-/* Copyright (C) 1999,2000,2001 Free Software Foundation, Inc.
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this software; see the file COPYING. If not, write to
- * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307 USA
- *
- * As a special exception, the Free Software Foundation gives permission
- * for additional uses of the text contained in its release of GUILE.
- *
- * The exception is that, if you link the GUILE library with other files
- * to produce an executable, this does not by itself cause the
- * resulting executable to be covered by the GNU General Public License.
- * Your use of that executable is in no way restricted on account of
- * linking the GUILE library code into it.
- *
- * This exception does not however invalidate any other reasons why
- * the executable file might be covered by the GNU General Public License.
- *
- * This exception applies only to the code released by the
- * Free Software Foundation under the name GUILE. If you copy
- * code from other Free Software Foundation releases into a copy of
- * GUILE, as the General Public License permits, the exception does
- * not apply to the code that you add in this way. To avoid misleading
- * anyone as to the status of such modified files, you must delete
- * this exception notice from them.
- *
- * If you write modifications of your own for GUILE, it is your choice
- * whether to permit this exception to apply to your modifications.
- * If you do not wish that, delete this exception notice. */
-
-
-
-/* Written in December 1998 by Roland Orre <orre@nada.kth.se>
- * This implements the same sort interface as slib/sort.scm
- * for lists and vectors where slib defines:
- * sorted?, merge, merge!, sort, sort!
- * For scsh compatibility sort-list and sort-list! are also defined.
- * In cases where a stable-sort is required use stable-sort or
- * stable-sort!. An additional feature is
- * (restricted-vector-sort! vector less? startpos endpos)
- * which allows you to sort part of a vector.
- * Thanks to Aubrey Jaffer for the slib/sort.scm library.
- * Thanks to Richard A. O'Keefe (based on Prolog code by D.H.D.Warren)
- * for the merge sort inspiration.
- * Thanks to Douglas C. Schmidt (schmidt@ics.uci.edu) for the
- * quicksort code.
- */
-
-/* We need this to get the definitions for HAVE_ALLOCA_H, etc. */
-#include "libguile/scmconfig.h"
-
-/* AIX requires this to be the first thing in the file. The #pragma
- directive is indented so pre-ANSI compilers will ignore it, rather
- than choke on it. */
-#ifndef __GNUC__
-# if HAVE_ALLOCA_H
-# include <alloca.h>
-# else
-# ifdef _AIX
- #pragma alloca
-# else
-# ifndef alloca /* predefined by HP cc +Olibcalls */
-char *alloca ();
-# endif
-# endif
-# endif
-#endif
-
-#include <string.h>
-#include "libguile/_scm.h"
-
-#include "libguile/eval.h"
-#include "libguile/unif.h"
-#include "libguile/ramap.h"
-#include "libguile/alist.h"
-#include "libguile/feature.h"
-#include "libguile/root.h"
-#include "libguile/vectors.h"
-
-#include "libguile/validate.h"
-#include "libguile/sort.h"
-
-/* The routine quicksort was extracted from the GNU C Library qsort.c
- written by Douglas C. Schmidt (schmidt@ics.uci.edu)
- and adapted to guile by adding an extra pointer less
- to quicksort by Roland Orre <orre@nada.kth.se>.
-
- The reason to do this instead of using the library function qsort
- was to avoid dependency of the ANSI-C extensions for local functions
- and also to avoid obscure pool based solutions.
-
- This sorting routine is not much more efficient than the stable
- version but doesn't consume extra memory.
- */
-
-/* Byte-wise swap two items of size SIZE. */
-#define SWAP(a, b, size) \
- do \
- { \
- register size_t __size = (size); \
- register char *__a = (a), *__b = (b); \
- do \
- { \
- char __tmp = *__a; \
- *__a++ = *__b; \
- *__b++ = __tmp; \
- } while (--__size > 0); \
- } while (0)
-
-/* Discontinue quicksort algorithm when partition gets below this size.
- This particular magic number was chosen to work best on a Sun 4/260. */
-#define MAX_THRESH 4
-
-/* Stack node declarations used to store unfulfilled partition obligations. */
-typedef struct
- {
- char *lo;
- char *hi;
- }
-stack_node;
-
-/* The next 4 #defines implement a very fast in-line stack abstraction. */
-#define STACK_SIZE (8 * sizeof(unsigned long int))
-#define PUSH(low, high) ((void) ((top->lo = (low)), (top->hi = (high)), ++top))
-#define POP(low, high) ((void) (--top, (low = top->lo), (high = top->hi)))
-#define STACK_NOT_EMPTY (stack < top)
-
-
-/* Order size using quicksort. This implementation incorporates
- four optimizations discussed in Sedgewick:
-
- 1. Non-recursive, using an explicit stack of pointer that store the
- next array partition to sort. To save time, this maximum amount
- of space required to store an array of MAX_INT is allocated on the
- stack. Assuming a 32-bit integer, this needs only 32 *
- sizeof(stack_node) == 136 bits. Pretty cheap, actually.
-
- 2. Chose the pivot element using a median-of-three decision tree.
- This reduces the probability of selecting a bad pivot value and
- eliminates certain extraneous comparisons.
-
- 3. Only quicksorts TOTAL_ELEMS / MAX_THRESH partitions, leaving
- insertion sort to order the MAX_THRESH items within each partition.
- This is a big win, since insertion sort is faster for small, mostly
- sorted array segments.
