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old-cross-binutils/gas/hash.c
Richard Henderson 252b5132c7 19990502 sourceware import
1999-05-03 07:29:11 +00:00

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/* hash.c - hash table lookup strings -
Copyright (C) 1987, 90, 91, 92, 93, 94, 95, 96, 1998
Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS 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.
GAS 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 GAS; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/*
* BUGS, GRIPES, APOLOGIA etc.
*
* A typical user doesn't need ALL this: I intend to make a library out
* of it one day - Dean Elsner.
* Also, I want to change the definition of a symbol to (address,length)
* so I can put arbitrary binary in the names stored. [see hsh.c for that]
*
* This slime is common coupled inside the module. Com-coupling (and other
* vandalism) was done to speed running time. The interfaces at the
* module's edges are adequately clean.
*
* There is no way to (a) run a test script through this heap and (b)
* compare results with previous scripts, to see if we have broken any
* code. Use GNU (f)utilities to do this. A few commands assist test.
* The testing is awkward: it tries to be both batch & interactive.
* For now, interactive rules!
*/
/*
* The idea is to implement a symbol table. A test jig is here.
* Symbols are arbitrary strings; they can't contain '\0'.
* [See hsh.c for a more general symbol flavour.]
* Each symbol is associated with a char*, which can point to anything
* you want, allowing an arbitrary property list for each symbol.
*
* The basic operations are:
*
* new creates symbol table, returns handle
* find (symbol) returns char*
* insert (symbol,char*) error if symbol already in table
* delete (symbol) returns char* if symbol was in table
* apply so you can delete all symbols before die()
* die destroy symbol table (free up memory)
*
* Supplementary functions include:
*
* say how big? what % full?
* replace (symbol,newval) report previous value
* jam (symbol,value) assert symbol:=value
*
* You, the caller, have control over errors: this just reports them.
*
* This package requires malloc(), free().
* Malloc(size) returns NULL or address of char[size].
* Free(address) frees same.
*/
/*
* The code and its structures are re-enterent.
*
* Before you do anything else, you must call hash_new() which will
* return the address of a hash-table-control-block. You then use
* this address as a handle of the symbol table by passing it to all
* the other hash_...() functions. The only approved way to recover
* the memory used by the symbol table is to call hash_die() with the
* handle of the symbol table.
*
* Before you call hash_die() you normally delete anything pointed to
* by individual symbols. After hash_die() you can't use that symbol
* table again.
*
* The char* you associate with a symbol may not be NULL (0) because
* NULL is returned whenever a symbol is not in the table. Any other
* value is OK, except DELETED, #defined below.
*
* When you supply a symbol string for insertion, YOU MUST PRESERVE THE
* STRING until that symbol is deleted from the table. The reason is that
* only the address you supply, NOT the symbol string itself, is stored
* in the symbol table.
*
* You may delete and add symbols arbitrarily.
* Any or all symbols may have the same 'value' (char *). In fact, these
* routines don't do anything with your symbol values.
*
* You have no right to know where the symbol:char* mapping is stored,
* because it moves around in memory; also because we may change how it
* works and we don't want to break your code do we? However the handle
* (address of struct hash_control) is never changed in
* the life of the symbol table.
*
* What you CAN find out about a symbol table is:
* how many slots are in the hash table?
* how many slots are filled with symbols?
* (total hashes,collisions) for (reads,writes) (*)
* All of the above values vary in time.
* (*) some of these numbers will not be meaningful if we change the
* internals. */
/*
* I N T E R N A L
*
* Hash table is an array of hash_entries; each entry is a pointer to a
* a string and a user-supplied value 1 char* wide.
*
* The array always has 2 ** n elements, n>0, n integer.
* There is also a 'wall' entry after the array, which is always empty
* and acts as a sentinel to stop running off the end of the array.
* When the array gets too full, we create a new array twice as large
* and re-hash the symbols into the new array, then forget the old array.
* (Of course, we copy the values into the new array before we junk the
* old array!)
