diff options
author | Joshua Haberman <joshua@reverberate.org> | 2010-07-09 20:20:33 -0700 |
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committer | Joshua Haberman <joshua@reverberate.org> | 2010-07-09 20:20:33 -0700 |
commit | 28ec9a1fa0f9b1d741920dfa8afc91fa2532c43d (patch) | |
tree | 6849230180a254424f4c1f385b919632211f3ac1 /src/upb_table.c | |
parent | 604c1a78bcbcc5b282ac6aab01a425baeaebdfbd (diff) |
Split src/ into core/ and stream/.
Diffstat (limited to 'src/upb_table.c')
-rw-r--r-- | src/upb_table.c | 411 |
1 files changed, 0 insertions, 411 deletions
diff --git a/src/upb_table.c b/src/upb_table.c deleted file mode 100644 index b91776c..0000000 --- a/src/upb_table.c +++ /dev/null @@ -1,411 +0,0 @@ -/* - * upb - a minimalist implementation of protocol buffers. - * - * Copyright (c) 2009 Joshua Haberman. See LICENSE for details. - */ - -#include "upb_table.h" -#include "upb_string.h" - -#include <assert.h> -#include <stdlib.h> -#include <string.h> - -static const upb_inttable_key_t EMPTYENT = 0; -static const double MAX_LOAD = 0.85; - -static uint32_t MurmurHash2(const void *key, size_t len, uint32_t seed); - -/* We use 1-based indexes into the table so that 0 can be "NULL". */ -static upb_inttable_entry *intent(upb_inttable *t, int32_t i) { - return UPB_INDEX(t->t.entries, i-1, t->t.entry_size); -} -static upb_strtable_entry *strent(upb_strtable *t, int32_t i) { - return UPB_INDEX(t->t.entries, i-1, t->t.entry_size); -} - -void upb_table_init(upb_table *t, uint32_t size, uint16_t entry_size) -{ - t->count = 0; - t->entry_size = entry_size; - t->size_lg2 = 1; - while(size >>= 1) t->size_lg2++; - size_t bytes = upb_table_size(t) * t->entry_size; - t->mask = upb_table_size(t) - 1; - t->entries = malloc(bytes); - memset(t->entries, 0, bytes); /* Both tables consider 0's an empty entry. */ -} - -void upb_inttable_init(upb_inttable *t, uint32_t size, uint16_t entsize) -{ - upb_table_init(&t->t, size, entsize); -} - -void upb_strtable_init(upb_strtable *t, uint32_t size, uint16_t entsize) -{ - upb_table_init(&t->t, size, entsize); -} - -void upb_table_free(upb_table *t) { free(t->entries); } -void upb_inttable_free(upb_inttable *t) { upb_table_free(&t->t); } -void upb_strtable_free(upb_strtable *t) { - // Free refs from the strtable. - upb_strtable_entry *e = upb_strtable_begin(t); - for(; e; e = upb_strtable_next(t, e)) { - upb_string_unref(e->key); - } - upb_table_free(&t->t); -} - -static uint32_t strtable_bucket(upb_strtable *t, upb_string *key) -{ - uint32_t hash = MurmurHash2(upb_string_getrobuf(key), upb_string_len(key), 0); - return (hash & (upb_strtable_size(t)-1)) + 1; -} - -void *upb_strtable_lookup(upb_strtable *t, upb_string *key) -{ - uint32_t bucket = strtable_bucket(t, key); - upb_strtable_entry *e; - do { - e = strent(t, bucket); - if(e->key && upb_streql(e->key, key)) return e; - } while((bucket = e->next) != UPB_END_OF_CHAIN); - return NULL; -} - -static uint32_t empty_intbucket(upb_inttable *table) -{ - /* TODO: does it matter that this is biased towards the front of the table? */ - for(uint32_t i = 1; i <= upb_inttable_size(table); i++) { - upb_inttable_entry *e = intent(table, i); - if(e->key == EMPTYENT) return i; - } - assert(false); - return 0; -} - -/* The insert routines have a lot more code duplication between int/string - * variants than I would like, but there's just a bit too much that varies to - * parameterize them. */ -static void intinsert(upb_inttable *t, upb_inttable_entry *e) -{ - assert(upb_inttable_lookup(t, e->key) == NULL); - t->t.count++; - uint32_t bucket = upb_inttable_bucket(t, e->key); - upb_inttable_entry *table_e = intent(t, bucket); - if(table_e->key != EMPTYENT) { /* Collision. */ - if(bucket == upb_inttable_bucket(t, table_e->key)) { - /* Existing element is in its main posisiton. Find an empty slot to - * place our new element and append it to this key's chain. */ - uint32_t empty_bucket = empty_intbucket(t); - while (table_e->next != UPB_END_OF_CHAIN) - table_e = intent(t, table_e->next); - table_e->next = empty_bucket; - table_e = intent(t, empty_bucket); - } else { - /* Existing element is not in its main position. Move it to an empty - * slot and put our element in its main position. */ - uint32_t empty_bucket = empty_intbucket(t); - uint32_t evictee_bucket = upb_inttable_bucket(t, table_e->key); - memcpy(intent(t, empty_bucket), table_e, t->t.entry_size); /* copies next */ - upb_inttable_entry *evictee_e = intent(t, evictee_bucket); - while(1) { - assert(evictee_e->key != UPB_EMPTY_ENTRY); - assert(evictee_e->next != UPB_END_OF_CHAIN); - if(evictee_e->next == bucket) { - evictee_e->next = empty_bucket; - break; - } - evictee_e = intent(t, evictee_e->next); - } - /* table_e remains set to our mainpos. */ - } - } - memcpy(table_e, e, t->t.entry_size); - table_e->next = UPB_END_OF_CHAIN; - assert(upb_inttable_lookup(t, e->key) == table_e); -} - -void upb_inttable_insert(upb_inttable *t, upb_inttable_entry *e) -{ - assert(e->key != 0); - if((double)(t->t.count + 1) / upb_inttable_size(t) > MAX_LOAD) { - /* Need to resize. New table of double the size, add old elements to it. */ - upb_inttable new_table; - upb_inttable_init(&new_table, upb_inttable_size(t)*2, t->t.entry_size); - new_table.t.count = t->t.count; - upb_inttable_entry *old_e; - for(old_e = upb_inttable_begin(t); old_e; old_e = upb_inttable_next(t, old_e)) - intinsert(&new_table, old_e); - upb_inttable_free(t); - *t = new_table; - } - intinsert(t, e); -} - -static uint32_t empty_strbucket(upb_strtable *table) -{ - /* TODO: does it matter that this is biased towards the front of the table? */ - for(uint32_t i = 1; i <= upb_strtable_size(table); i++) { - upb_strtable_entry *e = strent(table, i); - if(!e->key) return i; - } - assert(false); - return 0; -} - -static void strinsert(upb_strtable *t, upb_strtable_entry *e) -{ - assert(upb_strtable_lookup(t, e->key) == NULL); - e->key = upb_string_getref(e->key); - t->t.count++; - uint32_t bucket = strtable_bucket(t, e->key); - upb_strtable_entry *table_e = strent(t, bucket); - if(table_e->key) { /* Collision. */ - if(bucket == strtable_bucket(t, table_e->key)) { - /* Existing element is in its main posisiton. Find an empty slot to - * place our new element and append it to this key's chain. */ - uint32_t empty_bucket = empty_strbucket(t); - while (table_e->next != UPB_END_OF_CHAIN) - table_e = strent(t, table_e->next); - table_e->next = empty_bucket; - table_e = strent(t, empty_bucket); - } else { - /* Existing element is not in its main position. Move it to an empty - * slot and put our element in its main position. */ - uint32_t empty_bucket = empty_strbucket(t); - uint32_t evictee_bucket = strtable_bucket(t, table_e->key); - memcpy(strent(t, empty_bucket), table_e, t->t.entry_size); /* copies next */ - upb_strtable_entry *evictee_e = strent(t, evictee_bucket); - while(1) { - assert(!upb_string_isnull(evictee_e->key)); - assert(evictee_e->next != UPB_END_OF_CHAIN); - if(evictee_e->next == bucket) { - evictee_e->next = empty_bucket; - break; - } - evictee_e = strent(t, evictee_e->next); - } - /* table_e remains set to our mainpos. */ - } - } - memcpy(table_e, e, t->t.entry_size); - table_e->next = UPB_END_OF_CHAIN; - assert(upb_strtable_lookup(t, e->key) == table_e); -} - -void upb_strtable_insert(upb_strtable *t, upb_strtable_entry *e) -{ - if((double)(t->t.count + 1) / upb_strtable_size(t) > MAX_LOAD) { - /* Need to resize. New table of double the size, add old elements to it. */ - upb_strtable new_table; - upb_strtable_init(&new_table, upb_strtable_size(t)*2, t->t.entry_size); - upb_strtable_entry *old_e; - for(old_e = upb_strtable_begin(t); old_e; old_e = upb_strtable_next(t, old_e)) - strinsert(&new_table, old_e); - upb_strtable_free(t); - *t = new_table; - } - strinsert(t, e); -} - -void *upb_inttable_begin(upb_inttable *t) { - return upb_inttable_next(t, intent(t, 0)); -} - -void *upb_inttable_next(upb_inttable *t, upb_inttable_entry *cur) { - upb_inttable_entry *end = intent(t, upb_inttable_size(t)+1); - do { - cur = (void*)((char*)cur + t->t.entry_size); - if(cur == end) return