-
- 4. The larger of the two sub-partitions is always pushed onto the
- stack first, with the algorithm then concentrating on the
- smaller partition. This *guarantees* no more than log (n)
- stack size is needed (actually O(1) in this case)! */
-
-typedef int (*cmp_fun_t) (SCM less,
- const void*,
- const void*);
-
-static const char s_buggy_less[] = "buggy less predicate used when sorting";
-
-static void
-quicksort (void *const pbase,
- size_t total_elems,
- size_t size,
- cmp_fun_t cmp,
- SCM less)
-{
- register char *base_ptr = (char *) pbase;
-
- /* Allocating SIZE bytes for a pivot buffer facilitates a better
- algorithm below since we can do comparisons directly on the pivot. */
- char *pivot_buffer = (char *) alloca (size);
- const size_t max_thresh = MAX_THRESH * size;
-
- if (total_elems == 0)
- /* Avoid lossage with unsigned arithmetic below. */
- return;
-
- if (total_elems > MAX_THRESH)
- {
- char *lo = base_ptr;
- char *hi = &lo[size * (total_elems - 1)];
- /* Largest size needed for 32-bit int!!! */
- stack_node stack[STACK_SIZE];
- stack_node *top = stack + 1;
-
- while (STACK_NOT_EMPTY)
- {
- char *left_ptr;
- char *right_ptr;
-
- char *pivot = pivot_buffer;
-
- /* Select median value from among LO, MID, and HI. Rearrange
- LO and HI so the three values are sorted. This lowers the
- probability of picking a pathological pivot value and
- skips a comparison for both the LEFT_PTR and RIGHT_PTR. */
-
- char *mid = lo + size * ((hi - lo) / size >> 1);
-
- if ((*cmp) (less, (void *) mid, (void *) lo))
- SWAP (mid, lo, size);
- if ((*cmp) (less, (void *) hi, (void *) mid))
- SWAP (mid, hi, size);
- else
- goto jump_over;
- if ((*cmp) (less, (void *) mid, (void *) lo))
- SWAP (mid, lo, size);
- jump_over:;
- memcpy (pivot, mid, size);
- pivot = pivot_buffer;
-
- left_ptr = lo + size;
- right_ptr = hi - size;
-
- /* Here's the famous ``collapse the walls'' section of quicksort.
- Gotta like those tight inner loops! They are the main reason
- that this algorithm runs much faster than others. */
- do
- {
- while ((*cmp) (less, (void *) left_ptr, (void *) pivot))
- {
- left_ptr += size;
- /* The comparison predicate may be buggy */
- if (left_ptr > hi)
- scm_misc_error (NULL, s_buggy_less, SCM_EOL);
- }
-
- while ((*cmp) (less, (void *) pivot, (void *) right_ptr))
- {
- right_ptr -= size;
- /* The comparison predicate may be buggy */
- if (right_ptr < lo)
- scm_misc_error (NULL, s_buggy_less, SCM_EOL);
- }
-
- if (left_ptr < right_ptr)
- {
- SWAP (left_ptr, right_ptr, size);
- left_ptr += size;
- right_ptr -= size;
- }
- else if (left_ptr == right_ptr)
- {
- left_ptr += size;
- right_ptr -= size;
- break;
- }
- }
- while (left_ptr <= right_ptr);
-
- /* Set up pointers for next iteration. First determine whether
- left and right partitions are below the threshold size. If so,
- ignore one or both. Otherwise, push the larger partition's
- bounds on the stack and continue sorting the smaller one. */
-
- if ((size_t) (right_ptr - lo) <= max_thresh)
- {
- if ((size_t) (hi - left_ptr) <= max_thresh)
- /* Ignore both small partitions. */
- POP (lo, hi);
- else
- /* Ignore small left partition. */
- lo = left_ptr;
- }
- else if ((size_t) (hi - left_ptr) <= max_thresh)
- /* Ignore small right partition. */
- hi = right_ptr;
- else if ((right_ptr - lo) > (hi - left_ptr))
- {
- /* Push larger left partition indices. */
- PUSH (lo, right_ptr);
- lo = left_ptr;
- }
- else
- {
- /* Push larger right partition indices. */
- PUSH (left_ptr, hi);
- hi = right_ptr;
- }
- }
- }
-
- /* Once the BASE_PTR array is partially sorted by quicksort the rest
- is completely sorted using insertion sort, since this is efficient
- for partitions below MAX_THRESH size. BASE_PTR points to the beginning
- of the array to sort, and END_PTR points at the very last element in
- the array (*not* one beyond it!). */
-
- {
- char *const end_ptr = &base_ptr[size * (total_elems - 1)];
- char *tmp_ptr = base_ptr;
- char *thresh = min (end_ptr, base_ptr + max_thresh);
- register char *run_ptr;
-
- /* Find smallest element in first threshold and place it at the
- array's beginning. This is the smallest array element,
- and the operation speeds up insertion sort's inner loop. */
-
- for (run_ptr = tmp_ptr + size; run_ptr <= thresh; run_ptr += size)
- if ((*cmp) (less, (void *) run_ptr, (void *) tmp_ptr))
- tmp_ptr = run_ptr;
-
- if (tmp_ptr != base_ptr)
- SWAP (tmp_ptr, base_ptr, size);
-
- /* Insertion sort, running from left-hand-side up to right-hand-side. */
-
- run_ptr = base_ptr + size;
- while ((run_ptr += size) <= end_ptr)
- {
- tmp_ptr = run_ptr - size;
- while ((*cmp) (less, (void *) run_ptr, (void *) tmp_ptr))
- {
- tmp_ptr -= size;
- /* The comparison predicate may be buggy */
- if (tmp_ptr < base_ptr)
- scm_misc_error (NULL, s_buggy_less, SCM_EOL);
- }
-
- tmp_ptr += size;
- if (tmp_ptr != run_ptr)
- {
- char *trav;
-
- trav = run_ptr + size;
- while (--trav >= run_ptr)
- {
- char c = *trav;
- char *hi, *lo;
-
- for (hi = lo = trav; (lo -= size) >= tmp_ptr; hi = lo)
- *hi = *lo;
- *hi = c;
- }
- }
- }
- }
-} /* quicksort */
-
-
-/* comparison routines */
-
-static int
-subr2less (SCM less, const void *a, const void *b)
-{
- return SCM_NFALSEP (SCM_SUBRF (less) (*(SCM *) a, *(SCM *) b));
-} /* subr2less */
-
-static int
-subr2oless (SCM less, const void *a, const void *b)
-{
- return SCM_NFALSEP (SCM_SUBRF (less) (*(SCM *) a,
- *(SCM *) b,
- SCM_UNDEFINED));
-} /* subr2oless */
-
-static int
-lsubrless (SCM less, const void *a, const void *b)
-{
- return SCM_NFALSEP (SCM_SUBRF (less)
- (scm_cons (*(SCM *) a,
- scm_cons (*(SCM *) b, SCM_EOL))));
-} /* lsubrless */
-
-static int
-closureless (SCM code, const void *a, const void *b)
-{
- SCM env = SCM_EXTEND_ENV (SCM_CLOSURE_FORMALS (code),
- scm_cons (*(SCM *) a,
- scm_cons (*(SCM *) b, SCM_EOL)),
- SCM_ENV (code));
- /* Evaluate the closure body */
- return !SCM_FALSEP (scm_eval_body (SCM_CLOSURE_BODY (code), env));
-} /* closureless */
-
-static int
-applyless (SCM less, const void *a, const void *b)
-{
- return SCM_NFALSEP (scm_call_2 (less, *(SCM *) a, *(SCM *) b));
-} /* applyless */
-
-static cmp_fun_t
-scm_cmp_function (SCM p)
-{
- switch (SCM_TYP7 (p))
- {
- case scm_tc7_subr_2:
- case scm_tc7_rpsubr:
- case scm_tc7_asubr:
- return subr2less;
- case scm_tc7_subr_2o:
- return subr2oless;
- case scm_tc7_lsubr:
- return lsubrless;
- case scm_tcs_closures:
- return closureless;
- default:
- return applyless;
- }
-} /* scm_cmp_function */
-
-
-/* Question: Is there any need to make this a more general array sort?
