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new implementation of hash tables.

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This commit is contained in:
Roberto Ierusalimschy
1999-10-14 17:13:31 -02:00
parent b6ebbb2fee
commit 4e9f2d13d5
9 changed files with 287 additions and 129 deletions
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6
lapi.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lapi.c,v 1.52 1999/10/07 19:04:30 roberto Exp roberto $ ** $Id: lapi.c,v 1.53 1999/10/11 16:13:11 roberto Exp roberto $
** Lua API ** Lua API
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -422,11 +422,11 @@ const char *lua_nextvar (const char *varname) {
int luaA_next (const Hash *t, int i) { int luaA_next (const Hash *t, int i) {
int tsize = nhash(t); int tsize = t->size;
for (; i<tsize; i++) { for (; i<tsize; i++) {
Node *n = node(t, i); Node *n = node(t, i);
if (ttype(val(n)) != LUA_T_NIL) { if (ttype(val(n)) != LUA_T_NIL) {
luaA_pushobject(ref(n)); luaA_pushobject(key(n));
luaA_pushobject(val(n)); luaA_pushobject(val(n));
return i+1; /* index to be used next time */ return i+1; /* index to be used next time */
} }

73
lbuiltin.c
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@@ -1,5 +1,5 @@
/* /*
** $Id: lbuiltin.c,v 1.65 1999/10/07 19:04:30 roberto Exp roberto $ ** $Id: lbuiltin.c,v 1.66 1999/10/11 16:13:11 roberto Exp roberto $
** Built-in functions ** Built-in functions
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -44,13 +44,13 @@ static void pushtagstring (TaggedString *s) {
static real getsize (const Hash *h) { static real getsize (const Hash *h) {
real max = 0; real max = 0;
int i = nhash(h); int i = h->size;
Node *n = h->node; Node *n = h->node;
while (i--) { while (i--) {
if (ttype(ref(n)) == LUA_T_NUMBER && if (ttype(key(n)) == LUA_T_NUMBER &&
ttype(val(n)) != LUA_T_NIL && ttype(val(n)) != LUA_T_NIL &&
nvalue(ref(n)) > max) nvalue(key(n)) > max)
max = nvalue(ref(n)); max = nvalue(key(n));
n++; n++;
} }
return max; return max;
@@ -59,7 +59,7 @@ static real getsize (const Hash *h) {
static real getnarg (const Hash *a) { static real getnarg (const Hash *a) {
TObject index; TObject index;
TObject *value; const TObject *value;
/* value = table.n */ /* value = table.n */
ttype(&index) = LUA_T_STRING; ttype(&index) = LUA_T_STRING;
tsvalue(&index) = luaS_new("n"); tsvalue(&index) = luaS_new("n");
@@ -337,7 +337,13 @@ static void luaB_nextvar (void) {
static void luaB_next (void) { static void luaB_next (void) {
const Hash *a = gethash(1); const Hash *a = gethash(1);
const TObject *k = luaA_Address(luaL_nonnullarg(2)); const TObject *k = luaA_Address(luaL_nonnullarg(2));
int i = (ttype(k) == LUA_T_NIL) ? 0 : luaH_pos(a, k)+1; int i; /* will get first element after `i' */
if (ttype(k) == LUA_T_NIL)
i = 0; /* get first */
else {
i = luaH_pos(a, k)+1;
luaL_arg_check(i != 0, 2, "key not found");
}
if (luaA_next(a, i) == 0) if (luaA_next(a, i) == 0)
lua_pushnil(); lua_pushnil();
} }
@@ -408,7 +414,7 @@ static void luaB_foreachi (void) {
stack may be reallocated by the call. Moreover, some C compilers do not stack may be reallocated by the call. Moreover, some C compilers do not
initialize structs, so we must do the assignment after the declaration */ initialize structs, so we must do the assignment after the declaration */
