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symbols.c
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symbols.c
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/*** symbols.c ****************************************************************
**
** This file is part of BibTool.
** It is distributed under the GNU General Public License.
** See the file COPYING for details.
**
** (c) 1996-2020 Gerd Neugebauer
**
** Net: [email protected]
**
** 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, 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.
**
**-----------------------------------------------------------------------------
** Description:
** This module contains functions which deal with symbols and
** general memory management.
** This module implements a single symbol table.
**
** This module required initialization before all functions can
** be used. Especially the symbol table does not exist before
** initialization.
**
******************************************************************************/
#include <bibtool/general.h>
#include <bibtool/symbols.h>
#include <bibtool/error.h>
#include "config.h"
/*-----------------------------------------------------------------------------
** Typedef*: SymTab
** Purpose: This is the pointer type representing an entry in the symbol
** table. It contains a string and some integers.
**
**___________________________________________________ */
typedef struct STAB /* */
{ Symbol st_name; /* The symbol itself */
#ifndef COMPLEX_SYMBOL
int st_count; /* */
#endif
struct STAB *st_next; /* Pointer to the next item. */
} *SymTab;
/*-----------------------------------------------------------------------------
** Macro*: NextSymTab()
** Type: SymTab
** Purpose: The next |SymTab| of the argument. This macro
** can also be used as lvalue.
** Arguments:
** ST Current |SymTab|
** Returns: The next |SymTab| or |NULL|.
**___________________________________________________ */
#define NextSymTab(ST) ((ST)->st_next)
/*-----------------------------------------------------------------------------
** Macro*: SymTabCount()
** Type: int
** Purpose: The count slot of a |SymTab|. This macro
** can also be used as lvalue.
** Arguments:
** ST Current |SymTab|
** Returns: The count slot of |ST|.
**___________________________________________________ */
#ifdef COMPLEX_SYMBOL
#define SymTabCount(SYMTAB) SymbolCount(SymTabSymbol(SYMTAB))
#define SymCount(SYM,SYMTAB) SymbolCount(SymTabSymbol(SYMTAB))
#else
#define SymTabCount(SYMTAB) ((SYMTAB)->st_count)
#define SymCount(SYM,SYMTAB) SymTabCount(SYMTAB)
#endif
/*-----------------------------------------------------------------------------
** Macro*: SymTabSymbol()
** Type: Symbol
** Purpose: The name slot of a |SymTab|, i.e.\ the string
** representation. This macro can also be used as lvalue.
** Arguments:
** ST Current |SymTab|
** Returns: The name slot of |ST|.
**___________________________________________________ */
#define SymTabSymbol(ST) ((ST)->st_name)
/*****************************************************************************/
/* Internal Programs */
/*===========================================================================*/
#ifdef __STDC__
#define _ARG(A) A
#else
#define _ARG(A) ()
#endif
Symbol symbol _ARG((String s)); /* symbols.c */
Symbol sym_extract _ARG((String *sp, bool lowercase));/* symbols.c */
char * new_string _ARG((char * s)); /* symbols.c */
static SymTab new_sym_tab _ARG((String value)); /* symbols.c */
static int hashindex _ARG((String s)); /* symbols.c */
void init_symbols _ARG((void)); /* symbols.c */
void sym_del _ARG((Symbol sym)); /* symbols.c */
#ifdef SYMBOL_DUMP
void sym_dump _ARG((void)); /* symbols.c */
#endif
void sym_gc _ARG((void)); /* symbols.c */
void sym_unlink _ARG((Symbol s)); /* symbols.c */
/*****************************************************************************/
/* External Programs */
/*===========================================================================*/
#ifdef HASH_TABLE_SIZE
#define HASHMAX HASH_TABLE_SIZE
#else
#define HASHMAX 307
#endif
String s_empty = (String)"";
