PHP配列・ハッシュテーブルの実装と操作

1. PHP Hash表1. PHP数组定义

1. 键(key): 用于操作数据的标示，例如PHP数组中的索引，或者字符串键等等 2. 槽(slot/bucket): 哈希表中用于保存数据的一个单元，也就是数据真正存放的容器 3. 哈希函数(hash function): 将key映射(map)到数据应该存放的slot所在位置的函数 4. 哈希冲突(hash collision): 哈希函数将两个不同的key映射到同一个索引的情况 

h(key) -> index

开源算法和哈希实现的确定性以及可预测性， 这样攻击者才可以利用特殊构造的key来进行攻击。要解决这个问题的方法则是让攻击者无法轻易构造 能够进行攻击的key序列 

装载因子是哈希表保存的元素数量和哈希表容量的比1. 通常采用链接法解决冲突的哈希表的装载，因子最好不要大于1(等于1意味着Hash表已经存满了，接下来开始保存的键值都会导致冲突发生即链表增长，而链表的效率是低于Hash表的)2. 而采用开放寻址法的哈希表最好不要大于0.5 

1. 实现哈希函数2. 冲突的解决3. 操作接口的实现

#ifndef _HASH_TABLE_H_#define _HASH_TABLE_H_ 1typedef struct _Bucket{    char *key;    void *value;    struct _Bucket *next;} Bucket;typedef struct _HashTable{    int size;    //HashTable size/lines    int elem_num;    //total elements count    Bucket** buckets;} HashTable;#endif

//hashtable.c#include <stdio.h>#include <stdlib.h>#include <string.h>#include "hashtable.h" int hash_str(char *key); int hash_str(char *key){    int hash = 0;    char *cur = key;    while(*cur != '\0')        {        hash += *cur;        ++cur;        }        return hash;}//hashtable.h#define HASH_INDEX(ht, key) (hash_str((key)) % (ht)->size)

int hash_init(HashTable *ht);                               // 初始化哈希表int hash_lookup(HashTable *ht, char *key, void **result);   // 根据key查找内容int hash_insert(HashTable *ht, char *key, void *value);     // 将内容插入到哈希表中int hash_remove(HashTable *ht, char *key);                  // 删除key所指向的内容int hash_destroy(HashTable *ht);