- It is probably enough to manage the vector type. */
-/* endpos equal as for substring, i.e. endpos is not included. */
-/* More natural with length? */
-
-SCM_DEFINE (scm_restricted_vector_sort_x, "restricted-vector-sort!", 4, 0, 0,
- (SCM vec, SCM less, SCM startpos, SCM endpos),
- "Sort the vector @var{vec}, using @var{less} for comparing\n"
- "the vector elements. @var{startpos} and @var{endpos} delimit\n"
- "the range of the vector which gets sorted. The return value\n"
- "is not specified.")
-#define FUNC_NAME s_scm_restricted_vector_sort_x
-{
- size_t vlen, spos, len, size = sizeof (SCM);
- SCM *vp;
-
- SCM_VALIDATE_VECTOR (1,vec);
- SCM_VALIDATE_NIM (2,less);
-
- vp = SCM_VELTS (vec); /* vector pointer */
- vlen = SCM_VECTOR_LENGTH (vec);
-
- SCM_VALIDATE_INUM_MIN_COPY (3, startpos, 0, spos);
- SCM_ASSERT_RANGE (3,startpos, spos <= vlen);
- SCM_VALIDATE_INUM_RANGE (4,endpos,0,vlen+1);
- len = SCM_INUM (endpos) - spos;
-
- quicksort (&vp[spos], len, size, scm_cmp_function (less), less);
- return SCM_UNSPECIFIED;
- /* return vec; */
-}
-#undef FUNC_NAME
-
-/* (sorted? sequence less?)
- * is true when sequence is a list (x0 x1 ... xm) or a vector #(x0 ... xm)
- * such that for all 1 <= i <= m,
- * (not (less? (list-ref list i) (list-ref list (- i 1)))). */
-SCM_DEFINE (scm_sorted_p, "sorted?", 2, 0, 0,
- (SCM items, SCM less),
- "Return @code{#t} iff @var{items} is a list or a vector such that\n"
- "for all 1 <= i <= m, the predicate @var{less} returns true when\n"
- "applied to all elements i - 1 and i")
-#define FUNC_NAME s_scm_sorted_p
-{
- long len, j; /* list/vector length, temp j */
- SCM item, rest; /* rest of items loop variable */
- SCM *vp;
- cmp_fun_t cmp = scm_cmp_function (less);
-
- if (SCM_NULLP (items))
- return SCM_BOOL_T;
-
- SCM_VALIDATE_NIM (2,less);
-
- if (SCM_CONSP (items))
- {
- len = scm_ilength (items); /* also checks that it's a pure list */
- SCM_ASSERT_RANGE (1,items,len >= 0);
- if (len <= 1)
- return SCM_BOOL_T;
-
- item = SCM_CAR (items);
- rest = SCM_CDR (items);
- j = len - 1;
- while (j > 0)
- {
- if ((*cmp) (less, SCM_CARLOC(rest), &item))
- return SCM_BOOL_F;
- else
- {
- item = SCM_CAR (rest);
- rest = SCM_CDR (rest);
- j--;
- }
- }
- return SCM_BOOL_T;
- }
- else
- {
- SCM_VALIDATE_VECTOR (1, items);
-
- vp = SCM_VELTS (items); /* vector pointer */
- len = SCM_VECTOR_LENGTH (items);
- j = len - 1;
- while (j > 0)
- {
- if ((*cmp) (less, &vp[1], vp))
- return SCM_BOOL_F;
- else
- {
- vp++;
- j--;
- }
- }
- return SCM_BOOL_T;
- }
-
- return SCM_BOOL_F;
-}
-#undef FUNC_NAME
-
-/* (merge a b less?)
- takes two lists a and b such that (sorted? a less?) and (sorted? b less?)
- and returns a new list in which the elements of a and b have been stably
- interleaved so that (sorted? (merge a b less?) less?).
- Note: this does _not_ accept vectors. */
-SCM_DEFINE (scm_merge, "merge", 3, 0, 0,
- (SCM alist, SCM blist, SCM less),
- "Merge two already sorted lists into one.\n"
- "Given two lists @var{alist} and @var{blist}, such that\n"
- "@code{(sorted? alist less?)} and @code{(sorted? blist less?)},\n"
- "return a new list in which the elements of @var{alist} and\n"
- "@var{blist} have been stably interleaved so that\n"
- "@code{(sorted? (merge alist blist less?) less?)}.\n"
- "Note: this does _not_ accept vectors.")
