{"id":987,"date":"2014-08-12T02:54:45","date_gmt":"2014-08-12T02:54:45","guid":{"rendered":"http:\/\/ixyzero.com\/blog\/?p=987"},"modified":"2014-08-12T02:54:45","modified_gmt":"2014-08-12T02:54:45","slug":"php%e4%b8%ad%e7%9a%84%e5%93%88%e5%b8%8c%e8%a1%a8%e7%a2%b0%e6%92%9e%e6%94%bb%e5%87%bb","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/987.html","title":{"rendered":"PHP\u4e2d\u7684\u54c8\u5e0c\u8868\u78b0\u649e\u653b\u51fb"},"content":{"rendered":"

\u4e4b\u524d\u5176\u5b9e\u4e00\u76f4\u5bf9\u54c8\u5e0c\u8868\uff08HashTable\uff09\u8fd9\u4e2a\u7ed3\u6784\u65e0\u611f\u7684\uff0c\u4f46\u81ea\u4ece\u9762\u8bd5\u7684\u65f6\u5019\u88ab\u95ee\u5230\u4e86\u8fd9\u4e2a\u95ee\u9898\u4e4b\u540e\uff0c\u4e0b\u53bb\u81ea\u5df1\u4e86\u89e3\u4e86\u4e00\u4e0b\uff1a\u4ece\u7f51\u4e0a\u627e\u8d44\u6599\/\u4ee3\u7801\u770b\u4e86\u770b\uff0c\u7ffb\u7ffb\u4e66\u628a\u5927\u6982\u7684\u5185\u5bb9\u5f04\u660e\u767d\u4e86\u4e4b\u540e\uff0c\u4e5f\u5c31\u6ca1\u4ec0\u4e48\u4e0b\u6587\u4e86\uff0c\u4e0d\u8fc7\uff0c\u6628\u5929\u5728\u5b66\u8f66\u95f4\u9699\uff08\u5176\u5b9e\u5b66\u8f66\u7684\u7edd\u5927\u591a\u6570\u65f6\u95f4\u90fd\u7b97\u662f\u95f4\u9699\uff0c\u7b49\u5f85\u7684\u65f6\u95f4\u8fdc\u8fdc\u8d85\u8fc7\u4e0a\u8f66\u65f6\u95f4o(\u256f\u25a1\u2570)o\uff09\u9690\u7ea6\u89c9\u5f97\u4e4b\u524d\u597d\u50cf\u770b\u8fc7\u4e0e\u54c8\u5e0c\u8868\u76f8\u5173\u7684\u6587\u7ae0\uff0c\u5927\u4f53\u5370\u8c61\u5728\u901b\u5927\u725bLaruence<\/span><\/a>\u7684\u535a\u5ba2\u65f6\u770b\u5230\u7684\uff0c\u4e8e\u662f\u5c31\u6709\u4e86\u4e0b\u6587\uff08\u4e2d\u95f4\u7ecf\u5386\u4e86\u591a\u6b21\u641c\u7d22 && \u8bc4\u8bba\u533a\u7684\u201c\u6dd8\u91d1\u201d\uff09\uff1a<\/span><\/p>\n

\u54c8\u5e0c\u8868\u78b0\u649e\u653b\u51fb\u7684\u57fa\u672c\u539f\u7406<\/h4>\n

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\u4e0d\u8bba\u4f7f\u7528\u4e86\u54ea\u79cd\u78b0\u649e\u89e3\u51b3\u7b56\u7565\uff0c\u90fd\u5bfc\u81f4\u63d2\u5165\u548c\u67e5\u627e\u64cd\u4f5c\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u4e0d\u518d\u662fO(1)\u3002\u4ee5\u67e5\u627e\u4e3a\u4f8b\uff0c\u4e0d\u80fd\u901a\u8fc7key\u5b9a\u4f4d\u5230\u6876\u5c31\u7ed3\u675f\uff0c\u5fc5\u987b\u8fd8\u8981\u6bd4\u8f83\u539f\u59cbkey\uff08\u5373\u672a\u505a\u54c8\u5e0c\u4e4b\u524d\u7684key\uff09\u662f\u5426\u76f8\u7b49\uff0c\u5982\u679c\u4e0d\u76f8\u7b49\uff0c\u5219\u8981\u4f7f\u7528\u4e0e\u63d2\u5165\u76f8\u540c\u7684\u7b97\u6cd5\u7ee7\u7eed\u67e5\u627e\uff0c\u76f4\u5230\u627e\u5230\u5339\u914d\u7684\u503c\u6216\u786e\u8ba4\u6570\u636e\u4e0d\u5728\u54c8\u5e0c\u8868\u4e2d\u3002<\/p>\n

