+/************************************************************************
+ ************************************************************************
+ FAUST compiler
+ Copyright (C) 2003-2004 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 General Public License as published by
+ the Free Software Foundation; either version 2 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ ************************************************************************
+ ************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "symbol.hh"
+#include "compatibility.hh"
+#include <iostream>
+#include <cstring>
+#include <assert.h>
+
+using namespace std;
+
+/**
+ * Hash table used to store the symbols
+ */
+
+Symbol* Symbol::gSymbolTable[kHashTableSize];
+
+
+/**
+ * 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
+ */
+
+Symbol* Symbol::get(const string& str)
+{
+ char buf[1024];
+ int i;
+ int n = str.length();
+
+ if (n>1023) n = 1023;
+ for (i = 0; i < n; i++) { buf[i] = str[i]; }
+ buf[i] = 0;
+
+ return Symbol::get(buf);
+}
+
+
+
+/**
+ * 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
+ */
+
+Symbol* Symbol::get(const char* str)
+{
+ unsigned int hsh = calcHashKey(str);
+ int bckt = hsh % kHashTableSize;
+ Symbol* item = gSymbolTable[bckt];
+
+ while ( item && !item->equiv(hsh,str) ) item = item->fNext;
+ Symbol* 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 char* str)
+{
+ unsigned int hsh = calcHashKey(str);
+ int bckt = hsh % kHashTableSize;
+ Symbol* item = gSymbolTable[bckt];
+
+ while ( item && !item->equiv(hsh,str) ) item = item->fNext;
+ return item == 0;
+}
+
+
+/**
+ * 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
+ */
+
+Symbol* Symbol::prefix (const char* str)
+{
+ char name[256];
+
+ static map<const char*, unsigned int> gPrefixCounters;
+
+ for (int n = 0; n<10000; n++) {
+ snprintf(name, 256, "%s%d", str, gPrefixCounters[str]++);
+ if (isnew(name)) return get(name);
+ }
+ assert(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 (unsigned int hash, const char *str) const
+{
+ return (fHash == hash) && (strcmp(fName,str) == 0);
+}
+
+
+
+/**
+ * Compute the 32-bits hash key of string \p str
+ * \param str the string
+ * \return a 32-bits hash key
+ */
+
+unsigned int Symbol::calcHashKey (const char* str)
+{
+ unsigned int h = 0;
+
+ while (*str) h = (h << 1) ^ (h >> 20) ^ (*str++);
+ return h;
+}
+
+
+
+/**
+ * Constructs a symbol ready to be placed in the hash table.
+ * It makes a private copy of its name.
+ * \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 char* str, unsigned int hsh, Symbol* nxt)
+{
+ int len = strlen(str);
+
+ fName = new char [len+1];
+ memcpy(fName, str, len+1);
+ fHash = hsh;
+ fNext = nxt;
+ fData = 0;
+}
+
+Symbol::~Symbol ()
+{
+ delete [] fName;
+}
+
+ostream& Symbol::print (ostream& fout) const ///< print a symbol on a stream
+{
+ return fout << fName;
+}
projects / Faustine.git / blobdiff