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sparsemap/src/sparsemap.c

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/*
* Copyright (c) 2024 Gregory Burd <greg@burd.me>. All rights reserved.
*
* 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.
*/
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <popcount.h>
#include <sparsemap.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef SPARSEMAP_DIAGNOSTIC
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
#pragma GCC diagnostic ignored "-Wvariadic-macros"
#define __sm_diag(format, ...) __sm_diag_(__FILE__, __LINE__, __func__, format, ##__VA_ARGS__)
#pragma GCC diagnostic pop
void __attribute__((format(printf, 4, 5))) __sm_diag_(const char *file, int line, const char *func, const char *format, ...)
{
va_list args;
fprintf(stderr, "%s:%d:%s(): ", file, line, func);
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
}
#define __sm_assert(expr) \
if (!(expr)) \
fprintf(stderr, "%s:%d:%s(): assertion failed! %s\n", __FILE__, __LINE__, __func__, #expr)
#define __sm_when_diag(expr) \
if (1) \
expr
#else
#define __sm_diag(file, line, func, format, ...) ((void)0)
#define __sm_assert(expr) ((void)0)
#define __sm_when_diag(expr) \
if (0) \
expr
#endif
#define IS_8_BYTE_ALIGNED(addr) (((uintptr_t)(addr)&0x7) == 0)
enum __SM_CHUNK_INFO {
/* metadata overhead: 4 bytes for __sm_chunk_t count */
SM_SIZEOF_OVERHEAD = sizeof(uint32_t),
/* number of bits that can be stored in a sm_bitvec_t */
SM_BITS_PER_VECTOR = (sizeof(sm_bitvec_t) * 8),
/* number of flags that can be stored in a single index byte */
SM_FLAGS_PER_INDEX_BYTE = 4,
/* number of flags that can be stored in the index */
SM_FLAGS_PER_INDEX = (sizeof(sm_bitvec_t) * SM_FLAGS_PER_INDEX_BYTE),
/* maximum capacity of a __sm_chunk (in bits) */
SM_CHUNK_MAX_CAPACITY = (SM_BITS_PER_VECTOR * SM_FLAGS_PER_INDEX),
/* sm_bitvec_t payload is all zeros (2#00) */
SM_PAYLOAD_ZEROS = 0,
/* sm_bitvec_t payload is all ones (2#11) */
SM_PAYLOAD_ONES = 3,
/* sm_bitvec_t payload is mixed (2#10) */
SM_PAYLOAD_MIXED = 2,
/* sm_bitvec_t is not used (2#01) */
SM_PAYLOAD_NONE = 1,
/* a mask for checking flags (2 bits, 2#11) */
SM_FLAG_MASK = 3,
/* return code for set(): ok, no further action required */
SM_OK = 0,
/* return code for set(): needs to grow this __sm_chunk_t */
SM_NEEDS_TO_GROW = 1,
/* return code for set(): needs to shrink this __sm_chunk_t */
SM_NEEDS_TO_SHRINK = 2
};
#define SM_CHUNK_GET_FLAGS(from, at) (((from)) & ((sm_bitvec_t)SM_FLAG_MASK << ((at)*2))) >> ((at)*2)
typedef struct {
sm_bitvec_t *m_data;
} __sm_chunk_t;
struct __attribute__((aligned(8))) sparsemap {
size_t m_capacity; /* The total size of m_data */
size_t m_data_used; /* The used size of m_data */
uint8_t *m_data; /* The serialized bitmap data */
};
/**
* Calculates the number of sm_bitvec_ts required by a single byte with flags
* (in m_data[0]).
*/
static size_t
__sm_chunk_map_calc_vector_size(uint8_t b)
{
// clang-format off
static int lookup[] = {
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
2, 2, 3, 2, 2, 2, 3, 2, 3, 3, 4, 3, 2, 2, 3, 2,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0,
1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 3, 2, 1, 1, 2, 1,
0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 1, 0, 0, 1, 0
};
// clang-format on
return (size_t)lookup[b];
}
/** @brief Returns the position of a sm_bitvec_t in m_data.
*
* Each chunk has a set of bitvec that are sometimes abbreviated due to
* compression (e.g. when a bitvec is all zeros or ones there is no need
* to store anything, so no wasted space).
*
* @param[in] map The chunk in question.
* @param[in] bv The index of the vector to find in the chunk.
* @returns the position of a sm_bitvec_t in m_data
*/
static size_t
__sm_chunk_map_get_position(__sm_chunk_t *map, size_t bv)
{
/* Handle 4 indices (1 byte) at a time. */
size_t num_bytes = bv / ((size_t)SM_FLAGS_PER_INDEX_BYTE * SM_BITS_PER_VECTOR);
size_t position = 0;
register uint8_t *p = (uint8_t *)map->m_data;
for (size_t i = 0; i < num_bytes; i++, p++) {
position += __sm_chunk_map_calc_vector_size(*p);
}
bv -= num_bytes * SM_FLAGS_PER_INDEX_BYTE;
for (size_t i = 0; i < bv; i++) {
size_t flags = SM_CHUNK_GET_FLAGS(*map->m_data, i);
if (flags == SM_PAYLOAD_MIXED) {
position++;
}
}
return position;
}
/** @brief Initialize __sm_chunk_t with provided data.
*
* @param[in] map The chunk in question.
* @param[in] data The memory to use within this chunk.
*/
static inline void
__sm_chunk_map_init(__sm_chunk_t *map, uint8_t *data)
{
map->m_data = (sm_bitvec_t *)data;
}
/** @brief Examines the chunk to determine its current capacity.
*
* @param[in] map The chunk in question.
* @returns the maximum capacity in bytes of this __sm_chunk_t
*/
static size_t
__sm_chunk_map_get_capacity(__sm_chunk_t *map)
{
size_t capacity = SM_CHUNK_MAX_CAPACITY;
register uint8_t *p = (uint8_t *)map->m_data;
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
if (!*p) {
continue;
}
for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
if (flags == SM_PAYLOAD_NONE) {
capacity -= SM_BITS_PER_VECTOR;
}
}
}
return capacity;
}
/** @brief Sets the capacity of this chunk.
*
* @param[in] map The chunk in question.
* @param[in] capacity The new capacity in bytes to assign to the chunk,
* must be less than SM_CHUNK_MAX_CAPACITY.