PHP\u662f\u4f7f\u7528\u5355\u94fe\u8868\u5b58\u50a8\u78b0\u649e\u7684\u6570\u636e\uff08\u94fe\u63a5\u6cd5\uff09<\/span><\/span><\/strong>\uff0c\u56e0\u6b64\u5b9e\u9645\u4e0aPHP\u54c8\u5e0c\u8868\u7684\u5e73\u5747\u67e5\u627e\u590d\u6742\u5ea6\u4e3aO(L)\uff0c\u5176\u4e2dL\u4e3a\u6876\u94fe\u8868\u7684\u5e73\u5747\u957f\u5ea6\uff1b\u800c\u6700\u574f\u590d\u6742\u5ea6\u4e3aO(N)\uff0c\u6b64\u65f6\u6240\u6709\u6570\u636e\u5168\u90e8\u78b0\u649e\uff0c\u54c8\u5e0c\u8868\u9000\u5316\u6210\u5355\u94fe\u8868\u3002\u4e0b\u56fePHP\u4e2d\u6b63\u5e38\u54c8\u5e0c\u8868\u548c\u9000\u5316\u54c8\u5e0c\u8868\u7684\u793a\u610f\u56fe\uff1a<\/p>\n

\"hash_collision\"<\/a><\/p>\n

\u54c8\u5e0c\u8868\u78b0\u649e\u653b\u51fb\u5c31\u662f\u901a\u8fc7\u7cbe\u5fc3\u6784\u9020\u6570\u636e\uff0c\u4f7f\u5f97\u6240\u6709\u6570\u636e\u5168\u90e8\u78b0\u649e\uff0c\u4eba\u4e3a\u7684\u5c06\u54c8\u5e0c\u8868\u53d8\u6210\u4e00\u4e2a\u9000\u5316\u7684\u5355\u94fe\u8868<\/span>\uff0c\u6b64\u65f6\u54c8\u5e0c\u8868\u5404\u79cd\u64cd\u4f5c\u7684\u65f6\u95f4\u5747\u63d0\u5347\u4e86\u4e00\u4e2a\u6570\u91cf\u7ea7\uff0c\u56e0\u6b64\u4f1a\u6d88\u8017\u5927\u91cfCPU\u8d44\u6e90\uff0c\u5bfc\u81f4\u7cfb\u7edf\u65e0\u6cd5\u5feb\u901f\u54cd\u5e94\u8bf7\u6c42\uff0c\u4ece\u800c\u8fbe\u5230\u62d2\u7edd\u670d\u52a1\u653b\u51fb\uff08DoS\uff09\u7684\u76ee\u7684\u3002<\/p>\n

\u53ef\u4ee5\u770b\u5230\uff0c\u8fdb\u884c\u54c8\u5e0c\u78b0\u649e\u653b\u51fb\u7684\u524d\u63d0\u662f\u54c8\u5e0c\u7b97\u6cd5\u7279\u522b\u5bb9\u6613\u627e\u51fa\u78b0\u649e<\/span>\uff0c\u5982\u679c\u662fMD5\u6216\u8005SHA1\u90a3\u57fa\u672c\u5c31\u6ca1\u620f\u4e86\uff0c\u5e78\u8fd0\u7684\u662f\uff08\u4e5f\u53ef\u4ee5\u8bf4\u4e0d\u5e78\u7684\u662f\uff09\u5927\u591a\u6570\u7f16\u7a0b\u8bed\u8a00\u4f7f\u7528\u7684\u54c8\u5e0c\u7b97\u6cd5\u90fd\u5341\u5206\u7b80\u5355\uff08\u8fd9\u662f\u4e3a\u4e86\u6548\u7387\u8003\u8651\uff1b\u53e6\u4e00\u65b9\u9762\u4e5f\u662f\u56e0\u4e3a\u4ee3\u7801\u662f\u5f00\u6e90\u7684\uff0c\u6240\u4ee5\u4efb\u4f55\u4eba\u90fd\u53ef\u4ee5\u5bf9\u5176\u5206\u6790\u4ece\u800c\u627e\u5230\u7834\u7efd\uff09\uff0c\u56e0\u6b64\u53ef\u4ee5\u7cbe\u5fc3(\u8fd9\u662f\u9700\u8981\u5177\u6709\u76f8\u5f53\u7684\u80fd\u529b\u6c34\u5e73\u624d\u80fd\u8fbe\u5230\u7684)\u6784\u9020\u51fa\u653b\u51fb\u6570\u636e\u3002\u4e0b\u4e00\u8282\u5c06\u901a\u8fc7\u5206\u6790Zend\u76f8\u5173\u5185\u6838\u4ee3\u7801\uff0c\u627e\u51fa\u653b\u51fb\u54c8\u5e0c\u8868\u78b0\u649e\u653b\u51fbPHP\u7684\u65b9\u6cd5\u3002<\/p>\n

