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| author | Mehmet Samet Duman <yongdohyun@projecttick.org> | 2026-04-02 18:51:45 +0300 |
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| committer | Mehmet Samet Duman <yongdohyun@projecttick.org> | 2026-04-02 18:51:45 +0300 |
| commit | d3261e64152397db2dca4d691a990c6bc2a6f4dd (patch) | |
| tree | fac2f7be638651181a72453d714f0f96675c2b8b /archived/ptlibzippy/contrib/minizip/skipset.h | |
| parent | 31b9a8949ed0a288143e23bf739f2eb64fdc63be (diff) | |
| download | Project-Tick-d3261e64152397db2dca4d691a990c6bc2a6f4dd.tar.gz Project-Tick-d3261e64152397db2dca4d691a990c6bc2a6f4dd.zip | |
NOISSUE add archived projects
Signed-off-by: Mehmet Samet Duman <yongdohyun@projecttick.org>
Diffstat (limited to 'archived/ptlibzippy/contrib/minizip/skipset.h')
| -rw-r--r-- | archived/ptlibzippy/contrib/minizip/skipset.h | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/archived/ptlibzippy/contrib/minizip/skipset.h b/archived/ptlibzippy/contrib/minizip/skipset.h new file mode 100644 index 0000000000..f1b18e04ec --- /dev/null +++ b/archived/ptlibzippy/contrib/minizip/skipset.h @@ -0,0 +1,367 @@ +/* skipset.h -- set operations using a skiplist +// Copyright (C) 2024-2026 Mark Adler +// Copyright (C) 2026 Project Tick +// See MiniZip_info.txt for the license. + +// This implements a skiplist set, i.e. just keys, no data, with ~O(log n) time +// insert and search operations. The application defines the type of a key, and +// provides a function to compare two keys. + +// This header is not definitions of functions found in another source file -- +// it creates the set functions, with the application's key type, right where +// the #include is. Before this header is #included, these must be defined: +// +// 1. A macro or typedef for set_key_t, the type of a key. +// 2. A macro or function set_cmp(a, b) to compare two keys. The return values +// are < 0 for a < b, 0 for a == b, and > 0 for a > b. +// 3. A macro or function set_drop(s, k) to release the key k's resources, if +// any, when doing a set_end() or set_clear(). s is a pointer to the set +// that key is in, for use with set_free() if desired. +// +// Example usage: +// +// typedef int set_key_t; +// #define set_cmp(a, b) ((a) < (b) ? -1 : (a) == (b) ? 0 : 1) +// #define set_drop(s, k) +// #include "skipset.h" +// +// int test(void) { // return 0: good, 1: bad, -1: out of memory +// set_t set; +// if (setjmp(set.env)) +// return -1; +// set_start(&set); +// set_insert(&set, 2); +// set_insert(&set, 1); +// set_insert(&set, 7); +// int bad = !set_found(&set, 2); +// bad = bad || set_found(&set, 5); +// set_end(&set); +// return bad; +// } +// +// Interface summary (see more details below): +// - set_t is the type of the set being operated on (a set_t pointer is passed) +// - set_start() initializes a new, empty set (initialize set.env first) +// - set_insert() inserts a new key into the set, or not if it's already there +// - set_found() determines whether or not a key is in the set +// - set_end() ends the use of the set, freeing all memory +// - set_clear() empties the set, equivalent to set_end() and then set_start() +// - set_ok() checks if set appears to be usable, i.e. started and not ended +// +// Auxiliary functions available to the application: +// - set_alloc() allocates memory with optional tracking (#define SET_TRACK) +// - set_free() deallocates memory allocated by set_alloc() +// - set_rand() returns 32 random bits (seeded by set_start()) */ + +#ifndef SKIPSET_H +#define SKIPSET_H + +#include <stdlib.h> /* realloc(), free(), NULL, size_t */ +#include <stddef.h> /* ptrdiff_t */ +#include <setjmp.h> /* jmp_buf, longjmp() */ +#include <errno.h> /* ENOMEM */ +#include <time.h> /* time(), clock() */ +#include <assert.h> /* assert.h */ +#include "ints.h" /* i16_t, ui32_t, ui64_t */ + +/* Structures and functions below noted as "--private--" should not be used by +// the application. set_t is partially private and partially public -- see the +// comments there. + +// There is no POSIX random() in MSVC, and rand() is awful. For portability, we +// cannot rely on a library function for random numbers. Instead we use the +// fast and effective algorithm below, invented by Melissa O'Neill. + +// *Really* minimal PCG32 code / (c) 2014 M.E. O'Neill / www.pcg-random.org +// Licensed under Apache License 2.0 (NO WARRANTY, etc. see website) +// --private-- Random number generator state. */ +typedef struct { + ui64_t state; /* 64-bit generator state */ + ui64_t inc; /* 63-bit sequence id */ +} set_rand_t; +/* --private-- Initialize the state *gen using seed and seq. seed seeds the +// advancing 64-bit state. seq is a sequence selection constant. */ +void set_seed(set_rand_t *gen, ui64_t seed, ui64_t