*
*/
#include <stdio.h>
#ifndef FALSE
#define FALSE (0)
#define TRUE (!FALSE)
#endif /* no FALSE yet */
#include <ctype.h>
#define min(a, b) ((a) < (b) ? (a) : (b))
#include "as.h"
#define error as_fatal
static char _deleted_[1];
#define DELETED ((PTR)_deleted_) /* guarenteed unique address */
#define START_POWER (10) /* power of two: size of new hash table */
/* TRUE if a symbol is in entry @ ptr. */
#define islive(ptr) (ptr->hash_string && ptr->hash_string!=DELETED)
enum stat_enum {
/* Number of slots in hash table. The wall does not count here.
We expect this is always a power of 2. */
STAT_SIZE = 0,
/* Number of hash_ask calls. */
STAT_ACCESS,
STAT_ACCESS_w,
/* Number of collisions (total). This may exceed STAT_ACCESS if we
have lots of collisions/access. */
STAT_COLLIDE,
STAT_COLLIDE_w,
/* Slots used right now. */
STAT_USED,
/* How many string compares? */
STAT_STRCMP,
STAT_STRCMP_w,
/* Size of statistics block... this must be last. */
STATLENGTH
};
#define STAT__READ (0) /* reading */
#define STAT__WRITE (1) /* writing */
/* When we grow a hash table, by what power of two do we increase it? */
#define GROW_FACTOR 1
/* When should we grow it? */
#define FULL_VALUE(N) ((N) / 2)
/* #define SUSPECT to do runtime checks */
/* #define TEST to be a test jig for hash...() */
#ifdef TEST
/* TEST: use smaller hash table */
#undef START_POWER
#define START_POWER (3)
#undef START_SIZE
#define START_SIZE (8)
#undef START_FULL
#define START_FULL (4)
#endif
struct hash_entry
{
const char *hash_string; /* points to where the symbol string is */
/* NULL means slot is not used */
/* DELETED means slot was deleted */
PTR hash_value; /* user's datum, associated with symbol */
unsigned long h;
};
struct hash_control {
struct hash_entry *hash_where;/* address of hash table */
int hash_sizelog; /* Log of ( hash_mask + 1 ) */
int hash_mask; /* masks a hash into index into table */
int hash_full; /* when hash_stat[STAT_USED] exceeds this, */
/* grow table */
struct hash_entry *hash_wall; /* point just after last (usable) entry */
/* here we have some statistics */
int hash_stat[STATLENGTH]; /* lies & statistics */
};
/*------------------ plan ---------------------------------- i = internal
struct hash_control * c;
struct hash_entry * e; i
int b[z]; buffer for statistics
z size of b
char * s; symbol string (address) [ key ]
char * v; value string (address) [datum]
boolean f; TRUE if we found s in hash table i
char * t; error string; 0 means OK
int a; access type [0...n) i
c=hash_new () create new hash_control
hash_die (c) destroy hash_control (and hash table)
table should be empty.
doesn't check if table is empty.
c has no meaning after this.
hash_say (c,b,z) report statistics of hash_control.
also report number of available statistics.
v=hash_delete (c,s) delete symbol, return old value if any.
ask() NULL means no old value.
f
v=hash_replace (c,s,v) replace old value of s with v.
ask() NULL means no old value: no table change.
f
t=hash_insert (c,s,v) insert (s,v) in c.
ask() return error string.
f it is an error to insert if s is already
in table.
if any error, c is unchanged.
t=hash_jam (c,s,v) assert that new value of s will be v. i
ask() it may decide to GROW the table. i
f i
grow() i
t=hash_grow (c) grow the hash table. i
jam() will invoke JAM. i
?=hash_apply (c,y) apply y() to every symbol in c.
y evtries visited in 'unspecified' order.
v=hash_find (c,s) return value of s, or NULL if s not in c.