#include <stdio.h>#include <stdlib.h>#include <string.h>#include "hashtable.h"static void resize_hash_table_if_needed(HashTable *ht);static int hash_str(char *key);int hash_init(HashTable *ht){    ht->size         = HASH_TABLE_INIT_SIZE;    ht->elem_num     = 0;    ht->buckets        = (Bucket **)calloc(ht->size, sizeof(Bucket *));    if(ht->buckets == NULL) return FAILED;    LOG_MSG("[init]\tsize: %i\n", ht->size);    return SUCCESS;}int hash_lookup(HashTable *ht, char *key, void **result){    int index = HASH_INDEX(ht, key);    Bucket *bucket = ht->buckets[index];    if(bucket == NULL) goto failed;    while(bucket)    {        if(strcmp(bucket->key, key) == 0)        {            LOG_MSG("[lookup]\t found %s\tindex:%i value: %p\n",                key, index, bucket->value);            *result = bucket->value;                return SUCCESS;        }        bucket = bucket->next;    }failed:    LOG_MSG("[lookup]\t key:%s\tfailed\t\n", key);    return FAILED;}int hash_insert(HashTable *ht, char *key, void *value){    // check if we need to resize the hashtable    resize_hash_table_if_needed(ht);    int index = HASH_INDEX(ht, key);    Bucket *org_bucket = ht->buckets[index];    Bucket *tmp_bucket = org_bucket;    // check if the key exits already    while(tmp_bucket)    {        if(strcmp(key, tmp_bucket->key) == 0)        {            LOG_MSG("[update]\tkey: %s\n", key);            tmp_bucket->value = value;            return SUCCESS;        }        tmp_bucket = tmp_bucket->next;    }    Bucket *bucket = (Bucket *)malloc(sizeof(Bucket));    bucket->key      = key;    bucket->value = value;    bucket->next  = NULL;    ht->elem_num += 1;    if(org_bucket != NULL)    {        LOG_MSG("[collision]\tindex:%d key:%s\n", index, key);        bucket->next = org_bucket;    }    ht->buckets[index]= bucket;    LOG_MSG("[insert]\tindex:%d key:%s\tht(num:%d)\n",        index, key, ht->elem_num);    return SUCCESS;}int hash_remove(HashTable *ht, char *key){    int index = HASH_INDEX(ht, key);    Bucket *bucket  = ht->buckets[index];    Bucket *prev    = NULL;    if(bucket == NULL) return FAILED;    // find the right bucket from the link list     while(bucket)    {        if(strcmp(bucket->key, key) == 0)        {            LOG_MSG("[remove]\tkey:(%s) index: %d\n", key, index);            if(prev == NULL)            {                ht->buckets[index] = bucket->next;            }            else            {                prev->next = bucket->next;            }            free(bucket);            return SUCCESS;        }        prev   = bucket;        bucket = bucket->next;    }    LOG_MSG("[remove]\t key:%s not found remove \tfailed\t\n", key);    return FAILED;}int hash_destroy(HashTable *ht){    int i;    Bucket *cur = NULL;    Bucket *tmp = NULL;    for(i=0; i < ht->size; ++i)    {        cur = ht->buckets[i];        while(cur)        {            tmp = cur;            cur = cur->next;            free(tmp);        }    }    free(ht->buckets);    return SUCCESS;}static int hash_str(char *key){    int hash = 0;    char *cur = key;    while(*cur != '\0')    {        hash +=    *cur;        ++cur;    }    return hash;}static int hash_resize(HashTable *ht){    // double the size    int org_size = ht->size;    ht->size = ht->size * 2;    ht->elem_num = 0;    LOG_MSG("[resize]\torg size: %i\tnew size: %i\n", org_size, ht->size);    Bucket **buckets = (Bucket **)calloc(ht->size, sizeof(Bucket **));    Bucket **org_buckets = ht->buckets;    ht->buckets = buckets;    int i = 0;    for(i=0; i < org_size; ++i)    {        Bucket *cur = org_buckets[i];        Bucket *tmp;        while(cur)         {            // rehash: insert again            hash_insert(ht, cur->key, cur->value);            // free the org bucket, but not the element            tmp = cur;            cur = cur->next;            free(tmp);        }    }    free(org_buckets);    LOG_MSG("[resize] done\n");    return SUCCESS;}// if the elem_num is almost as large as the capacity of the hashtable// we need to resize the hashtable to contain enough elementsstatic void resize_hash_table_if_needed(HashTable *ht){    if(ht->size - ht->elem_num < 1)    {        hash_resize(ht);        }}

#ifndef _HASH_TABLE_H_#define _HASH_TABLE_H_ 1#define HASH_TABLE_INIT_SIZE 6#define HASH_INDEX(ht, key) (hash_str((key)) % (ht)->size)#if defined(DEBUG)#  define LOG_MSG printf#else#  define LOG_MSG(...)#endif#define SUCCESS 0#define FAILED -1typedef struct _Bucket{    char *key;    void *value;    struct _Bucket *next;} Bucket;typedef struct _HashTable{    int size;        // 哈希表的大小    int elem_num;    // 已经保存元素的个数    Bucket **buckets;} HashTable;int hash_init(HashTable *ht);int hash_lookup(HashTable *ht, char *key, void **result);int hash_insert(HashTable *ht, char *key, void *value);int hash_remove(HashTable *ht, char *key);int hash_destroy(HashTable *ht);#endif