*/
static void
__sm_chunk_map_set_capacity(__sm_chunk_t *map, size_t capacity)
{
if (capacity >= SM_CHUNK_MAX_CAPACITY) {
return;
}
__sm_assert(capacity % SM_BITS_PER_VECTOR == 0);
size_t reduced = 0;
register uint8_t *p = (uint8_t *)map->m_data;
for (ssize_t i = sizeof(sm_bitvec_t) - 1; i >= 0; i--) {
for (int j = SM_FLAGS_PER_INDEX_BYTE - 1; j >= 0; j--) {
p[i] &= ~((sm_bitvec_t)SM_PAYLOAD_ONES << (j * 2));
p[i] |= ((sm_bitvec_t)SM_PAYLOAD_NONE << (j * 2));
reduced += SM_BITS_PER_VECTOR;
if (capacity + reduced == SM_CHUNK_MAX_CAPACITY) {
__sm_assert(__sm_chunk_map_get_capacity(map) == capacity);
return;
}
}
}
__sm_assert(__sm_chunk_map_get_capacity(map) == capacity);
}
/** @brief Examines the chunk to determine if it is empty.
*
* @param[in] map The chunk in question.
* @returns true if this __sm_chunk_t is empty
*/
static bool
__sm_chunk_map_is_empty(__sm_chunk_t *map)
{
/* The __sm_chunk_t is empty if all flags (in m_data[0]) are zero. */
if (map->m_data[0] == 0) {
return true;
}
/* It's also empty if all flags are Zero or None. */
register uint8_t *p = (uint8_t *)map->m_data;
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
if (*p) {
for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
if (flags != SM_PAYLOAD_NONE && flags != SM_PAYLOAD_ZEROS) {
return false;
}
}
}
}
return true;
}
/** @brief Examines the chunk to determine its size.
*
* @param[in] map The chunk in question.
* @returns the size of the data buffer, in bytes.
*/
static size_t
__sm_chunk_map_get_size(__sm_chunk_t *map)
{
/* At least one sm_bitvec_t is required for the flags (m_data[0]) */
size_t size = sizeof(sm_bitvec_t);
/* Use a lookup table for each byte of the flags */
register uint8_t *p = (uint8_t *)map->m_data;
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
size += sizeof(sm_bitvec_t) * __sm_chunk_map_calc_vector_size(*p);
}
return size;
}
/** @brief Examines the chunk at \b idx to determine that bit's state (set,
* or unset).
*
* @param[in] map The chunk in question.
* @param[in] idx The 0-based index into this chunk to examine.
* @returns the value of a bit at index \b idx
*/
static bool
__sm_chunk_map_is_set(__sm_chunk_t *map, size_t idx)
{
/* in which sm_bitvec_t is |idx| stored? */
size_t bv = idx / SM_BITS_PER_VECTOR;
__sm_assert(bv < SM_FLAGS_PER_INDEX);
/* now retrieve the flags of that sm_bitvec_t */
size_t flags = SM_CHUNK_GET_FLAGS(*map->m_data, bv);
switch (flags) {
case SM_PAYLOAD_ZEROS:
case SM_PAYLOAD_NONE:
return false;
case SM_PAYLOAD_ONES:
return true;
default:
__sm_assert(flags == SM_PAYLOAD_MIXED);
/* FALLTHROUGH */
}
/* get the sm_bitvec_t at |bv| */
sm_bitvec_t w = map->m_data[1 + __sm_chunk_map_get_position(map, bv)];
/* and finally check the bit in that sm_bitvec_t */
return (w & ((sm_bitvec_t)1 << (idx % SM_BITS_PER_VECTOR))) > 0;
}
/** @brief Assigns a state to a bit in the chunk (set or unset).
*
* Sets the value of a bit at index \b idx. Then updates position \b pos to the
* position of the sm_bitvec_t which is inserted/deleted and \b fill - the value
* of the fill word (used when growing).
*
* @param[in] map The chunk in question.
* @param[in] idx The 0-based index into this chunk to mutate.
* @param[in] value The new state for the \b idx'th bit.
* @param[in,out] pos The position of the sm_bitvec_t inserted/deleted within the chunk.
* @param[in,out] fill The value of the fill word (when growing).
* @param[in] retired When not retried, grow the map by a bitvec.
* @returns \b SM_NEEDS_TO_GROW, \b SM_NEEDS_TO_SHRINK, or \b SM_OK
* @note, the caller MUST to perform the relevant actions and call set() again,
* this time with \b retried = true.
*/
static int
__sm_chunk_map_set(__sm_chunk_t *map, size_t idx, bool value, size_t *pos, sm_bitvec_t *fill, bool retried)
{
/* In which sm_bitvec_t is |idx| stored? */
size_t bv = idx / SM_BITS_PER_VECTOR;
__sm_assert(bv < SM_FLAGS_PER_INDEX);
/* Now retrieve the flags of that sm_bitvec_t. */
size_t flags = SM_CHUNK_GET_FLAGS(*map->m_data, bv);
assert(flags != SM_PAYLOAD_NONE);
if (flags == SM_PAYLOAD_ZEROS) {
/* Easy - set bit to 0 in a sm_bitvec_t of zeroes. */
if (value == false) {
*pos = 0;
*fill = 0;
return SM_OK;
}
/* The sparsemap must grow this __sm_chunk_t by one additional sm_bitvec_t,
then try again. */
if (!retried) {
*pos = 1 + __sm_chunk_map_get_position(map, bv);
*fill = 0;
return SM_NEEDS_TO_GROW;
}
/* New flags are 2#10 meaning SM_PAYLOAD_MIXED. Currently, flags are set
to 2#00, so 2#00 | 2#10 = 2#10. */
*map->m_data |= ((sm_bitvec_t)SM_PAYLOAD_MIXED << (bv * 2));
/* FALLTHROUGH */
} else if (flags == SM_PAYLOAD_ONES) {
/* Easy - set bit to 1 in a sm_bitvec_t of ones. */
if (value == true) {
*pos = 0;
*fill = 0;
return SM_OK;
}
/* The sparsemap must grow this __sm_chunk_t by one additional sm_bitvec_t,
then try again. */
if (!retried) {
*pos = 1 + __sm_chunk_map_get_position(map, bv);
*fill = (sm_bitvec_t)-1;
return SM_NEEDS_TO_GROW;
}
/* New flags are 2#10 meaning SM_PAYLOAD_MIXED. Currently, flags are
set to 2#11, so 2#11 ^ 2#01 = 2#10. */
map->m_data[0] ^= ((sm_bitvec_t)SM_PAYLOAD_NONE << (bv * 2));
/* FALLTHROUGH */
}
/* Now flip the bit. */
size_t position = 1 + __sm_chunk_map_get_position(map, bv);
sm_bitvec_t w = map->m_data[position];
if (value) {
w |= (sm_bitvec_t)1 << (idx % SM_BITS_PER_VECTOR);
} else {
w &= ~((sm_bitvec_t)1 << (idx % SM_BITS_PER_VECTOR));
}
/* If this sm_bitvec_t is now all zeroes or ones then we can remove it. */
if (w == 0) {
map->m_data[0] &= ~((sm_bitvec_t)SM_PAYLOAD_ONES << (bv * 2));
*pos = position;
*fill = 0;
return SM_NEEDS_TO_SHRINK;
}
if (w == (sm_bitvec_t)-1) {
map->m_data[0] |= (sm_bitvec_t)SM_PAYLOAD_ONES << (bv * 2);
*pos = position;
*fill = 0;
return SM_NEEDS_TO_SHRINK;
}
map->m_data[position] = w;
*pos = 0;
*fill = 0;
return SM_OK;
}
/** @brief Merges into the chunk at \b offset all set bits from \b src.