ask()
f
f,e=hash_ask() (c,s,a) return slot where s SHOULD live. i
code() maintain collision stats in c. i
.=hash_code (c,s) compute hash-code for s, i
from parameters of c. i
*/
/* Returned by hash_ask() to stop extra testing. hash_ask() wants to
return both a slot and a status. This is the status. TRUE: found
symbol FALSE: absent: empty or deleted slot Also returned by
hash_jam(). TRUE: we replaced a value FALSE: we inserted a value. */
static char hash_found;
static struct hash_entry *hash_ask PARAMS ((struct hash_control *,
const char *, int));
static int hash_code PARAMS ((struct hash_control *, const char *));
static const char *hash_grow PARAMS ((struct hash_control *));
/* Create a new hash table. Return NULL if failed; otherwise return handle
(address of struct hash). */
struct hash_control *
hash_new ()
{
struct hash_control *retval;
struct hash_entry *room; /* points to hash table */
struct hash_entry *wall;
struct hash_entry *entry;
int *ip; /* scan stats block of struct hash_control */
int *nd; /* limit of stats block */
room = (struct hash_entry *) xmalloc (sizeof (struct hash_entry)
/* +1 for the wall entry */
* ((1 << START_POWER) + 1));
retval = (struct hash_control *) xmalloc (sizeof (struct hash_control));
nd = retval->hash_stat + STATLENGTH;
for (ip = retval->hash_stat; ip < nd; ip++)
*ip = 0;
retval->hash_stat[STAT_SIZE] = 1 << START_POWER;
retval->hash_mask = (1 << START_POWER) - 1;
retval->hash_sizelog = START_POWER;
/* works for 1's compl ok */
retval->hash_where = room;
retval->hash_wall =
wall = room + (1 << START_POWER);
retval->hash_full = FULL_VALUE (1 << START_POWER);
for (entry = room; entry <= wall; entry++)
entry->hash_string = NULL;
return retval;
}
/*
* h a s h _ d i e ( )
*
* Table should be empty, but this is not checked.
* To empty the table, try hash_apply()ing a symbol deleter.
* Return to free memory both the hash table and it's control
* block.
* 'handle' has no meaning after this function.
* No errors are recoverable.
*/
void
hash_die (handle)
struct hash_control *handle;
{
free ((char *) handle->hash_where);
free ((char *) handle);
}
#ifdef TEST
/*
* h a s h _ s a y ( )
*
* Return the size of the statistics table, and as many statistics as
* we can until either (a) we have run out of statistics or (b) caller
* has run out of buffer.
* NOTE: hash_say treats all statistics alike.
* These numbers may change with time, due to insertions, deletions
* and expansions of the table.
* The first "statistic" returned is the length of hash_stat[].
* Then contents of hash_stat[] are read out (in ascending order)
* until your buffer or hash_stat[] is exausted.
*/
static void
hash_say (handle, buffer, bufsiz)
struct hash_control *handle;
int buffer[ /*bufsiz*/ ];
int bufsiz;
{
int *nd; /* limit of statistics block */
int *ip; /* scan statistics */
ip = handle->hash_stat;
nd = ip + min (bufsiz - 1, STATLENGTH);
if (bufsiz > 0) /* trust nothing! bufsiz<=0 is dangerous */
{
*buffer++ = STATLENGTH;
for (; ip < nd; ip++, buffer++)
{
*buffer = *ip;
}
}
}
#endif
/*
* h a s h _ d e l e t e ( )
*
* Try to delete a symbol from the table.
* If it was there, return its value (and adjust STAT_USED).
* Otherwise, return NULL.
* Anyway, the symbol is not present after this function.
*
*/
PTR /* NULL if string not in table, else */
/* returns value of deleted symbol */
hash_delete (handle, string)
struct hash_control *handle;
const char *string;
{
PTR retval;
struct hash_entry *entry;
entry = hash_ask (handle, string, STAT__WRITE);
if (hash_found)
{
retval = entry->hash_value;
entry->hash_string = DELETED;
handle->hash_stat[STAT_USED] -= 1;
#ifdef SUSPECT
if (handle->hash_stat[STAT_USED] < 0)
{
error ("hash_delete");
}
#endif /* def SUSPECT */
}
else
{
retval = NULL;
}
return (retval);
}
/*
* h a s h _ r e p l a c e ( )
*
* Try to replace the old value of a symbol with a new value.