Zend\u54c8\u5e0c\u8868\u7684\u5185\u90e8\u5b9e\u73b0<\/h4>\n
\u6570\u636e\u7ed3\u6784<\/h6>\n

PHP\u4e2d\u4f7f\u7528\u4e00\u4e2a\u53ebBacket\u7684\u7ed3\u6784\u4f53\u8868\u793a\u6876\uff0c\u540c\u4e00\u54c8\u5e0c\u503c\u7684\u6240\u6709\u6876\u88ab\u7ec4\u7ec7\u4e3a\u4e00\u4e2a\u5355\u94fe\u8868\u3002\u54c8\u5e0c\u8868\u4f7f\u7528HashTable\u7ed3\u6784\u4f53\u8868\u793a\u3002\u76f8\u5173\u6e90\u7801\u5728zend\/Zend_hash.h\u4e0b\uff1a<\/p>\n

typedef struct bucket {\n    ulong h;                        \/* Used for numeric indexing *\/\n    uint nKeyLength;\n    void *pData;\n    void *pDataPtr;\n    struct bucket *pListNext;\n    struct bucket *pListLast;\n    struct bucket *pNext;\n    struct bucket *pLast;\n    char arKey[1]; \/* Must be last element *\/\n} Bucket;\n\ntypedef struct _hashtable {\n    uint nTableSize;\n    uint nTableMask;\n    uint nNumOfElements;\n    ulong nNextFreeElement;\n    Bucket *pInternalPointer;   \/* Used for element traversal *\/\n    Bucket *pListHead;\n    Bucket *pListTail;\n    Bucket **arBuckets;\n    dtor_func_t pDestructor;\n    zend_bool persistent;\n    unsigned char nApplyCount;\n    zend_bool bApplyProtection;\n#if ZEND_DEBUG\n    int inconsistent;\n#endif\n} HashTable;<\/pre>\n
\u5b57\u6bb5\u540d\u5f88\u6e05\u695a\u7684\u8868\u660e\u5176\u7528\u9014\uff0c\u56e0\u6b64\u4e0d\u505a\u8fc7\u591a\u89e3\u91ca\u3002\u91cd\u70b9\u660e\u786e\u4e0b\u9762\u51e0\u4e2a\u5b57\u6bb5\uff1aBucket\u4e2d\u7684\u201ch\u201d\u7528\u4e8e\u5b58\u50a8\u539f\u59cbkey\uff1bHashTable\u4e2d\u7684nTableMask\u662f\u4e00\u4e2a\u63a9\u7801\uff0c\u4e00\u822c\u88ab\u8bbe\u4e3anTableSize – 1\uff0c\u4e0e\u54c8\u5e0c\u7b97\u6cd5\u6709\u5bc6\u5207\u5173\u7cfb\uff0c\u540e\u9762\u8ba8\u8bba\u54c8\u5e0c\u7b97\u6cd5\u65f6\u4f1a\u8be6\u8ff0\uff1barBuckets\u6307\u5411\u4e00\u4e2a\u6307\u9488\u6570\u7ec4\uff0c\u5176\u4e2d\u6bcf\u4e2a\u5143\u7d20\u662f\u4e00\u4e2a\u6307\u5411Bucket\u94fe\u8868\u7684\u5934\u6307\u9488\u3002<\/p>\n
\u54c8\u5e0c\u7b97\u6cd5<\/h6>\n