-#define FUNC_NAME s_scm_merge
-{
- long alen, blen; /* list lengths */
- SCM build, last;
- cmp_fun_t cmp = scm_cmp_function (less);
- SCM_VALIDATE_NIM (3,less);
-
- if (SCM_NULLP (alist))
- return blist;
- else if (SCM_NULLP (blist))
- return alist;
- else
- {
- SCM_VALIDATE_NONEMPTYLIST_COPYLEN (1,alist,alen);
- SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2,blist,blen);
- if ((*cmp) (less, SCM_CARLOC (blist), SCM_CARLOC (alist)))
- {
- build = scm_cons (SCM_CAR (blist), SCM_EOL);
- blist = SCM_CDR (blist);
- blen--;
- }
- else
- {
- build = scm_cons (SCM_CAR (alist), SCM_EOL);
- alist = SCM_CDR (alist);
- alen--;
- }
- last = build;
- while ((alen > 0) && (blen > 0))
- {
- if ((*cmp) (less, SCM_CARLOC (blist), SCM_CARLOC (alist)))
- {
- SCM_SETCDR (last, scm_cons (SCM_CAR (blist), SCM_EOL));
- blist = SCM_CDR (blist);
- blen--;
- }
- else
- {
- SCM_SETCDR (last, scm_cons (SCM_CAR (alist), SCM_EOL));
- alist = SCM_CDR (alist);
- alen--;
- }
- last = SCM_CDR (last);
- }
- if ((alen > 0) && (blen == 0))
- SCM_SETCDR (last, alist);
- else if ((alen == 0) && (blen > 0))
- SCM_SETCDR (last, blist);
- }
- return build;
-}
-#undef FUNC_NAME
-
-
-static SCM
-scm_merge_list_x (SCM alist, SCM blist,
- long alen, long blen,
- cmp_fun_t cmp, SCM less)
-{
- SCM build, last;
-
- if (SCM_NULLP (alist))
- return blist;
- else if (SCM_NULLP (blist))
- return alist;
- else
- {
- if ((*cmp) (less, SCM_CARLOC (blist), SCM_CARLOC (alist)))
- {
- build = blist;
- blist = SCM_CDR (blist);
- blen--;
- }
- else
- {
- build = alist;
- alist = SCM_CDR (alist);
- alen--;
- }
- last = build;
- while ((alen > 0) && (blen > 0))
- {
- if ((*cmp) (less, SCM_CARLOC (blist), SCM_CARLOC (alist)))
- {
- SCM_SETCDR (last, blist);
- blist = SCM_CDR (blist);
- blen--;
- }
- else
- {
- SCM_SETCDR (last, alist);
- alist = SCM_CDR (alist);
- alen--;
- }
- last = SCM_CDR (last);
- }
- if ((alen > 0) && (blen == 0))
- SCM_SETCDR (last, alist);
- else if ((alen == 0) && (blen > 0))
- SCM_SETCDR (last, blist);
- }
- return build;
-} /* scm_merge_list_x */
-
-SCM_DEFINE (scm_merge_x, "merge!", 3, 0, 0,
- (SCM alist, SCM blist, SCM less),
- "Takes two lists @var{alist} and @var{blist} such that\n"
- "@code{(sorted? alist less?)} and @code{(sorted? blist less?)} and\n"
- "returns a new list in which the elements of @var{alist} and\n"
- "@var{blist} have been stably interleaved so that\n"
- " @code{(sorted? (merge alist blist less?) less?)}.\n"
- "This is the destructive variant of @code{merge}\n"
- "Note: this does _not_ accept vectors.")
-#define FUNC_NAME s_scm_merge_x
-{
- long alen, blen; /* list lengths */
-
- SCM_VALIDATE_NIM (3,less);
- if (SCM_NULLP (alist))
- return blist;
- else if (SCM_NULLP (blist))
- return alist;
- else
- {
- SCM_VALIDATE_NONEMPTYLIST_COPYLEN (1,alist,alen);
- SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2,blist,blen);
- return scm_merge_list_x (alist, blist,
- alen, blen,
- scm_cmp_function (less),
- less);
- }
-}
-#undef FUNC_NAME
-
-/* This merge sort algorithm is same as slib's by Richard A. O'Keefe.
- The algorithm is stable. We also tried to use the algorithm used by
- scsh's merge-sort but that algorithm showed to not be stable, even
- though it claimed to be.
-*/
-static SCM
-scm_merge_list_step (SCM * seq,
- cmp_fun_t cmp,
- SCM less,
- long n)
-{
- SCM a, b;
-
- if (n > 2)
- {
- long mid = n / 2;
- a = scm_merge_list_step (seq, cmp, less, mid);
- b = scm_merge_list_step (seq, cmp, less, n - mid);
- return scm_merge_list_x (a, b, mid, n - mid, cmp, less);
- }
- else if (n == 2)
- {
- SCM p = *seq;
- SCM rest = SCM_CDR (*seq);
- SCM x = SCM_CAR (*seq);
- SCM y = SCM_CAR (SCM_CDR (*seq));
- *seq = SCM_CDR (rest);
- SCM_SETCDR (rest, SCM_EOL);
- if ((*cmp) (less, &y, &x))
- {
- SCM_SETCAR (p, y);
- SCM_SETCAR (rest, x);
- }
- return p;
- }
- else if (n == 1)
- {
- SCM p = *seq;
- *seq = SCM_CDR (p);
- SCM_SETCDR (p, SCM_EOL);
- return p;
- }
- else
- return SCM_EOL;
-} /* scm_merge_list_step */
-
-
-/* scm_sort_x manages lists and vectors, not stable sort */
-SCM_DEFINE (scm_sort_x, "sort!", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the sequence @var{items}, which may be a list or a\n"
- "vector. @var{less} is used for comparing the sequence\n"
- "elements. The sorting is destructive, that means that the\n"
- "input sequence is modified to produce the sorted result.\n"
- "This is not a stable sort.")
-#define FUNC_NAME s_scm_sort_x
-{
- long len; /* list/vector length */
- if (SCM_NULLP(items))
- return SCM_EOL;
-
- SCM_VALIDATE_NIM (2,less);
-
- if (SCM_CONSP (items))
- {
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
- }
- else if (SCM_VECTORP (items))
- {
- len = SCM_VECTOR_LENGTH (items);
- scm_restricted_vector_sort_x (items,
- less,
- SCM_MAKINUM (0L),
- SCM_MAKINUM (len));
- return items;
- }
- else
- SCM_WRONG_TYPE_ARG (1, items);
-}
-#undef FUNC_NAME
-
-/* scm_sort manages lists and vectors, not stable sort */
-
-SCM_DEFINE (scm_sort, "sort", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the sequence @var{items}, which may be a list or a\n"
- "vector. @var{less} is used for comparing the sequence\n"
- "elements. This is not a stable sort.")
