diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/nnn.c | 21 | ||||
| -rw-r--r-- | src/qsort.h | 186 |
2 files changed, 204 insertions, 3 deletions
@@ -116,6 +116,10 @@ #include "icons.h" #endif +#ifdef TOURBIN_QSORT +#include "qsort.h" +#endif + /* Macro definitions */ #define VERSION "3.4" #define GENERAL_INFO "BSD 2-Clause\nhttps://github.com/jarun/nnn" @@ -732,6 +736,14 @@ static haiku_nm_h haiku_hnd; #define xisdigit(c) ((unsigned int) (c) - '0' <= 9) #define xerror() perror(xitoa(__LINE__)) +#ifdef TOURBIN_QSORT +#define ENTLESS(i,j) (entrycmpfn(pdents + (i), pdents + (j)) < 0) +#define ENTSWAP(i,j) (swap_ent((i),(j))) +#define ENTSORT(pdents, ndents, entrycmpfn) QSORT((ndents), ENTLESS, ENTSWAP) +#else +#define ENTSORT(pdents, ndents, entrycmpfn) qsort((pdents), (ndents), sizeof(*(pdents)), (entrycmpfn)) +#endif + #ifdef __GNUC__ #define UNUSED(x) UNUSED_##x __attribute__((__unused__)) #else @@ -2513,6 +2525,9 @@ static int handle_alt_key(wint_t *wch) */ static int nextsel(int presel) { +#ifdef BENCH + return SEL_QUIT; +#endif int c = presel; uint i; @@ -2710,7 +2725,7 @@ static int matches(const char *fltr) regfree(&re); #endif - qsort(pdents, ndents, sizeof(*pdents), entrycmpfn); + ENTSORT(pdents, ndents, entrycmpfn); return ndents; } @@ -5122,7 +5137,7 @@ static void populate(char *path, char *lastname) if (!ndents) return; - qsort(pdents, ndents, sizeof(*pdents), entrycmpfn); + ENTSORT(pdents, ndents, entrycmpfn); #ifdef DBGMODE clock_gettime(CLOCK_REALTIME, &ts2); @@ -6317,7 +6332,7 @@ nochange: if (r == 'd' || r == 'a') goto begin; - qsort(pdents, ndents, sizeof(*pdents), entrycmpfn); + ENTSORT(pdents, ndents, entrycmpfn); move_cursor(ndents ? dentfind(lastname, ndents) : 0, 0); } continue; diff --git a/src/qsort.h b/src/qsort.h new file mode 100644 index 0000000..f177e95 --- /dev/null +++ b/src/qsort.h @@ -0,0 +1,186 @@ +/* + * Copyright (c) 2013, 2017 Alexey Tourbin + * + * 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. + */ + +/* + * This is a traditional Quicksort implementation which mostly follows + * [Sedgewick 1978]. Sorting is performed entirely on array indices, + * while actual access to the array elements is abstracted out with the + * user-defined `LESS` and `SWAP` primitives. + * + * Synopsis: + * QSORT(N, LESS, SWAP); + * where + * N - the number of elements in A[]; + * LESS(i, j) - compares A[i] to A[j]; + * SWAP(i, j) - exchanges A[i] with A[j]. + */ + +#ifndef QSORT_H +#define QSORT_H + +/* Sort 3 elements. */ +#define Q_SORT3(q_a1, q_a2, q_a3, Q_LESS, Q_SWAP) \ +do { \ + if (Q_LESS(q_a2, q_a1)) { \ + if (Q_LESS(q_a3, q_a2)) \ + Q_SWAP(q_a1, q_a3); \ + else { \ + Q_SWAP(q_a1, q_a2); \ + if (Q_LESS(q_a3, q_a2)) \ + Q_SWAP(q_a2, q_a3); \ + } \ + } \ + else if (Q_LESS(q_a3, q_a2)) { \ + Q_SWAP(q_a2, q_a3); \ + if (Q_LESS(q_a2, q_a1)) \ + Q_SWAP(q_a1, q_a2); \ + } \ +} while (0) + +/* Partition [q_l,q_r] around a pivot. After partitioning, + * [q_l,q_j] are the elements that are less than or equal to the pivot, + * while [q_i,q_r] are the elements greater than or equal to the pivot. */ +#define Q_PARTITION(q_l, q_r, q_i, q_j, Q_UINT, Q_LESS, Q_SWAP) \ +do { \ + /* The middle element, not to be confused with the median. */ \ + Q_UINT q_m = (q_l) + (((q_r) - (q_l)) >> 1); \ + /* Reorder the second, the middle, and the last items. \ + * As [Edelkamp Weiss 2016] explain, using the second element \ + * instead of the first one helps avoid bad behaviour for \ + * decreasingly sorted arrays. This method is used in recent \ + * versions of gcc's std::sort, see gcc bug 58437#c13, although \ + * the details are somewhat different (cf. #c14). */ \ + Q_SORT3((q_l) + 1, q_m, q_r, Q_LESS, Q_SWAP); \ + /* Place the median at the beginning. */ \ + Q_SWAP(q_l, q_m); \ + /* Partition [q_l+2, q_r-1] around the median which is in q_l. \ + * q_i and q_j are initially off by one, they get decremented \ + * in the do-while loops. */ \ + (q_i) = (q_l) + 