diff options
Diffstat (limited to 'src/stdlib/lists.c')
| -rw-r--r-- | src/stdlib/lists.c | 813 |
1 files changed, 813 insertions, 0 deletions
diff --git a/src/stdlib/lists.c b/src/stdlib/lists.c new file mode 100644 index 00000000..69ac7026 --- /dev/null +++ b/src/stdlib/lists.c @@ -0,0 +1,813 @@ +// Functions that operate on lists + +#include <gc.h> +#include <stdbool.h> +#include <stdint.h> +#include <sys/param.h> + +#include "lists.h" +#include "integers.h" +#include "math.h" +#include "metamethods.h" +#include "optionals.h" +#include "tables.h" +#include "text.h" +#include "util.h" + +// Use inline version of siphash code: +#include "siphash.h" +#include "siphash-internals.h" + +PUREFUNC static INLINE int64_t get_padded_item_size(const TypeInfo_t *info) +{ + int64_t size = info->ListInfo.item->size; + if (info->ListInfo.item->align > 1 && size % info->ListInfo.item->align) + errx(1, "Item size is not padded!"); + return size; +} + +// Replace the list's .data pointer with a new pointer to a copy of the +// data that is compacted and has a stride of exactly `padded_item_size` +public void List$compact(List_t *list, int64_t padded_item_size) +{ + void *copy = NULL; + if (list->length > 0) { + copy = list->atomic ? GC_MALLOC_ATOMIC((size_t)list->length * (size_t)padded_item_size) + : GC_MALLOC((size_t)list->length * (size_t)padded_item_size); + if ((int64_t)list->stride == padded_item_size) { + memcpy(copy, list->data, (size_t)list->length * (size_t)padded_item_size); + } else { + for (int64_t i = 0; i < list->length; i++) + memcpy(copy + i*padded_item_size, list->data + list->stride*i, (size_t)padded_item_size); + } + } + *list = (List_t){ + .data=copy, + .length=list->length, + .stride=padded_item_size, + .atomic=list->atomic, + }; +} + +public void List$insert(List_t *list, const void *item, Int_t int_index, int64_t padded_item_size) +{ + int64_t index = Int64$from_int(int_index, false); + if (index <= 0) index = list->length + index + 1; + + if (index < 1) index = 1; + else if (index > (int64_t)list->length + 1) + fail("Invalid insertion index ", index, " for a list with length ", (int64_t)list->length); + + if (!list->data) { + list->free = 4; + list->data = list->atomic ? GC_MALLOC_ATOMIC((size_t)list->free * (size_t)padded_item_size) + : GC_MALLOC((size_t)list->free * (size_t)padded_item_size); + list->stride = padded_item_size; + } else if (list->free < 1 || list->data_refcount != 0 || (int64_t)list->stride != padded_item_size) { + // Resize policy: +50% growth (clamped between 8 and LIST_MAX_FREE_ENTRIES) + list->free = MIN(LIST_MAX_FREE_ENTRIES, MAX(8, list->length)/2); + void *copy = list->atomic ? GC_MALLOC_ATOMIC((size_t)(list->length + list->free) * (size_t)padded_item_size) + : GC_MALLOC((size_t)(list->length + list->free) * (size_t)padded_item_size); + for (int64_t i = 0; i < index-1; i++) + memcpy(copy + i*padded_item_size, list->data + list->stride*i, (size_t)padded_item_size); + for (int64_t i = index-1; i < (int64_t)list->length; i++) + memcpy(copy + (i+1)*padded_item_size, list->data + list->stride*i, (size_t)padded_item_size); + list->data = copy; + list->data_refcount = 0; + list->stride = padded_item_size; + } else { + if (index != list->length+1) + memmove( + list->data + index*padded_item_size, + list->data + (index-1)*padded_item_size, + (size_t)((list->length - index + 1)*padded_item_size)); + } + assert(list->free > 0); + --list->free; + ++list->length; + memcpy((void*)list->data + (index-1)*padded_item_size, item, (size_t)padded_item_size); +} + +public