PHP\u54c8\u5e0c\u8868\u6700\u5c0f\u5bb9\u91cf\u662f8\uff082^3\uff09\uff0c\u6700\u5927\u5bb9\u91cf\u662f0x80000000\uff082^31\uff09\uff0c\u5e76\u54112\u7684\u6574\u6570\u6b21\u5e42\u5706\u6574\uff08\u5373\u957f\u5ea6\u4f1a\u81ea\u52a8\u6269\u5c55\u4e3a2\u7684\u6574\u6570\u6b21\u5e42\uff0c\u598213\u4e2a\u5143\u7d20\u7684\u54c8\u5e0c\u8868\u957f\u5ea6\u4e3a16\uff1b100\u4e2a\u5143\u7d20\u7684\u54c8\u5e0c\u8868\u957f\u5ea6\u4e3a128\uff09\u3002nTableMask\u88ab\u521d\u59cb\u5316\u4e3a\u54c8\u5e0c\u8868\u957f\u5ea6\uff08\u5706\u6574\u540e\uff09\u51cf1\u3002\u5177\u4f53\u4ee3\u7801\u5728zend\/Zend_hash.c\u7684_zend_hash_init\u51fd\u6570\u4e2d\uff0c\u8fd9\u91cc\u622a\u53d6\u4e0e\u672c\u6587\u76f8\u5173\u7684\u90e8\u5206\u5e76\u52a0\u4e0a\u5c11\u91cf\u6ce8\u91ca\uff1a<\/p>\n
ZEND_API int _zend_hash_init(HashTable *ht, uint nSize, hash_func_t pHashFunction, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC)\n{\n    uint i = 3;\n    Bucket **tmp;\n\n    SET_INCONSISTENT(HT_OK);\n\n    \/\/\u957f\u5ea6\u54112\u7684\u6574\u6570\u6b21\u5e42\u5706\u6574\n    if (nSize >= 0x80000000) {\n        \/* prevent overflow *\/\n        ht->nTableSize = 0x80000000;\n    } else {\n        while ((1U << i) < nSize) {\n            i++;\n        }\n        ht->nTableSize = 1 << i;\n    }\n\n    ht->nTableMask = ht->nTableSize - 1;\n\n    \/*\u6b64\u5904\u7701\u7565\u82e5\u5e72\u4ee3\u7801\u2026*\/\n\n    return SUCCESS;\n}<\/pre>\n
\u503c\u5f97\u4e00\u63d0\u7684\u662fPHP\u54112\u7684\u6574\u6570\u6b21\u5e42\u53d6\u5706\u6574\u65b9\u6cd5\u975e\u5e38\u5de7\u5999\uff0c\u53ef\u4ee5\u80cc\u4e0b\u6765\u5728\u9700\u8981\u7684\u65f6\u5019\u4f7f\u7528\uff08\u5c31\u662f\u56e0\u4e3a\u8fd9\u6bb5\u5de7\u5999\u7684\u4ee3\u7801\u7ed9\u6211\u7684\u5370\u8c61\u975e\u5e38\u6df1\u523b\uff0c\u6240\u4ee5\u6211\u624d\u80fd\u60f3\u8d77\u6765\u5728\u54ea\u53bb\u627e\uff09\u3002<\/p>\n
Zend HashTable\u7684\u54c8\u5e0c\u7b97\u6cd5\u5f02\u5e38\u7b80\u5355<\/strong><\/span>\uff1a<\/p>\n
hash(key)=key & nTableMask<\/p>\n
\u5373\u7b80\u5355\u5c06\u6570\u636e\u7684\u539f\u59cbkey\u4e0eHashTable\u7684nTableMask\u8fdb\u884c\u6309\u4f4d\u4e0e\u5373\u53ef\u3002<\/p>\n
\u5982\u679c\u539f\u59cbkey\u4e3a\u5b57\u7b26\u4e32\uff0c\u5219\u9996\u5148\u4f7f\u7528Times33\u7b97\u6cd5\u5c06\u5b57\u7b26\u4e32\u8f6c\u4e3a\u6574\u5f62\u518d\u4e0enTableMask\u6309\u4f4d\u4e0e\u3002<\/p>\n
hash(strkey)=time33(strkey) & nTableMask<\/p>\n
\u4e0b\u9762\u662fZend\u6e90\u7801\u4e2d\u67e5\u627e\u54c8\u5e0c\u8868\u7684\u4ee3\u7801\uff1a<\/p>\n
