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Small speedup to inflate [psumbera].

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Seeing a few percent speedup by using a pointer instead of an
assigned structure. This seems to help the compiler to optimize
better.
This commit is contained in:
Mark Adler 2017-02-11 23:21:41 -08:00
parent e1f1a3a146
commit 60a5ecc62b
1 changed files with 14 additions and 14 deletions
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28
inffast.c
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@ -70,7 +70,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
code const FAR *dcode; /* local strm->distcode */ code const FAR *dcode; /* local strm->distcode */
unsigned lmask; /* mask for first level of length codes */ unsigned lmask; /* mask for first level of length codes */
unsigned dmask; /* mask for first level of distance codes */ unsigned dmask; /* mask for first level of distance codes */
code here; /* retrieved table entry */ code const *here; /* retrieved table entry */
unsigned op; /* code bits, operation, extra bits, or */ unsigned op; /* code bits, operation, extra bits, or */
/* window position, window bytes to copy */ /* window position, window bytes to copy */
unsigned len; /* match length, unused bytes */ unsigned len; /* match length, unused bytes */
@ -107,20 +107,20 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
hold += (unsigned long)(*in++) << bits; hold += (unsigned long)(*in++) << bits;
bits += 8; bits += 8;
} }
here = lcode[hold & lmask]; here = lcode + (hold & lmask);
dolen: dolen:
op = (unsigned)(here.bits); op = (unsigned)(here->bits);
hold >>= op; hold >>= op;
bits -= op; bits -= op;
op = (unsigned)(here.op); op = (unsigned)(here->op);
if (op == 0) { /* literal */ if (op == 0) { /* literal */
Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? Tracevv((stderr, here->val >= 0x20 && here->val < 0x7f ?
"inflate: literal '%c'\n" : "inflate: literal '%c'\n" :
"inflate: literal 0x%02x\n", here.val)); "inflate: literal 0x%02x\n", here->val));
*out++ = (unsigned char)(here.val); *out++ = (unsigned char)(here->val);
} }
else if (op & 16) { /* length base */ else if (op & 16) { /* length base */
len = (unsigned)(here.val); len = (unsigned)(here->val);
op &= 15; /* number of extra bits */ op &= 15; /* number of extra bits */
if (op) { if (op) {
if (bits < op) { if (bits < op) {
@ -138,14 +138,14 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
hold += (unsigned long)(*in++) << bits; hold += (unsigned long)(*in++) << bits;
bits += 8; bits += 8;
} }
here = dcode[hold & dmask]; here = dcode + (hold & dmask);
dodist: dodist:
op = (unsigned)(here.bits); op = (unsigned)(here->bits);
hold >>= op; hold >>= op;
bits -= op; bits -= op;
op = (unsigned)(here.op); op = (unsigned)(here->op);
if (op & 16) { /* distance base */ if (op & 16) { /* distance base */
dist = (unsigned)(here.val); dist = (unsigned)(here->val);
op &= 15; /* number of extra bits */ op &= 15; /* number of extra bits */
if (bits < op) { if (bits < op) {
hold += (unsigned long)(*in++) << bits; hold += (unsigned long)(*in++) << bits;
@ -264,7 +264,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
} }
} }
else if ((op & 64) == 0) { /* 2nd level distance code */ else if ((op & 64) == 0) { /* 2nd level distance code */
here = dcode[here.val + (hold & ((1U << op) - 1))]; here = dcode + here->val + (hold & ((1U << op) - 1));
goto dodist; goto dodist;
} }
else { else {
@ -274,7 +274,7 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
} }
} }
else if ((op & 64) == 0) { /* 2nd level length code */ else if ((op & 64) == 0) { /* 2nd level length code */
here = lcode[here.val + (hold & ((1U << op) - 1))]; here = lcode + here->val + (hold & ((1U << op) - 1));
goto dolen; goto dolen;
} }
else if (op & 32) { /* end-of-block */ else if (op & 32) { /* end-of-block */