*
* @param[in] map The chunk in question.
* @param[in] offset The fully aligned offset of the chunk to be merged.
*/
void
__sm_chunk_map_merge(sparsemap_t *map, sparsemap_idx_t offset, __sm_chunk_t src)
{
size_t capacity = __sm_chunk_map_get_capacity(&src);
for (sparsemap_idx_t j = 0; j < capacity; j++, offset++) {
if (__sm_chunk_map_is_set(&src, j)) {
sparsemap_set(map, offset, true);
}
}
}
/** @brief Finds the index of the \b n'th bit after \b offset bits with \b
* value.
*
* Scans the chunk \b map until after \b offset bits (of any value) have
* passed and then begins counting the bits that match \b value looking
* for the \b n'th bit. It may not be in this chunk, when it is offset is
*
* @param[in] map The chunk in question.
* @param[in] value Informs what we're seeking, a set or unset bit's position.
* @param offset[in,out] Sets \b offset to 0 if the n'th bit was found
* in this __sm_chunk_t, or reduced value of \b n bits observed the search up
* to a maximum of SM_BITS_PER_VECTOR.
* @returns the 0-based index of the n'th set bit when found, otherwise
* SM_BITS_PER_VECTOR
*/
static size_t
__sm_chunk_map_select(__sm_chunk_t *map, size_t n, ssize_t *offset, bool value)
{
size_t ret = 0;
register uint8_t *p;
p = (uint8_t *)map->m_data;
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
if (*p == 0 && value) {
ret += (size_t)SM_FLAGS_PER_INDEX_BYTE * SM_BITS_PER_VECTOR;
continue;
}
for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
if (flags == SM_PAYLOAD_NONE) {
continue;
}
if (flags == SM_PAYLOAD_ZEROS) {
if (value == true) {
ret += SM_BITS_PER_VECTOR;
continue;
} else {
if (n > SM_BITS_PER_VECTOR) {
n -= SM_BITS_PER_VECTOR;
ret += SM_BITS_PER_VECTOR;
continue;
}
*offset = -1;
return ret + n;
}
}
if (flags == SM_PAYLOAD_ONES) {
if (value == true) {
if (n > SM_BITS_PER_VECTOR) {
n -= SM_BITS_PER_VECTOR;
ret += SM_BITS_PER_VECTOR;
continue;
}
*offset = -1;
return ret + n;
} else {
ret += SM_BITS_PER_VECTOR;
continue;
}
}
if (flags == SM_PAYLOAD_MIXED) {
sm_bitvec_t w = map->m_data[1 + __sm_chunk_map_get_position(map, i * SM_FLAGS_PER_INDEX_BYTE + j)];
for (int k = 0; k < SM_BITS_PER_VECTOR; k++) {
if (value) {
if (w & ((sm_bitvec_t)1 << k)) {
if (n == 0) {
*offset = -1;
return ret;
}
n--;
}
ret++;
} else {
if (!(w & ((sm_bitvec_t)1 << k))) {
if (n == 0) {
*offset = -1;
return ret;
}
n--;
}
ret++;
}
}
}
}
}
*offset = n;
return ret;
}
/** @brief Counts the bits matching \b value in the range [0, \b idx]
* inclusive after ignoring the first \b offset bits in the chunk.
*
* Scans the chunk \b map until after \b offset bits (of any value) have
* passed and then begins counting the bits that match \b value. The
* result should never be greater than \b idx + 1 maxing out at
* SM_BITS_PER_VECTOR. A range of [0, 0] will count 1 bit at \b offset
* + 1 in this chunk. A range of [0, 9] will count 10 bits, starting
* with the 0th and ending with the 9th and return at most a count of
* 10.
*
* @param[in] map The chunk in question.
* @param offset[in,out] Decreases \b offset by the number of bits ignored,
* at most by SM_BITS_PER_VECTOR.
* @param[in] idx The ending value of the range (inclusive) to count.
* @param[out] pos The position of the last bit examined in this chunk, always
* <= SM_BITS_PER_VECTOR, used when counting unset bits that fall within this
* chunk's range but after the last set bit.
* @param[out] vec The last sm_bitvec_t, masked and shifted, so as to be able
* to examine the bits used in the last portion of the ranking as a way to
* skip forward during a #span() operation.
* @param[in] value Informs what we're seeking, set or unset bits.
* @returns the count of the bits matching \b value within the range.