void List$insert_all(List_t *list, List_t to_insert, Int_t int_index, int64_t padded_item_size) +{ + int64_t index = Int64$from_int(int_index, false); + if (to_insert.length == 0) + return; + + if (!list->data) { + *list = to_insert; + LIST_INCREF(*list); + return; + } + + if (index < 1) index = list->length + index + 1; + + if (index < 1) index = 1; + else if (index > (int64_t)list->length + 1) + fail("Invalid insertion index ", index, " for a list with length ", (int64_t)list->length); + + if ((int64_t)list->free >= (int64_t)to_insert.length // Adequate free space + && list->data_refcount == 0 // Not aliased memory + && (int64_t)list->stride == padded_item_size) { // Contiguous list + // If we can fit this within the list's preallocated free space, do that: + list->free -= to_insert.length; + list->length += to_insert.length; + if (index != list->length+1) + memmove((void*)list->data + index*padded_item_size, + list->data + (index-1)*padded_item_size, + (size_t)((list->length - index + to_insert.length-1)*padded_item_size)); + for (int64_t i = 0; i < to_insert.length; i++) + memcpy((void*)list->data + (index-1 + i)*padded_item_size, + to_insert.data + i*to_insert.stride, (size_t)padded_item_size); + } else { + // Otherwise, allocate a new chunk of memory for the list and populate it: + int64_t new_len = list->length + to_insert.length; + list->free = MIN(LIST_MAX_FREE_ENTRIES, MAX(8, new_len/4)); + void *data = list->atomic ? GC_MALLOC_ATOMIC((size_t)((new_len + list->free) * padded_item_size)) + : GC_MALLOC((size_t)((new_len + list->free) * padded_item_size)); + void *p = data; + + // Copy first chunk of `list` if needed: + if (index > 1) { + if (list->stride == padded_item_size) { + memcpy(p, list->data, (size_t)((index-1)*padded_item_size)); + p += (index-1)*padded_item_size; + } else { + for (int64_t i = 0; i < index-1; i++) { + memcpy(p, list->data + list->stride*i, (size_t)padded_item_size); + p += padded_item_size; + } + } + } + + // Copy `to_insert` + if (to_insert.stride == padded_item_size) { + memcpy(p, to_insert.data, (size_t)(to_insert.length*padded_item_size)); + p += to_insert.length*padded_item_size; + } else { + for (int64_t i = 0; i < index-1; i++) { + memcpy(p, to_insert.data + to_insert.stride*i, (size_t)padded_item_size); + p += padded_item_size; + } + } + + // Copy last chunk of `list` if needed: + if (index < list->length + 1) { + if (list->stride == padded_item_size) { + memcpy(p, list->data + padded_item_size*(index-1), (size_t)((list->length - index + 1)*padded_item_size)); + p += (list->length - index + 1)*padded_item_size; + } else { + for (int64_t i = index-1; i < list->length-1; i++) { + memcpy(p, list->data + list->stride*i, (size_t)padded_item_size); + p += padded_item_size; + } + } + } + list->length = new_len; + list->stride = padded_item_size; + list->data = data; + list->data_refcount = 0; + } +} + +public void List$remove_at(List_t *list, Int_t int_index, Int_t int_count, int64_t padded_item_size) +{ + int64_t index = Int64$from_int(int_index, false); + if (index < 1) index = list->length + index + 1; + + int64_t count = Int64$from_int(int_count, false); + if (index < 1 || index > (int64_t)list->length || count < 1) return; + + if (count > list->length - index + 1) + count = (list->length - index) + 1; + + if (index == 1) { + list->data += list->stride * count; + } else if (index + count > list->length) { + list->free += count; + } else if (list->data_refcount != 0 || (int64_t)list->stride != padded_item_size) { + void *copy = list->atomic ? GC_MALLOC_ATOMIC((size_t)((list->length-1) * padded_item_size)) + : GC_MALLOC((size_t)((list->length-1) * padded_item_size)); + for (int64_t src = 1, dest = 1; src <= (int64_t)list->length; src++) { + if (src < index || src >= index + count) { + memcpy(copy + (dest - 1)*padded_item_size, list->data + list->stride*(src - 1), (size_t)padded_item_size); + ++dest; + } + } + list->data = copy; + list->free = 0; + list->data_refcount = 0; + } else { + memmove((void*)list->data + (index-1)*padded_item_size, list->data + (index-1 + count)*padded_item_size, + (size_t)((list->length - index + count - 1)*padded_item_size)); + list->free += count; + } + list->length -= count; + if (list->length == 0) list->data = NULL; +} + +public void List$remove_item(List_t *list, void *item, Int_t max_removals, const TypeInfo_t *type) +{ + int64_t padded_item_size = get_padded_item_size(type); + const Int_t ZERO = (Int_t){.small=(0<<2)|1}; + const Int_t ONE = (Int_t){.small=(1<<2)|1}; + const TypeInfo_t *item_type = type->ListInfo.item; + for (int64_t i = 0; i < list->length; ) { + if (max_removals.small == ZERO.small) // zero + break; + + if (generic_equal(item, list->data + i*list->stride, item_type)) { + List$remove_at(list, I(i+1), ONE, padded_item_size); + max_removals = Int$minus(max_removals, ONE); + } else { + i++; + } + } +} + +public OptionalInt_t List$find(List_t list, void *item, const TypeInfo_t *type) +{ + const TypeInfo_t *item_type = type->ListInfo.item; + for (int64_t i = 0; i < list.length; i++) { + if (generic_equal(item, list.data + i*list.stride, item_type)) + return I(i+1); + } + return NONE_INT; +} + +public OptionalInt_t List$first(List_t list, Closure_t predicate) +{ + bool (*is_good)(void*, void*) = (void*)predicate.fn; + for (int64_t i = 0; i < list.length; i++) { + if (is_good(list.data + i*list.stride, predicate.userdata)) + return I(i+1); + } + return NONE_INT; +} + +static Closure_t _sort_comparison = {.fn=NULL}; + +int _compare_closure(const void *a, const void *b) +{ + typedef int (*comparison_t)(const void*, const void*, void*); + return ((comparison_t)_sort_comparison.fn)(a, b, _sort_comparison.userdata); +} + +public void List$sort(List_t *list, Closure_t comparison, int64_t padded_item_size) +{ + if (list->data_refcount != 0 || (int64_t)list->stride != padded_item_size) + List$compact(list, padded_item_size); + + _sort_comparison = comparison; + qsort(list->data, (size_t)list->length, (size_t)padded_item_size, _compare_closure); +} + +public List_t List$sorted(List_t list, Closure_t comparison, int64_t padded_item_size) +{ + List$compact(&list, padded_item_size); + _sort_comparison = comparison; + qsort(list.data, (size_t)list.length, (size_t)padded_item_size, _compare_closure); + return list; +} + +#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__) +static ssize_t getrandom(void *buf, size_t buflen, unsigned int flags) { + (void)flags; + arc4random_buf(buf, buflen); + return buflen; +} +#elif defined(__linux__) +// Use getrandom() +# include <sys/random.h> +#else + #error "Unsupported platform for secure random number generation" +#endif + +static int64_t _default_random_int64(int64_t min, int64_t max, void *userdata) +{ + (void)userdata; + if (min > max) fail("Random minimum value (", min, ") is larger than the maximum value (", max, ")"); + if (min == max) return min; + uint64_t range = (uint64_t)max - (uint64_t)min + 1; + uint64_t min_r = -range % range; + uint64_t r; + for (;;) { + getrandom(&r, sizeof(r), 0); + if (r >= min_r) break; + } + return (int64_t)((uint64_t)min + (r % range)); +} + +public void List$shuffle(List_t *list, OptionalClosure_t random_int64, int64_t padded_item_size) +{ + if (list->data_refcount != 0 || (int64_t)list->stride != padded_item_size) + List$compact(list, padded_item_size); + + typedef int64_t (*rng_fn_t)(int64_t, int64_t, void*); + rng_fn_t rng_fn = random_int64.fn ? (rng_fn_t)random_int64.fn : _default_random_int64; + char tmp[padded_item_size]; + for (int64_t i = list->length-1; i > 1; i--) { + int64_t j = rng_fn(0, i, random_int64.userdata); + if unlikely (j < 0 || j > list->length-1) + fail("The provided random number function returned an invalid value: ", j, " (not between 0 and ", i, ")"); + memcpy(tmp, list->data + i*padded_item_size, (size_t)padded_item_size); + memcpy((void*)list->data + i*padded_item_size, list->data + j*padded_item_size, (size_t)padded_item_size); + memcpy((void*)list->data + j*padded_item_size, tmp, (size_t)padded_item_size); + } +} + +public List_t List$shuffled(List_t list, Closure_t random_int64, int64_t padded_item_size) +{ + List$compact(&list, padded_item_size); + List$shuffle(&list, random_int64, padded_item_size); + return list; +} + +public void *List$random(List_t list, OptionalClosure_t random_int64) +{ + if (list.length == 0) + return NULL; // fail("Cannot get a random item from an empty list!"); + + typedef int64_t (*rng_fn_t)(int64_t, int64_t, void*); + rng_fn_t rng_fn = random_int64.fn ? (rng_fn_t)random_int64.fn : _default_random_int64; + int64_t index = rng_fn(0, list.length-1, random_int64.userdata); + if unlikely (index < 0 || index > list.length-1) + fail("The provided random number function returned an invalid value: ", index, " (not between 0 and ", (int64_t)list.length, ")"); + return list.data + list.stride*index; +} + +public Table_t List$counts(List_t list, const TypeInfo_t *type) +{ + Table_t counts = {}; + const TypeInfo_t count_type = *Table$info(type->ListInfo.item, &Int$info); + for (int64_t i = 0; i < list.length; i++) { + void *key = list.data + i*list.stride; + int64_t *count = Table$get(counts, key, &count_type); + int64_t val = count ? *count + 1 : 1; + Table$set(&counts, key, &val, &count_type); + } + return counts; +} + +static double _default_random_num(void *userdata) +{ + (void)userdata; + union { + Num_t num; + uint64_t bits; + } r = {.bits=0}, one = {.num=1.0}; + getrandom((uint8_t*)&r, sizeof(r), 0); + + // Set r.num to 1.<random-bits> + r.bits &= ~(0xFFFULL << 52); + r.bits |= (one.bits & (0xFFFULL << 52)); + return r.num - 1.0; +} + +public List_t List$sample(List_t list, Int_t int_n, List_t weights, OptionalClosure_t random_num, int64_t padded_item_size) +{ + int64_t n = Int64$from_int(int_n, false); + if (n < 0) + fail("Cannot select a negative number of values"); + + if (n == 0) + return (List_t){}; + + if (list.length == 0) + fail("There are no elements in this list!"); + + if (weights.length != list.length) + fail("List has ", (int64_t)list.length, " elements, but there are ", (int64_t)weights.length, " weights given"); + + double total = 0.0; + for (int64_t i = 0; i < weights.length && i < list.length; i++) { + double weight = *(double*)(weights.data + weights.stride*i); + if (isinf(weight)) + fail("Infinite weight!"); + else if (isnan(weight)) + fail("NaN weight!"); + else if (weight < 0.0) + fail("Negative weight!"); + else + total += weight; + } + + if (isinf(total)) + fail("Sample weights have overflowed to infinity"); + + if (total == 0.0) + fail("None of the given weights are nonzero"); + + double inverse_average = (double)list.length / total; + + struct { + int64_t alias; + double odds; + } aliases[list.length]; + + for (int64_t i = 0; i < list.length; i++) { + double weight = i >= weights.length ? 