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Core: String::Find(String) once again optimized

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git-svn-id: svn://ultimatepp.org/upp/trunk@6993 f0d560ea-af0d-0410-9eb7-867de7ffcac7
This commit is contained in:
cxl 2014-03-05 17:42:15 +00:00
parent cfd5bccc10
commit cbf2f4de95
1 changed files with 108 additions and 0 deletions
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108
uppsrc/Core/String.cpp
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@ -2,6 +2,112 @@
NAMESPACE_UPP
#ifdef CPU_X86 // Use unaligned access
inline
bool equal_back_8(const char *a, const char *b, int len)
{
while(len > 8) {
len -= 8;
if(Peek64le(a + len) != Peek64le(b + len))
return false;
}
return true;
}
template <int step> // Template parameter to be a constant
int t_find(const char *ptr, int slen, const char *p, int len, int from)
{
ASSERT(from >= 0 && from <= slen);
int l = slen - len - from;
if(l < 0)
return -1;
const char *s = ptr + from;
const char *e = s + l;
if(len <= 8) {
if(len > 4) {
len -= 4;
int32 p0 = Peek32le(p);
int32 p1 = Peek32le(p + len);
while(s <= e) {
if(Peek32le(s) == p0 && Peek32le(s + len) == p1)
return (int)(s - ptr);
s += step;
}
}
else
if(len == 4) {
int32 p0 = Peek32le(p);
while(s <= e) {
if(Peek32le(s) == p0)
return (int)(s - ptr);
s += step;
}
}
else
if(len == 3) {
int16 p0 = Peek16le(p);
char p1 = p[2];
while(s <= e) {
if(Peek16le(s) == p0 && s[2] == p1)
return (int)(s - ptr);
s += step;
}
}
else
if(len == 2) {
int16 p0 = Peek16le(p);
while(s <= e) {
if(Peek16le(s) == p0)
return (int)(s - ptr);
s += step;
}
}
else
if(len == 1) {
char p0 = p[0];
while(s <= e) {
if(*s == p0)
return (int)(s - ptr);
s += step;
}
}
else
return true;
}
else {
int64 p0 = Peek64le(p);
if(len <= 16) {
len -= 8;
int64 p1 = Peek64le(p + len);
while(s <= e) {
if(Peek64le(s) == p0 && Peek64le(s + len) == p1)
return (int)(s - ptr);
s += step;
}
}
else
while(s <= e) {
if(Peek64le(s) == p0 && equal_back_8(s, p, len))
return (int)(s - ptr);
s += step;
}
}
return -1;
}
int find(const char *text, int len, const char *needle, int nlen, int from)
{
return t_find<1>(text, len, needle, nlen, from);
}
int find(const wchar *text, int len, const wchar *needle, int nlen, int from)
{
return t_find<2>((const char *)text, 2 * len, (const char *)needle, 2 * nlen, from) / 2;
}
#else
template <class tchar>
int t_find(const tchar *ptr, int plen, const tchar *s, int len, int from)
{
@ -79,6 +185,8 @@ int find(const wchar *text, int len, const wchar *needle, int nlen, int from)
{
return t_find(text, len, needle, nlen, from);
}
#endif
#ifdef _DEBUG
void String0::Dsyn()