* Normally return the old value.
* Return NULL and don't change the table if the symbol is not already
* in the table.
*/
PTR
hash_replace (handle, string, value)
struct hash_control *handle;
const char *string;
PTR value;
{
struct hash_entry *entry;
char *retval;
entry = hash_ask (handle, string, STAT__WRITE);
if (hash_found)
{
retval = entry->hash_value;
entry->hash_value = value;
}
else
{
retval = NULL;
}
;
return retval;
}
/*
* h a s h _ i n s e r t ( )
*
* Insert a (symbol-string, value) into the hash table.
* Return an error string, 0 means OK.
* It is an 'error' to insert an existing symbol.
*/
const char * /* return error string */
hash_insert (handle, string, value)
struct hash_control *handle;
const char *string;
PTR value;
{
struct hash_entry *entry;
const char *retval;
retval = 0;
if (handle->hash_stat[STAT_USED] > handle->hash_full)
{
retval = hash_grow (handle);
}
if (!retval)
{
entry = hash_ask (handle, string, STAT__WRITE);
if (hash_found)
{
retval = "exists";
}
else
{
entry->hash_value = value;
entry->hash_string = string;
handle->hash_stat[STAT_USED] += 1;
}
}
return retval;
}
/*
* h a s h _ j a m ( )
*
* Regardless of what was in the symbol table before, after hash_jam()
* the named symbol has the given value. The symbol is either inserted or
* (its value is) replaced.
* An error message string is returned, 0 means OK.
*
* WARNING: this may decide to grow the hashed symbol table.
* To do this, we call hash_grow(), WHICH WILL recursively CALL US.
*
* We report status internally: hash_found is TRUE if we replaced, but
* false if we inserted.
*/
const char *
hash_jam (handle, string, value)
struct hash_control *handle;
const char *string;
PTR value;
{
const char *retval;
struct hash_entry *entry;
retval = 0;
if (handle->hash_stat[STAT_USED] > handle->hash_full)
{
retval = hash_grow (handle);
}
if (!retval)
{
entry = hash_ask (handle, string, STAT__WRITE);
if (!hash_found)
{
entry->hash_string = string;
handle->hash_stat[STAT_USED] += 1;
}
entry->hash_value = value;
}
return retval;
}
/*
* h a s h _ g r o w ( )
*
* Grow a new (bigger) hash table from the old one.
* We choose to double the hash table's size.
* Return a human-scrutible error string: 0 if OK.
* Warning! This uses hash_jam(), which had better not recurse
* back here! Hash_jam() conditionally calls us, but we ALWAYS
* call hash_jam()!
* Internal.
*/
static const char *
hash_grow (handle) /* make a hash table grow */
struct hash_control *handle;
{
struct hash_entry *newwall;
struct hash_entry *newwhere;
struct hash_entry *newtrack;
struct hash_entry *oldtrack;
struct hash_entry *oldwhere;
struct hash_entry *oldwall;
int temp;
int newsize;
const char *string;
const char *retval;
#ifdef SUSPECT
int oldused;
#endif
/*
* capture info about old hash table
*/
oldwhere = handle->hash_where;
oldwall = handle->hash_wall;
#ifdef SUSPECT
oldused = handle->hash_stat[STAT_USED];
#endif
/*
* attempt to get enough room for a hash table twice as big
*/
temp = handle->hash_stat[STAT_SIZE];
newwhere = ((struct hash_entry *)
xmalloc ((unsigned long) ((temp << (GROW_FACTOR + 1))
/* +1 for wall slot */
* sizeof (struct hash_entry))));
if (newwhere == NULL)
return "no_room";
/*
* have enough room: now we do all the work.