Symbol sym_empty = NO_SYMBOL; /* */
Symbol sym_space = NO_SYMBOL; /* */
Symbol sym_star = NO_SYMBOL; /* */
Symbol sym_crossref = NO_SYMBOL; /* */
Symbol sym_xdata = NO_SYMBOL; /* */
Symbol sym_xref = NO_SYMBOL; /* */
Symbol sym_qqq = NO_SYMBOL; /* */
Symbol sym_comma = NO_SYMBOL; /* */
Symbol sym_double_quote = NO_SYMBOL; /* */
Symbol sym_open_brace = NO_SYMBOL; /* */
Symbol sym_close_brace = NO_SYMBOL; /* */
Symbol sym_et = NO_SYMBOL; /* */
Symbol sym_key = NO_SYMBOL; /* */
Symbol sym_sortkey = NO_SYMBOL; /* */
/*****************************************************************************/
/*** Misc string allocation routine ***/
/*****************************************************************************/
/*-----------------------------------------------------------------------------
** Function: new_string()
** Purpose: Allocate a space for a string and copy the argument
** there. Note this is just a new copy of the memory not
** a symbol!
**
** If no more memory is available then an error is raised
** and the program is terminated.
** Arguments:
** s String to duplicate
** Returns: Pointer to newly allocated memory containing a
** duplicate of the argument string.
**___________________________________________________ */
char * new_string(s) /* */
register char * s; /* */
{ register char * t; /* */
if ( (t=malloc((size_t)strlen(s) + 1)) == NULL ) /* */
{ OUT_OF_MEMORY("string"); } /* */
(void)strcpy(t, s); /* */
return t; /* */
} /*------------------------*/
/*****************************************************************************/
/*** Symbol Table Section ***/
/*****************************************************************************/
/*-----------------------------------------------------------------------------
** Function*: new_sym_tab()
** Purpose: Allocate a new |SymTab| structure and fill it with initial
** values.
**
** If no more memory is available then an error is raised
** and the program is terminated.
** Arguments:
** value String value of the |SymTab| node.
** Returns: Pointer to a new instance of a |SymTab|.
**___________________________________________________ */
static SymTab new_sym_tab(value) /* */
String value; /* */
{ register SymTab new_symtab; /* */
Symbol sym; /* */
/* */
if ((new_symtab=(SymTab)malloc(sizeof(struct STAB))) == 0L)/* */
{ OUT_OF_MEMORY("SymTab"); } /* */
/* */
#ifdef COMPLEX_SYMBOL
if ((sym=(Symbol)malloc(sizeof(sSymbol))) /* */
== NO_SYMBOL) /* */
{ OUT_OF_MEMORY("Symbol"); } /* */
SymbolValue(sym) = newString(value); /* */
#else
sym = newString(value); /* */
#endif
SymTabSymbol(new_symtab) = sym; /* */
SymCount(sym, new_symtab) = 1; /* */
NextSymTab(new_symtab) = (SymTab)NULL; /* */
return new_symtab; /* */
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Function*: hashindex()