*/
static size_t
__sm_chunk_map_rank(__sm_chunk_t *map, size_t *offset, size_t idx, size_t *pos, sm_bitvec_t *vec, bool value)
{
size_t ret = 0;
*pos = 0;
/* A chunk can only hold at most SM_CHUNK_MAX_CAPACITY bits, so if the
offset is larger than that, we're basically done. */
if (*offset > SM_CHUNK_MAX_CAPACITY) {
*pos = SM_CHUNK_MAX_CAPACITY;
*offset -= SM_CHUNK_MAX_CAPACITY;
return 0;
}
register uint8_t *p = (uint8_t *)map->m_data;
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
if (flags == SM_PAYLOAD_NONE) {
continue;
}
if (flags == SM_PAYLOAD_ZEROS) {
*vec = 0;
if (idx >= SM_BITS_PER_VECTOR) {
*pos += SM_BITS_PER_VECTOR;
idx -= SM_BITS_PER_VECTOR;
if (*offset > SM_BITS_PER_VECTOR) {
*offset = *offset - SM_BITS_PER_VECTOR;
} else {
if (value == false) {
ret += SM_BITS_PER_VECTOR - *offset;
}
*offset = 0;
}
} else {
*pos += idx + 1;
if (value == false) {
if (*offset > idx) {
*offset = *offset - idx;
} else {
ret += idx + 1 - *offset;
*offset = 0;
return ret;
}
} else {
return ret;
}
}
} else if (flags == SM_PAYLOAD_ONES) {
*vec = UINT64_MAX;
if (idx >= SM_BITS_PER_VECTOR) {
*pos += SM_BITS_PER_VECTOR;
idx -= SM_BITS_PER_VECTOR;
if (*offset > SM_BITS_PER_VECTOR) {
*offset = *offset - SM_BITS_PER_VECTOR;
} else {
if (value == true) {
ret += SM_BITS_PER_VECTOR - *offset;
}
*offset = 0;
}
} else {
*pos += idx + 1;
if (value == true) {
if (*offset > idx) {
*offset = *offset - idx;
} else {
ret += idx + 1 - *offset;
*offset = 0;
return ret;
}
} else {
return ret;
}
}
} else if (flags == SM_PAYLOAD_MIXED) {
sm_bitvec_t w = map->m_data[1 + __sm_chunk_map_get_position(map, i * SM_FLAGS_PER_INDEX_BYTE + j)];
if (idx >= SM_BITS_PER_VECTOR) {
*pos += SM_BITS_PER_VECTOR;
idx -= SM_BITS_PER_VECTOR;
uint64_t mask = *offset == 0 ? UINT64_MAX : ~(UINT64_MAX >> (SM_BITS_PER_VECTOR - (*offset >= 64 ? 64 : *offset)));
sm_bitvec_t mw;
if (value == true) {
mw = w & mask;
} else {
mw = ~w & mask;
}
size_t pc = popcountll(mw);
ret += pc;
*offset = (*offset > SM_BITS_PER_VECTOR) ? *offset - SM_BITS_PER_VECTOR : 0;
} else {
*pos += idx + 1;
sm_bitvec_t mw;
uint64_t mask;
uint64_t idx_mask = (idx == 63) ? UINT64_MAX : ((uint64_t)1 << (idx + 1)) - 1;
uint64_t offset_mask = *offset == 0 ? UINT64_MAX : ~(UINT64_MAX >> (SM_BITS_PER_VECTOR - (*offset >= 64 ? 64 : *offset)));
/* To count the set bits we need to mask off the portion of the vector that we need
to count then call popcount(). So, let's create a mask for the range between
offset and idx inclusive [*offset, idx]. */
mask = idx_mask & offset_mask;
if (value) {
mw = w & mask;
} else {
mw = ~w & mask;
}
int pc = popcountll(mw);
ret += pc;
*vec = mw >> ((*offset > 63) ? 63 : *offset);
*offset = *offset > idx ? *offset - idx + 1 : 0;
return ret;
}
}
}
}
return ret;
}
/** @brief Calls \b scanner with sm_bitmap_t for each vector in this chunk.
*
* Decompresses the whole chunk into separate bitmaps then calls visitor's
* \b #operator() function for all bits.
*
* @param[in] map The chunk in question.
* @param[in] start
* @param[in] scanner
* @param[in] skip The number of
* @returns the number of (set) bits that were passed to the scanner
*/
static size_t
__sm_chunk_map_scan(__sm_chunk_t *map, sm_idx_t start, void (*scanner)(sm_idx_t[], size_t, void *aux), size_t skip, void *aux)
{
size_t ret = 0;
register uint8_t *p = (uint8_t *)map->m_data;
sm_idx_t buffer[SM_BITS_PER_VECTOR];
for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
if (*p == 0) {
/* Skip chunks that are all zeroes. */
skip -= skip > SM_BITS_PER_VECTOR ? SM_BITS_PER_VECTOR : skip;
continue;
}
for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
if (flags == SM_PAYLOAD_NONE || flags == SM_PAYLOAD_ZEROS) {
/* Skip when all zeroes. */
skip -= skip > SM_BITS_PER_VECTOR ? SM_BITS_PER_VECTOR : skip;
} else if (flags == SM_PAYLOAD_ONES) {
if (skip) {
if (skip >= SM_BITS_PER_VECTOR) {
skip -= SM_BITS_PER_VECTOR;
ret += SM_BITS_PER_VECTOR;
continue;
}
size_t n = 0;
for (size_t b = skip; b < SM_BITS_PER_VECTOR; b++) {
buffer[n++] = start + b;
}
scanner(&buffer[0], n, aux);
ret += n;
skip = 0;
} else {
for (size_t b = 0; b < SM_BITS_PER_VECTOR; b++) {
buffer[b] = start + b;
}
scanner(&buffer[0], SM_BITS_PER_VECTOR, aux);
ret += SM_BITS_PER_VECTOR;
}
} else if (flags == SM_PAYLOAD_MIXED) {
sm_bitvec_t w = map->m_data[1 + __sm_chunk_map_get_position(map, i * SM_FLAGS_PER_INDEX_BYTE + j)];
size_t n = 0;
if (skip) {
if (skip >= SM_BITS_PER_VECTOR) {
skip -= SM_BITS_PER_VECTOR;
ret += SM_BITS_PER_VECTOR;
continue;
}
for (int b = 0; b < SM_BITS_PER_VECTOR; b++) {
if (skip > 0) {
skip--;
continue;
}
if (w & ((sm_bitvec_t)1 << b)) {
buffer[n++] = start + b;
ret++;
}
}
} else {
for (int b = 0; b < SM_BITS_PER_VECTOR; b++) {
if (w & ((sm_bitvec_t)1 << b)) {
buffer[n++] = start + b;
}
}
ret += n;
}
__sm_assert(n > 0);
scanner(&buffer[0], n, aux);
}
}
}
return ret;
}
/** @brief Provides the number of chunks currently in the map.
*
* @param[in] map The sparsemap_t in question.
* @returns the number of chunk maps in the sparsemap
*/
static size_t
__sm_get_chunk_map_count(sparsemap_t *map)
{
return *(uint32_t *)&map->m_data[0];
}
/** @brief Encapsulates the method to find the starting address of a chunk's
* data.
*
* @param[in] map The sparsemap_t in question.
* @param[in] offset The offset in bytes for the desired chunk map.
* @returns the data for the specified \b offset
*/
static inline uint8_t *
__sm_get_chunk_map_data(sparsemap_t *map, size_t offset)
{
return &map->m_data[SM_SIZEOF_OVERHEAD + offset];
}
/** @brief Encapsulates the method to find the address of the first unused byte
* in \b m_data.
*
* @param[in] map The sparsemap_t in question.