#include <stdio.h>#include <stdlib.h>#include <assert.h>#include <string.h>#include "hashtable.h"#define TEST(tcase) printf(">>> [START CASE] " tcase "<<<\n")#define PASS(tcase) printf(">>> [PASSED] " tcase " <<<\n")int main(int argc, char **argv){    HashTable *ht = (HashTable *)malloc(sizeof(HashTable));    int result = hash_init(ht);    assert(result == SUCCESS);    /* Data */    int  int1 = 10;    int  int2 = 20;    char str1[] = "Hello TIPI";    char str2[] = "Value";    /* to find data container */    int *j = NULL;    char *find_str = NULL;    /* Test Key insert */    TEST("Key insert");    hash_insert(ht, "KeyInt", &int1);    hash_insert(ht, "asdfKeyStrass", str1);    hash_insert(ht, "K13eyStras", str1);    hash_insert(ht, "KeyStr5", str1);    hash_insert(ht, "KeyStr", str1);    PASS("Key insert");    /* Test key lookup */    TEST("Key lookup");    hash_lookup(ht, "KeyInt", (void **)&j);    hash_lookup(ht, "KeyStr", (void **)&find_str);    assert(strcmp(find_str, str1) == 0);    assert(*j = int1);    PASS("Key lookup");    /* Test Key update */    TEST("Test key update");    hash_insert(ht, "KeyInt", &int2);    hash_lookup(ht, "KeyInt", (void **)&j);    assert(*j = int2);    PASS("Test key update");    TEST(">>>     Test key not found        <<< ");    result = hash_lookup(ht, "non-exits-key", (void **)&j);    assert(result == FAILED);    PASS("non-exist-key lookup");    TEST("Test key not found after remove");    char strMyKey[] = "My-Key-Value";    find_str = NULL;    hash_insert(ht, "My-Key", &strMyKey);    result = hash_remove(ht, "My-Key");    assert(result == SUCCESS);    result = hash_lookup(ht, "My-Key", (void **)&find_str);    assert(find_str == NULL);    assert(result == FAILED);    PASS("Test key not found after remove");    PASS(">>>     Test key not found        <<< ");    TEST("Add many elements and make hashtable rehash");    hash_insert(ht, "a1", &int2);    hash_insert(ht, "a2", &int1);    hash_insert(ht, "a3", &int1);    hash_insert(ht, "a4", &int1);    hash_insert(ht, "a5", &int1);    hash_insert(ht, "a6", &int1);    hash_insert(ht, "a7", &int1);    hash_insert(ht, "a8", str2);    hash_insert(ht, "a9", &int1);    hash_insert(ht, "a10", &int1);    hash_insert(ht, "a11", &int1);    hash_insert(ht, "a12", &int1);    hash_insert(ht, "a13", &int1);    hash_insert(ht, "a14", &int1);    hash_insert(ht, "a15", &int1);    hash_insert(ht, "a16", &int1);    hash_insert(ht, "a17", &int1);    hash_insert(ht, "a18", &int1);    hash_insert(ht, "a19", &int1);    hash_insert(ht, "a20", &int1);    hash_insert(ht, "a21", &int1);    hash_insert(ht, "a22", &int1);    hash_insert(ht, "a23", &int1);    hash_insert(ht, "a24", &int1);    hash_insert(ht, "a24", &int1);    hash_insert(ht, "a24", &int1);    hash_insert(ht, "a25", &int1);    hash_insert(ht, "a26", &int1);    hash_insert(ht, "a27", &int1);    hash_insert(ht, "a28", &int1);    hash_insert(ht, "a29", &int1);    hash_insert(ht, "a30", &int1);    hash_insert(ht, "a31", &int1);    hash_insert(ht, "a32", &int1);    hash_insert(ht, "a33", &int1);    hash_lookup(ht, "a23", (void **)&j);    assert(*j = int1);    hash_lookup(ht, "a30", (void **)&j);    assert(*j = int1);    PASS("Add many elements and make hashtable rehash");    hash_destroy(ht);    free(ht);    printf("Woohoo, It looks like HashTable works properly\n");    return 0;}