1; (q_j) = q_r; \ + while (1) { \ + do (q_i)++; while (Q_LESS(q_i, q_l)); \ + do (q_j)--; while (Q_LESS(q_l, q_j)); \ + if ((q_i) >= (q_j)) break; /* Sedgewick says "until j < i" */ \ + Q_SWAP(q_i, q_j); \ + } \ + /* Compensate for the i==j case. */ \ + (q_i) = (q_j) + 1; \ + /* Put the median to its final place. */ \ + Q_SWAP(q_l, q_j); \ + /* The median is not part of the left subfile. */ \ + (q_j)--; \ +} while (0) + +/* Insertion sort is applied to small subfiles - this is contrary to + * Sedgewick's suggestion to run a separate insertion sort pass after + * the partitioning is done. The reason I don't like a separate pass + * is that it triggers extra comparisons, because it can't see that the + * medians are already in their final positions and need not be rechecked. + * Since I do not assume that comparisons are cheap, I also do not try + * to eliminate the (q_j > q_l) boundary check. */ +#define Q_INSERTION_SORT(q_l, q_r, Q_UINT, Q_LESS, Q_SWAP) \ +do { \ + Q_UINT q_i, q_j; \ + /* For each item starting with the second... */ \ + for (q_i = (q_l) + 1; q_i <= (q_r); q_i++) \ + /* move it down the array so that the first part is sorted. */ \ + for (q_j = q_i; q_j > (q_l) && (Q_LESS(q_j, q_j - 1)); q_j--) \ + Q_SWAP(q_j, q_j - 1); \ +} while (0) + +/* When the size of [q_l,q_r], i.e. q_r-q_l+1, is greater than or equal to + * Q_THRESH, the algorithm performs recursive partitioning. When the size + * drops below Q_THRESH, the algorithm switches to insertion sort. + * The minimum valid value is probably 5 (with 5 items, the second and + * the middle items, the middle itself being rounded down, are distinct). */ +#define Q_THRESH 16 + +/* The main loop. */ +#define Q_LOOP(Q_UINT, Q_N, Q_LESS, Q_SWAP) \ +do { \ + Q_UINT q_l = 0; \ + Q_UINT q_r = (Q_N) - 1; \ + Q_UINT q_sp = 0; /* the number of frames pushed to the stack */ \ + struct { Q_UINT q_l, q_r; } \ + /* On 32-bit platforms, to sort a "char[3GB+]" array, \ + * it may take full 32 stack frames. On 64-bit CPUs, \ + * though, the address space is limited to 48 bits. \ + * The usage is further reduced if Q_N has a 32-bit type. */ \ + q_st[sizeof(Q_UINT) > 4 && sizeof(Q_N) > 4 ? 48 : 32]; \ + while (1) { \ + if (q_r - q_l + 1 >= Q_THRESH) { \ + Q_UINT q_i, q_j; \ + Q_PARTITION(q_l, q_r, q_i, q_j, Q_UINT, Q_LESS, Q_SWAP); \ + /* Now have two subfiles: [q_l,q_j] and [q_i,q_r]. \ + * Dealing with them depends on which one is bigger. */ \ + if (q_j - q_l >= q_r - q_i) \ + Q_SUBFILES(q_l, q_j, q_i, q_r); \ + else \ + Q_SUBFILES(q_i, q_r, q_l, q_j); \ + } \ + else { \ + Q_INSERTION_SORT(q_l, q_r, Q_UINT, Q_LESS, Q_SWAP); \ + /* Pop subfiles from the stack, until it gets empty. */ \ + if (q_sp == 0) break; \ + q_sp--; \ + q_l = q_st[q_sp].q_l; \ + q_r = q_st[q_sp].q_r; \ + } \ + } \ +} while (0) + +/* The missing part: dealing with subfiles. + * Assumes that the first subfile is not smaller than the second. */ +#define Q_SUBFILES(q_l1, q_r1, q_l2, q_r2) \ +do { \ + /* If the second subfile is only a single element, it needs \ + * no further processing. The first subfile will be processed \ + * on the next iteration (both subfiles cannot be only a single \ + * element, due to Q_THRESH). */ \ + if ((q_l2) == (q_r2)) { \ + q_l = q_l1; \ + q_r = q_r1; \ + } \ + else { \ + /* Otherwise, both subfiles need processing. \ + * Push the larger subfile onto the stack. */ \ + q_st[q_sp].q_l = q_l1; \ + q_st[q_sp].q_r = q_r1; \ + q_sp++; \ + /* Process the smaller subfile on the next iteration. */ \ + q_l = q_l2; \ + q_r = q_r2; \ + } \ +} while (0) + +/* And now, ladies and gentlemen, may I proudly present to you... */ +#define QSORT(Q_N, Q_LESS, Q_SWAP) \ +do { \ + if ((Q_N) > 1) \ + /* We could check sizeof(Q_N) and use "unsigned", but at least \ + * on x86_64, this has the performance penalty of up to 5%. */ \ + Q_LOOP(unsigned long, Q_N, Q_LESS, Q_SWAP); \ +} while (0) + +#endif + +/* ex:set ts=8 sts=4 sw=4 noet: */ |