** Purpose: Compute the sum of ASCII values modulo |HASHMAX|
** to be used as an hash index.
** Arguments:
** s string to be analyzed.
** Returns: hash index
**___________________________________________________ */
static int hashindex(s) /* */
String s; /* */
{ int index = 0; /* */
while (*s) index = (index + *(s++)) % HASHMAX; /* */
return ( index < 0 ? -index : index ); /* */
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Variable*: sym_tab
** Purpose:
**
**___________________________________________________ */
static SymTab sym_tab[HASHMAX]; /* */
/*-----------------------------------------------------------------------------
** Function: init_symbols()
** Purpose: Initialize the symbols module.
** The symbol table is cleared. This is not secure when
** the symbols have already been initialized because it
** would lead to a memory leak and a violation of the
** symbol comparison assumption. Thus this case is caught
** and nothing is done when the initialization seems to
** be requested for the second time.
**
** If no more memory is available then an error is raised
** and the program is terminated.
**
** Note that this function is for internal purposes
** only. The normal user should call |init_bibtool()|
** instead.
** Arguments: none
** Returns: nothing
**___________________________________________________ */
void init_symbols() /* */
{ register int i; /* */
/* */
if (sym_empty) return; /* */
/* */
for (i = 0; i < HASHMAX; i++) sym_tab[i] = NULL; /* */
/* */
sym_empty = symbol((String)s_empty); /* */
sym_space = symbol((String)" "); /* */
sym_star = symbol((String)"*"); /* */
sym_crossref = symbol((String)"crossref"); /* */
sym_xref = symbol((String)"xref"); /* */
sym_xdata = symbol((String)"xdata"); /* */
sym_qqq = symbol((String)"???"); /* */
sym_comma = symbol((String)","); /* */
sym_double_quote = symbol((String)"\""); /* */
sym_open_brace = symbol((String)"{"); /* */
sym_close_brace = symbol((String)"}"); /* */
sym_et = symbol((String)"&"); /* */
sym_key = symbol((String)"$key"); /* */
sym_sortkey = symbol((String)"$sortkey"); /* */
} /*------------------------*/
#if defined(DEBUG) || defined(COMPLEX_SYMBOL)
/*-----------------------------------------------------------------------------
** Function*: get_sym_tab()
** Type: SymTab
** Purpose:
**
** Arguments:
** sym the symbol to search for
** Returns:
**___________________________________________________ */
static SymTab* get_sym_tab(sym) /* */
register Symbol sym; /* */
{ register SymTab *stp; /* */
/* */
if (sym == NO_SYMBOL) return NULL; /* ignore dummies. */
/* */
for (stp = &sym_tab[hashindex(SymbolValue(sym))];/* */
*stp != NULL; /* */
stp = &NextSymTab(*stp) ) /* */
{ if (sym == SymTabSymbol(*stp)) /* */
{ DebugPrint2("Symbol found ", /* */
SymbolValue(sym)); /* */
return stp; /* */
} /* */
} /* */
/* */
return NULL; /* */
} /*------------------------*/
#endif
/*-----------------------------------------------------------------------------
** Function: symbol()
** Purpose: Add a symbol to the global symbol table. If the string
** already has a symbol assigned to it then this symbol
** is returned. If the symbol is not static then the use
** count is incremented by |count|.
**
** If the symbol does not exist already then a new symbol
** is added to the symbol table and the use count is
** initialized to |count|. A negative value for |count|
** indicates that a static symbol is requested. A static
** symbol will never be deleted from the symbol table.
** Static can be used at places where one does not care
** about the memory occupied.
**
** If no more memory is available then an error is raised
** and the program is terminated.
**
** See also the macro |symbol()| in |symbols.h| for a
** convenient alternative to this function.
** Arguments:
** s String which should be translated into a symbol.
** Returns: The new symbol.
**___________________________________________________ */
Symbol symbol(s) /* */
String s; /* */
{ register SymTab *stp; /* */
Symbol sym; /* */
/* */
if (s == StringNULL) return NO_SYMBOL; /* ignore dummies. */
/* */
DebugPrint2("Lookup symbol ", s); /* */
/* */
for ( stp = &sym_tab[hashindex(s)]; /* */
*stp != NULL; /* */
stp = &NextSymTab(*stp) ) /* */
{ sym = SymTabSymbol(*stp); /* */
DebugPrintF3("\tlooking at '%s' == '%s'\n", /* */
(char*)s, (char*)SymbolValue(sym)); /* */
if (strcmp((char*)s, /* */
(char*)SymbolValue(sym)) == 0 ) /* */
{ DebugPrint2("Symbol found ", /* */
SymbolValue(sym)); /* */
SymCount(sym,*stp)++; /* */
return sym; /* */
} /* */
} /* */
/* */
*stp = new_sym_tab(s); /* */
DebugPrint2("Symbol created ", /* */
SymbolValue(SymTabSymbol(*stp))); /* */
return SymTabSymbol(*stp); /* */
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Function: sym_unlink()
** Purpose: Free a symbol since it is no longer used.
** This does not mean that the memory is also freed. The
** symbol can be static or used at other places. The real
** free operation requires the garbage collector
** |sym_gc()| to be called.
**
** If the argument is |NULL| or an arbitrary string (no
** symbol) then this case is also dealt with.
** Arguments:
** sym Symbol to be released.
** Returns: nothing
**___________________________________________________ */
void sym_unlink(sym) /* */
register Symbol sym; /* */
{ /* */
if (sym == NO_SYMBOL) return; /* ignore dummies. */
#ifdef COMPLEX_SYMBOL
if (--SymbolCount(sym) > 0) return; /* double check used. */
DebugPrint2("Symbol removed ", /* */
SymbolValue(sym)); /* */
#else
/* */
#ifdef DEBUG
if (get_sym_tab(sym) == NULL) /* */
{ ErrPrintF("*** Attempt to free an undefined symbol: %s\n",/* */
SymbolValue(sym)); /* */
} /* */
#endif
#endif
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Constant: SYM_PIPE_SIZE
** Type:
** Purpose:
**
** Returns:
**___________________________________________________ */
#define SYM_PIPE_SIZE 32
#ifdef COMPLEX_SYMBOL
static Symbol sym_pipe[SYM_PIPE_SIZE];
static int sym_pipe_ptr = 0;
#endif
/*-----------------------------------------------------------------------------
** Function: sym_del()
** Type: void
** Purpose:
**
** Arguments:
** sym
** Returns: nothing
**___________________________________________________ */
void sym_del(sym) /* */
Symbol sym; /* */
{ /* */
#ifdef COMPLEX_SYMBOL
SymTab *stp; /* */
SymTab st; /* */
/* */
sym_pipe[sym_pipe_ptr] = sym; /* */
if ( ++sym_pipe_ptr < SYM_PIPE_SIZE) return; /* */
/* */
while (--sym_pipe_ptr > 0) /* */
{ sym = sym_pipe[sym_pipe_ptr]; /* */
if (SymbolCount(sym) > 0) continue; /* */
/* */
stp = get_sym_tab(sym); /* */
if (stp == NULL) continue; /* */
st = *stp; /* */
*stp = NextSymTab(st); /* */
free(st); /* */
free(SymbolValue(sym)); /* */
free(sym); /* */
} /* */
#endif
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Function*: sym_gc()
