解析strtr函数的效率问题(2)

static void php_strtr_array(zval *return_value, char *str, int slen, HashTable *hash)
{
        zval **entry;
        char  *string_key;
        uint   string_key_len;
        zval **trans;
        zval   ctmp;
        ulong num_key;
        int minlen = 128*1024;
        int maxlen = 0, pos, len, found;
        char *key;
        HashPosition hpos;
        smart_str result = {0};
        HashTable tmp_hash;
        //把替换数组从hash复制到tmp_hash,并记录下标字符串的最大和最小长度
        zend_hash_init(&tmp_hash, 0, NULL, NULL, 0);
        zend_hash_internal_pointer_reset_ex(hash, &hpos);
        while (zend_hash_get_current_data_ex(hash, (void **)&entry, &hpos) == SUCCESS) {
                switch (zend_hash_get_current_key_ex(hash, &string_key, &string_key_len, &num_key, 0, &hpos)) {
                        case HASH_KEY_IS_STRING:
                                len = string_key_len-1;
                                if (len < 1) {
                                        zend_hash_destroy(&tmp_hash);
                                        RETURN_FALSE;
                                }
                                zend_hash_add(&tmp_hash, string_key, string_key_len, entry, sizeof(zval*), NULL);
                                if (len > maxlen) {
                                        maxlen = len;
                                }
                                if (len < minlen) {
                                        minlen = len;
                                }
                                break;
                        //下标如果是整形的话会转换成字符串类型，例如：array(10=>'aa')转换成array('10'=>'aa')
                        case HASH_KEY_IS_LONG:
                                Z_TYPE(ctmp) = IS_LONG;
                                Z_LVAL(ctmp) = num_key;
                                convert_to_string(&ctmp);
                                len = Z_STRLEN(ctmp);
                                zend_hash_add(&tmp_hash, Z_STRVAL(ctmp), len+1, entry, sizeof(zval*), NULL);
                                zval_dtor(&ctmp);
                                if (len > maxlen) {
                                        maxlen = len;
                                }
                                if (len < minlen) {
                                        minlen = len;
                                }
                                break;
                }
                zend_hash_move_forward_ex(hash, &hpos);
        }
        key = emalloc(maxlen+1);
        pos = 0;
        //从字符串的第一个字符开始循环匹配，pos记录当前查找的位置
        while (pos < slen) {
                //当前位置加上最大长度，如果大于字符串长度，则最大长度就需要改变
                if ((pos + maxlen) > slen) {
                        maxlen = slen - pos;
                }
                found = 0;
                memcpy(key, str+pos, maxlen);
                //从最大长度开始匹配，就是说对'abcd'，若array('a'=>'e','ab'=>'f')，则会先把ab替换为f，而不是先把a换成e。
                for (len = maxlen; len >= minlen; len--) {
                        key[len] = 0;
                        //因为使用了hash表，所以这样的效率还是挺高的
                        if (zend_hash_find(&tmp_hash, key, len+1, (void**)&trans) == SUCCESS) {
                                char *tval;
                                int tlen;
                                zval tmp;
                                if (Z_TYPE_PP(trans) != IS_STRING) {
                                        tmp = **trans;
                                        zval_copy_ctor(&tmp);
                                        convert_to_string(&tmp);
                                        tval = Z_STRVAL(tmp);
                                        tlen = Z_STRLEN(tmp);
                                } else {
                                        tval = Z_STRVAL_PP(trans);
                                        tlen = Z_STRLEN_PP(trans);
                                }
                                //加入结果
                                smart_str_appendl(&result, tval, tlen);
                                //向前跳跃
                                pos += len;
                                found = 1;
                                if (Z_TYPE_PP(trans) != IS_STRING) {
                                        zval_dtor(&tmp);
                                }
                                break;
                        }
                }
                if (! found) {
                        smart_str_appendc(&result, str[pos++]);
                }
        }
        efree(key);
        zend_hash_destroy(&tmp_hash);
        smart_str_0(&result);
        RETVAL_STRINGL(result.c, result.len, 0);
}

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