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bzip2: optimize zPend variable code

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function                                             old     new   delta
generateMTFValues                                    433     378     -55

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2018-02-03 15:26:00 +01:00
parent fc228b48c9
commit 1cbcb02316
3 changed files with 39 additions and 23 deletions
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42
archival/libarchive/bz/compress.c
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@@ -162,7 +162,7 @@ void generateMTFValues(EState* s)
{
uint8_t yy[256];
int32_t i, j;
int32_t zPend;
int zPend;
int32_t wr;
int32_t EOB;
@@ -217,6 +217,7 @@ void generateMTFValues(EState* s)
if (zPend > 0) {
zPend--;
while (1) {
#if 0
if (zPend & 1) {
mtfv[wr] = BZ_RUNB; wr++;
s->mtfFreq[BZ_RUNB]++;
@@ -224,10 +225,18 @@ void generateMTFValues(EState* s)
mtfv[wr] = BZ_RUNA; wr++;
s->mtfFreq[BZ_RUNA]++;
}
if (zPend < 2) break;
zPend = (uint32_t)(zPend - 2) / 2;
#else /* same as above, since BZ_RUNA is 0 and BZ_RUNB is 1 */
unsigned run = zPend & 1;
mtfv[wr] = run;
wr++;
s->mtfFreq[run]++;
#endif
zPend -= 2;
if (zPend < 0)
break;
zPend = (unsigned)zPend / 2;
/* bbox: unsigned div is easier */
};
}
zPend = 0;
}
{
@@ -244,7 +253,7 @@ void generateMTFValues(EState* s)
rtmp2 = rtmp;
rtmp = *ryy_j;
*ryy_j = rtmp2;
};
}
yy[0] = rtmp;
j = ryy_j - &(yy[0]);
mtfv[wr] = j+1;
@@ -257,6 +266,7 @@ void generateMTFValues(EState* s)
if (zPend > 0) {
zPend--;
while (1) {
#if 0
if (zPend & 1) {
mtfv[wr] = BZ_RUNB;
wr++;
@@ -266,12 +276,18 @@ void generateMTFValues(EState* s)
wr++;
s->mtfFreq[BZ_RUNA]++;
}
if (zPend < 2)
#else /* same as above, since BZ_RUNA is 0 and BZ_RUNB is 1 */
unsigned run = zPend & 1;
mtfv[wr] = run;
wr++;
s->mtfFreq[run]++;
#endif
zPend -= 2;
if (zPend < 0)
break;
zPend = (uint32_t)(zPend - 2) / 2;
zPend = (unsigned)zPend / 2;
/* bbox: unsigned div is easier */
};
zPend = 0;
}
}
mtfv[wr] = EOB;
@@ -528,11 +544,11 @@ void sendMTFValues(EState* s)
tmp2 = tmp;
tmp = pos[j];
pos[j] = tmp2;
};
}
pos[0] = tmp;
s->selectorMtf[i] = j;
}
};
}
/*--- Assign actual codes for the tables. --*/
for (t = 0; t < nGroups; t++) {
@@ -595,8 +611,8 @@ void sendMTFValues(EState* s)
unsigned curr = s->len[t][0];
bsW(s, 5, curr);
for (i = 0; i < alphaSize; i++) {
while (curr < s->len[t][i]) { bsW(s, 2, 2); curr++; /* 10 */ };
while (curr > s->len[t][i]) { bsW(s, 2, 3); curr--; /* 11 */ };
while (curr < s->len[t][i]) { bsW(s, 2, 2); curr++; /* 10 */ }
while (curr > s->len[t][i]) { bsW(s, 2, 3); curr--; /* 11 */ }
bsW1_0(s);
}
}