* @returns a pointer after the end of the used data
*/
static uint8_t *
__sm_get_chunk_map_end(sparsemap_t *map)
{
uint8_t *p = __sm_get_chunk_map_data(map, 0);
size_t count = __sm_get_chunk_map_count(map);
for (size_t i = 0; i < count; i++) {
p += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p);
p += __sm_chunk_map_get_size(&chunk);
}
return p;
}
/** @brief Provides the byte size amount of \b m_data consumed.
*
* @param[in] map The sparsemap_t in question.
* @returns the used size in the data buffer
*/
static size_t
__sm_get_size_impl(sparsemap_t *map)
{
uint8_t *start = __sm_get_chunk_map_data(map, 0);
uint8_t *p = start;
size_t count = __sm_get_chunk_map_count(map);
for (size_t i = 0; i < count; i++) {
p += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p);
p += __sm_chunk_map_get_size(&chunk);
}
return SM_SIZEOF_OVERHEAD + p - start;
}
/** @brief Aligns to SM_BITS_PER_VECTOR a given index \b idx.
*
* @param[in] idx The index to align.
* @returns the aligned offset (aligned to sm_bitvec_t capacity).
*/
static sm_idx_t
__sm_get_aligned_offset(size_t idx)
{
const size_t capacity = SM_BITS_PER_VECTOR;
return (idx / capacity) * capacity;
}
/** @brief Aligns to SM_CHUNK_MAP_CAPACITY a given index \b idx.
*
* @param[in] idx The index to align.
* @returns the aligned offset (aligned to __sm_chunk_t capacity)
*/
static sm_idx_t
__sm_get_fully_aligned_offset(size_t idx)
{
const size_t capacity = SM_CHUNK_MAX_CAPACITY;
return (idx / capacity) * capacity;
}
/** @brief Provides the byte offset of a chunk map at index \b idx.
*
* @param[in] map The sparsemap_t in question.
* @param[in] idx The index of the chunk map to locate.
* @returns the byte offset of a __sm_chunk_t in m_data, or -1 there
* are no chunks.
*/
static size_t
__sm_get_chunk_map_offset(sparsemap_t *map, sparsemap_idx_t idx)
{
size_t count = __sm_get_chunk_map_count(map);
if (count == 0) {
return -1;
}
uint8_t *start = __sm_get_chunk_map_data(map, 0);
uint8_t *p = start;
for (sparsemap_idx_t i = 0; i < count - 1; i++) {
sm_idx_t s = *(sm_idx_t *)p;
__sm_assert(s == __sm_get_aligned_offset(s));
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p + sizeof(sm_idx_t));
if (s >= idx || idx < s + __sm_chunk_map_get_capacity(&chunk)) {
break;
}
p += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&chunk);
}
return (ssize_t)(p - start);
}
/** @brief Sets the number of __sm_chunk_t's.
*
* @param[in] map The sparsemap_t in question.
* @param[in] new_count The new number of chunks in the map.
*/
static void
__sm_set_chunk_map_count(sparsemap_t *map, size_t new_count)
{
*(uint32_t *)&map->m_data[0] = (uint32_t)new_count;
}
/** @brief Appends raw data at the end of used portion of \b m_data.
*
* @param[in] map The sparsemap_t in question.
* @param[in] buffer The bytes to copy into \b m_data.
* @param[in] buffer_size The size of the byte array \b buffer to copy.
*/
static void
__sm_append_data(sparsemap_t *map, uint8_t *buffer, size_t buffer_size)
{
memcpy(&map->m_data[map->m_data_used], buffer, buffer_size);
map->m_data_used += buffer_size;
}
/** @brief Inserts data at \b offset in the middle of \b m_data.
*
* @param[in] map The sparsemap_t in question.
* @param[in] offset The offset in bytes into \b m_data to place the buffer.
* @param[in] buffer The bytes to copy into \b m_data.
* @param[in] buffer_size The size of the byte array \b buffer to copy.
*/
void
__sm_insert_data(sparsemap_t *map, size_t offset, uint8_t *buffer, size_t buffer_size)
{
uint8_t *p = __sm_get_chunk_map_data(map, offset);
memmove(p + buffer_size, p, map->m_data_used - offset);
memcpy(p, buffer, buffer_size);
map->m_data_used += buffer_size;
}
/** @brief Removes data from \b m_data.
*
* @param[in] map The sparsemap_t in question.
* @param[in] offset The offset in bytes into \b m_data at which to excise data.
* @param[in] gap_size The size of the excision.
*/
static void
__sm_remove_data(sparsemap_t *map, size_t offset, size_t gap_size)
{
assert(map->m_data_used >= offset + gap_size);
uint8_t *p = __sm_get_chunk_map_data(map, offset);
memmove(p, p + gap_size, map->m_data_used - offset - gap_size);
map->m_data_used -= gap_size;
}
/*
* The following is the "Sparsemap" implementation, it uses chunk maps (code above)
* and is the public API for this compressed bitmap representation.