-#define FUNC_NAME s_scm_sort
-{
- if (SCM_NULLP(items))
- return SCM_EOL;
-
- SCM_VALIDATE_NIM (2,less);
- if (SCM_CONSP (items))
- {
- long len;
-
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- items = scm_list_copy (items);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
- }
-#ifdef HAVE_ARRAYS
- /* support ordinary vectors even if arrays not available? */
- else if (SCM_VECTORP (items))
- {
- long len = SCM_VECTOR_LENGTH (items);
- SCM sortvec = scm_make_uve (len, scm_array_prototype (items));
-
- scm_array_copy_x (items, sortvec);
- scm_restricted_vector_sort_x (sortvec,
- less,
- SCM_MAKINUM (0L),
- SCM_MAKINUM (len));
- return sortvec;
- }
-#endif
- else
- SCM_WRONG_TYPE_ARG (1, items);
-}
-#undef FUNC_NAME
-
-static void
-scm_merge_vector_x (void *const vecbase,
- void *const tempbase,
- cmp_fun_t cmp,
- SCM less,
- long low,
- long mid,
- long high)
-{
- register SCM *vp = (SCM *) vecbase;
- register SCM *temp = (SCM *) tempbase;
- long it; /* Index for temp vector */
- long i1 = low; /* Index for lower vector segment */
- long i2 = mid + 1; /* Index for upper vector segment */
-
- /* Copy while both segments contain more characters */
- for (it = low; (i1 <= mid) && (i2 <= high); ++it)
- if ((*cmp) (less, &vp[i2], &vp[i1]))
- temp[it] = vp[i2++];
- else
- temp[it] = vp[i1++];
-
- /* Copy while first segment contains more characters */
- while (i1 <= mid)
- temp[it++] = vp[i1++];
-
- /* Copy while second segment contains more characters */
- while (i2 <= high)
- temp[it++] = vp[i2++];
-
- /* Copy back from temp to vp */
- for (it = low; it <= high; ++it)
- vp[it] = temp[it];
-} /* scm_merge_vector_x */
-
-static void
-scm_merge_vector_step (void *const vp,
- void *const temp,
- cmp_fun_t cmp,
- SCM less,
- long low,
- long high)
-{
- if (high > low)
- {
- long mid = (low + high) / 2;
- scm_merge_vector_step (vp, temp, cmp, less, low, mid);
- scm_merge_vector_step (vp, temp, cmp, less, mid+1, high);
- scm_merge_vector_x (vp, temp, cmp, less, low, mid, high);
- }
-} /* scm_merge_vector_step */
-
-
-/* stable-sort! manages lists and vectors */
-
-SCM_DEFINE (scm_stable_sort_x, "stable-sort!", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the sequence @var{items}, which may be a list or a\n"
- "vector. @var{less} is used for comparing the sequence elements.\n"
- "The sorting is destructive, that means that the input sequence\n"
- "is modified to produce the sorted result.\n"
- "This is a stable sort.")
-#define FUNC_NAME s_scm_stable_sort_x
-{
- long len; /* list/vector length */
-
- if (SCM_NULLP (items))
- return SCM_EOL;
-
- SCM_VALIDATE_NIM (2,less);
- if (SCM_CONSP (items))
- {
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
- }
- else if (SCM_VECTORP (items))
- {
- SCM *temp, *vp;
- len = SCM_VECTOR_LENGTH (items);
- temp = malloc (len * sizeof(SCM));
- vp = SCM_VELTS (items);
- scm_merge_vector_step (vp,
- temp,
- scm_cmp_function (less),
- less,
- 0,
- len - 1);
- free(temp);
- return items;
- }
- else
- SCM_WRONG_TYPE_ARG (1, items);
-}
-#undef FUNC_NAME
-
-/* stable_sort manages lists and vectors */
-
-SCM_DEFINE (scm_stable_sort, "stable-sort", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the sequence @var{items}, which may be a list or a\n"
- "vector. @var{less} is used for comparing the sequence elements.\n"
- "This is a stable sort.")
-#define FUNC_NAME s_scm_stable_sort
-{
- long len; /* list/vector length */
- if (SCM_NULLP (items))
- return SCM_EOL;
-
- SCM_VALIDATE_NIM (2,less);
- if (SCM_CONSP (items))
- {
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- items = scm_list_copy (items);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
- }
-#ifdef HAVE_ARRAYS
- /* support ordinary vectors even if arrays not available? */
- else if (SCM_VECTORP (items))
- {
- SCM retvec;
- SCM *temp, *vp;
- len = SCM_VECTOR_LENGTH (items);
- retvec = scm_make_uve (len, scm_array_prototype (items));
- scm_array_copy_x (items, retvec);
- temp = malloc (len * sizeof (SCM));
- vp = SCM_VELTS (retvec);
- scm_merge_vector_step (vp,
- temp,
- scm_cmp_function (less),
- less,
- 0,
- len - 1);
- free (temp);
- return retvec;
- }
-#endif
- else
- SCM_WRONG_TYPE_ARG (1, items);
-}
-#undef FUNC_NAME
-
-/* stable */
-SCM_DEFINE (scm_sort_list_x, "sort-list!", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the list @var{items}, using @var{less} for comparing the\n"
- "list elements. The sorting is destructive, that means that the\n"
- "input list is modified to produce the sorted result.\n"
- "This is a stable sort.")
-#define FUNC_NAME s_scm_sort_list_x
-{
- long len;
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- SCM_VALIDATE_NIM (2,less);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
-}
-#undef FUNC_NAME
-
-/* stable */
-SCM_DEFINE (scm_sort_list, "sort-list", 2, 0, 0,
- (SCM items, SCM less),
- "Sort the list @var{items}, using @var{less} for comparing the\n"
- "list elements. This is a stable sort.")
-#define FUNC_NAME s_scm_sort_list
-{
- long len;
- SCM_VALIDATE_LIST_COPYLEN (1,items,len);
- SCM_VALIDATE_NIM (2,less);
- items = scm_list_copy (items);
- return scm_merge_list_step (&items, scm_cmp_function (less), less, len);
-}
-#undef FUNC_NAME
-
-void
-scm_init_sort ()
-{
-#ifndef SCM_MAGIC_SNARFER
-#include "libguile/sort.x"
-#endif
-
- scm_add_feature ("sort");
-}
-
-/*
- Local Variables:
- c-file-style: "gnu"
- End:
-*/
+/* Copyright (C) 1999, 2000, 2001, 2002, 2004, 2006, 2007, 2008, 2009,
+ * 2010, 2011, 2012, 2014 Free Software Foundation, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+
+
+/* Written in December 1998 by Roland Orre <orre@nada.kth.se>
+ * This implements the same sort interface as slib/sort.scm
+ * for lists and vectors where slib defines:
+ * sorted?, merge, merge!, sort, sort!
