Shell sort implementation with parameters as in the qsort function from stdlib.

The implementation is based on code from the ShellSort article. But the ability to sort any kind of array was added, like in the qsort function. The implementation doesn’t use dynamic memory allocation when swapping items, but uses static allocation with a setting in the STATIC_ALLOC_BUFFER define. That lets to use a sorting algorithm in embedded projects with smaller memory usage than the qsort function from stdlib.

1. qsort
   text data bss dec hex filename
   15656 1656 112 17424 4410 ./prog.exe
2. shell_sort
   text data bss dec hex filename
   15640 1636 112 17388 43ec ./prog.exe

1. before sorting
   text data bss dec hex filename
   1516 12 1572 3100 c1c cipher_suite.elf
2. qsort
   text data bss dec hex filename
   2416 12 1572 4000 fa0 cipher_suite.elf
3. shell_sort (-520 bytes text ref qsort)
   text data bss dec hex filename
   1896 12 1572 3480 d98 cipher_suite.elf

1. before sorting
   text data bss dec hex filename
   1040 12 1572 2624 a40 cipher_suite.elf
2. qsort
   text data bss dec hex filename
   1952 12 1572 3536 dd0 cipher_suite.elf
3. shell_sort (-596 bytes text ref qsort)
   text data bss dec hex filename
   1356 12 1572 2940 b7c cipher_suite.elf

1. ShellSort
2. Sorting (in) embedded systems