0.0 : *(double*)(weights.data + weights.stride*i); + aliases[i].odds = weight * inverse_average; + aliases[i].alias = -1; + } + + int64_t small = 0; + for (int64_t big = 0; big < list.length; big++) { + while (aliases[big].odds >= 1.0) { + while (small < list.length && (aliases[small].odds >= 1.0 || aliases[small].alias != -1)) + ++small; + + if (small >= list.length) { + aliases[big].odds = 1.0; + aliases[big].alias = big; + break; + } + + aliases[small].alias = big; + aliases[big].odds = (aliases[small].odds + aliases[big].odds) - 1.0; + } + if (big < small) small = big; + } + + for (int64_t i = small; i < list.length; i++) + if (aliases[i].alias == -1) + aliases[i].alias = i; + + typedef double (*rng_fn_t)(void*); + rng_fn_t rng_fn = random_num.fn ? (rng_fn_t)random_num.fn : _default_random_num; + + List_t selected = { + .data=list.atomic ? GC_MALLOC_ATOMIC((size_t)(n * padded_item_size)) : GC_MALLOC((size_t)(n * padded_item_size)), + .length=n, + .stride=padded_item_size, .atomic=list.atomic}; + for (int64_t i = 0; i < n; i++) { + double r = rng_fn(random_num.userdata); + if unlikely (r < 0.0 || r >= 1.0) + fail("The random number function returned a value not between 0.0 (inclusive) and 1.0 (exclusive): ", r); + r *= (double)list.length; + int64_t index = (int64_t)r; + assert(index >= 0 && index < list.length); + if ((r - (double)index) > aliases[index].odds) + index = aliases[index].alias; + memcpy(selected.data + i*selected.stride, list.data + index*list.stride, (size_t)padded_item_size); + } + return selected; +} + +public List_t List$from(List_t list, Int_t first) +{ + return List$slice(list, first, I_small(-1)); +} + +public List_t List$to(List_t list, Int_t last) +{ + return List$slice(list, I_small(1), last); +} + +public List_t List$by(List_t list, Int_t int_stride, int64_t padded_item_size) +{ + int64_t stride = Int64$from_int(int_stride, false); + // In the unlikely event that the stride value would be too large to fit in + // a 15-bit integer, fall back to creating a copy of the list: + if (unlikely(list.stride*stride < LIST_MIN_STRIDE || list.stride*stride > LIST_MAX_STRIDE)) { + void *copy = NULL; + int64_t len = (stride < 0 ? list.length / -stride : list.length / stride) + ((list.length % stride) != 0); + if (len > 0) { + copy = list.atomic ? GC_MALLOC_ATOMIC((size_t)(len * padded_item_size)) : GC_MALLOC((size_t)(len * padded_item_size)); + void *start = (stride < 0 ? list.data + (list.stride * (list.length - 1)) : list.data); + for (int64_t i = 0; i < len; i++) + memcpy(copy + i*padded_item_size, start + list.stride*stride*i, (size_t)padded_item_size); + } + return (List_t){ + .data=copy, + .length=len, + .stride=padded_item_size, + .atomic=list.atomic, + }; + } + + if (stride == 0) + return (List_t){.atomic=list.atomic}; + + return (List_t){ + .atomic=list.atomic, + .data=(stride < 0 ? list.data + (list.stride * (list.length - 1)) : list.data), + .length=(stride < 0 ? list.length / -stride : list.length / stride) + ((list.length % stride) != 0), + .stride=list.stride * stride, + .data_refcount=list.data_refcount, + }; +} + +public List_t List$slice(List_t list, Int_t int_first, Int_t int_last) + +{ + int64_t first = Int64$from_int(int_first, false); + if (first < 0) + first = list.length + first + 1; + + int64_t last = Int64$from_int(int_last, false); + if (last < 0) + last = list.length + last + 1; + + if (last > list.length) + last = list.length; + + if (first < 1 || first > list.length || last == 0) + return (List_t){.atomic=list.atomic}; + + return (List_t){ + .atomic=list.atomic, + .data=list.data + list.stride*(first-1), + .length=last - first + 1, + .stride=list.stride, + .data_refcount=list.data_refcount, + }; +} + +public List_t List$reversed(List_t list, int64_t padded_item_size) +{ + // Just in case negating the stride gives a value that doesn't fit into a + // 15-bit integer, fall back to List$by()'s more general method of copying + // the list. This should only happen if list.stride is MIN_STRIDE to + // begin with (very unlikely). + if (unlikely(-list.stride < LIST_MIN_STRIDE || -list.stride > LIST_MAX_STRIDE)) + return List$by(list, I(-1), padded_item_size); + + List_t reversed = list; + reversed.stride = -list.stride; + reversed.data = list.data + (list.length-1)*list.stride; + return reversed; +} + +public List_t List$concat(List_t x, List_t y, int64_t padded_item_size) +{ + void *data = x.atomic ? GC_MALLOC_ATOMIC((size_t)(padded_item_size*(x.length + y.length))) + : GC_MALLOC((size_t)(padded_item_size*(x.length + y.length))); + if (x.stride == padded_item_size) { + memcpy(data, x.data, (size_t)(padded_item_size*x.length)); + } else { + for (int64_t i = 0; i < x.length; i++) + memcpy(data + i*padded_item_size, x.data + i*padded_item_size, (size_t)padded_item_size); + } + + void *dest = data + padded_item_size*x.length; + if (y.stride == padded_item_size) { + memcpy(dest, y.data, (size_t)(padded_item_size*y.length)); + } else { + for (int64_t i = 0; i < y.length; i++) + memcpy(dest + i*padded_item_size, y.data + i*y.stride, (size_t)padded_item_size); + } + + return (List_t){ + .data=data, + .length=x.length + y.length, + .stride=padded_item_size, + .atomic=x.atomic, + }; +} + +public bool List$has(List_t list, void *item, const TypeInfo_t *type) +{ + const TypeInfo_t *item_type = type->ListInfo.item; + for (int64_t i = 0; i < list.length; i++) { + if (generic_equal(list.data + i*list.stride, item, item_type)) + return true; + } + return false; +} + +public void List$clear(List_t *list) +{ + *list = (List_t){.data=0, .length=0}; +} + +public int32_t List$compare(const void *vx, const void *vy, const TypeInfo_t *type) +{ + const List_t *x = (List_t*)vx, *y = (List_t*)vy; + // Early out for lists with the same data, e.g. two copies of the same list: + if (x->data == y->data && x->stride == y->stride) + return (x->length > y->length) - (x->length < y->length); + + const TypeInfo_t *item = type->ListInfo.item; + if (item->tag == PointerInfo || !item->metamethods.compare) { // data comparison + int64_t item_padded_size = type->ListInfo.item->size; + if (type->ListInfo.item->align > 1 && item_padded_size % type->ListInfo.item->align) + errx(1, "Item size is not padded!"); + + if ((int64_t)x->stride == item_padded_size && (int64_t)y->stride == item_padded_size && item->size == item_padded_size) { + int32_t cmp = (int32_t)memcmp(x->data, y->data, (size_t)(MIN(x->length, y->length)*item_padded_size)); + if (cmp != 0) return cmp; + } else { + for (int32_t i = 0, len = MIN(x->length, y->length); i < len; i++) { + int32_t cmp = (int32_t)memcmp(x->data+ x->stride*i, y->data + y->stride*i, (size_t)(item->size)); + if (cmp != 0) return cmp; + } + } + } else { + for (int32_t i = 0, len = MIN(x->length, y->length); i < len; i++) { + int32_t cmp = generic_compare(x->data + x->stride*i, y->data + y->stride*i, item); + if (cmp != 0) return cmp; + } + } + return (x->length > y->length) - (x->length < y->length); +} + +public bool List$equal(const void *x, const void *y, const TypeInfo_t *type) +{ + return x == y || (((List_t*)x)->length == ((List_t*)y)->length && List$compare(x, y, type) == 0); +} + +public Text_t List$as_text(const void *obj, bool colorize, const TypeInfo_t *type) +{ + List_t *list = (List_t*)obj; + if (!list) + return Text$concat(Text("["), generic_as_text(NULL, false, type->ListInfo.item), Text("]")); + + const TypeInfo_t *item_type = type->ListInfo.item; + Text_t text = Text("["); + for (int64_t i = 0; i < list->length; i++) { + if (i > 0) + text = Text$concat(text, Text(", ")); + Text_t item_text = generic_as_text(list->data + i*list->stride, colorize, item_type); + text = Text$concat(text, item_text); + } + text = Text$concat(text, Text("]")); + return text; +} + +public uint64_t List$hash(const void *obj, const TypeInfo_t *type) +{ + const List_t *list = (List_t*)obj; + const TypeInfo_t *item = type->ListInfo.item; + siphash sh; + siphashinit(&sh, sizeof(uint64_t[list->length])); + if (item->tag == PointerInfo || (!item->metamethods.hash && item->size == sizeof(void*))) { // Raw data hash + for (int64_t i = 0; i < list->length; i++) + siphashadd64bits(&sh, (uint64_t)(list->data + i*list->stride)); + } else { + for (int64_t i = 0; i < list->length; i++) { + uint64_t item_hash = generic_hash(list->data + i*list->stride, item); + siphashadd64bits(&sh, item_hash); + } + } + return siphashfinish_last_part(&sh, 0); +} + +static void siftdown(List_t *heap, int64_t startpos, int64_t pos, Closure_t comparison, int64_t padded_item_size) +{ + assert(pos > 0 && pos < heap->length); + char newitem[padded_item_size]; + memcpy(newitem, heap->data + heap->stride*pos, (size_t)(padded_item_size)); + while (pos > startpos) { + int64_t parentpos = (pos - 1) >> 1; + typedef int32_t (*cmp_fn_t)(void*, void*, void*); + int32_t cmp = ((cmp_fn_t)comparison.fn)(newitem, heap->data + heap->stride*parentpos, comparison.userdata); + if (cmp >= 0) + break; + + memcpy(heap->data + heap->stride*pos, heap->data + heap->stride*parentpos, (size_t)(padded_item_size)); + pos = parentpos; + } + memcpy(heap->data + heap->stride*pos, newitem, (size_t)(padded_item_size)); +} + +static void siftup(List_t *heap, int64_t pos, Closure_t comparison, int64_t padded_item_size) +{ + int64_t endpos = heap->length; + int64_t startpos = pos; + assert(pos < endpos); + + char old_top[padded_item_size]; + memcpy(old_top, heap->data + heap->stride*pos, (size_t)(padded_item_size)); + // Bubble up the smallest leaf node + int64_t limit = endpos >> 1; + while (pos < limit) { + int64_t childpos = 2*pos + 1; // Smaller of the two child nodes + if (childpos + 1 < endpos) { + typedef int32_t (*cmp_fn_t)(void*, void*, void*); + int32_t cmp = ((cmp_fn_t)comparison.fn)( + heap->data + heap->stride*childpos, + heap->data + heap->stride*(childpos + 1), + comparison.userdata); + childpos += (cmp >= 0); + } + + // Move the child node up: + memcpy(heap->data + heap->stride*pos, heap->data + heap->stride*childpos, (size_t)(padded_item_size)); + pos = childpos; + } + memcpy(heap->data + heap->stride*pos, old_top, (size_t)(padded_item_size)); + // Shift the node's parents down: + siftdown(heap, startpos, pos, comparison, padded_item_size); +} + +public void List$heap_push(List_t *heap, const void *item, Closure_t comparison, int64_t padded_item_size) +{ + List$insert(heap, item, I(0), padded_item_size); + + if (heap->length > 1) { + if (heap->data_refcount != 0) + List$compact(heap, padded_item_size); + siftdown(heap, 0, heap->length-1, comparison, padded_item_size); + } +} + +public void List$heap_pop(List_t *heap, Closure_t comparison, int64_t padded_item_size) +{ + if (heap->length == 0) + fail("Attempt to pop from an empty list"); + + if (heap->length == 1) { + *heap = (List_t){}; + } else if (heap->length == 2) { + heap->data += heap->stride; + --heap->length; + } else { + if (heap->data_refcount != 0) + List$compact(heap, padded_item_size); + memcpy(heap->data, heap->data + heap->stride*(heap->length-1), (size_t)(padded_item_size)); + --heap->length; + siftup(heap, 0, comparison, padded_item_size); + } +} + +public void List$heapify(List_t *heap, Closure_t comparison, int64_t padded_item_size) +{ + if (heap->data_refcount != 0) + List$compact(heap, padded_item_size); + + // It's necessary to bump the refcount because the user's comparison + // function could do stuff that modifies the heap's data. + LIST_INCREF(*heap); + int64_t i, n = heap->length; + for (i = (n >> 1) - 1 ; i >= 0 ; i--) + siftup(heap, i, comparison, padded_item_size); + LIST_DECREF(*heap); +} + +public Int_t List$binary_search(List_t list, void *target, Closure_t comparison) +{ + typedef int32_t (*cmp_fn_t)(void*, void*, void*); + int64_t lo = 0, hi = list.length-1; + while (lo <= hi) { + int64_t mid = (lo + hi) / 2; + int32_t cmp = ((cmp_fn_t)comparison.fn)( + list.data + list.stride*mid, target, comparison.userdata); + if (cmp == 0) + return I(mid+1); + else if (cmp < 0) + lo = mid + 1; + else if (cmp > 0) + hi = mid - 1; + } + return I(lo+1); // Return the index where the target would be inserted +} + +public PUREFUNC bool List$is_none(const void *obj, const TypeInfo_t*) +{ + return ((List_t*)obj)->length < 0; +} + +public void List$serialize(const void *obj, FILE *out, Table_t *pointers, const TypeInfo_t *type) +{ + List_t list = *(List_t*)obj; + int64_t len = list.length; + Int64$serialize(&len, out, pointers, &Int64$info); + auto item_serialize = type->ListInfo.item->metamethods.serialize; + if (item_serialize) { + for (int64_t i = 0; i < len; i++) + item_serialize(list.data + i*list.stride, out, pointers, type->ListInfo.item); + } else if (list.stride == type->ListInfo.item->size) { + fwrite(list.data, (size_t)type->ListInfo.item->size, (size_t)len, out); + } else { + for (int64_t i = 0; i < len; i++) + fwrite(list.data + i*list.stride, (size_t)type->ListInfo.item->size, 1, out); + } +} + +public void List$deserialize(FILE *in, void *obj, List_t *pointers, const TypeInfo_t *type) +{ + int64_t len = -1; + Int64$deserialize(in, &len, pointers, &Int64$info); + int64_t padded_size = type->ListInfo.item->size; + if (type->ListInfo.item->align > 0 && padded_size % type->ListInfo.item->align > 0) + padded_size += type->ListInfo.item->align - (padded_size % type->ListInfo.item->align); + List_t list = { + .length=len, + .data=GC_MALLOC((size_t)(len*padded_size)), + .stride=padded_size, + }; + auto item_deserialize = type->ListInfo.item->metamethods.deserialize; + if (item_deserialize) { + for (int64_t i = 0; i < len; i++) + item_deserialize(in, list.data + i*list.stride, pointers, type->ListInfo.item); + } else if (list.stride == type->ListInfo.item->size) { + fread(list.data, (size_t)type->ListInfo.item->size, (size_t)len, in); + } else { + for (int64_t i = 0; i < len; i++) + fread(list.data + i*list.stride, (size_t)type->ListInfo.item->size, 1, in); + } + *(List_t*)obj = list; +} + +// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0 |