NULL; - } while(cur->key == UPB_EMPTY_ENTRY); - return cur; -} - -void *upb_strtable_begin(upb_strtable *t) { - return upb_strtable_next(t, strent(t, 0)); -} - -void *upb_strtable_next(upb_strtable *t, upb_strtable_entry *cur) { - upb_strtable_entry *end = strent(t, upb_strtable_size(t)+1); - do { - cur = (void*)((char*)cur + t->t.entry_size); - if(cur == end) return NULL; - } while(cur->key == NULL); - return cur; -} - -#ifdef UPB_UNALIGNED_READS_OK -//----------------------------------------------------------------------------- -// MurmurHash2, by Austin Appleby (released as public domain). -// Reformatted and C99-ified by Joshua Haberman. -// Note - This code makes a few assumptions about how your machine behaves - -// 1. We can read a 4-byte value from any address without crashing -// 2. sizeof(int) == 4 (in upb this limitation is removed by using uint32_t -// And it has a few limitations - -// 1. It will not work incrementally. -// 2. It will not produce the same results on little-endian and big-endian -// machines. -static uint32_t MurmurHash2(const void *key, size_t len, uint32_t seed) -{ - // 'm' and 'r' are mixing constants generated offline. - // They're not really 'magic', they just happen to work well. - const uint32_t m = 0x5bd1e995; - const int32_t r = 24; - - // Initialize the hash to a 'random' value - uint32_t h = seed ^ len; - - // Mix 4 bytes at a time into the hash - const uint8_t * data = (const uint8_t *)key; - while(len >= 4) { - uint32_t k = *(uint32_t *)data; - - k *= m; - k ^= k >> r; - k *= m; - - h *= m; - h ^= k; - - data += 4; - len -= 4; - } - - // Handle the last few bytes of the input array - switch(len) { - case 3: h ^= data[2] << 16; - case 2: h ^= data[1] << 8; - case 1: h ^= data[0]; h *= m; - }; - - // Do a few final mixes of the hash to ensure the last few - // bytes are well-incorporated. - h ^= h >> 13; - h *= m; - h ^= h >> 15; - - return h; -} - -#else // !UPB_UNALIGNED_READS_OK - -//----------------------------------------------------------------------------- -// MurmurHashAligned2, by Austin Appleby -// Same algorithm as MurmurHash2, but only does aligned reads - should be safer -// on certain platforms. -// Performance will be lower than MurmurHash2 - -#define MIX(h,k,m) { k *= m; k ^= k >> r; k *= m; h *= m; h ^= k; } - -static uint32_t MurmurHash2(const void * key, size_t len, uint32_t seed) -{ - const uint32_t m = 0x5bd1e995; - const int32_t r = 24; - const uint8_t * data = (const uint8_t *)key; - uint32_t h = seed ^ len; - uint8_t align = (uintptr_t)data & 3; - - if(align && (len >= 4)) { - // Pre-load the temp registers - uint32_t t = 0, d = 0; - - switch(align) { - case 1: t |= data[2] << 16; - case 2: t |= data[1] << 8; - case 3: t |= data[0]; - } - - t <<= (8 * align); - - data += 4-align; - len -= 4-align; - - int32_t sl = 8 * (4-align); - int32_t sr = 8 * align; - - // Mix - - while(len >= 4) { - d = *(uint32_t *)data; - t = (t >> sr) | (d << sl); - - uint32_t k = t; - - MIX(h,k,m); - - t = d; - - data += 4; - len -= 4; - } - - // Handle leftover data in temp registers - - d = 0; - - if(len >= align) { - switch(align) { - case 3: d |= data[2] << 16; - case 2: d |= data[1] << 8; - case 1: d |= data[0]; - } - - uint32_t k = (t >> sr) | (d << sl); - MIX(h,k,m); - - data += align; - len -= align; - - //---------- - // Handle tail bytes - - switch(len) { - case 3: h ^= data[2] << 16; - case 2: h ^= data[1] << 8; - case 1: h ^= data[0]; h *= m; - }; - } else { - switch(len) { - case 3: d |= data[2] << 16; - case 2: d |= data[1] << 8; - case 1: d |= data[0]; - case 0: h ^= (t >> sr) | (d << sl); h *= m; - } - } - - h ^= h >> 13; - h *= m; - h ^= h >> 15; - - return h; - } else { - while(len >= 4) { - uint32_t k = *(uint32_t *)data; - - MIX(h,k,m); - - data += 4; - len -= 4; - } - - //---------- - // Handle tail bytes - - switch(len) { - case 3: h ^= data[2] << 16; - case 2: h ^= data[1] << 8; - case 1: h ^= data[0]; h *= m; - }; - - h ^= h >> 13; - h *= m; - h ^= h >> 15; - - return h; - } -} -#undef MIX - -#endif // UPB_UNALIGNED_READS_OK |