ZEND_API int zend_hash_index_find(const HashTable *ht, ulong h, void **pData)\n{\n    uint nIndex;\n    Bucket *p;\n\n    IS_CONSISTENT(ht);\n\n    nIndex = h & ht->nTableMask;\n\n    p = ht->arBuckets[nIndex];\n    while (p != NULL) {\n        if ((p->h == h) && (p->nKeyLength == 0)) {\n            *pData = p->pData;\n            return SUCCESS;\n        }\n        p = p->pNext;\n    }\n    return FAILURE;\n}\n\nZEND_API int zend_hash_find(const HashTable *ht, const char *arKey, uint nKeyLength, void **pData)\n{\n    ulong h;\n    uint nIndex;\n    Bucket *p;\n\n    IS_CONSISTENT(ht);\n\n    h = zend_inline_hash_func(arKey, nKeyLength);\n    nIndex = h & ht->nTableMask;\n\n    p = ht->arBuckets[nIndex];\n    while (p != NULL) {\n        if ((p->h == h) && (p->nKeyLength == nKeyLength)) {\n            if (!memcmp(p->arKey, arKey, nKeyLength)) {\n                *pData = p->pData;\n                return SUCCESS;\n            }\n        }\n        p = p->pNext;\n    }\n    return FAILURE;\n}<\/pre>\n
\u5176\u4e2dzend_hash_index_find\u7528\u4e8e\u67e5\u627e\u6574\u6570key\u7684\u60c5\u51b5\uff0czend_hash_find\u7528\u4e8e\u67e5\u627e\u5b57\u7b26\u4e32key\u3002\u903b\u8f91\u57fa\u672c\u4e00\u81f4\uff0c\u53ea\u662f\u5b57\u7b26\u4e32key\u4f1a\u901a\u8fc7zend_inline_hash_func\u8f6c\u4e3a\u6574\u6570key\uff0czend_inline_hash_func\u5c01\u88c5\u4e86times33\u7b97\u6cd5\uff0c\u5177\u4f53\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
static inline ulong zend_inline_hash_func(char *arKey, uint nKeyLength)\n{\n    register ulong hash = 5381;\n\n    \/* variant with the hash unrolled eight times *\/\n    for (; nKeyLength >= 8; nKeyLength -= 8) {\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n        hash = ((hash << 5) + hash) + *arKey++;\n    }\n    switch (nKeyLength) {\n        case 7: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 6: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 5: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 4: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 3: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 2: hash = ((hash << 5) + hash) + *arKey++; \/* fallthrough... *\/\n        case 1: hash = ((hash << 5) + hash) + *arKey++; break;\n        case 0: break;\nEMPTY_SWITCH_DEFAULT_CASE()\n    }\n    return hash;\n}<\/pre>\n
hash(i) = hash(i-1) * 33 + str[i]  \/\/Apache\u548cPerl\u4e2d\u662f\u76f4\u63a5\u91c7\u7528\u7684\u7ecf\u5178Times 33\u7b97\u6cd5\n\nhash << 5 + hash  \/\/PHP\u4e2d\u6ca1\u6709\u76f4\u63a5\u4e5833\uff0c\u800c\u662f\u9009\u7528\u7684\u79fb\u4f4d\uff0c\u8981\u6bd4\u76f4\u63a5\u4e58\u66f4\u5feb<\/pre>\n
