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From:   Junio C Hamano <gitster@pobox.com>
To:     "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
Cc:     git@vger.kernel.org, Carlo Arenas <carenas@gmail.com>,
        "brian m. carlson" <sandals@crustytoothpaste.net>,
        Johannes Schindelin <johannes.schindelin@gmx.de>
Subject: Re: [PATCH v3 2/8] test-tool genzeros: generate large amounts of
 data more efficiently
References: <pull.1068.v2.git.1635454237.gitgitgadget@gmail.com>
        <pull.1068.v3.git.1635515959.gitgitgadget@gmail.com>
        <052197200141c321118b7766f5615a61f951e59f.1635515959.git.gitgitgadget@gmail.com>
Date:   Fri, 29 Oct 2021 15:50:53 -0700
In-Reply-To: <052197200141c321118b7766f5615a61f951e59f.1635515959.git.gitgitgadget@gmail.com>
        (Johannes Schindelin via GitGitGadget's message of "Fri, 29 Oct 2021
        13:59:13 +0000")
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"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> @@ -12,9 +15,19 @@ int cmd__genzeros(int argc, const char **argv)
>  
>  	count = argc > 1 ? strtoimax(argv[1], NULL, 0) : -1;
>  
> -	while (count < 0 || count--) {
> -		if (putchar(0) == EOF)
> +	/* Writing out individual NUL bytes is slow... */
> +	while (count < 0)
> +		if (write(1, zeros, ARRAY_SIZE(zeros)) < 0)
>  			return -1;
> +
> +	while (count > 0) {
> +		n = write(1, zeros, count < ARRAY_SIZE(zeros) ?
> +			  count : ARRAY_SIZE(zeros));
> +
> +		if (n < 0)
> +			return -1;
> +
> +		count -= n;
>  	}
>  
>  	return 0;

This round looks OK to me.