f = *luaA_Address(luaL_functionarg(2)); f = *luaA_Address(luaL_functionarg(2));
luaD_checkstack(3); /* for f, ref, and val */ luaD_checkstack(3); /* for f, key, and val */
for (i=1; i<=n; i++) { for (i=1; i<=n; i++) {
*(L->stack.top++) = f; *(L->stack.top++) = f;
ttype(L->stack.top) = LUA_T_NUMBER; nvalue(L->stack.top++) = i; ttype(L->stack.top) = LUA_T_NUMBER; nvalue(L->stack.top++) = i;
@@ -426,12 +432,12 @@ static void luaB_foreach (void) {
int i; int i;
TObject f; /* see comment in 'foreachi' */ TObject f; /* see comment in 'foreachi' */
f = *luaA_Address(luaL_functionarg(2)); f = *luaA_Address(luaL_functionarg(2));
luaD_checkstack(3); /* for f, ref, and val */ luaD_checkstack(3); /* for f, key, and val */
for (i=0; i<a->nhash; i++) { for (i=0; i<a->size; i++) {
const Node *nd = &(a->node[i]); const Node *nd = &(a->node[i]);
if (ttype(val(nd)) != LUA_T_NIL) { if (ttype(val(nd)) != LUA_T_NIL) {
*(L->stack.top++) = f; *(L->stack.top++) = f;
*(L->stack.top++) = *ref(nd); *(L->stack.top++) = *key(nd);
*(L->stack.top++) = *val(nd); *(L->stack.top++) = *val(nd);
luaD_calln(2, 1); luaD_calln(2, 1);
if (ttype(L->stack.top-1) != LUA_T_NIL) if (ttype(L->stack.top-1) != LUA_T_NIL)
@@ -531,36 +537,37 @@ static int sort_comp (lua_Object f, const TObject *a, const TObject *b) {
} }
static void auxsort (Hash *a, int l, int u, lua_Object f) { static void auxsort (Hash *a, int l, int u, lua_Object f) {
StkId P = L->stack.top - L->stack.stack; /* temporary place for pivot */
L->stack.top++;
ttype(L->stack.stack+P) = LUA_T_NIL;
while (l < u) { /* for tail recursion */ while (l < u) { /* for tail recursion */
TObject *P;
int i, j; int i, j;
/* sort elements a[l], a[(l+u)/2] and a[u] */ /* sort elements a[l], a[(l+u)/2] and a[u] */
if (sort_comp(f, luaH_getint(a, u), luaH_getint(a, l))) /* a[l]>a[u]? */ if (sort_comp(f, luaH_getint(a, u), luaH_getint(a, l))) /* a[u]<a[l]? */
swap(a, l, u); swap(a, l, u);
if (u-l == 1) break; /* only 2 elements */ if (u-l == 1) break; /* only 2 elements */
i = (l+u)/2; i = (l+u)/2;
P = luaH_getint(a, i); *(L->stack.stack+P) = *luaH_getint(a, i); /* P = a[i] */
if (sort_comp(f, P, luaH_getint(a, l))) /* a[l]>a[i]? */ if (sort_comp(f, L->stack.stack+P, luaH_getint(a, l))) /* a[i]<a[l]? */
swap(a, l, i); swap(a, l, i);
else if (sort_comp(f, luaH_getint(a, u), P)) /* a[i]>a[u]? */ else if (sort_comp(f, luaH_getint(a, u), L->stack.stack+P)) /* a[u]<a[i]? */
swap(a, i, u); swap(a, i, u);
if (u-l == 2) break; /* only 3 elements */ if (u-l == 2) break; /* only 3 elements */
P = L->stack.top++; *(L->stack.stack+P) = *luaH_getint(a, i); /* save pivot on stack (for GC) */
*P = *luaH_getint(a, i); /* save pivot on stack (for GC) */
swap(a, i, u-1); /* put median element as pivot (a[u-1]) */ swap(a, i, u-1); /* put median element as pivot (a[u-1]) */
/* a[l] <= P == a[u-1] <= a[u], only needs to sort from l+1 to u-2 */ /* a[l] <= P == a[u-1] <= a[u], only needs to sort from l+1 to u-2 */
i = l; j = u-1; i = l; j = u-1;
for (;;) { for (;;) { /* invariant: a[l..i] <= P <= a[j..u] */
/* invariant: a[l..i] <= P <= a[j..u] */ /* repeat i++ until a[i] >= P */
while (sort_comp(f, luaH_getint(a, ++i), P)) /* stop when a[i] >= P */ while (sort_comp(f, luaH_getint(a, ++i), L->stack.stack+P))
