path: root/data_structures.c

/* 
Dynamic arrays and hash tables in C

This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.
In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.
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 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.
For more information, please refer to <http://unlicense.org/>
*/

/* OPTIM: is it faster to store void *end? */
typedef struct ArrHeader {
	size_t len;
	size_t cap;
	MaxAlign data[];
} ArrHeader;

static inline ArrHeader *arr_hdr(void *arr) {
	ArrHeader *hdr = (ArrHeader *)((char *)arr - offsetof(ArrHeader, data));
	return hdr;
}

static inline size_t arr_len(void *arr) {
	if (arr == NULL) return 0;
	return arr_hdr(arr)->len;
}

static inline void arr_zero_(void *arr, size_t item_sz) {
	memset(arr, 0, item_sz * arr_len(arr));
}

static void arr_resv_(void **arr, size_t n, size_t item_sz) {
	if (*arr == NULL) {
		ArrHeader *hdr = err_malloc(item_sz * n + sizeof(ArrHeader) + 1); /* +1 => prevent ptr overflow */
		hdr->len = 0;
		hdr->cap = n;
		*arr = hdr->data;
	} else {
		ArrHeader *hdr = arr_hdr(*arr);
		hdr->cap = n;
		hdr = err_realloc(hdr, item_sz * n + sizeof(ArrHeader) + 1);
		if (hdr->len > hdr->cap) hdr->len = hdr->cap;
		*arr = hdr->data;
	}		
}
static void arr_resva_(void **arr, size_t n, size_t item_sz, Allocator *a) {
	if (*arr == NULL) {
		ArrHeader *hdr = allocr_malloc(a, item_sz * n + sizeof(ArrHeader));
		hdr->len = 0;
		hdr->cap = n;
		*arr = hdr->data;
	} else {
		ArrHeader *hdr = arr_hdr(*arr);
		hdr = allocr_realloc(a, hdr, item_sz * hdr->cap + sizeof(ArrHeader), item_sz * n + sizeof(ArrHeader));
		hdr->cap = n;
		if (hdr->len > hdr->cap) hdr->len = hdr->cap;
		*arr = hdr->data;
	}		
}

static void arr_clear_(void **arr) {
	if (*arr) {
		free(arr_hdr(*arr));
		*arr = NULL;
	}
}

static void arr_cleara_(void **arr, size_t size, Allocator *allocr) {
	if (*arr) {
		ArrHeader *header = arr_hdr(*arr);
		allocr_free(allocr, header, header->cap * size);
		*arr = NULL;
	}
}

static void arr_set_len_(void **arr, size_t n, size_t item_sz) {
	if (n == 0) {
		arr_clear_(arr);
		return;
	}
	if (n > arr_len(*arr)) {
		arr_resv_(arr, n, item_sz);
	}
	arr_hdr(*arr)->len = n;
	/* OPTIM: shrink */
}
static void arr_set_lena_(void **arr, size_t n, size_t item_sz, Allocator *a) {
	if (n == 0) {
		arr_cleara_(arr, item_sz, a);
		return;
	}
	arr_resva_(arr, n, item_sz, a);
	arr_hdr(*arr)->len = n;
}

static void *arr_add_(void **arr, size_t item_sz) {
	ArrHeader *hdr;
	if (*arr == NULL) {
		arr_resv_(arr, 10, item_sz);
		hdr = arr_hdr(*arr);
	} else {
		hdr = arr_hdr(*arr);
		if (hdr->len >= hdr->cap) {
			arr_resv_(arr, hdr->len * 2 + 1, item_sz);
			hdr = arr_hdr(*arr);
		}
	}
	return &(((char *)hdr->data)[(hdr->len++) * item_sz]);
}
static void *arr_adda_(void **arr, size_t item_sz, Allocator *a) {
	ArrHeader *hdr;
	if (*arr == NULL) {
		arr_resva_(arr, 10, item_sz, a);
		hdr = arr_hdr(*arr);
	} else {
		hdr = arr_hdr(*arr);
		if (hdr->len >= hdr->cap) {
			arr_resva_(arr, hdr->len * 2 + 1, item_sz, a);
			hdr = arr_hdr(*arr);
		}
	}
	return &(((char *)hdr->data)[(hdr->len++) * item_sz]);
}


static void *arr_last_(void *arr, size_t item_sz) {
	if (arr) {
		ArrHeader *hdr = arr_hdr(arr);
		return hdr->len == 0 ? NULL : (char *)hdr->data + (hdr->len-1) * item_sz;
	} else {
		return NULL;
	}
}

static void *arr_end_(void *arr, size_t item_sz) {
	if (arr) {
		ArrHeader *hdr = arr_hdr(arr);
		return hdr->len == 0 ? NULL : (char *)hdr->data + hdr->len * item_sz;
	} else {
		return NULL;
	}
}