* double the size of everything in handle.
*/
handle->hash_mask = ((handle->hash_mask + 1) << GROW_FACTOR) - 1;
handle->hash_stat[STAT_SIZE] <<= GROW_FACTOR;
newsize = handle->hash_stat[STAT_SIZE];
handle->hash_where = newwhere;
handle->hash_full <<= GROW_FACTOR;
handle->hash_sizelog += GROW_FACTOR;
handle->hash_wall = newwall = newwhere + newsize;
/* Set all those pesky new slots to vacant. */
for (newtrack = newwhere; newtrack <= newwall; newtrack++)
newtrack->hash_string = NULL;
/* We will do a scan of the old table, the hard way, using the
* new control block to re-insert the data into new hash table. */
handle->hash_stat[STAT_USED] = 0;
for (oldtrack = oldwhere; oldtrack < oldwall; oldtrack++)
if (((string = oldtrack->hash_string) != NULL) && string != DELETED)
if ((retval = hash_jam (handle, string, oldtrack->hash_value)))
return retval;
#ifdef SUSPECT
if (handle->hash_stat[STAT_USED] != oldused)
return "hash_used";
#endif
/* We have a completely faked up control block.
Return the old hash table. */
free ((char *) oldwhere);
return 0;
}
#ifdef TEST
/*
* h a s h _ a p p l y ( )
*
* Use this to scan each entry in symbol table.
* For each symbol, this calls (applys) a nominated function supplying the
* symbol's value (and the symbol's name).
* The idea is you use this to destroy whatever is associted with
* any values in the table BEFORE you destroy the table with hash_die.
* Of course, you can use it for other jobs; whenever you need to
* visit all extant symbols in the table.
*
* We choose to have a call-you-back idea for two reasons:
* asthetic: it is a neater idea to use apply than an explicit loop
* sensible: if we ever had to grow the symbol table (due to insertions)
* then we would lose our place in the table when we re-hashed
* symbols into the new table in a different order.
*
* The order symbols are visited depends entirely on the hashing function.
* Whenever you insert a (symbol, value) you risk expanding the table. If
* you do expand the table, then the hashing function WILL change, so you
* MIGHT get a different order of symbols visited. In other words, if you
* want the same order of visiting symbols as the last time you used
* hash_apply() then you better not have done any hash_insert()s or
* hash_jam()s since the last time you used hash_apply().
*
* In future we may use the value returned by your nominated function.
* One idea is to abort the scan if, after applying the function to a
* certain node, the function returns a certain code.
*
* The function you supply should be of the form:
* void myfunct(string,value)
* char * string; |* the symbol's name *|
* char * value; |* the symbol's value *|
* {
* |* ... *|
* }
*
*/
void
hash_apply (handle, function)
struct hash_control *handle;
void (*function) ();
{
struct hash_entry *entry;
struct hash_entry *wall;
wall = handle->hash_wall;
for (entry = handle->hash_where; entry < wall; entry++)
{
if (islive (entry)) /* silly code: tests entry->string twice! */
{
(*function) (entry->hash_string, entry->hash_value);
}
}
}
#endif
/*
* h a s h _ f i n d ( )
*
* Given symbol string, find value (if any).
* Return found value or NULL.
*/
PTR
hash_find (handle, string)
struct hash_control *handle;
const char *string;
{
struct hash_entry *entry;
entry = hash_ask (handle, string, STAT__READ);
if (hash_found)
return entry->hash_value;
else
return NULL;
}
/*
* h a s h _ a s k ( )
*
* Searches for given symbol string.
* Return the slot where it OUGHT to live. It may be there.
* Return hash_found: TRUE only if symbol is in that slot.
* Access argument is to help keep statistics in control block.
* Internal.