\u653b\u51fb<\/h4>\n
\u57fa\u672c\u653b\u51fb<\/h6>\n
\u77e5\u9053\u4e86PHP\u5185\u90e8\u54c8\u5e0c\u8868\u7684\u7b97\u6cd5\uff0c\u5c31\u53ef\u4ee5\u5229\u7528\u5176\u539f\u7406\u6784\u9020\u7528\u4e8e\u653b\u51fb\u7684\u6570\u636e\u3002\u4e00\u79cd\u6700\u7b80\u5355\u7684\u65b9\u6cd5\u662f\u5229\u7528\u63a9\u7801\u89c4\u5f8b\u5236\u9020\u78b0\u649e\u3002\u4e0a\u6587\u63d0\u5230Zend HashTable\u7684\u957f\u5ea6nTableSize\u4f1a\u88ab\u5706\u6574\u4e3a2\u7684\u6574\u6570\u6b21\u5e42\uff0c\u5047\u8bbe\u6211\u4eec\u6784\u9020\u4e00\u4e2a2^16\u7684\u54c8\u5e0c\u8868\uff0c\u5219nTableSize\u7684\u4e8c\u8fdb\u5236\u8868\u793a\u4e3a\uff1a1 0000 0000 0000 0000\uff0c\u800cnTableMask = nTableSize \u2013 1\u4e3a\uff1a0 1111 1111 1111 1111\u3002\u63a5\u4e0b\u6765\uff0c\u53ef\u4ee5\u4ee50\u4e3a\u521d\u59cb\u503c\uff0c\u4ee52^16\u4e3a\u6b65\u957f\uff0c\u5236\u9020\u8db3\u591f\u591a\u7684\u6570\u636e\uff0c\u53ef\u4ee5\u5f97\u5230\u5982\u4e0b\u63a8\u6d4b\uff1a<\/p>\n
0000 0000 0000 0000 0000 & 0 1111 1111 1111 1111 = 0<\/p>\n
0001 0000 0000 0000 0000 & 0 1111 1111 1111 1111 = 0<\/p>\n
0010 0000 0000 0000 0000 & 0 1111 1111 1111 1111 = 0<\/p>\n
0011 0000 0000 0000 0000 & 0 1111 1111 1111 1111 = 0<\/p>\n
0100 0000 0000 0000 0000 & 0 1111 1111 1111 1111 = 0<\/p>\n
\u2026\u2026<\/p>\n
\u6982\u51b5\u6765\u8bf4\u53ea\u8981\u4fdd\u8bc1\u540e16\u4f4d\u5747\u4e3a0\uff0c\u5219\u4e0e\u63a9\u7801\u4f4d\u4e8e\u540e\u5f97\u5230\u7684\u54c8\u5e0c\u503c\u5168\u90e8\u78b0\u649e\u5728\u4f4d\u7f6e0<\/span>\u3002<\/p>\n
\u4e0b\u9762\u662f\u5229\u7528\u8fd9\u4e2a\u539f\u7406\u5199\u7684\u4e00\u6bb5\u653b\u51fb\u4ee3\u7801\uff1a<\/p>\n
<?php\n$size = pow(2, 16);\n$startTime = microtime(true);\n$array = array();\nfor ($key = 0, $maxKey = ($size - 1) * $size; $key <= $maxKey; $key += $size) {\n\t$array[$key] = 0;\n}\n$endTime = microtime(true);\necho $endTime - $startTime, ' seconds', \"n\";<\/pre>\n
\u5c06\u4e0a\u9762\u7684\u4ee3\u7801\u4e0e\u6b63\u5e38\u60c5\u51b5\u4e0b\u7684Hash\u8868\u63d2\u5165\u7b97\u6cd5\u8fdb\u884c\u5bf9\u6bd4\uff1a<\/p>\n
<?php\n$size = pow(2, 16);\n$startTime = microtime(true);\n$array = array();\nfor ($key = 0, $maxKey = ($size - 1) * $size; $key <= $maxKey; $key += $size) {\n\t$array[$key] = 0;\n}\n$endTime = microtime(true);\necho $endTime - $startTime, ' seconds', \"n\";\n\n\/\/\u4e0b\u9762\u6a21\u62df\u7684\u662f\u6b63\u5e38\u60c5\u51b5\u4e0b\u7684\u8017\u65f6\u5206\u6790\n$size = pow(2, 16);\n$startTime = microtime(true);\n$array = array();\nfor ($key = 0, $maxKey = ($size - 1) * $size; $key <= $size; $key += 1) {\n\t$array[$key] = 0;\n}\n$endTime = microtime(true);\necho $endTime - $startTime, ' seconds', \"n\";<\/pre>\n