/* OPTIM: shrink array */
static void arr_remove_last_(void **arr) {
	assert(arr_hdr(*arr)->len);
	if (--arr_hdr(*arr)->len == 0) {
		arr_clear_(arr);
	}
}

static void arr_remove_lasta_(void **arr, size_t item_sz, Allocator *a) {
	assert(arr_hdr(*arr)->len);
	if (--arr_hdr(*arr)->len == 0) {
		arr_cleara_(arr, item_sz, a);
	}
}



static void arr_copya_(void **out, void *in, size_t item_sz, Allocator *a) {
	size_t len = arr_len(in);
	arr_resva_(out, len, item_sz, a);
	memcpy(*out, in, len * item_sz);
}

#ifdef __GNUC__
#define typeof __typeof__
#endif

#if defined(__GNUC__) || defined(__TINYC__)
#define HAS_TYPEOF 1
#endif

#if HAS_TYPEOF
/* 
this is to cast the return value of arr_add so that gcc produces a warning if you
do something like:
float *arr = NULL;
// ...
int *x = arr_add(&arr);
You shouldn't rely on this, though, e.g. by doing
*arr_add(&arr) = 17;
 */
#define arr_ptr_type(arr) __typeof__(*(arr))
#else
#define arr_ptr_type(arr) void *
#endif

#define arr_zero(arr) arr_zero_(arr, sizeof *(arr))
#define arr_add(arr) (arr_ptr_type(arr))arr_add_((void **)(arr), sizeof **(arr))
#define arr_adda(arr, allocr) (arr_ptr_type(arr))arr_adda_((void **)(arr), sizeof **(arr), (allocr))
#define arr_resv(arr, n) arr_resv_((void **)(arr), n, sizeof **(arr))
#define arr_resva(arr, n, allocr) arr_resva_((void **)(arr), n, sizeof **(arr), (allocr))
#define arr_set_len(arr, n) arr_set_len_((void **)(arr), n, sizeof **(arr))
#define arr_set_lena(arr, n, a) arr_set_lena_((void **)(arr), n, sizeof **(arr), (a))
#define arr_clear(arr) arr_clear_((void **)(arr)), (void)sizeof **arr /* second part makes sure most of the time that you don't accidentally call it without taking the address */
#define arr_cleara(arr, allocr) arr_cleara_((void **)(arr), sizeof **(arr), (allocr))
#define arr_last(arr) arr_last_((void *)(arr), sizeof *(arr))
/* one past last, or NULL if empty */
#define arr_end(arr) arr_end_((void *)(arr), sizeof *(arr))
#define arr_foreach(arr, type, var) for (type *var = (arr), *var##_foreach_end = arr_end(arr); var != var##_foreach_end; ++var)
#define arr_foreach_reversed(arr, type, var) for (type *var = arr_last(arr), *var##_foreach_last = arr; var; var = var == var##_foreach_last ? NULL : (var-1))
#define arr_remove_last(arr) arr_remove_last_((void **)(arr)), (void)sizeof **(arr)
#define arr_remove_lasta(arr, a) arr_remove_lasta_((void **)(arr), sizeof **(arr), (a))
#define arr_copya(out, in, a) do { assert(sizeof *(in) == sizeof **(out)); arr_copya_((void **)(out), (in), sizeof **(out), (a)); } while(0)

#ifdef RUN_TESTS
static void arr_test(void) {
	int *foos = NULL;
	for (int i = 0; i < 10; ++i) {
		*(int *)arr_add(&foos) = i;
	}
	for (int i = 0; i < (int)arr_len(foos); ++i) {
		assert(foos[i] == i);
	}
	int lastx = -1;
	arr_foreach(foos, int, x) {
		assert(*x == lastx + 1);
		lastx = *x;
	}
	arr_clear(&foos);
}
#endif

/* string hash table. entries are zero initialized (toc stuff depends on this!) */

static U64 str_hash(const char *s, size_t len) {
	U32 x = 0xabcdef01;
	U32 y = 0x31415926;
	U64 hash = 0;
	for (size_t i = 0; i < len; ++i) {
		hash += (U64)x * (unsigned char)(*s) + y;
		x = rand_u32(x);
		y = rand_u32(y);
		++s;
	}
	return hash;
}

static inline void str_hash_table_create(StrHashTable *t, size_t data_size, Allocator *allocr) {
	t->slots = NULL;
	t->data_size = data_size;
	t->nentries = 0;
	t->allocr = allocr;
	t->rand_seed = 0xabacabad;
}