*/
void
sparsemap_clear(sparsemap_t *map)
{
if (map == NULL) {
return;
}
memset(map->m_data, 0, map->m_capacity);
map->m_data_used = SM_SIZEOF_OVERHEAD;
__sm_set_chunk_map_count(map, 0);
}
sparsemap_t *
sparsemap(size_t size)
{
if (size == 0) {
size = 1024;
}
size_t data_size = (size * sizeof(uint8_t));
/* Ensure that m_data is 8-byte aligned. */
size_t total_size = sizeof(sparsemap_t) + data_size;
size_t padding = total_size % 8 == 0 ? 0 : 8 - (total_size % 8);
total_size += padding;
sparsemap_t *map = (sparsemap_t *)calloc(1, total_size);
if (map) {
uint8_t *data = (uint8_t *)(((uintptr_t)map + sizeof(sparsemap_t)) & ~(uintptr_t)7);
sparsemap_init(map, data, size);
__sm_when_diag({ __sm_assert(IS_8_BYTE_ALIGNED(map->m_data)); });
}
sparsemap_clear(map);
return map;
}
sparsemap_t *
sparsemap_wrap(uint8_t *data, size_t size)
{
sparsemap_t *map = (sparsemap_t *)calloc(1, sizeof(sparsemap_t));
if (map) {
sparsemap_init(map, data, size);
}
return map;
}
void
sparsemap_init(sparsemap_t *map, uint8_t *data, size_t size)
{
map->m_data = data;
map->m_data_used = 0;
map->m_capacity = size;
sparsemap_clear(map);
}
void
sparsemap_open(sparsemap_t *map, uint8_t *data, size_t size)
{
map->m_data = data;
map->m_data_used = map->m_data_used > 0 ? map->m_data_used : 0;
map->m_capacity = size;
}
sparsemap_t *
sparsemap_set_data_size(sparsemap_t *map, size_t size, uint8_t *data)
{
size_t data_size = (size * sizeof(uint8_t));
/* If this sparsemap was allocated by the sparsemap() API and we're not handed
a new data, it's up to us to resize it. */
if (data == NULL && (uintptr_t)map->m_data == (uintptr_t)map + sizeof(sparsemap_t) && size > map->m_capacity) {
/* Ensure that m_data is 8-byte aligned. */
size_t total_size = sizeof(sparsemap_t) + data_size;
size_t padding = total_size % 8 == 0 ? 0 : 8 - (total_size % 8);
total_size += padding;
sparsemap_t *m = (sparsemap_t *)realloc(map, total_size);
if (!m) {
return NULL;
}
memset(((uint8_t *)m) + sizeof(sparsemap_t) + (m->m_capacity * sizeof(uint8_t)), 0, size - m->m_capacity + padding);
m->m_capacity = data_size;
m->m_data = (uint8_t *)(((uintptr_t)m + sizeof(sparsemap_t)) & ~(uintptr_t)7);
__sm_when_diag({ __sm_assert(IS_8_BYTE_ALIGNED(m->m_data)); }) return m;
} else {
/* NOTE: It is up to the caller to realloc their buffer and provide it here
for reassignment. */
if (data != NULL && data_size > sparsemap_get_capacity(map) && data != map->m_data) {
map->m_data = data;
}
map->m_capacity = size;
return map;
}
}
double
sparsemap_capacity_remaining(sparsemap_t *map)
{
if (map->m_data_used > map->m_capacity) {
return 0;
}
if (map->m_capacity == 0) {
return 100.0;
}
return 100 - (((double)map->m_data_used / (double)map->m_capacity) * 100);
}
size_t
sparsemap_get_capacity(sparsemap_t *map)
{
return map->m_capacity;
}
bool
sparsemap_is_set(sparsemap_t *map, sparsemap_idx_t idx)
{
__sm_assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
/* Get the __sm_chunk_t which manages this index */
ssize_t offset = __sm_get_chunk_map_offset(map, idx);
/* No __sm_chunk_t's available -> the bit is not set */
if (offset == -1) {
return false;
}
/* Otherwise load the __sm_chunk_t */
uint8_t *p = __sm_get_chunk_map_data(map, offset);
sm_idx_t start = *(sm_idx_t *)p;
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p + sizeof(sm_idx_t));
/* Determine if the bit is out of bounds of the __sm_chunk_t; if yes then
the bit is not set. */
if (idx < start || (unsigned long)idx - start >= __sm_chunk_map_get_capacity(&chunk)) {
return false;
}
/* Otherwise ask the __sm_chunk_t whether the bit is set. */
return __sm_chunk_map_is_set(&chunk, idx - start);
}
sparsemap_idx_t
sparsemap_set(sparsemap_t *map, sparsemap_idx_t idx, bool value)
{
__sm_assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
/* Get the __sm_chunk_t which manages this index */
ssize_t offset = __sm_get_chunk_map_offset(map, idx);
bool dont_grow = false;
if (map->m_data_used + sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2 > map->m_capacity) {
errno = ENOSPC;
return SPARSEMAP_IDX_MAX;
}
/* If there are no __sm_chunk_t and the bit is set to zero then return
immediately; otherwise create an initial __sm_chunk_t. */
if (offset == -1) {
if (value == false) {
return idx;
}
uint8_t buf[sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2] = { 0 };
__sm_append_data(map, &buf[0], sizeof(buf));
uint8_t *p = __sm_get_chunk_map_data(map, 0);
*(sm_idx_t *)p = __sm_get_fully_aligned_offset(idx);
__sm_set_chunk_map_count(map, 1);
/* We already inserted an additional sm_bitvec_t; given that has happened
there is no need to grow the vector even further. */
dont_grow = true;
offset = 0;
}
/* Load the __sm_chunk_t */
uint8_t *p = __sm_get_chunk_map_data(map, offset);
sm_idx_t start = *(sm_idx_t *)p;
/* The new index is smaller than the first __sm_chunk_t: create a new
__sm_chunk_t and insert it at the front. */
if (idx < start) {
if (value == false) {
/* nothing to do */
return idx;
}
uint8_t buf[sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2] = { 0 };
__sm_insert_data(map, offset, &buf[0], sizeof(buf));
size_t aligned_idx = __sm_get_fully_aligned_offset(idx);
if (start - aligned_idx < SM_CHUNK_MAX_CAPACITY) {
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p + sizeof(sm_idx_t));
__sm_chunk_map_set_capacity(&chunk, start - aligned_idx);
}
*(sm_idx_t *)p = start = aligned_idx;
/* We just added another chunk map! */
__sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) + 1);
/* We already inserted an additional sm_bitvec_t; later on there
is no need to grow the vector even further. */
dont_grow = true;
}
/* A __sm_chunk_t exists, but the new index exceeds its capacities: create
a new __sm_chunk_t and insert it after the current one. */
else {
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p + sizeof(sm_idx_t));
if (idx - start >= (sparsemap_idx_t)__sm_chunk_map_get_capacity(&chunk)) {
if (value == false) {
/* nothing to do */
return idx;
}
size_t size = __sm_chunk_map_get_size(&chunk);
offset += (sizeof(sm_idx_t) + size);
p += sizeof(sm_idx_t) + size;
uint8_t buf[sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2] = { 0 };
__sm_insert_data(map, offset, &buf[0], sizeof(buf));
start += __sm_chunk_map_get_capacity(&chunk);
if ((sparsemap_idx_t)start + SM_CHUNK_MAX_CAPACITY < idx) {
start = __sm_get_fully_aligned_offset(idx);
}
*(sm_idx_t *)p = start;
/* We just added another chunk map! */
__sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) + 1);
/* We already inserted an additional sm_bitvec_t; later on there
is no need to grow the vector even further. */
dont_grow = true;
}
}
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p + sizeof(sm_idx_t));
/* Now update the __sm_chunk_t. */
size_t position;
sm_bitvec_t fill;
int code = __sm_chunk_map_set(&chunk, idx - start, value, &position, &fill, false);
switch (code) {
case SM_OK:
break;
case SM_NEEDS_TO_GROW:
if (!dont_grow) {
offset += (sizeof(sm_idx_t) + position * sizeof(sm_bitvec_t));
__sm_insert_data(map, offset, (uint8_t *)&fill, sizeof(sm_bitvec_t));
}
__sm_chunk_map_set(&chunk, idx - start, value, &position, &fill, true);
break;
case SM_NEEDS_TO_SHRINK:
/* If the __sm_chunk_t is empty then remove it. */
if (__sm_chunk_map_is_empty(&chunk)) {
__sm_assert(position == 1);
__sm_remove_data(map, offset, sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2);
__sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) - 1);
} else {
offset += (sizeof(sm_idx_t) + position * sizeof(sm_bitvec_t));
__sm_remove_data(map, offset, sizeof(sm_bitvec_t));
}
break;
default:
__sm_assert(!"shouldn't be here");
#ifdef DEBUG
abort();
#endif
break;
}
__sm_assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
return idx;
}
sparsemap_idx_t
sparsemap_get_starting_offset(sparsemap_t *map)
{
size_t count = __sm_get_chunk_map_count(map);
if (count == 0) {
return 0;
}
sm_idx_t *chunk = (sm_idx_t *)__sm_get_chunk_map_data(map, 0);
return (sparsemap_idx_t)*chunk;
}
/**
* Returns the used size in the data buffer.