+ * For scsh compatibility sort-list and sort-list! are also defined.
+ * In cases where a stable-sort is required use stable-sort or
+ * stable-sort!. An additional feature is
+ * (restricted-vector-sort! vector less? startpos endpos)
+ * which allows you to sort part of a vector.
+ * Thanks to Aubrey Jaffer for the slib/sort.scm library.
+ * Thanks to Richard A. O'Keefe (based on Prolog code by D.H.D.Warren)
+ * for the merge sort inspiration.
+ * Thanks to Douglas C. Schmidt (schmidt@ics.uci.edu) for the
+ * quicksort code.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/_scm.h"
+#include "libguile/eval.h"
+#include "libguile/arrays.h"
+#include "libguile/array-map.h"
+#include "libguile/feature.h"
+#include "libguile/vectors.h"
+#include "libguile/async.h"
+#include "libguile/dynwind.h"
+
+#include "libguile/validate.h"
+#include "libguile/sort.h"
+
+/* We have two quicksort variants: one for contigous vectors and one
+ for vectors with arbitrary increments between elements. Note that
+ increments can be negative.
+*/
+
+#define NAME quicksort1
+#define INC_PARAM /* empty */
+#define INC 1
+#include "libguile/quicksort.i.c"
+
+#define NAME quicksort
+#define INC_PARAM ssize_t inc,
+#define INC inc
+#include "libguile/quicksort.i.c"
+
+
+SCM_DEFINE (scm_restricted_vector_sort_x, "restricted-vector-sort!", 4, 0, 0,
+ (SCM vec, SCM less, SCM startpos, SCM endpos),
+ "Sort the vector @var{vec}, using @var{less} for comparing\n"
+ "the vector elements. @var{startpos} (inclusively) and\n"
+ "@var{endpos} (exclusively) delimit\n"
+ "the range of the vector which gets sorted. The return value\n"
+ "is not specified.")
+#define FUNC_NAME s_scm_restricted_vector_sort_x
+{
+ size_t vlen, spos, len;
+ ssize_t vinc;
+ scm_t_array_handle handle;
+ SCM *velts;
+
+ velts = scm_vector_writable_elements (vec, &handle, &vlen, &vinc);
+ spos = scm_to_unsigned_integer (startpos, 0, vlen);
+ len = scm_to_unsigned_integer (endpos, spos, vlen) - spos;
+
+ if (vinc == 1)
+ quicksort1 (velts + spos*vinc, len, less);
+ else
+ quicksort (velts + spos*vinc, len, vinc, less);
+
+ scm_array_handle_release (&handle);
+
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+
+/* (sorted? sequence less?)
+ * is true when sequence is a list (x0 x1 ... xm) or a vector #(x0 ... xm)
+ * such that for all 1 <= i <= m,
+ * (not (less? (list-ref list i) (list-ref list (- i 1)))). */
+SCM_DEFINE (scm_sorted_p, "sorted?", 2, 0, 0,
+ (SCM items, SCM less),
+ "Return @code{#t} iff @var{items} is a list or vector such that, "
+ "for each element @var{x} and the next element @var{y} of "
+ "@var{items}, @code{(@var{less} @var{y} @var{x})} returns "
+ "@code{#f}.")
+#define FUNC_NAME s_scm_sorted_p
+{
+ long len, j; /* list/vector length, temp j */
+ SCM item, rest; /* rest of items loop variable */
+
+ if (SCM_NULL_OR_NIL_P (items))
+ return SCM_BOOL_T;
+
+ if (scm_is_pair (items))
+ {
+ len = scm_ilength (items); /* also checks that it's a pure list */
+ SCM_ASSERT_RANGE (1, items, len >= 0);
+ if (len <= 1)
+ return SCM_BOOL_T;
+
+ item = SCM_CAR (items);
+ rest = SCM_CDR (items);
+ j = len - 1;
+ while (j > 0)
+ {
+ if (scm_is_true (scm_call_2 (less, SCM_CAR (rest), item)))
+ return SCM_BOOL_F;
+ else
+ {
+ item = SCM_CAR (rest);
+ rest = SCM_CDR (rest);
+ j--;
+ }
+ }
+ return SCM_BOOL_T;
+ }
+ else
+ {
+ scm_t_array_handle handle;
+ size_t i, len;
+ ssize_t inc;
+ const SCM *elts;
+ SCM result = SCM_BOOL_T;
+
+ elts = scm_vector_elements (items, &handle, &len, &inc);
+
+ for (i = 1; i < len; i++, elts += inc)
+ {
+ if (scm_is_true (scm_call_2 (less, elts[inc], elts[0])))
+ {
+ result = SCM_BOOL_F;
+ break;
+ }
+ }
+
+ scm_array_handle_release (&handle);
+
+ return result;
+ }
+
+ return SCM_BOOL_F;
+}
+#undef FUNC_NAME
+
+
+/* (merge a b less?)
+ takes two lists a and b such that (sorted? a less?) and (sorted? b less?)
+ and returns a new list in which the elements of a and b have been stably
+ interleaved so that (sorted? (merge a b less?) less?).
+ Note: this does _not_ accept vectors. */
+SCM_DEFINE (scm_merge, "merge", 3, 0, 0,
+ (SCM alist, SCM blist, SCM less),
+ "Merge two already sorted lists into one.\n"
+ "Given two lists @var{alist} and @var{blist}, such that\n"
+ "@code{(sorted? alist less?)} and @code{(sorted? blist less?)},\n"
+ "return a new list in which the elements of @var{alist} and\n"
+ "@var{blist} have been stably interleaved so that\n"
+ "@code{(sorted? (merge alist blist less?) less?)}.\n"
+ "Note: this does _not_ accept vectors.")
