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/************************************************************************
************************************************************************
FAUST compiler
Copyright (C) 2003-2018 GRAME, Centre National de Creation Musicale
---------------------------------------------------------------------
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
************************************************************************
************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cstring>
#include <iostream>
#include "compatibility.hh"
#include "exception.hh"
#include "symbol.hh"
using namespace std;
/**
* Hash table used to store the symbols.
*/
Sym Symbol::gSymbolTable[kHashTableSize];
map<string, size_t> Symbol::gPrefixCounters;
/**
* Search the hash table for the symbol of name \p str or returns a new one.
* \param str the name of the symbol
* \return a symbol of name str
*/
Sym Symbol::get(const string& rawstr)
{
// ---replaces control characters with white spaces---
string str = rawstr;
for (size_t i = 0; i < str.size(); i++) {
char c = rawstr[i];
str[i] = (c >= 0 && c < 32) ? 32 : c;
}
size_t hsh = calcHashKey(str);
int bckt = hsh % kHashTableSize;
Sym item = gSymbolTable[bckt];
while (item && !item->equiv(hsh, str)) {
item = item->fNext;
}
Sym r = item ? item : (gSymbolTable[bckt] = new Symbol(str, hsh, gSymbolTable[bckt]));
return r;
}
/**
* Static method that searches the symbol table for a string.
* \param str string to search
* \return true if the string is NOT in the table (it is a new string)
*/
bool Symbol::isnew(const string& str)
{
size_t hsh = calcHashKey(str);
int bckt = hsh % kHashTableSize;
Sym item = gSymbolTable[bckt];
while (item && !item->equiv(hsh, str)) {
item = item->fNext;
}
return item == nullptr;
}
/**
* Creates a new symbol with a name obtained by concatenating the \p str prefix with a number in
* order to make it unique. \param str the prefix of the name \return a symbol of name \p prefix++n
*/
Sym Symbol::prefix(const string& str)
{
string name;
for (int n = 0; n < 10000; n++) {
name = str + std::to_string(gPrefixCounters[str]++);
if (isnew(name)) {
return get(name);
}
}
faustassert(false);
return get("UNIQUEOVERFLOW");
}
/**
* Check if the name of the symbol is equal to string \p str
* This method is used by isnew() and make() when searching the hashtable
* for an existing symbol.
*
* \param hash the hash key of the string (used to speedup the comparison)
* \param str the string to compare
* \return \p true if the name of the symbol and \p str are the same
*/
bool Symbol::equiv(size_t hash, const string& str) const
{
return (fHash == hash) && (fName == str);
}
/**
* Compute the 32-bits hash key of string \p str.
* \param str the string
* \return a 32-bits hash key
*/
std::size_t Symbol::calcHashKey(const std::string& str)
{
std::size_t hk = 0;
for (char c : str) {
// Taken from by boost::hash_combine
hk = hk ^ (static_cast<std::size_t>(c) + 0x9e3779b9 + (hk << 6) + (hk >> 2));
}
return hk;
}
/**
* Constructs a symbol ready to be placed in the hash table.
* Gets a string to be kept.
* \param str the name of the symbol
* \param hsh the hash key of the symbol
* \param nxt a pointer to the next symbol in the hash table entry
*/
Symbol::Symbol(const string& str, size_t hsh, Sym nxt)
{
fName = str;
fHash = hsh;
fNext = nxt;
fData = 0;
}
Symbol::~Symbol()
{
}
ostream& Symbol::print(ostream& fout) const ///< print a symbol on a stream
{
return fout << fName;
}
void Symbol::init()
{
gPrefixCounters.clear();
memset(gSymbolTable, 0, sizeof(Sym) * kHashTableSize);
}
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