*/
size_t
sparsemap_get_size(sparsemap_t *map)
{
if (map->m_data_used) {
__sm_when_diag({ __sm_assert(map->m_data_used == __sm_get_size_impl(map)); });
return map->m_data_used;
}
return map->m_data_used = __sm_get_size_impl(map);
}
/**
* Decompresses the whole bitmap; calls scanner for all bits.
*/
void
sparsemap_scan(sparsemap_t *map, void (*scanner)(sm_idx_t[], size_t, void *aux), size_t skip, void *aux)
{
uint8_t *p = __sm_get_chunk_map_data(map, 0);
size_t count = __sm_get_chunk_map_count(map);
for (size_t i = 0; i < count; i++) {
sm_idx_t start = *(sm_idx_t *)p;
p += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p);
size_t skipped = __sm_chunk_map_scan(&chunk, start, scanner, skip, aux);
if (skip) {
assert(skip >= skipped);
skip -= skipped;
}
p += __sm_chunk_map_get_size(&chunk);
}
}
void
sparsemap_merge(sparsemap_t *map, sparsemap_t *other)
{
uint8_t *src, *dst;
size_t src_count = __sm_get_chunk_map_count(other), dst_count = __sm_get_chunk_map_count(map), max_chunk_count = src_count + dst_count;
// TODO: ensure there is space, or ENOSPC
dst = __sm_get_chunk_map_data(map, 0);
src = __sm_get_chunk_map_data(other, 0);
for (size_t i = 0; i < max_chunk_count && src_count; i++) {
sm_idx_t src_start = *(sm_idx_t *)src;
sm_idx_t dst_start = *(sm_idx_t *)dst;
src_start = __sm_get_fully_aligned_offset(src_start);
dst_start = __sm_get_fully_aligned_offset(dst_start);
if (src_start > dst_start && dst_count > 0) {
__sm_chunk_t dst_chunk;
__sm_chunk_map_init(&dst_chunk, dst + sizeof(sm_idx_t));
dst += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&dst_chunk);
dst_count--;
continue;
}
if (src_start == dst_start && dst_count > 0) {
/* Chunks overlap, merge them. */
__sm_chunk_t src_chunk;
__sm_chunk_map_init(&src_chunk, src + sizeof(sm_idx_t));
__sm_chunk_t dst_chunk;
__sm_chunk_map_init(&dst_chunk, dst + sizeof(sm_idx_t));
__sm_chunk_map_merge(map, src_start, src_chunk);
*(sm_idx_t *)dst = __sm_get_fully_aligned_offset(src_start);
src += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&src_chunk);
dst += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&dst_chunk);
dst_count--;
src_count--;
continue;
}
if (src_start < dst_start || dst_count == 0) {
__sm_chunk_t src_chunk;
__sm_chunk_map_init(&src_chunk, src + sizeof(sm_idx_t));
size_t src_size = __sm_chunk_map_get_size(&src_chunk);
if (dst_count == 0) {
__sm_append_data(map, src, sizeof(sm_idx_t) + src_size);
} else {
size_t offset = __sm_get_chunk_map_offset(map, dst_start);
__sm_insert_data(map, offset, src, sizeof(sm_idx_t) + src_size);
}
/* Update the chunk count and data_used. */
__sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) + 1);
/* Carry on to the next chunk. */
__sm_chunk_t dst_chunk;
__sm_chunk_map_init(&dst_chunk, dst + sizeof(sm_idx_t));
src += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&src_chunk);
dst += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&dst_chunk);
src_count--;
}
}
}
void
sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
{
assert(offset % SM_BITS_PER_VECTOR == 0);
/* |dst| points to the destination buffer */
uint8_t *dst = __sm_get_chunk_map_end(other);
/* |src| points to the source-chunk map */
uint8_t *src = __sm_get_chunk_map_data(map, 0);
/* |offset| is relative to the beginning of this sparsemap_t; best
make it absolute. */
offset += *(sm_idx_t *)src;
bool in_middle = false;
uint8_t *prev = src;
size_t i, count = __sm_get_chunk_map_count(map);
for (i = 0; i < count; i++) {
sm_idx_t start = *(sm_idx_t *)src;
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, src + sizeof(sm_idx_t));
if (start == offset) {
break;
}
if (start + __sm_chunk_map_get_capacity(&chunk) > (unsigned long)offset) {
in_middle = true;
break;
}
if (start > offset) {
src = prev;
i--;
break;
}
prev = src;
src += sizeof(sm_idx_t) + __sm_chunk_map_get_size(&chunk);
}
if (i == count) {
assert(sparsemap_get_size(map) > SM_SIZEOF_OVERHEAD);
assert(sparsemap_get_size(other) > SM_SIZEOF_OVERHEAD);
return;
}
/* Now copy all the remaining chunks. */
int moved = 0;
/* If |offset| is in the middle of a chunk then this chunk has to be split */
if (in_middle) {
uint8_t buf[sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2] = { 0 };
memcpy(dst, &buf[0], sizeof(buf));
*(sm_idx_t *)dst = offset;
dst += sizeof(sm_idx_t);
/* the |other| sparsemap_t now has one additional chunk */
__sm_set_chunk_map_count(other, __sm_get_chunk_map_count(other) + 1);
if (other->m_data_used != 0) {
other->m_data_used += sizeof(sm_idx_t) + sizeof(sm_bitvec_t);
}
src += sizeof(sm_idx_t);
__sm_chunk_t s_chunk;
__sm_chunk_map_init(&s_chunk, src);
size_t capacity = __sm_chunk_map_get_capacity(&s_chunk);
__sm_chunk_t d_chunk;
__sm_chunk_map_init(&d_chunk, dst);
__sm_chunk_map_set_capacity(&d_chunk, capacity - (offset % capacity));
/* Now copy the bits. */
sparsemap_idx_t d = offset;
for (size_t j = offset % capacity; j < capacity; j++, d++) {
if (__sm_chunk_map_is_set(&s_chunk, j)) {
sparsemap_set(other, d, true);
}
}
src += __sm_chunk_map_get_size(&s_chunk);
size_t dsize = __sm_chunk_map_get_size(&d_chunk);
dst += dsize;
i++;
/* Reduce the capacity of the source-chunk map. */