+#define FUNC_NAME s_scm_merge
+{
+ SCM build;
+
+ if (SCM_NULL_OR_NIL_P (alist))
+ return blist;
+ else if (SCM_NULL_OR_NIL_P (blist))
+ return alist;
+ else
+ {
+ long alen, blen; /* list lengths */
+ SCM last;
+
+ SCM_VALIDATE_NONEMPTYLIST_COPYLEN (1, alist, alen);
+ SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2, blist, blen);
+ if (scm_is_true (scm_call_2 (less, SCM_CAR (blist), SCM_CAR (alist))))
+ {
+ build = scm_cons (SCM_CAR (blist), SCM_EOL);
+ blist = SCM_CDR (blist);
+ blen--;
+ }
+ else
+ {
+ build = scm_cons (SCM_CAR (alist), SCM_EOL);
+ alist = SCM_CDR (alist);
+ alen--;
+ }
+ last = build;
+ while ((alen > 0) && (blen > 0))
+ {
+ SCM_TICK;
+ if (scm_is_true (scm_call_2 (less, SCM_CAR (blist), SCM_CAR (alist))))
+ {
+ SCM_SETCDR (last, scm_cons (SCM_CAR (blist), SCM_EOL));
+ blist = SCM_CDR (blist);
+ blen--;
+ }
+ else
+ {
+ SCM_SETCDR (last, scm_cons (SCM_CAR (alist), SCM_EOL));
+ alist = SCM_CDR (alist);
+ alen--;
+ }
+ last = SCM_CDR (last);
+ }
+ if ((alen > 0) && (blen == 0))
+ SCM_SETCDR (last, alist);
+ else if ((alen == 0) && (blen > 0))
+ SCM_SETCDR (last, blist);
+ }
+ return build;
+}
+#undef FUNC_NAME
+
+
+static SCM
+scm_merge_list_x (SCM alist, SCM blist,
+ long alen, long blen,
+ SCM less)
+{
+ SCM build, last;
+
+ if (SCM_NULL_OR_NIL_P (alist))
+ return blist;
+ else if (SCM_NULL_OR_NIL_P (blist))
+ return alist;
+ else
+ {
+ if (scm_is_true (scm_call_2 (less, SCM_CAR (blist), SCM_CAR (alist))))
+ {
+ build = blist;
+ blist = SCM_CDR (blist);
+ blen--;
+ }
+ else
+ {
+ build = alist;
+ alist = SCM_CDR (alist);
+ alen--;
+ }
+ last = build;
+ while ((alen > 0) && (blen > 0))
+ {
+ SCM_TICK;
+ if (scm_is_true (scm_call_2 (less, SCM_CAR (blist), SCM_CAR (alist))))
+ {
+ SCM_SETCDR (last, blist);
+ blist = SCM_CDR (blist);
+ blen--;
+ }
+ else
+ {
+ SCM_SETCDR (last, alist);
+ alist = SCM_CDR (alist);
+ alen--;
+ }
+ last = SCM_CDR (last);
+ }
+ if ((alen > 0) && (blen == 0))
+ SCM_SETCDR (last, alist);
+ else if ((alen == 0) && (blen > 0))
+ SCM_SETCDR (last, blist);
+ }
+ return build;
+} /* scm_merge_list_x */
+
+
+SCM_DEFINE (scm_merge_x, "merge!", 3, 0, 0,
+ (SCM alist, SCM blist, SCM less),
+ "Takes two lists @var{alist} and @var{blist} such that\n"
+ "@code{(sorted? alist less?)} and @code{(sorted? blist less?)} and\n"
+ "returns a new list in which the elements of @var{alist} and\n"
+ "@var{blist} have been stably interleaved so that\n"
+ " @code{(sorted? (merge alist blist less?) less?)}.\n"
+ "This is the destructive variant of @code{merge}\n"
+ "Note: this does _not_ accept vectors.")
+#define FUNC_NAME s_scm_merge_x
+{
+ if (SCM_NULL_OR_NIL_P (alist))
+ return blist;
+ else if (SCM_NULL_OR_NIL_P (blist))
+ return alist;
+ else
+ {
+ long alen, blen; /* list lengths */
+ SCM_VALIDATE_NONEMPTYLIST_COPYLEN (1, alist, alen);
+ SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2, blist, blen);
+ return scm_merge_list_x (alist, blist, alen, blen, less);
+ }
+}
+#undef FUNC_NAME
+
+
+/* This merge sort algorithm is same as slib's by Richard A. O'Keefe.
+ The algorithm is stable. We also tried to use the algorithm used by
+ scsh's merge-sort but that algorithm showed to not be stable, even
+ though it claimed to be.
+*/
+static SCM
+scm_merge_list_step (SCM * seq, SCM less, long n)
+{
+ SCM a, b;
+
+ if (n > 2)
+ {
+ long mid = n / 2;
+ SCM_TICK;
+ a = scm_merge_list_step (seq, less, mid);
+ b = scm_merge_list_step (seq, less, n - mid);
+ return scm_merge_list_x (a, b, mid, n - mid, less);
+ }
+ else if (n == 2)
+ {
+ SCM p = *seq;
+ SCM rest = SCM_CDR (*seq);
+ SCM x = SCM_CAR (*seq);
+ SCM y = SCM_CAR (SCM_CDR (*seq));
+ *seq = SCM_CDR (rest);
+ SCM_SETCDR (rest, SCM_EOL);
+ if (scm_is_true (scm_call_2 (less, y, x)))
+ {
+ SCM_SETCAR (p, y);
+ SCM_SETCAR (rest, x);
+ }
+ return p;
+ }
+ else if (n == 1)
+ {
+ SCM p = *seq;
+ *seq = SCM_CDR (p);
+ SCM_SETCDR (p, SCM_EOL);
+ return p;
+ }
+ else
+ return SCM_EOL;
+} /* scm_merge_list_step */
+
+
+SCM_DEFINE (scm_sort_x, "sort!", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the sequence @var{items}, which may be a list or a\n"
+ "vector. @var{less} is used for comparing the sequence\n"
+ "elements. The sorting is destructive, that means that the\n"
+ "input sequence is modified to produce the sorted result.\n"
+ "This is not a stable sort.")