gcc -g -Wall -DDEBUG -o a.out main.c hashtable.c

typedef struct bucket {    ulong h;                        /* Used for numeric indexing */    uint nKeyLength;                //key长度    void *pData;                    //指向 Bucke保存的数据 指针    void *pDataPtr;                    //指针数据    struct bucket *pListNext;        //下一个元素指针    struct bucket *pListLast;        //上一个元素指针    struct bucket *pNext;    struct bucket *pLast;    const char *arKey;} Bucket;typedef struct _hashtable {    uint nTableSize;            //HashTable的大小    uint nTableMask;            //等于nTableSize-1    uint nNumOfElements;        //对象个数    ulong nNextFreeElement;        //指向下一个空元素位置 nTableSize+1    Bucket *pInternalPointer;    /* Used for element traversal 保存当前遍历的指针 */    Bucket *pListHead;            //头元素指针    Bucket *pListTail;            //尾元素指针    Bucket **arBuckets;            //存储hash数组数据    dtor_func_t pDestructor;    //类似于析构函数    zend_bool persistent;        //用哪种方法分配内存空间 PHP统一管理内存还是用普通的malloc    unsigned char nApplyCount;    //当前hash bucket被访问的次数,是否遍历过数据,防止无限递归循环    zend_bool bApplyProtection;#if ZEND_DEBUG    int inconsistent;#endif} H

http://www.imsiren.com/archives/6http://www.php-internals.com/book/?p=chapt03/03-01-01-hashtable https://github.com/reeze/tipi/tree/master/book/sample/chapt03/03-01-01-hashtable 

1. 真正的数组2. 列表(向量)3. 散列表(是映射的一种实现)4. 字典5. 集合6. 栈7. 队列以及更多可能性

<?php    $array = array();    $array["key"] = "values";?>

static int ZEND_FASTCALL  ZEND_INIT_ARRAY_SPEC_CV_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS){    USE_OPLINE    array_init(&EX_T(opline->result.var).tmp_var);    if (IS_CV == IS_UNUSED) {        ZEND_VM_NEXT_OPCODE();#if 0 || IS_CV != IS_UNUSED    } else {        return ZEND_ADD_ARRAY_ELEMENT_SPEC_CV_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU);#endif    }}

ZEND_API int _array_init(zval *arg, uint size ZEND_FILE_LINE_DC) /* {{{ */{    ALLOC_HASHTABLE_REL(Z_ARRVAL_P(arg));    _zend_hash_init(Z_ARRVAL_P(arg), size, ZVAL_PTR_DTOR, 0 ZEND_FILE_LINE_RELAY_CC);    Z_TYPE_P(arg) = IS_ARRAY;    return SUCCESS;}

ZEND_API int _zend_hash_init(HashTable *ht, uint nSize, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC){    uint i = 3;    SET_INCONSISTENT(HT_OK);    if (nSize >= 0x80000000) {        /* prevent overflow */        //HASH表大小大于0x80000000则初始化为0x80000000        ht->nTableSize = 0x80000000;    } else {        while ((1U << i) < nSize) {            i++;        }        //申请的数组Size空间调整为2的n次方，这样有利于内存对齐，i=3,nTableSize最小值为8        ht->nTableSize = 1 << i;    }    ht->nTableMask = 0;    /* 0 means that ht->arBuckets is uninitialized */    ht->pDestructor = pDestructor;    //一个函数指针,当HashTable发生增,删,改时调用    ht->arBuckets = (Bucket**)&uninitialized_bucket;    ht->pListHead = NULL;    ht->pListTail = NULL;    ht->nNumOfElements = 0;    ht->nNextFreeElement = 0;    ht->pInternalPointer = NULL;    ht->persistent = persistent;    //如果persisient为TRUE，则使用操作系统本身的内存分配函数为Bucket分配内存，否则使用PHP的内存分配函数    ht->nApplyCount = 0;    ht->bApplyProtection = 1;    return SUCCESS;}ZEND_API int _zend_hash_init_ex(HashTable *ht, uint nSize, dtor_func_t pDestructor, zend_bool persistent, zend_bool bApplyProtection ZEND_FILE_LINE_DC){    int retval = _zend_hash_init(ht, nSize, pDestructor, persistent ZEND_FILE_LINE_CC);    ht->bApplyProtection = bApplyProtection;    return retval;}