if (i>u) lua_error("invalid order function for sorting"); if (i>u) lua_error("invalid order function for sorting");
while (sort_comp(f, P, luaH_getint(a, --j))) /* stop when a[j] <= P */ /* repeat j-- until a[j] <= P */
while (sort_comp(f, (L->stack.stack+P), luaH_getint(a, --j)))
if (j<l) lua_error("invalid order function for sorting"); if (j<l) lua_error("invalid order function for sorting");
if (j<i) break; if (j<i) break;
swap(a, i, j); swap(a, i, j);
} }
swap(a, u-1, i); /* swap pivot (a[u-1]) with a[i] */ swap(a, u-1, i); /* swap pivot (a[u-1]) with a[i] */
L->stack.top--; /* remove pivot from stack */
/* a[l..i-1] <= a[i] == P <= a[i+1..u] */ /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
/* adjust so that smaller "half" is in [j..i] and larger one in [l..u] */ /* adjust so that smaller "half" is in [j..i] and larger one in [l..u] */
if (i-l < u-i) { if (i-l < u-i) {
@@ -571,6 +578,7 @@ static void auxsort (Hash *a, int l, int u, lua_Object f) {
} }
auxsort(a, j, i, f); /* call recursively the smaller one */ auxsort(a, j, i, f); /* call recursively the smaller one */
} /* repeat the routine for the larger one */ } /* repeat the routine for the larger one */
L->stack.top--; /* remove pivot from stack */
} }
static void luaB_sort (void) { static void luaB_sort (void) {
@@ -608,7 +616,23 @@ static void mem_query (void) {
static void hash_query (void) { static void hash_query (void) {
const TObject *o = luaA_Address(luaL_nonnullarg(1)); const TObject *o = luaA_Address(luaL_nonnullarg(1));
lua_pushnumber(luaH_hashindex(o)); luaL_arg_check(ttype(o) == LUA_T_STRING, 1, "string expected");
lua_pushnumber(tsvalue(o)->hash);
}
static void table_query (void) {
const Hash *t = avalue(luaA_Address(luaL_tablearg(1)));
int i = luaL_opt_int(2, -1);
if (i == -1) {
lua_pushnumber(t->size);
lua_pushnumber(t->firstfree - t->node);
}
else if (i < t->size) {
luaA_pushobject(&t->node[i].key);
luaA_pushobject(&t->node[i].val);
lua_pushnumber(t->node[i].next == NULL ? 0 : t->node[i].next - t->node);
}
} }
@@ -715,6 +739,7 @@ static const struct luaL_reg builtin_funcs[] = {
{"extra", extra_services}, {"extra", extra_services},
{"hash", hash_query}, {"hash", hash_query},
{"querystr", query_strings}, {"querystr", query_strings},
{"querytab", table_query},
{"testC", testC}, {"testC", testC},
{"totalmem", mem_query}, {"totalmem", mem_query},
#endif #endif

19
lgc.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lgc.c,v 1.27 1999/10/04 17:51:04 roberto Exp roberto $ ** $Id: lgc.c,v 1.28 1999/10/11 16:13:11 roberto Exp roberto $
** Garbage Collector ** Garbage Collector
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -51,10 +51,10 @@ static void hashmark (Hash *h) {
if (!h->marked) { if (!h->marked) {
int i; int i;
h->marked = 1; h->marked = 1;
for (i=nhash(h)-1; i>=0; i--) { for (i=h->size-1; i>=0; i--) {
Node *n = node(h,i); Node *n = node(h,i);
if (ttype(ref(n)) != LUA_T_NIL) { if (ttype(key(n)) != LUA_T_NIL) {
markobject(&n->ref); markobject(&n->key);
markobject(&n->val); markobject(&n->val);
} }
} }
@@ -157,11 +157,11 @@ static void collecttable (void) {
} }
static void clear_global_list (void) { static void clear_global_list (int limit) {
TaggedString **p = &L->rootglobal; TaggedString **p = &L->rootglobal;
TaggedString *next; TaggedString *next;
