diff --git a/src/hb-algs.hh b/src/hb-algs.hh index 39bb2f1ac..07abffbcf 100644 --- a/src/hb-algs.hh +++ b/src/hb-algs.hh @@ -653,115 +653,213 @@ hb_bsearch (const void *key, const void *base, /* From https://github.com/noporpoise/sort_r - * With following modifications: - * - * 10 November 2018: - * https://github.com/noporpoise/sort_r/issues/7 - */ + Feb 5, 2019 (c8c65c1e) + Modified to support optional argument using templates */ /* Isaac Turner 29 April 2014 Public Domain */ /* - -hb_sort_r function to be exported. - +hb_qsort function to be exported. Parameters: base is the array to be sorted nel is the number of elements in the array width is the size in bytes of each element of the array compar is the comparison function - arg is a pointer to be passed to the comparison function + arg (optional) is a pointer to be passed to the comparison function -void hb_sort_r(void *base, size_t nel, size_t width, - int (*compar)(const void *_a, const void *_b, void *_arg), - void *arg); +void hb_sort(void *base, size_t nel, size_t width, + int (*compar)(const void *_a, const void *_b, [void *_arg]), + [void *arg]); */ +#define SORT_R_SWAP(a,b,tmp) ((tmp) = (a), (a) = (b), (b) = (tmp)) + +/* swap a and b */ +/* a and b must not be equal! */ +static inline void sort_r_swap(char *__restrict a, char *__restrict b, + size_t w) +{ + char tmp, *end = a+w; + for(; a < end; a++, b++) { SORT_R_SWAP(*a, *b, tmp); } +} /* swap a, b iff a>b */ +/* a and b must not be equal! */ /* __restrict is same as restrict but better support on old machines */ -static int sort_r_cmpswap(char *__restrict a, char *__restrict b, size_t w, - int (*compar)(const void *_a, const void *_b, - void *_arg), - void *arg) +template +static inline int sort_r_cmpswap(char *__restrict a, + char *__restrict b, size_t w, + int (*compar)(const void *_a, + const void *_b, + Ts... _ds), + Ts... ds) { - char tmp, *end = a+w; - if(compar(a, b, arg) > 0) { - for(; a < end; a++, b++) { tmp = *a; *a = *b; *b = tmp; } + if(compar(a, b, ds...) > 0) { + sort_r_swap(a, b, w); return 1; } return 0; } +/* +Swap consecutive blocks of bytes of size na and nb starting at memory addr ptr, +with the smallest swap so that the blocks are in the opposite order. Blocks may +be internally re-ordered e.g. + 12345ab -> ab34512 + 123abc -> abc123 + 12abcde -> deabc12 +*/ +static inline void sort_r_swap_blocks(char *ptr, size_t na, size_t nb) +{ + if(na > 0 && nb > 0) { + if(na > nb) { sort_r_swap(ptr, ptr+na, nb); } + else { sort_r_swap(ptr, ptr+nb, na); } + } +} + +/* Implement recursive quicksort ourselves */ /* Note: quicksort is not stable, equivalent values may be swapped */ +template static inline void sort_r_simple(void *base, size_t nel, size_t w, - int (*compar)(const void *_a, const void *_b, - void *_arg), - void *arg) + int (*compar)(const void *_a, + const void *_b, + Ts... _ds), + Ts... ds) { char *b = (char *)base, *end = b + nel*w; - if(nel < 7) { + + /* for(size_t i=0; i b && sort_r_cmpswap(pj-w,pj,w,compar,arg); pj -= w) {} + for(pj = pi; pj > b && sort_r_cmpswap(pj-w,pj,w,compar,ds...); pj -= w) {} } } else { - /* nel > 6; Quicksort */ + /* nel > 9; Quicksort */ - /* Use median of first, middle and last items as pivot */ - char *x, *y, *xend, ch; - char *pl, *pm, *pr; + int cmp; + char *pl, *ple, *pr, *pre, *pivot; char *last = b+w*(nel-1), *tmp; + + /* + Use median of second, middle and second-last items as pivot. + First and last may have been swapped with pivot and therefore be extreme + */ char *l[3]; - l[0] = b; + l[0] = b + w; l[1] = b+w*(nel/2); - l[2] = last; + l[2] = last - w; - if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } - if(compar(l[1],l[2],arg) > 0) { - tmp=l[1]; l[1]=l[2]; l[2]=tmp; /* swap(l[1],l[2]) */ - if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } - } + /* printf("pivots: %i, %i, %i\n", *(int*)l[0], *(int*)l[1], *(int*)l[2]); */ - /* swap l[id], l[2] to put pivot as last element */ - for(x = l[1], y = last, xend = x+w; x 