//初始化PHP数组array_init(zval *arg);array_init_size(zval *arg, uint size); //关联数组赋值的操作函数，等同于$array[$stringKey] = $value;add_assoc_null(zval *aval, char *key);add_assoc_bool(zval *aval, char *key, zend_bool bval);add_assoc_long(zval *aval, char *key, long lval);add_assoc_double(zval *aval, char *key, double dval);add_assoc_string(zval *aval, char *key, char *strval, int dup);add_assoc_stringl(zval *aval, char *key,char *strval, uint strlen, int dup);add_assoc_zval(zval *aval, char *key, zval *value);//上述函数均为宏函数，都是对add_assoc_*_ex函数的封装 //数字索引数组赋值的操作函数，等效于$array[$numKey] = $value;ZEND_API int add_index_long(zval *arg, ulong idx, long n);ZEND_API int add_index_null(zval *arg, ulong idx);ZEND_API int add_index_bool(zval *arg, ulong idx, int b);ZEND_API int add_index_resource(zval *arg, ulong idx, int r);ZEND_API int add_index_double(zval *arg, ulong idx, double d);ZEND_API int add_index_string(zval *arg, ulong idx, const char *str, int duplicate);ZEND_API int add_index_stringl(zval *arg, ulong idx, const char *str, uint length, int duplicate);ZEND_API int add_index_zval(zval *arg, ulong index, zval *value); //使用内置数字索引的数组赋值的操作函数，等效于$array[] = $value;ZEND_API int add_next_index_long(zval *arg, long n);ZEND_API int add_next_index_null(zval *arg);ZEND_API int add_next_index_bool(zval *arg, int b);ZEND_API int add_next_index_resource(zval *arg, int r);ZEND_API int add_next_index_double(zval *arg, double d);ZEND_API int add_next_index_string(zval *arg, const char *str, int duplicate);ZEND_API int add_next_index_stringl(zval *arg, const char *str, uint length, int duplicate);ZEND_API int add_next_index_zval(zval *arg, zval *value); //数组元素赋值并返回，等效于{ $array[$key] = $value; return $value; }ZEND_API int add_get_assoc_string_ex(zval *arg, const char *key, uint key_len, const char *str, void **dest, int duplicate);ZEND_API int add_get_assoc_stringl_ex(zval *arg, const char *key, uint key_len, const char *str, uint length, void **dest, int duplicate);#define add_get_assoc_string(__arg, __key, __str, __dest, __duplicate) add_get_assoc_string_ex(__arg, __key, strlen(__key)+1, __str, __dest, __duplicate)#define add_get_assoc_stringl(__arg, __key, __str, __length, __dest, __duplicate) add_get_assoc_stringl_ex(__arg, __key, strlen(__key)+1, __str, __length, __dest, __duplicate)ZEND_API int add_get_index_long(zval *arg, ulong idx, long l, void **dest);ZEND_API int add_get_index_double(zval *arg, ulong idx, double d, void **dest);ZEND_API int add_get_index_string(zval *arg, ulong idx, const char *str, void **dest, int duplicate);ZEND_API int add_get_index_stringl(zval *arg, ulong idx, const char *str, uint length, void **dest, int duplicate);

http://thiniki.sinaapp.com/?p=155http://www.imsiren.com/archives/250http://www.cnblogs.com/ohmygirl/p/internal-4.htmlhttp://weizhifeng.net/write-php-extension-part2-1.htmlhttp://blog.csdn.net/a600423444/article/details/7073854