seq) { + gen->inc = (seq << 1) | 1; + gen->state = (seed + gen->inc) * 6364136223846793005ULL + gen->inc; +} +/* Start a unique random number sequence using bits from noise sources. */ +void set_uniq(set_rand_t *gen, const void *ptr) { + set_seed(gen, ((ui64_t)(ptrdiff_t)ptr << 32) ^ + ((ui64_t)time(NULL) << 12) ^ clock(), 0); +} +/* Return 32 random bits, advancing the state *gen. */ +ui32_t set_rand(set_rand_t *gen) { + ui64_t state = gen->state; + gen->state = state * 6364136223846793005ULL + gen->inc; + ui32_t mix = (ui32_t)(((state >> 18) ^ state) >> 27); + int rot = state >> 59; + return (mix >> rot) | (mix << ((-rot) & 31)); +} +/* End of PCG32 code. */ + +/* --private-- Linked-list node. */ +typedef struct set_node_s set_node_t; +struct set_node_s { + set_key_t key; /* the key (not used for head or path) */ + i16_t size; /* number of allocated pointers in right[] */ + i16_t fill; /* number of pointers in right[] filled in */ + set_node_t **right; /* pointer for each level, each to the right */ +}; + +/* A set. The application sets env, may use gen with set_rand(), and may read +// allocs and memory. The remaining variables are --private-- . */ +typedef struct set_s { + set_node_t *head; /* skiplist head -- no key, just links */ + set_node_t *path; /* right[] is path to key from set_found() */ + set_node_t *node; /* node under construction, in case of longjmp() */ + i16_t depth; /* maximum depth of the skiplist */ + ui64_t ran; /* a precious trove of random bits */ + set_rand_t gen; /* random number generator state */ + jmp_buf env; /* setjmp() environment for allocation errors */ +#ifdef SET_TRACK + size_t allocs; /* number of allocations */ + size_t memory; /* total amount of allocated memory (>= requests) */ +#endif +} set_t; + +/* Memory allocation and deallocation. set_alloc(set, ptr, size) returns a +// pointer to an allocation of size bytes if ptr is NULL, or the previous +// allocation ptr resized to size bytes. set_alloc() will never return NULL. +// set_free(set, ptr) frees an allocation created by set_alloc(). These may be +// used by the application. e.g. if allocation tracking is desired. */ +#ifdef SET_TRACK +/* Track the number of allocations and the total backing memory size. */ +# if defined(_WIN32) +# include <malloc.h> +# define SET_ALLOC_SIZE(ptr) _msize(ptr) +# elif defined(__MACH__) +# include <malloc/malloc.h> +# define SET_ALLOC_SIZE(ptr) malloc_size(ptr) +# elif defined(__linux__) +# include <malloc.h> +# define SET_ALLOC_SIZE(ptr) malloc_usable_size(ptr) +# elif defined(__FreeBSD__) +# include <malloc_np.h> +# define SET_ALLOC_SIZE(ptr) malloc_usable_size(ptr) +# elif defined(__NetBSD__) +# include <jemalloc/jemalloc.h> +# define SET_ALLOC_SIZE(ptr) malloc_usable_size(ptr) +# else // e.g. OpenBSD +# define SET_ALLOC_SIZE(ptr) 0 +# endif +// With tracking. +void *set_alloc(set_t *set, void *ptr, size_t size) { + size_t had = ptr == NULL ? 0 : SET_ALLOC_SIZE(ptr); + void *mem = realloc(ptr, size); + if (mem == NULL) + longjmp(set->env, ENOMEM); + set->allocs += ptr == NULL; + set->memory += SET_ALLOC_SIZE(mem) - had; + return mem; +} +void set_free(set_t *set, void *ptr) { + if (ptr != NULL) { + set->allocs--; + set->memory -= SET_ALLOC_SIZE(ptr); + free(ptr); + } +} +#else +/* Without tracking. */ +void *set_alloc(set_t *set, void *ptr, size_t size) { + void *mem = realloc(ptr, size); + if (mem == NULL) + longjmp(set->env, ENOMEM); + return mem; +} +void set_free(set_t *set, void *ptr) { + (void)set; + free(ptr); +} +#endif + +/* --private-- Grow node's array right[] as needed to be able to hold at least +// want links. If fill is true, assure that the first want links are filled in, +// setting them to set->head if not previously filled in. Otherwise it is +// assumed that the first want links are about to be filled in. */ +void set_grow(set_t *set, set_node_t *node, int want, int fill) { + if (node->size < want) { + int more = node->size ? node->size : 1; + while (more < want) + more <<= 1; + node->right = set_alloc(set, node->right, + (size_t)more * sizeof(set_node_t *)); + node->size = (i16_t)more; + } + int i; + if (fill) + for (i = node->fill; i < want; i++) + node->right[i] = set->head; + node->fill = (i16_t)want; +} + +/* --private-- Return a new node. key is left uninitialized. */ +set_node_t *set_node(set_t *set) { + set_node_t *node = set_alloc(set, NULL, sizeof(set_node_t)); + node->size = 0; + node->fill = 0; + node->right = NULL; + return node; +} + +/* --private-- Free the list linked from head, along with the keys. */ +void set_sweep(set_t *set) { + set_node_t *step = set->head->right[0]; + while (step != set->head) { + set_node_t *next = step->right[0]; /* save link to next node */ + set_drop(set, step->key); + set_free(set, step->right); + set_free(set, step); + step = next; + } +} + +/* Initialize a new set. set->env must be initialized using setjmp() before +// set_start() is called. A longjmp(set->env, ENOMEM) will be used to handle a +// memory allocation failure during any of the operations. (See setjmp.h and +// errno.h.) The set can still be used if this happens, assuming that it didn't +// happen during set_start(). Whether set_start() completed or not, set_end() +// can be used to free the set's memory after a longjmp(). */ +void set_start(set_t *set) { +#ifdef SET_TRACK + set->allocs = 0; + set->memory = 0; +#endif + set->head = set->path = set->node = NULL; /* in case set_node() fails */ + set->path = set_node(set); + set->head = set_node(set); + set_grow(set, set->head, 1, 1); /* one link back to head for an empty set */ + *(unsigned char *)&set->head->key = 137; /* set id */ + set->depth = 0; + set_uniq(&set->gen, set); + set->ran = 1; +} + +/* Return true if *set appears to be in a usable state. If *set has been zeroed +// out, then set_ok(set) will be false and set_end(set) will be safe. */ +int set_ok(set_t *set) { + return set->head != NULL && + set->head->right != NULL && + *(unsigned char *)&set->head->key == 137; +} + +/* Empty the set. This frees the memory used for the previous set contents. +// After set_clear(), *set is ready for use, as if after a set_start(). */ +void set_clear(set_t *set) { + assert(set_ok(set) && "improper use"); + + /* Free all the keys and their nodes. */ + set_sweep(set); + + /* Leave the head and path allocations as is. Clear their contents, with + // head pointing to itself and setting depth to zero, for an empty set. */ + set->head->right[0] = set->head; + set->head->fill = 1; + set->path->fill = 0; + set->depth = 0; +} + +/* Done using the set -- free all allocations. The only operation on *set +// permitted after this is set_start(). Though another set_end() would do no +// harm. This can be done at any time after a set_start(), or after a longjmp() +// on any allocation failure, including during a set_start(). */ +void set_end(set_t *set) { + if (set->head != NULL) { + /* Empty the set and free the head node. */ + if (set->head->right != NULL) { + set_sweep(set); + set_free(set, set->head->right); + } + set_free(set, set->head); + set->head = NULL; + } + if (set->path != NULL) { + /* Free the path work area. */ + set_free(set, set->path->right); + set_free(set, set->path); + set->path = NULL; + } + if (set->node != NULL) { + /* Free the node that was under construction when longjmp() hit. */ + set_drop(set, set->node->key); + set_free(set, set->node->right); + set_free(set, set->node); + set->node = NULL; + } +} + +/* Look for key. Return 1 if found or 0 if not. This also puts the path to get +// there in set->path, for use by set_insert(). */ +int set_found(set_t *set, set_key_t key) { + assert(set_ok(set) && "improper use"); + + /* Start at depth and work down and right as determined by key comparisons. */ + set_node_t *head = set->head, *here = head; + int i = set->depth; + set_grow(set, set->path, i + 1, 0); + do { + while (here->right[i] != head && + set_cmp(here->right[i]->key, key) < 0) + here = here->right[i]; + set->path->right[i] = here; + } while (i--); + + /* See if the key matches. */ + here = here->right[0]; + return here != head && set_cmp(here->key, key) == 0; +} + +/* Insert the key key. Return 0 on success, or 1 if key is already in the set. */ +int set_insert(set_t *set, set_key_t key) { + assert(set_ok(set) && "improper use"); + + if (set_found(set, key)) + /* That key is already in the set. */ + return 1; + + /* Randomly generate a new level-- level 0 with probability 1/2, 1 with + // probability 1/4, 2 with probability 1/8, etc. */ + int level = 0; + for (;;) { + if (set->ran == 1) + /* Ran out. Get another 32 random bits. */ + set->ran = set_rand(&set->gen) | (1ULL << 32); + int bit = set->ran & 1; + set->ran >>= 1; + if (bit) + break; + assert(level < 32767 && + "Overhead, without any fuss, the stars were going out."); + level++; + } + if (level > set->depth) { + /* The maximum depth is now deeper. Update the structures. */ + set_grow(set, set->path, level + 1, 1); + set_grow(set, set->head, level + 1, 1); + set->depth = (i16_t)level; + } + + /* Make a new node for the provided key, and insert it in the lists up to + // and including level. */ + set->node = set_node(set); + set->node->key = key; + set_grow(set, set->node, level + 1, 0); + int i; + for (i = 0; i <= level; i++) { + set->node->right[i] = set->path->right[i]->right[i]; + set->path->right[i]->right[i] = set->node; + } + set->node = NULL; + return 0; +} + +#else +#error ** another skiplist set already created here +/* Would need to implement a prefix in order to support multiple sets. */ +#endif |