__sm_chunk_map_set_capacity(&s_chunk, offset % capacity);
}
/* Now continue with all remaining chunk maps. */
for (; i < count; i++) {
sm_idx_t start = *(sm_idx_t *)src;
src += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, src);
size_t s = __sm_chunk_map_get_size(&chunk);
*(sm_idx_t *)dst = start;
dst += sizeof(sm_idx_t);
memcpy(dst, src, s);
src += s;
dst += s;
moved++;
}
/* Force new calculation. */
other->m_data_used = 0;
map->m_data_used = 0;
/* Update the Chunk Map counters. */
__sm_set_chunk_map_count(map, __sm_get_chunk_map_count(map) - moved);
__sm_set_chunk_map_count(other, __sm_get_chunk_map_count(other) + moved);
assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
assert(sparsemap_get_size(other) > SM_SIZEOF_OVERHEAD);
}
sparsemap_idx_t
sparsemap_select(sparsemap_t *map, sparsemap_idx_t n, bool value)
{
assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
sm_idx_t start;
size_t count = __sm_get_chunk_map_count(map);
uint8_t *p = __sm_get_chunk_map_data(map, 0);
for (size_t i = 0; i < count; i++) {
start = *(sm_idx_t *)p;
/* Start of this chunk is greater than n meaning there are a set of 0s
before the first 1 sufficient to consume n. */
if (value == false && i == 0 && start > n) {
return n;
}
p += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p);
ssize_t new_n = n;
size_t index = __sm_chunk_map_select(&chunk, n, &new_n, value);
if (new_n == -1) {
return start + index;
}
n = new_n;
p += __sm_chunk_map_get_size(&chunk);
}
return SPARSEMAP_IDX_MAX;
}
size_t
sparsemap_rank_vec(sparsemap_t *map, size_t x, size_t y, bool value, sm_bitvec_t *vec)
{
assert(sparsemap_get_size(map) >= SM_SIZEOF_OVERHEAD);
size_t amt, gap, pos = 0, result = 0, prev = 0, count, len = y - x + 1;
uint8_t *p;
if (x > y) {
return 0;
}
count = __sm_get_chunk_map_count(map);
if (count == 0) {
if (value == false) {
/* The count/rank of unset bits in an empty map is inf, so what you requested is the answer. */
return len;
}
}
p = __sm_get_chunk_map_data(map, 0);
for (size_t i = 0; i < count; i++) {
sm_idx_t start = *(sm_idx_t *)p;
/* [prev, start + pos), prev is the last bit examined 0-based. */
if (i == 0) {
gap = start;
} else {
if (prev + SM_CHUNK_MAX_CAPACITY == start) {
gap = 0;
} else {
gap = start - (prev + pos);
}
}
/* Start of this chunk is greater than the end of the desired range. */
if (start > y) {
if (value == true) {
/* We're counting set bits and this chunk starts after the range
[x, y], we're done. */
return result;
} else {
if (i == 0) {
/* We're counting unset bits and the first chunk starts after the
range meaning everything proceeding this chunk was zero and should
be counted, also we're done. */
result += (y - x) + 1;
return result;
} else {
/* We're counting unset bits and some chunk starts after the range, so
we've counted enough, we're done. */
if (pos > y) {
return result;
} else {
if (y - pos < gap) {
result += y - pos;
return result;
} else {
result += gap;
return result;
}
}
}
}
} else {
/* The range and this chunk overlap. */
if (value == false) {
if (x > gap) {
x -= gap;
} else {
result += gap - x;
x = 0;
}
} else {
if (x > gap) {
x -= gap;
}
}
}
prev = start;
p += sizeof(sm_idx_t);
__sm_chunk_t chunk;
__sm_chunk_map_init(&chunk, p);
/* Count all the set/unset inside this chunk. */
amt = __sm_chunk_map_rank(&chunk, &x, y - start, &pos, vec, value);
result += amt;
p += __sm_chunk_map_get_size(&chunk);
}
/* Count any additional unset bits that fall outside the last chunk but
within the range. */
if (value == false) {
size_t last = prev - 1 + pos;
if (y > last) {
result += y - last - x;
}
}
return result;
}
size_t
sparsemap_rank(sparsemap_t *map, size_t x, size_t y, bool value)
{
sm_bitvec_t vec;
return sparsemap_rank_vec(map, x, y, value, &vec);
}
size_t
sparsemap_span(sparsemap_t *map, sparsemap_idx_t idx, size_t len, bool value)
{
size_t rank, nth;
sm_bitvec_t vec = 0;
sparsemap_idx_t offset;
/* When skipping forward to `idx` offset in the map we can determine how
many selects we can avoid by taking the rank of the range and starting
at that bit. */
nth = (idx == 0) ? 0 : sparsemap_rank(map, 0, idx - 1, value);
/* Find the first bit that matches value, then... */
offset = sparsemap_select(map, nth, value);
do {
/* See if the rank of the bits in the range starting at offset is equal
to the desired amount. */
rank = (len == 1) ? 1 : sparsemap_rank_vec(map, offset, offset + len - 1, value, &vec);
if (rank >= len) {
/* We've found what we're looking for, return the index of the first
bit in the range. */
break;
}
/* Now we try to jump forward as much as possible before we look for a
new match. We do this by counting the remaining bits in the returned
vec from the call to rank_vec(). */
int amt = 1;
if (vec > 0) {
/* The returned vec had som set bits, let's move forward in the map as much
as possible (max: 64 bit positions). */
int max = len > SM_BITS_PER_VECTOR ? SM_BITS_PER_VECTOR : len;
while (amt < max && (vec & 1 << amt)) {
amt++;
}
}
nth += amt;
offset = sparsemap_select(map, nth, value);
} while (SPARSEMAP_FOUND(offset));
return offset;
}
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