while ((next = *p) != NULL) { while ((next = *p) != NULL) {
if (next->marked) p = &next->nextglobal; if (next->marked >= limit) p = &next->nextglobal;
else *p = next->nextglobal; else *p = next->nextglobal;
} }
} }
@@ -176,7 +176,7 @@ static void collectstring (int limit) {
TObject o; /* to call userdata 'gc' tag method */ TObject o; /* to call userdata 'gc' tag method */
int i; int i;
ttype(&o) = LUA_T_USERDATA; ttype(&o) = LUA_T_USERDATA;
clear_global_list(); clear_global_list(limit);
for (i=0; i<NUM_HASHS; i++) { /* for each hash table */ for (i=0; i<NUM_HASHS; i++) { /* for each hash table */
stringtable *tb = &L->string_root[i]; stringtable *tb = &L->string_root[i];
int j; int j;
@@ -200,6 +200,8 @@ static void collectstring (int limit) {
} }
} }
} }
if ((tb->nuse+1)*6 < tb->size)
luaS_grow(tb); /* table is too big; `grow' it to a smaller size */
} }
} }
@@ -237,7 +239,8 @@ void luaC_collect (int all) {
collectstring(all?MAX_INT:1); collectstring(all?MAX_INT:1);
collectproto(); collectproto();
collectclosure(); collectclosure();
luaD_gcIM(&luaO_nilobject); /* GC tag method for nil (signal end of GC) */ if (!all)
luaD_gcIM(&luaO_nilobject); /* GC tag method for nil (signal end of GC) */
} }

15
lobject.h
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@@ -1,5 +1,5 @@
/* /*
** $Id: lobject.h,v 1.31 1999/10/04 17:51:04 roberto Exp roberto $ ** $Id: lobject.h,v 1.32 1999/10/11 16:13:11 roberto Exp roberto $
** Type definitions for Lua objects ** Type definitions for Lua objects
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -162,27 +162,30 @@ typedef struct Closure {
typedef struct node { typedef struct node {
TObject ref; TObject key;
TObject val; TObject val;
struct node *next; /* for chaining */
} Node; } Node;
typedef struct Hash { typedef struct Hash {
int htag;
Node *node;
unsigned int size;
Node *firstfree; /* this position is free; all positions after it are full */
struct Hash *next; struct Hash *next;
int marked; int marked;
Node *node;
int nhash;
int nuse;
int htag;
} Hash; } Hash;
extern const char *const luaO_typenames[]; extern const char *const luaO_typenames[];
#define luaO_typename(o) luaO_typenames[-ttype(o)] #define luaO_typename(o) luaO_typenames[-ttype(o)]
extern const TObject luaO_nilobject; extern const TObject luaO_nilobject;
#define luaO_equalObj(t1,t2) ((ttype(t1) != ttype(t2)) ? 0 \ #define luaO_equalObj(t1,t2) ((ttype(t1) != ttype(t2)) ? 0 \
: luaO_equalval(t1,t2)) : luaO_equalval(t1,t2))
int luaO_equalval (const TObject *t1, const TObject *t2); int luaO_equalval (const TObject *t1, const TObject *t2);

9
lstring.c
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@@ -1,5 +1,5 @@
/* /*
** $Id: lstring.c,v 1.22 1999/10/04 17:51:04 roberto Exp roberto $ ** $Id: lstring.c,v 1.23 1999/10/11 16:13:11 roberto Exp roberto $
** String table (keeps all strings handled by Lua) ** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -48,6 +48,7 @@ void luaS_freeall (void) {
luaM_free(L->string_root[i].hash); luaM_free(L->string_root[i].hash);
} }
luaM_free(L->string_root); luaM_free(L->string_root);
LUA_ASSERT(init_hash[0] == NULL, "init_hash corrupted");
} }
@@ -59,8 +60,8 @@ static unsigned long hash_s (const char *s, long l) {
} }
static void grow (stringtable *tb) { void luaS_grow (stringtable *tb) {
