xdiff: use unambiguous types in xdl_bogo_sqrt()

There is no real square root for a negative number and size_t may not
be large enough for certain applications, replace long with uint64_t.

Signed-off-by: Ezekiel Newren <ezekielnewren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: ezekielnewren

xdiff/xdiffi.c

@@ -348,7 +348,7 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	kvdf += xe->xdf2.nreff + 1;
 	kvdb += xe->xdf2.nreff + 1;
 
-	xenv.mxcost = xdl_bogosqrt(ndiags);
+	xenv.mxcost = (long)xdl_bogosqrt((uint64_t)ndiags);
 	if (xenv.mxcost < XDL_MAX_COST_MIN)
 		xenv.mxcost = XDL_MAX_COST_MIN;
 	xenv.snake_cnt = XDL_SNAKE_CNT;

xdiff/xprepare.c

@@ -290,7 +290,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 	/*
 	 * Initialize temporary arrays with DISCARD, KEEP, or INVESTIGATE.
 	 */
-	if ((mlim = xdl_bogosqrt((long)xdf1->nrec)) > XDL_MAX_EQLIMIT)
+	if ((mlim = (long)xdl_bogosqrt((uint64_t)xdf1->nrec)) > XDL_MAX_EQLIMIT)
 		mlim = XDL_MAX_EQLIMIT;
 	for (i = xdf1->dstart; i <= xdf1->dend; i++) {
 		size_t mph1 = xdf1->recs[i].minimal_perfect_hash;
@@ -299,7 +299,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 		action1[i] = (nm == 0) ? DISCARD: (nm >= mlim && !need_min) ? INVESTIGATE: KEEP;
 	}
 
-	if ((mlim = xdl_bogosqrt((long)xdf2->nrec)) > XDL_MAX_EQLIMIT)
+	if ((mlim = (long)xdl_bogosqrt((uint64_t)xdf2->nrec)) > XDL_MAX_EQLIMIT)
 		mlim = XDL_MAX_EQLIMIT;
 	for (i = xdf2->dstart; i <= xdf2->dend; i++) {
 		size_t mph2 = xdf2->recs[i].minimal_perfect_hash;

xdiff/xutils.c

@@ -23,8 +23,8 @@
 #include "xinclude.h"
 
 
-long xdl_bogosqrt(long n) {
-	long i;
+uint64_t xdl_bogosqrt(uint64_t n) {
+	uint64_t i;
 
 	/*
 	 * Classical integer square root approximation using shifts.

xdiff/xutils.h

@@ -25,7 +25,7 @@
 
 
 
-long xdl_bogosqrt(long n);
+uint64_t xdl_bogosqrt(uint64_t n);
 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
 		     xdemitcb_t *ecb);
 int xdl_cha_init(chastore_t *cha, long isize, long icount);