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bzip2: rewrite bit of code which depends on integer overflow

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function                                             old     new   delta
sendMTFValues                                       2093    2070     -23

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-02-03 03:34:40 +01:00
parent 83dd4ff696
commit 982c44d030
1 changed files with 5 additions and 5 deletions
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10
archival/libarchive/bz/compress.c
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@ -297,7 +297,7 @@ void sendMTFValues(EState* s)
// 200..599 = 3 // 200..599 = 3
// 600..1199 = 4 // 600..1199 = 4
// 1200..2399 = 5 // 1200..2399 = 5
// else 6 // 2400..99999 = 6
nGroups = 2; nGroups = 2;
nGroups += (s->nMTF >= 200); nGroups += (s->nMTF >= 200);
nGroups += (s->nMTF >= 600); nGroups += (s->nMTF >= 600);
@ -317,12 +317,12 @@ void sendMTFValues(EState* s)
unsigned tFreq, aFreq; unsigned tFreq, aFreq;
tFreq = remF / nPart; tFreq = remF / nPart;
ge = gs - 1; //underflows on 1st iteration ge = gs;
aFreq = 0; aFreq = 0;
while (aFreq < tFreq && (int)ge < (int)alphaSize-1) { while (aFreq < tFreq && ge < alphaSize) {
ge++; aFreq += s->mtfFreq[ge++];
aFreq += s->mtfFreq[ge];
} }
ge--;
if (ge > gs if (ge > gs
&& nPart != nGroups && nPart != 1 && nPart != nGroups && nPart != 1