int ns = luaO_redimension(tb->size*2); /* new size */ int ns = luaO_redimension(tb->nuse*2); /* new size */
TaggedString **newhash = luaM_newvector(ns, TaggedString *); TaggedString **newhash = luaM_newvector(ns, TaggedString *);
int i; int i;
for (i=0; i<ns; i++) newhash[i] = NULL; for (i=0; i<ns; i++) newhash[i] = NULL;
@@ -122,7 +123,7 @@ static void newentry (stringtable *tb, TaggedString *ts, int h) {
tb->hash = luaM_newvector(1, TaggedString *); /* so, `clone' it */ tb->hash = luaM_newvector(1, TaggedString *); /* so, `clone' it */
tb->hash[0] = NULL; tb->hash[0] = NULL;
} }
grow(tb); luaS_grow(tb);
h = ts->hash%tb->size; /* new hash position */ h = ts->hash%tb->size; /* new hash position */
} }
ts->nexthash = tb->hash[h]; /* chain new entry */ ts->nexthash = tb->hash[h]; /* chain new entry */

4
lstring.h
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lstring.h,v 1.9 1999/10/04 17:51:04 roberto Exp roberto $ ** $Id: lstring.h,v 1.10 1999/10/11 16:13:11 roberto Exp roberto $
** String table (keep all strings handled by Lua) ** String table (keep all strings handled by Lua)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -9,6 +9,7 @@
#include "lobject.h" #include "lobject.h"
#include "lstate.h"
#define NUM_HASHSTR 31 /* a prime not in array `dimensions' */ #define NUM_HASHSTR 31 /* a prime not in array `dimensions' */
@@ -25,6 +26,7 @@
void luaS_init (void); void luaS_init (void);
void luaS_grow (stringtable *tb);
TaggedString *luaS_createudata (void *udata, int tag); TaggedString *luaS_createudata (void *udata, int tag);
void luaS_freeall (void); void luaS_freeall (void);
void luaS_free (TaggedString *ts); void luaS_free (TaggedString *ts);

271
ltable.c
View File

@@ -1,10 +1,23 @@
/* /*
** $Id: ltable.c,v 1.24 1999/09/22 14:38:45 roberto Exp roberto $ ** $Id: ltable.c,v 1.25 1999/10/04 17:51:04 roberto Exp roberto $
** Lua tables (hash) ** Lua tables (hash)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
/*
** Implementation of tables (aka arrays, objects, or hash tables);
** uses a mix of chained scatter table with Brent's variation.
** A main invariant of these tables is that, if an element is not
** in its main position (i.e. the `original' position that its hash gives
** to it), then the colliding element is in its own main position.
** In other words, there are collisions only when two elements have the
** same main position (i.e. the same hash values for that table size).
** Because of that, the load factor of these tables can be 100% without
** performance penalties.
*/
#include "lauxlib.h" #include "lauxlib.h"
#include "lmem.h" #include "lmem.h"
#include "lobject.h" #include "lobject.h"
@@ -15,93 +28,104 @@
#define gcsize(n) (1+(n/16)) #define gcsize(n) (1+(n/16))
#define nuse(t) ((t)->nuse)
#define nodevector(t) ((t)->node)
#define TagDefault LUA_T_ARRAY; #define TagDefault LUA_T_ARRAY;
static long int hashindex (const TObject *ref) { /*
long int h; ** returns the `main' position of an element in a table (that is, the index
switch (ttype(ref)) { ** of its hash value)
*/
static Node *luaH_mainposition (const Hash *t, const TObject *key) {
unsigned long h;
switch (ttype(key)) {
case LUA_T_NUMBER: case LUA_T_NUMBER:
h = (long int)nvalue(ref); h = (unsigned long)(long)nvalue(key);
break; break;
