hereby licensed under the MIT Public License:

Copyright (c) 2010 Christopher Swenson.

Copyright (c) 2012 Google Inc. All Rights Reserved.

Copyright (c) 2012 Vojtech Fried.

In-place mergesort is:

Copyright (c) 2012, Andrey Astrelin, astrelin@tochka.ru

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.

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