** Purpose: This is the garbage collector. It analyzes the symbol
** table and releases all |SymbolTab| nodes not needed
** any more.
**
** Right now it is purely experimental. Better let your
** hands off.
**
** Arguments: none
** Returns: nothing
**___________________________________________________ */
void sym_gc() /* */
{
#ifdef COMPLEX_SYMBOL
#else
register SymTab st, st2; /* */
register int i; /* */
/* */
for ( i = 0; i < HASHMAX; i++ ) /* */
{ /* */
while (sym_tab[i] && /* */
SymTabCount(sym_tab[i]) <= 0) /* */
{ st = sym_tab[i]; /* */
sym_tab[i] = NextSymTab(st); /* */
free(SymTabSymbol(st)); /* */
free(st); /* */
} /* */
st = sym_tab[i]; /* */
if ( st ) /* */
{ /* */
while ( (st2=NextSymTab(st)) != NULL && /* */
SymTabCount(st) <= 0 ) /* */
{ NextSymTab(st) = NextSymTab(st2); /* */
free(SymTabSymbol(st2)); /* */
free(st2); /* */
} /* */
} /* */
} /* */
#endif
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Function: sym_extract()
** Purpose: Extract a symbol from a string.
** Arguments:
** sp pointer to the string
** lowercase indicate that lowering is requested
** Returns:
**___________________________________________________ */
Symbol sym_extract(sp, lowercase) /* */
register String *sp; /* pointer to first char */
bool lowercase; /* */
{ Uchar c; /* */
String t = *sp; /* */
Symbol sym; /* */
/* */
while (is_allowed(**sp)) (*sp)++; /* */
c = **sp; /* */
**sp = '\0'; /* */
if (lowercase) /* */
{ t = lower(newString(t)); /* */
sym = symbol(t); /* */
free((void *)t); /* */
} else { /* */
sym = symbol(t); /* */
} /* */
**sp = c; /* */
return sym; /* */
} /*------------------------*/
/*-----------------------------------------------------------------------------
** Function: free_sym_array()
** Type: void
** Purpose:
**
** Arguments:
** sym_arr symbol array
** Returns: nothing
**___________________________________________________ */
void free_sym_array(sym_arr) /* */
Symbol *sym_arr; /* */
{ Symbol *a; /* */
for (a = sym_arr; *a; a++) /* */
{ if (*a) UnlinkSymbol(*a); } /* */
free(sym_arr); /* */
} /*------------------------*/
#ifdef SYMBOL_DUMP
/*-----------------------------------------------------------------------------
** Function: sym_dump()
** Purpose: Dump the symbol table to the error stream---see module
** |error.c|.
** The symbols are printed according to their hash value
** and the sequence they are occurring in the buckets. A
** summary of the memory used is also printed.
** Arguments: none
** Returns: nothing
**___________________________________________________ */
void sym_dump() /* */
{ register int i,l; /* */
register SymTab st; /* */
register long len = 0l; /* */
register long cnt = 0l; /* */
register long used = 0l; /* */
/* */
for ( i = 0; i < HASHMAX; i++ ) /* */
{ for ( st = sym_tab[i]; st; st=NextSymTab(st) ) /* */
{ ErrPrintF2("--- BibTool symbol %4d %s\n", /* */
SymTabCount(st), /* */
SymbolValue(SymTabSymbol(st))); /* */
l = symlen(SymTabSymbol(st)) + 1; /* */
len += l; /* */
used += l * SymTabCount(st); /* */
++cnt; /* */
} /* */
} /* */
ErrPrintF2("--- BibTool symbol table: %ld bytes for %ld symbols\n",/* */
len, cnt); /* */
ErrPrintF("--- BibTool symbol table emulates %ld bytes\n",/* */
used); /* */
} /*------------------------*/
#endif