int MLSymbolTable::getSymbolID(const char * sym)
{
int r = 0;
bool found = false;
// process characters in place. On failure, return null symbol.
int len = processSymbolText(sym);
if(!(len > 0)) return 0;
// look up ID by symbol
// This is the fast path, and how we look up symbols from char* in typical code.
const std::vector<int>& bin = mHashTable[KRhash(sym)];
// there should be few collisions, so probably the first ID in the hash bin
// will be the symbol we are looking for. Unfortunately to test for equality we have to
// compare the entire string.
// if we replace std::string with a custom char * type that stores its length,
// and use SSE to do the compares, they could probably be significantly faster.
{
MLScopedLock lock(mLock);
for(int ID : bin)
{
const char* symB = mSymbolsByID[ID].c_str();
int lenB = processSymbolText(symB);
if(!strncmp(sym, symB, std::max(len, lenB)))
{
r = ID;
found = true;
break;
}
}
if(!found)
{
r = addEntry(sym, len);
}
}
return r;
}
MLSymbol::MLSymbol(const char *sym, int maxLen)
{
int len = processSymbolText(sym, maxLen);
mID = theSymbolTable().getSymbolID(sym, len);
}
MLSymbol::MLSymbol(const std::string& str)
{
int len = processSymbolText(str.c_str());
mID = theSymbolTable().getSymbolID(str.c_str(), len);
}
