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add QSORT Add the macro QSORT, a convenient wrapper for qsort(3) that infers the size of the array elements and supports the convention of initializing empty arrays with a NULL pointer, which we use in some places. Calling qsort(3) directly with a NULL pointer is undefined -- even with an element count of zero -- and allows the compiler to optimize away any following NULL checks. Using the macro avoids such surprises. Add a semantic patch as well to demonstrate the macro's usage and to automate the transformation of trivial cases. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com> 2016-09-29 17:23:43 +02:00			`@@`
			`expression base, nmemb, compar;`
			`@@`
			`- qsort(base, nmemb, sizeof(*base), compar);`
			`+ QSORT(base, nmemb, compar);`

			`@@`
			`expression base, nmemb, compar;`
			`@@`
			`- qsort(base, nmemb, sizeof(base[0]), compar);`
			`+ QSORT(base, nmemb, compar);`

			`@@`
			`type T;`
			`T *base;`
			`expression nmemb, compar;`
			`@@`
			`- qsort(base, nmemb, sizeof(T), compar);`
			`+ QSORT(base, nmemb, compar);`
remove unnecessary check before QSORT Add a semantic patch for removing checks similar to the one that QSORT already does internally and apply it to the code base. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com> 2016-09-29 17:29:29 +02:00
			`@@`
			`expression base, nmemb, compar;`
			`@@`
			`- if (nmemb)`
			`QSORT(base, nmemb, compar);`

			`@@`
			`expression base, nmemb, compar;`
			`@@`
			`- if (nmemb > 0)`
			`QSORT(base, nmemb, compar);`

			`@@`
			`expression base, nmemb, compar;`
			`@@`
			`- if (nmemb > 1)`
			`QSORT(base, nmemb, compar);`