Re: PHP - I give up.

From: Ben Pfaff (blp_at_cs.stanford.edu)
Date: 03/03/04 

Date: Wed, 03 Mar 2004 11:34:56 -0800

Richard Heathfield <dontmail@address.co.uk.invalid> writes:

> Having said that, I have to admit that the STL is cool. :-)

Incidentally, lately I've started using some code in my C
programs which is inspired by the STL. Although it isn't as
flexible as the STL, I still find it to be useful fairly often.
Here's the current header file, presented for feedback.

#ifndef ALGORITHM_H
#define ALGORITHM_H 1

#include <stddef.h>

/* Compares A and B, given auxiliary data AUX, and returns a
   strcmp()-type result. */
typedef int algo_compare_func (const void *a, const void *b, void *aux);

/* Tests a predicate on DATA, given auxiliary data AUX, and
   returns nonzero if true or zero if false. */
typedef int algo_predicate_func (const void *data, void *aux);

/* Returns a random number in the range 0 through MAX exclusive,
   given auxiliary data AUX. */
typedef unsigned algo_random_func (unsigned max, void *aux);

/* A generally suitable random function. */
algo_random_func algo_default_random;

/* Finds an element in ARRAY, which contains COUNT elements of
   SIZE bytes each, using COMPARE for comparisons. Returns the
   first element in ARRAY that matches TARGET, or a null pointer
   on failure. AUX is passed to each comparison as auxiliary
   data. */
void *find (const void *array, size_t count, size_t size,
            const void *target,
            algo_compare_func *compare, void *aux);

/* Counts and return the number of elements in ARRAY, which
   contains COUNT elements of SIZE bytes each, which are equal to
   ELEMENT as compared with COMPARE. AUX is passed as auxiliary
   data to COMPARE. */
size_t count_equal (const void *array, size_t count, size_t size,
                    const void *element,
                    algo_compare_func *compare, void *aux);

/* Counts and return the number of elements in ARRAY, which
   contains COUNT elements of SIZE bytes each, for which
   PREDICATE returns nonzero. AUX is passed as auxiliary data to
   PREDICATE. */
size_t count_if (const void *array, size_t count, size_t size,
                 algo_predicate_func *predicate, void *aux);

/* Sorts ARRAY, which contains COUNT elements of SIZE bytes each,
   using COMPARE for comparisons. AUX is passed to each
   comparison as auxiliary data. */
void sort (void *array, size_t count, size_t size,
           algo_compare_func *compare, void *aux);

/* Tests whether ARRAY, which contains COUNT elements of SIZE
   bytes each, is sorted in order according to COMPARE. AUX is
   passed to COMPARE as auxiliary data. */
int is_sorted (const void *array, size_t count, size_t size,
               algo_compare_func *compare, void *aux);

/* Makes the elements in ARRAY unique, by moving up duplicates,
   and returns the new number of elements in the array. Sorted
   arrays only. Arguments same as for sort() above. */
size_t unique (void *array, size_t count, size_t size,
               algo_compare_func *compare, void *aux);

/* Helper function that calls sort(), then unique(). */
size_t sort_unique (void *array, size_t count, size_t size,
                    algo_compare_func *compare, void *aux);

/* Reorders ARRAY, which contains COUNT elements of SIZE bytes
   each, so that the elements for which PREDICATE returns nonzero
   precede those for which PREDICATE returns zero. AUX is passed
   as auxiliary data to PREDICATE. Returns the number of
   elements for which PREDICATE returns nonzero. Not stable. */
size_t partition (void *array, size_t count, size_t size,
                  algo_predicate_func *predicate, void *aux);

/* Checks whether ARRAY, which contains COUNT elements of SIZE
   bytes each, is partitioned such that PREDICATE returns nonzero
   for the first NONZERO_CNT elements and zero for the remaining
   elements. AUX is passed as auxiliary data to PREDICATE. */
int is_partitioned (const void *array, size_t count, size_t size,
                    size_t nonzero_cnt,
                    algo_predicate_func *predicate, void *aux);

/* Randomly reorders ARRAY, which contains COUNT elements of SIZE
   bytes each. Uses RANDOM as a source of random data, passing
   AUX as the auxiliary data. RANDOM may be null to use a
   default random source. */
void random_shuffle (void *array, size_t count, size_t size,
                     algo_random_func *random, void *aux);

/* Copies the COUNT elements of SIZE bytes each from ARRAY to
   RESULT, except that elements for which PREDICATE is false are
   not copied. Returns the number of elements copied. AUX is
   passed to PREDICATE as auxiliary data. */
size_t copy_if (const void *array, size_t count, size_t size,
                void *result,
                algo_predicate_func *predicate, void *aux);