\u5728\u6211\u7684\u7535\u8111\uff08i3 M330\u7684CPU\uff09\u4e0a\u7684\u6267\u884c\u60c5\u51b5\u5982\u4e0b\uff08\u591a\u6b21\u6267\u884c\u7684\u5747\u503c\uff09\uff0c\u671f\u95f4CPU\u5360\u7528\u7387\u572830%\u5de6\u53f3\uff1a<\/p>\n
48.9493360519 seconds\n0.0371470451355 seconds<\/pre>\n
\u53ef\u4ee5\u8bc1\u660e\u7b2c\u4e8c\u6bb5\u4ee3\u7801\u63d2\u5165N\u4e2a\u5143\u7d20\u7684\u65f6\u95f4\u5728O(N)\u6c34\u5e73\uff0c\u800c\u7b2c\u4e00\u6bb5\u653b\u51fb\u4ee3\u7801\u5219\u9700O(N^2)\u7684\u65f6\u95f4\u53bb\u63d2\u5165N\u4e2a\u5143\u7d20\u3002<\/p>\n
POST\u653b\u51fb<\/h6>\n
\u5f53\u7136\uff0c\u4e00\u822c\u60c5\u51b5\u4e0b\u5f88\u96be\u9047\u5230\u653b\u51fb\u8005\u53ef\u4ee5\u76f4\u63a5\u4fee\u6539PHP\u4ee3\u7801\u7684\u60c5\u51b5\uff0c\u4f46\u662f\u653b\u51fb\u8005\u4ecd\u53ef\u4ee5\u901a\u8fc7\u4e00\u4e9b\u65b9\u6cd5\u95f4\u63a5\u6784\u9020\u54c8\u5e0c\u8868\u6765\u8fdb\u884c\u653b\u51fb\u3002\u4f8b\u5982PHP\u4f1a\u5c06\u63a5\u6536\u5230\u7684HTTP POST\u8bf7\u6c42\u4e2d\u7684\u6570\u636e\u6784\u9020\u4e3a$_POST\uff0c\u800c\u8fd9\u662f\u4e00\u4e2aArray\uff0c\u5185\u90e8\u5c31\u662f\u901a\u8fc7Zend HashTable\u8868\u793a\uff0c\u56e0\u6b64\u653b\u51fb\u8005\u53ea\u8981\u6784\u9020\u4e00\u4e2a\u542b\u6709\u5927\u91cf\u78b0\u649ekey\u7684post\u8bf7\u6c42\uff0c\u5c31\u53ef\u4ee5\u8fbe\u5230\u653b\u51fb\u7684\u76ee\u7684\u3002\u5177\u4f53\u505a\u6cd5\u4e0d\u518d\u6f14\u793a\u3002<\/p>\n
\u9632\u62a4<\/h4>\n
POST\u653b\u51fb\u7684\u9632\u62a4<\/h6>\n
\u9488\u5bf9POST\u65b9\u5f0f\u7684\u54c8\u5e0c\u78b0\u649e\u653b\u51fb\uff0c\u76ee\u524dPHP\u7684\u9632\u62a4\u63aa\u65bd\u662f\u63a7\u5236POST\u6570\u636e\u7684\u6570\u91cf\u3002\u5728>=PHP5.3.9\u7684\u7248\u672c\u4e2d\u589e\u52a0\u4e86\u4e00\u4e2a\u914d\u7f6e\u9879max_input_vars\uff0c\u7528\u4e8e\u6807\u8bc6\u4e00\u6b21http\u8bf7\u6c42\u6700\u5927\u63a5\u6536\u7684\u53c2\u6570\u4e2a\u6570\uff0c\u9ed8\u8ba4\u4e3a1000\u3002\u56e0\u6b64PHP5.3.x\u7684\u7528\u6237\u53ef\u4ee5\u901a\u8fc7\u5347\u7ea7\u81f35.3.9\u6765\u907f\u514d\u54c8\u5e0c\u78b0\u649e\u653b\u51fb\u30025.2.x\u7684\u7528\u6237\u53ef\u4ee5\u4f7f\u7528Laruence\u5927\u725b\u7ed9\u51fa\u7684patch\uff1ahttps:\/\/github.com\/laruence\/laruence.github.com\/tree\/master\/php-5.2-max-input-vars<\/a>\u3002<\/p>\n