static StrHashTableSlot **str_hash_table_slot_get(StrHashTableSlot **slots, const char *s, size_t s_len, size_t i) {
	StrHashTableSlot **slot;
	size_t slots_cap = arr_len(slots);
	while (1) {
		assert(i < slots_cap);
		slot = &slots[i];
		if (!*slot) break;
		if (s && (*slot)->str &&
			s_len == (*slot)->len && memcmp(s, (*slot)->str, s_len) == 0)
			break;
		i = (i+1) % slots_cap;
	}
	return slot;
}

static void str_hash_table_grow(StrHashTable *t) {
	size_t slots_cap = arr_len(t->slots);
	if (slots_cap <= 2 * t->nentries) {
		StrHashTableSlot **new_slots = NULL;
		size_t new_slots_cap = slots_cap * 2 + 10;
		arr_set_lena(&new_slots, new_slots_cap, t->allocr);
		arr_zero(new_slots);
		arr_foreach(t->slots, StrHashTableSlotPtr, slotp) {
			StrHashTableSlot *slot = *slotp;
			if (slot) {
				U64 new_hash = str_hash(slot->str, slot->len);
				StrHashTableSlot **new_slot = str_hash_table_slot_get(new_slots, slot->str, slot->len, new_hash % new_slots_cap);
				*new_slot = slot;
			}
		}
		arr_cleara(&t->slots, t->allocr);
		t->slots = new_slots;
	}
}

static inline size_t str_hash_table_slot_size(StrHashTable *t) {
	return sizeof(StrHashTableSlot) + ((t->data_size + sizeof(MaxAlign) - 1) / sizeof(MaxAlign)) * sizeof(MaxAlign);
}

static StrHashTableSlot *str_hash_table_insert_(StrHashTable *t, const char *str, size_t len) {
	str_hash_table_grow(t);
	size_t slots_cap = arr_len(t->slots);
	U64 hash = str_hash(str, len);
	StrHashTableSlot **slot = str_hash_table_slot_get(t->slots, str, len, hash % slots_cap);
	if (!*slot) {
		*slot = allocr_calloc(t->allocr, 1, str_hash_table_slot_size(t));
		(*slot)->str = str;
		(*slot)->len = len;
		++t->nentries;
	}
	return *slot;
}

/* use this if you don't need the slot */
static inline void *str_hash_table_insert(StrHashTable *t, const char *str, size_t len) {
	return str_hash_table_insert_(t, str, len)->data;
}

static StrHashTableSlot *str_hash_table_insert_anonymous_(StrHashTable *t) {
	str_hash_table_grow(t);
	size_t slots_cap = arr_len(t->slots);
	U32 slot_idx = (U32)((t->rand_seed = rand_u32(t->rand_seed)) % slots_cap);
	StrHashTableSlot **slot = str_hash_table_slot_get(t->slots, NULL, 0, slot_idx);
	if (!*slot) {
		*slot = allocr_calloc(t->allocr, 1, str_hash_table_slot_size(t));
		++t->nentries;
	}
	return *slot;
}

/* use this if you don't need the slot */
static inline void *str_hash_table_insert_anonymous(StrHashTable *t) {
	return str_hash_table_insert_anonymous_(t)->data;
}


static void str_hash_table_free(StrHashTable *t) {
	arr_foreach(t->slots, StrHashTableSlotPtr, slotp) {
		allocr_free(t->allocr, *slotp, str_hash_table_slot_size(t));
	}
	arr_cleara(&t->slots, t->allocr);
}

static StrHashTableSlot *str_hash_table_get_(StrHashTable *t, const char *str, size_t len) {
	size_t nslots = arr_len(t->slots);
	if (!nslots) return NULL;
	size_t slot_index = str_hash(str, len) % arr_len(t->slots);
	return *str_hash_table_slot_get(t->slots, str, len, slot_index);
}

static inline void *str_hash_table_get(StrHashTable *t, const char *str, size_t len) {
	StrHashTableSlot *slot = str_hash_table_get_(t, str, len);
	if (!slot) return NULL;
	return slot->data;
}

#ifdef RUN_TESTS
static void str_hash_table_test(void) {
	StrHashTable t;
	str_hash_table_create(&t, sizeof(int), NULL);
	int *p = str_hash_table_insert(&t, "Hello", 5);
	*p = 182;
	int *q = str_hash_table_insert(&t, "Hello", 5);
	assert(p == q);
	assert(*q == 182);
	*q = 112;
	int *r = str_hash_table_insert(&t, "Hellop", 6);
	assert(p != r);
	assert(*r == 0);
	*r = 999;
	int *s = str_hash_table_insert_anonymous(&t);
	assert(p != s && r != s);
	*s = 123;
	int *u = str_hash_table_get(&t, "Hello", 5);
	assert(p == u);
	assert(!str_hash_table_get(&t, "Hellopf", 7));
	str_hash_table_free(&t);
}
#endif