*/
static struct hash_entry * /* string slot, may be empty or deleted */
hash_ask (handle, string, access_type)
struct hash_control *handle;
const char *string;
int access_type;
{
const char *s;
struct hash_entry *slot;
int collision; /* count collisions */
int strcmps;
int hcode;
/* start looking here */
hcode = hash_code (handle, string);
slot = handle->hash_where + (hcode & handle->hash_mask);
handle->hash_stat[STAT_ACCESS + access_type] += 1;
collision = strcmps = 0;
hash_found = FALSE;
while (((s = slot->hash_string) != NULL) && s != DELETED)
{
if (string == s)
{
hash_found = TRUE;
break;
}
if (slot->h == (unsigned long) hcode)
{
if (!strcmp (string, s))
{
hash_found = TRUE;
break;
}
strcmps++;
}
collision++;
slot++;
}
/*
* slot: return:
* in use: we found string slot
* at empty:
* at wall: we fell off: wrap round ????
* in table: dig here slot
* at DELETED: dig here slot
*/
if (slot == handle->hash_wall)
{
slot = handle->hash_where;/* now look again */
while (((s = slot->hash_string) != NULL) && s != DELETED)
{
if (string == s)
{
hash_found = TRUE;
break;
}
if (slot->h == (unsigned long) hcode)
{
if (!strcmp (string, s))
{
hash_found = TRUE;
break;
}
strcmps++;
}
collision++;
slot++;
}
/*
* slot: return:
* in use: we found it slot
* empty: wall: ERROR IMPOSSIBLE !!!!
* in table: dig here slot
* DELETED:dig here slot
*/
}
handle->hash_stat[STAT_COLLIDE + access_type] += collision;
handle->hash_stat[STAT_STRCMP + access_type] += strcmps;
if (!hash_found)
slot->h = hcode;
return slot; /* also return hash_found */
}
/*
* h a s h _ c o d e
*
* Does hashing of symbol string to hash number.
* Internal.
*/
static int
hash_code (handle, string)
struct hash_control *handle;
const char *string;
{
#if 1 /* There seems to be some interesting property of this function
that prevents the bfd version below from being an adequate
substitute. @@ Figure out what this property is! */
long h; /* hash code built here */
long c; /* each character lands here */
int n; /* Amount to shift h by */
n = (handle->hash_sizelog - 3);
h = 0;
while ((c = *string++) != 0)
{
h += c;
h = (h << 3) + (h >> n) + c;
}
return h;
#else
/* from bfd */
unsigned long h = 0;
unsigned int len = 0;
unsigned int c;
while ((c = *string++) != 0)
{
h += c + (c << 17);
h ^= h >> 2;
++len;
}
h += len + (len << 17);
h ^= h >> 2;
return h;
#endif
}
void
hash_print_statistics (file, name, h)
FILE *file;
const char *name;
struct hash_control *h;
{
unsigned long sz, used, pct;
if (h == 0)
return;
sz = h->hash_stat[STAT_SIZE];
used = h->hash_stat[STAT_USED];
pct = (used * 100 + sz / 2) / sz;
fprintf (file, "%s hash statistics:\n\t%lu/%lu slots used (%lu%%)\n",
name, used, sz, pct);
#define P(name, off) \
fprintf (file, "\t%-16s %6dr + %6dw = %7d\n", name, \
h->hash_stat[off+STAT__READ], \
h->hash_stat[off+STAT__WRITE], \
h->hash_stat[off+STAT__READ] + h->hash_stat[off+STAT__WRITE])
P ("accesses:", STAT_ACCESS);
P ("collisions:", STAT_COLLIDE);
P ("string compares:", STAT_STRCMP);
#undef P
}
/*
* Here is a test program to exercise above.