0) { SORT_R_SWAP(l[0], l[1], tmp); } + if(compar(l[1],l[2],ds...) > 0) { + SORT_R_SWAP(l[1], l[2], tmp); + if(compar(l[0],l[1],ds...) > 0) { SORT_R_SWAP(l[0], l[1], tmp); } } - pl = b; - pr = last; - + /* swap mid value (l[1]), and last element to put pivot as last element */ + if(l[1] != last) { sort_r_swap(l[1], last, w); } + + /* + pl is the next item on the left to be compared to the pivot + pr is the last item on the right that was compared to the pivot + ple is the left position to put the next item that equals the pivot + ple is the last right position where we put an item that equals the pivot + v- end (beyond the array) + EEEEEELLLLLLLLuuuuuuuuGGGGGGGEEEEEEEE. + ^- b ^- ple ^- pl ^- pr ^- pre ^- last (where the pivot is) + Pivot comparison key: + E = equal, L = less than, u = unknown, G = greater than, E = equal + */ + pivot = last; + ple = pl = b; + pre = pr = last; + + /* + Strategy: + Loop into the list from the left and right at the same time to find: + - an item on the left that is greater than the pivot + - an item on the right that is less than the pivot + Once found, they are swapped and the loop continues. + Meanwhile items that are equal to the pivot are moved to the edges of the + array. + */ while(pl < pr) { - pm = pl+((pr-pl+1)>>1); - for(; pl < pm; pl += w) { - if(sort_r_cmpswap(pl, pr, w, compar, arg)) { - pr -= w; /* pivot now at pl */ - break; + /* Move left hand items which are equal to the pivot to the far left. + break when we find an item that is greater than the pivot */ + for(; pl < pr; pl += w) { + cmp = compar(pl, pivot, ds...); + if(cmp > 0) { break; } + else if(cmp == 0) { + if(ple < pl) { sort_r_swap(ple, pl, w); } + ple += w; } } - pm = pl+((pr-pl)>>1); - for(; pm < pr; pr -= w) { - if(sort_r_cmpswap(pl, pr, w, compar, arg)) { - pl += w; /* pivot now at pr */ + /* break if last batch of left hand items were equal to pivot */ + if(pl >= pr) { break; } + /* Move right hand items which are equal to the pivot to the far right. + break when we find an item that is less than the pivot */ + for(; pl < pr; ) { + pr -= w; /* Move right pointer onto an unprocessed item */ + cmp = compar(pr, pivot, ds...); + if(cmp == 0) { + pre -= w; + if(pr < pre) { sort_r_swap(pr, pre, w); } + } + else if(cmp < 0) { + if(pl < pr) { sort_r_swap(pl, pr, w); } + pl += w; break; } } } - sort_r_simple(b, (pl-b)/w, w, compar, arg); - sort_r_simple(pl+w, (end-(pl+w))/w, w, compar, arg); + pl = pr; /* pr may have gone below pl */ + + /* + Now we need to go from: EEELLLGGGGEEEE + to: LLLEEEEEEEGGGG + Pivot comparison key: + E = equal, L = less than, u = unknown, G = greater than, E = equal + */ + sort_r_swap_blocks(b, ple-b, pl-ple); + sort_r_swap_blocks(pr, pre-pr, end-pre); + + /*for(size_t i=0; i, Type&> hb_sorted_array_t qsort (int (*cmp_)(const void*, const void*)) { if (likely (length)) - ::qsort (arrayZ, length, this->item_size, cmp_); + hb_qsort (arrayZ, length, this->item_size, cmp_); return hb_sorted_array_t (*this); } hb_sorted_array_t qsort () { if (likely (length)) - ::qsort (arrayZ, length, this->item_size, Type::cmp); + hb_qsort (arrayZ, length, this->item_size, Type::cmp); return hb_sorted_array_t (*this); } void qsort (unsigned int start, unsigned int end) @@ -155,7 +155,7 @@ struct hb_array_t : hb_iter_with_fallback_t, Type&> end = hb_min (end, length); assert (start <= end); if (likely (start < end)) - ::qsort (arrayZ + start, end - start, this->item_size, Type::cmp); + hb_qsort (arrayZ + start, end - start, this->item_size, Type::cmp); } /* diff --git a/src/hb-ot-post-table.hh b/src/hb-ot-post-table.hh index 9177a5393..720e03bac 100644 --- a/src/hb-ot-post-table.hh +++ b/src/hb-ot-post-table.hh @@ -157,7 +157,7 @@ struct post for (unsigned int i = 0; i < count; i++) gids[i] = i; - hb_sort_r (gids, count, sizeof (gids[0]), cmp_gids, (void *) this); + hb_qsort (gids, count, sizeof (gids[0]), cmp_gids, (void *) this); if (unlikely (!gids_sorted_by_name.cmpexch (nullptr, gids))) {