/* Removes elements equal to ELEMENT from ARRAY, which consists
   of COUNT elements of SIZE bytes each. Returns the number of
   remaining elements. AUX is passed to COMPARE as auxiliary
   data. */
size_t remove_equal (void *array, size_t count, size_t size,
                     void *element,
                     algo_compare_func *compare, void *aux);

/* Copies the COUNT elements of SIZE bytes each from ARRAY to
   RESULT, except that elements for which PREDICATE is true are
   not copied. Returns the number of elements copied. AUX is
   passed to PREDICATE as auxiliary data. */
size_t remove_copy_if (const void *array, size_t count, size_t size,
                       void *result,
                       algo_predicate_func *predicate, void *aux);

/* Searches ARRAY, which contains COUNT elements of SIZE bytes
   each, for VALUE, using a binary search. ARRAY must ordered
   according to COMPARE. AUX is passed to COMPARE as auxiliary
   data. */
void *binary_search (const void *array, size_t count, size_t size,
                     void *value,
                     algo_compare_func *compare, void *aux);

/* Lexicographically compares ARRAY1, which contains COUNT1
   elements of SIZE bytes each, to ARRAY2, which contains COUNT2
   elements of SIZE bytes, according to COMPARE. Returns a
   strcmp()-type result. AUX is passed to COMPARE as auxiliary
   data. */
int lexicographical_compare_3way (const void *array1, size_t count1,
                                  const void *array2, size_t count2,
                                  size_t size,
                                  algo_compare_func *compare, void *aux);

/* Computes the generalized set difference, ARRAY1 minus ARRAY2,
   into RESULT, and returns the number of elements written to
   RESULT. If a value appears M times in ARRAY1 and N times in
   ARRAY2, then it will appear max(M - N, 0) in RESULT. ARRAY1
   and ARRAY2 must be sorted, and RESULT is sorted and stable.
   ARRAY1 consists of COUNT1 elements, ARRAY2 of COUNT2 elements,
   each SIZE bytes. AUX is passed to COMPARE as auxiliary
   data. */
size_t set_difference (const void *array1, size_t count1,
                       const void *array2, size_t count2,
                       size_t size,
                       void *result,
                       algo_compare_func *compare, void *aux);

/* Finds the first pair of adjacent equal elements in ARRAY,
   which has COUNT elements of SIZE bytes. Returns the first
   element in ARRAY such that COMPARE returns zero when it and
   its successor element are compared. AUX is passed to COMPARE
   as auxiliary data. */
void *adjacent_find_equal (const void *array, size_t count, size_t size,
                           algo_compare_func *compare, void *aux);

/* ARRAY contains COUNT elements of SIZE bytes each. Initially
   the first COUNT - 1 elements of these form a heap, followed by
   a single element not part of the heap. This function adds the
   final element, forming a heap of COUNT elements in ARRAY.
   Uses COMPARE to compare elements, passing AUX as auxiliary
   data. */
void push_heap (void *array, size_t count, size_t size,
                algo_compare_func *compare, void *aux);

/* ARRAY contains COUNT elements of SIZE bytes each. Initially
   all COUNT elements form a heap. This function moves the
   largest element in the heap to the final position in ARRAY and
   reforms a heap of the remaining COUNT - 1 elements at the
   beginning of ARRAY. Uses COMPARE to compare elements, passing
   AUX as auxiliary data. */
void pop_heap (void *array, size_t count, size_t size,
               algo_compare_func *compare, void *aux);

/* Turns ARRAY, which contains COUNT elements of SIZE bytes, into
   a heap. Uses COMPARE to compare elements, passing AUX as
   auxiliary data. */
void make_heap (void *array, size_t count, size_t size,
                algo_compare_func *compare, void *aux);

/* ARRAY contains COUNT elements of SIZE bytes each. Initially
   all COUNT elements form a heap. This function turns the heap
   into a fully sorted array. Uses COMPARE to compare elements,
   passing AUX as auxiliary data. */
void sort_heap (void *array, size_t count, size_t size,
                algo_compare_func *compare, void *aux);

/* ARRAY contains COUNT elements of SIZE bytes each. This
   function tests whether ARRAY is a heap and returns 1 if so, 0
   otherwise. Uses COMPARE to compare elements, passing AUX as
   auxiliary data. */
int is_heap (const void *array, size_t count, size_t size,
             algo_compare_func *compare, void *aux);

#endif /* algorithm.h */ 

-- 
"I didn't say it was your fault.
 I said I was going to blame it on you."

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