*/
#ifdef TEST
#define TABLES (6) /* number of hash tables to maintain */
/* (at once) in any testing */
#define STATBUFSIZE (12) /* we can have 12 statistics */
int statbuf[STATBUFSIZE]; /* display statistics here */
char answer[100]; /* human farts here */
char *hashtable[TABLES]; /* we test many hash tables at once */
char *h; /* points to curent hash_control */
char **pp;
char *p;
char *name;
char *value;
int size;
int used;
char command;
int number; /* number 0:TABLES-1 of current hashed */
/* symbol table */
main ()
{
void applicatee ();
void destroy ();
char *what ();
int *ip;
number = 0;
h = 0;
printf ("type h <RETURN> for help\n");
for (;;)
{
printf ("hash_test command: ");
gets (answer);
command = answer[0];
if (isupper (command))
command = tolower (command); /* ecch! */
switch (command)
{
case '#':
printf ("old hash table #=%d.\n", number);
whattable ();
break;
case '?':
for (pp = hashtable; pp < hashtable + TABLES; pp++)
{
printf ("address of hash table #%d control block is %xx\n"
,pp - hashtable, *pp);
}
break;
case 'a':
hash_apply (h, applicatee);
break;
case 'd':
hash_apply (h, destroy);
hash_die (h);
break;
case 'f':
p = hash_find (h, name = what ("symbol"));
printf ("value of \"%s\" is \"%s\"\n", name, p ? p : "NOT-PRESENT");
break;
case 'h':
printf ("# show old, select new default hash table number\n");
printf ("? display all hashtable control block addresses\n");
printf ("a apply a simple display-er to each symbol in table\n");
printf ("d die: destroy hashtable\n");
printf ("f find value of nominated symbol\n");
printf ("h this help\n");
printf ("i insert value into symbol\n");
printf ("j jam value into symbol\n");
printf ("n new hashtable\n");
printf ("r replace a value with another\n");
printf ("s say what %% of table is used\n");
printf ("q exit this program\n");
printf ("x delete a symbol from table, report its value\n");
break;
case 'i':
p = hash_insert (h, name = what ("symbol"), value = what ("value"));
if (p)
{
printf ("symbol=\"%s\" value=\"%s\" error=%s\n", name, value,
p);
}
break;
case 'j':
p = hash_jam (h, name = what ("symbol"), value = what ("value"));
if (p)
{
printf ("symbol=\"%s\" value=\"%s\" error=%s\n", name, value, p);
}
break;
case 'n':
h = hashtable[number] = (char *) hash_new ();
break;
case 'q':
exit (EXIT_SUCCESS);
case 'r':
p = hash_replace (h, name = what ("symbol"), value = what ("value"));
printf ("old value was \"%s\"\n", p ? p : "{}");
break;
case 's':
hash_say (h, statbuf, STATBUFSIZE);
for (ip = statbuf; ip < statbuf + STATBUFSIZE; ip++)
{
printf ("%d ", *ip);
}
printf ("\n");
break;
case 'x':
p = hash_delete (h, name = what ("symbol"));
printf ("old value was \"%s\"\n", p ? p : "{}");
break;
default:
printf ("I can't understand command \"%c\"\n", command);
break;
}
}
}
char *
what (description)
char *description;
{
char *retval;
char *malloc ();
printf (" %s : ", description);
gets (answer);
/* will one day clean up answer here */
retval = malloc (strlen (answer) + 1);
if (!retval)
{
error ("room");
}
(void) strcpy (retval, answer);
return (retval);
}
void
destroy (string, value)
char *string;
char *value;
{
free (string);
free (value);
}
void
applicatee (string, value)
char *string;
char *value;
{
printf ("%.20s-%.20s\n", string, value);
}
whattable () /* determine number: what hash table to use */
/* also determine h: points to hash_control */
{
for (;;)
{
printf (" what hash table (%d:%d) ? ", 0, TABLES - 1);
gets (answer);
sscanf (answer, "%d", &number);
if (number >= 0 && number < TABLES)
{
h = hashtable[number];
if (!h)
{
printf ("warning: current hash-table-#%d. has no hash-control\n", number);
}
return;
}
else
{
printf ("invalid hash table number: %d\n", number);
}
}
}
#endif /* #ifdef TEST */
/* end of hash.c */
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