\u53e6\u5916\u7684\u9632\u62a4\u65b9\u6cd5\u662f\u5728Web\u670d\u52a1\u5668\u5c42\u9762\u8fdb\u884c\u5904\u7406\uff0c\u4f8b\u5982\u9650\u5236http\u8bf7\u6c42body\u7684\u5927\u5c0f\u548c\u53c2\u6570\u7684\u6570\u91cf\u7b49\uff0c\u8fd9\u4e2a\u662f\u73b0\u5728\u7528\u7684\u6700\u591a\u7684\u4e34\u65f6\u5904\u7406\u65b9\u6848\u3002\u5177\u4f53\u505a\u6cd5\u4e0e\u4e0d\u540cWeb\u670d\u52a1\u5668\u76f8\u5173\uff0c\u4e0d\u518d\u8be6\u8ff0\u3002<\/p>\n
\u5176\u5b83\u9632\u62a4<\/h6>\n
\u4e0a\u9762\u7684\u9632\u62a4\u65b9\u6cd5\u53ea\u662f\u9650\u5236POST\u6570\u636e\u7684\u6570\u91cf\uff0c\u800c\u4e0d\u80fd\u5f7b\u5e95\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002\u4f8b\u5982\uff0c\u5982\u679c\u67d0\u4e2aPOST\u5b57\u6bb5\u662f\u4e00\u4e2ajson\u6570\u636e\u7c7b\u578b\uff0c\u4f1a\u88abPHP json_decode\uff0c\u90a3\u4e48\u53ea\u8981\u6784\u9020\u4e00\u4e2a\u8d85\u5927\u7684json\u653b\u51fb\u6570\u636e\u7167\u6837\u53ef\u4ee5\u8fbe\u5230\u653b\u51fb\u76ee\u7684\u3002\u7406\u8bba\u4e0a\uff0c\u53ea\u8981PHP\u4ee3\u7801\u4e2d\u67d0\u5904\u6784\u9020Array\u7684\u6570\u636e\u4f9d\u8d56\u4e8e\u5916\u90e8\u8f93\u5165\uff0c\u5219\u90fd\u53ef\u80fd\u9020\u6210\u8fd9\u4e2a\u95ee\u9898\uff0c\u56e0\u6b64\u5f7b\u5e95\u7684\u89e3\u51b3\u65b9\u6848\u8981\u4eceZend\u5e95\u5c42HashTable\u7684\u5b9e\u73b0\u52a8\u624b\u3002<\/span>\u4e00\u822c\u6765\u8bf4\u6709\u4e24\u79cd\u65b9\u5f0f\uff0c\u4e00\u662f\u9650\u5236\u6bcf\u4e2a\u6876\u94fe\u8868\u7684\u6700\u957f\u957f\u5ea6\uff1b\u4e8c\u662f\u4f7f\u7528\u5176\u5b83\u6570\u636e\u7ed3\u6784\u5982\u7ea2\u9ed1\u6811\u53d6\u4ee3\u94fe\u8868\u7ec4\u7ec7\u78b0\u649e\u54c8\u5e0c\uff08\u5e76\u4e0d\u89e3\u51b3\u54c8\u5e0c\u78b0\u649e\uff0c\u53ea\u662f\u51cf\u8f7b\u653b\u51fb\u5f71\u54cd\uff0c\u5c06N\u4e2a\u6570\u636e\u7684\u64cd\u4f5c\u65f6\u95f4\u4eceO(N^2)\u964d\u81f3O(NlogN)\uff0c\u4ee3\u4ef7\u662f\u666e\u901a\u60c5\u51b5\u4e0b\u63a5\u8fd1O(1)\u7684\u64cd\u4f5c\u5747\u53d8\u4e3aO(logN)\uff09\u3002<\/p>\n
\u76ee\u524d\u4f7f\u7528\u6700\u591a\u7684\u4ecd\u7136\u662fPOST\u6570\u636e\u653b\u51fb\uff0c\u56e0\u6b64\u5efa\u8bae\u751f\u4ea7\u73af\u5883\u7684PHP\u5747\u8fdb\u884c\u5347\u7ea7\u6216\u6253\u8865\u4e01\u3002\u81f3\u4e8e\u4ece\u6570\u636e\u7ed3\u6784\u5c42\u9762\u4fee\u590d\u8fd9\u4e2a\u95ee\u9898\uff0c\u76ee\u524d\u8fd8\u6ca1\u6709\u4efb\u4f55\u65b9\u9762\u7684\u6d88\u606f\u3002<\/p>\n
\u53c2\u8003\u94fe\u63a5\uff1a<\/h6>\n