+#define FUNC_NAME s_scm_sort_x
+{
+ long len; /* list/vector length */
+ if (SCM_NULL_OR_NIL_P (items))
+ return items;
+
+ if (scm_is_pair (items))
+ {
+ SCM_VALIDATE_LIST_COPYLEN (1, items, len);
+ return scm_merge_list_step (&items, less, len);
+ }
+ else if (scm_is_array (items) && scm_c_array_rank (items) == 1)
+ {
+ scm_restricted_vector_sort_x (items,
+ less,
+ scm_from_int (0),
+ scm_array_length (items));
+ return items;
+ }
+ else
+ SCM_WRONG_TYPE_ARG (1, items);
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_sort, "sort", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the sequence @var{items}, which may be a list or a\n"
+ "vector. @var{less} is used for comparing the sequence\n"
+ "elements. This is not a stable sort.")
+#define FUNC_NAME s_scm_sort
+{
+ if (SCM_NULL_OR_NIL_P (items))
+ return items;
+
+ if (scm_is_pair (items))
+ return scm_sort_x (scm_list_copy (items), less);
+ else if (scm_is_array (items) && scm_c_array_rank (items) == 1)
+ return scm_sort_x (scm_vector_copy (items), less);
+ else
+ SCM_WRONG_TYPE_ARG (1, items);
+}
+#undef FUNC_NAME
+
+
+static void
+scm_merge_vector_x (SCM *vec,
+ SCM *temp,
+ SCM less,
+ size_t low,
+ size_t mid,
+ size_t high,
+ ssize_t inc)
+{
+ size_t it; /* Index for temp vector */
+ size_t i1 = low; /* Index for lower vector segment */
+ size_t i2 = mid + 1; /* Index for upper vector segment */
+
+#define VEC(i) vec[(i)*inc]
+
+ /* Copy while both segments contain more characters */
+ for (it = low; (i1 <= mid) && (i2 <= high); ++it)
+ {
+ if (scm_is_true (scm_call_2 (less, VEC(i2), VEC(i1))))
+ temp[it] = VEC(i2++);
+ else
+ temp[it] = VEC(i1++);
+ }
+
+ {
+ /* Copy while first segment contains more characters */
+ while (i1 <= mid)
+ temp[it++] = VEC(i1++);
+
+ /* Copy while second segment contains more characters */
+ while (i2 <= high)
+ temp[it++] = VEC(i2++);
+
+ /* Copy back from temp to vp */
+ for (it = low; it <= high; it++)
+ VEC(it) = temp[it];
+ }
+} /* scm_merge_vector_x */
+
+
+static void
+scm_merge_vector_step (SCM *vec,
+ SCM *temp,
+ SCM less,
+ size_t low,
+ size_t high,
+ ssize_t inc)
+{
+ if (high > low)
+ {
+ size_t mid = (low + high) / 2;
+ SCM_TICK;
+ scm_merge_vector_step (vec, temp, less, low, mid, inc);
+ scm_merge_vector_step (vec, temp, less, mid+1, high, inc);
+ scm_merge_vector_x (vec, temp, less, low, mid, high, inc);
+ }
+} /* scm_merge_vector_step */
+
+
+SCM_DEFINE (scm_stable_sort_x, "stable-sort!", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the sequence @var{items}, which may be a list or a\n"
+ "vector. @var{less} is used for comparing the sequence elements.\n"
+ "The sorting is destructive, that means that the input sequence\n"
+ "is modified to produce the sorted result.\n"
+ "This is a stable sort.")
+#define FUNC_NAME s_scm_stable_sort_x
+{
+ long len; /* list/vector length */
+
+ if (SCM_NULL_OR_NIL_P (items))
+ return items;
+
+ if (scm_is_pair (items))
+ {
+ SCM_VALIDATE_LIST_COPYLEN (1, items, len);
+ return scm_merge_list_step (&items, less, len);
+ }
+ else if (scm_is_array (items) && 1 == scm_c_array_rank (items))
+ {
+ scm_t_array_handle temp_handle, vec_handle;
+ SCM temp, *temp_elts, *vec_elts;
+ size_t len;
+ ssize_t inc;
+
+ vec_elts = scm_vector_writable_elements (items, &vec_handle,
+ &len, &inc);
+ if (len == 0) {
+ scm_array_handle_release (&vec_handle);
+ return items;
+ }
+
+ temp = scm_c_make_vector (len, SCM_UNDEFINED);
+ temp_elts = scm_vector_writable_elements (temp, &temp_handle,
+ NULL, NULL);
+
+ scm_merge_vector_step (vec_elts, temp_elts, less, 0, len-1, inc);
+
+ scm_array_handle_release (&temp_handle);
+ scm_array_handle_release (&vec_handle);
+
+ return items;
+ }
+ else
+ SCM_WRONG_TYPE_ARG (1, items);
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_stable_sort, "stable-sort", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the sequence @var{items}, which may be a list or a\n"
+ "vector. @var{less} is used for comparing the sequence elements.\n"
+ "This is a stable sort.")
+#define FUNC_NAME s_scm_stable_sort
+{
+ if (SCM_NULL_OR_NIL_P (items))
+ return SCM_EOL;
+
+ if (scm_is_pair (items))
+ return scm_stable_sort_x (scm_list_copy (items), less);
+ else
+ return scm_stable_sort_x (scm_vector_copy (items), less);
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_sort_list_x, "sort-list!", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the list @var{items}, using @var{less} for comparing the\n"
+ "list elements. The sorting is destructive, that means that the\n"
+ "input list is modified to produce the sorted result.\n"
+ "This is a stable sort.")
+#define FUNC_NAME s_scm_sort_list_x
+{
+ long len;
+
+ SCM_VALIDATE_LIST_COPYLEN (1, items, len);
+ return scm_merge_list_step (&items, less, len);
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_sort_list, "sort-list", 2, 0, 0,
+ (SCM items, SCM less),
+ "Sort the list @var{items}, using @var{less} for comparing the\n"
+ "list elements. This is a stable sort.")
+#define FUNC_NAME s_scm_sort_list
+{
+ long len;
+
+ SCM_VALIDATE_LIST_COPYLEN (1, items, len);
+ items = scm_list_copy (items);
+ return scm_merge_list_step (&items, less, len);
+}
+#undef FUNC_NAME
+
+
+void
+scm_init_sort ()
+{
+#include "libguile/sort.x"
+
+ scm_add_feature ("sort");
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
HCoop / bpt / guile.git / blobdiff