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From: Quan Zongliang <zongliang.quan@postgresdata.com>
To: pgsql-zh-general@postgresql.org <pgsql-zh-general@postgresql.org>
Subject: 随机字符串函数的C语言实现
Date: Tue, 5 Sep 2017 16:28:18 +0800
Message-ID: <e4b2ab08-6847-e431-9ccb-d42ac805a3d7@postgresdata.com> (raw)
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各位下午好
邮件列表沉寂太久，激活一下大家的情绪。

分享一个C语言实现的随机字符串函数：
PG_FUNCTION_INFO_V1(random_string);
Datum
random_string(PG_FUNCTION_ARGS)
{
	int32 length = PG_GETARG_INT32(0);
	int32 i;
	const char chars[] = 
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
	char *result;

	if (length < 0)
		PG_RETURN_NULL();

	if (length == 0)
		PG_RETURN_TEXT_P(cstring_to_text(""));

	result = palloc(length + 1);
	if (result == NULL)
		ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY),
					errmsg("out of memory")));

	for (i=0; i<length; i++)
	{
		result[i] = chars[random()%(sizeof(chars)-1)];
	}
	result[i] = '\0';

	PG_RETURN_TEXT_P(cstring_to_text(result));
}

原文见：
https://my.oschina.net/quanzl/blog/1529438

欢迎关注我司公众号：postgresdata-news

-- 
权宗亮
神州飞象（北京）数据科技有限公司
我们的力量源自最先进的开源数据库PostgreSQL
zongliang.quan@postgresdata.com



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