case LUA_T_STRING: case LUA_T_USERDATA: case LUA_T_STRING: case LUA_T_USERDATA:
h = (IntPoint)tsvalue(ref); h = tsvalue(key)->hash;
break; break;
case LUA_T_ARRAY: case LUA_T_ARRAY:
h = (IntPoint)avalue(ref); h = (IntPoint)avalue(key);
break; break;
case LUA_T_PROTO: case LUA_T_PROTO:
h = (IntPoint)tfvalue(ref); h = (IntPoint)tfvalue(key);
break; break;
case LUA_T_CPROTO: case LUA_T_CPROTO:
h = (IntPoint)fvalue(ref); h = (IntPoint)fvalue(key);
break; break;
case LUA_T_CLOSURE: case LUA_T_CLOSURE:
h = (IntPoint)clvalue(ref); h = (IntPoint)clvalue(key);
break; break;
default: default:
lua_error("unexpected type to index table"); lua_error("unexpected type to index table");
h = 0; /* to avoid warnings */ h = 0; /* to avoid warnings */
} }
return (h >= 0 ? h : -(h+1)); return &t->node[h%t->size];
} }
Node *luaH_present (const Hash *t, const TObject *key) { const TObject *luaH_get (const Hash *t, const TObject *key) {
const int tsize = nhash(t); Node *n = luaH_mainposition(t, key);
const long int h = hashindex(key); do {
int h1 = h%tsize; if (luaO_equalObj(key, &n->key))
Node *n = node(t, h1); return &n->val;
/* keep looking until an entry with "ref" equal to key or nil */ n = n->next;
while ((ttype(ref(n)) == ttype(key)) ? !luaO_equalval(key, ref(n)) } while (n);
: ttype(ref(n)) != LUA_T_NIL) { return &luaO_nilobject;
h1 += (h&(tsize-2)) + 1; /* double hashing */
if (h1 >= tsize) h1 -= tsize;
n = node(t, h1);
}
return n;
} }
int luaH_pos (const Hash *t, const TObject *key) {
const TObject *v = luaH_get(t, key);
return (v == &luaO_nilobject) ? -1 : /* key not found */
((const char *)v - (const char *)(&t->node[0].val))/sizeof(Node);
}
static Node *hashnodecreate (int nhash) { static Node *hashnodecreate (int nhash) {
Node *const v = luaM_newvector(nhash, Node); Node *v = luaM_newvector(nhash, Node);
int i; int i;
for (i=0; i<nhash; i++) for (i=0; i<nhash; i++) {
ttype(ref(&v[i])) = ttype(val(&v[i])) = LUA_T_NIL; ttype(key(&v[i])) = ttype(val(&v[i])) = LUA_T_NIL;
v[i].next = NULL;
}
return v; return v;
} }
Hash *luaH_new (int nhash) { static void setnodevector (Hash *t, int size) {
Hash *const t = luaM_new(Hash); t->node = hashnodecreate(size);
nhash = luaO_redimension(nhash*3/2); t->size = size;
nodevector(t) = hashnodecreate(nhash); t->firstfree = &t->node[size-1]; /* first free position to be used */
nhash(t) = nhash; L->nblocks += gcsize(size);
nuse(t) = 0; }
Hash *luaH_new (int size) {
Hash *t = luaM_new(Hash);
setnodevector(t, luaO_redimension(size+1));
t->htag = TagDefault; t->htag = TagDefault;
t->next = L->roottable; t->next = L->roottable;
L->roottable = t; L->roottable = t;
t->marked = 0; t->marked = 0;
L->nblocks += gcsize(nhash);
return t; return t;
} }
void luaH_free (Hash *t) { void luaH_free (Hash *t) {
L->nblocks -= gcsize(t->nhash); L->nblocks -= gcsize(t->size);
luaM_free(nodevector(t)); luaM_free(t->node);
luaM_free(t); luaM_free(t);
} }
static int newsize (Hash *t) { static int newsize (const Hash *t) {
Node *const v = t->node; Node *v = t->node;
const int size = nhash(t); int size = t->size;
int realuse = 0; int realuse = 0;
int i; int i;
for (i=0; i<size; i++) { for (i=0; i<size; i++) {
@@ -112,57 +136,158 @@ static int newsize (Hash *t) {
} }
#ifdef DEBUG
/* check invariant of a table */
static int listfind (const Node *m, const Node *n) {
do {
if (m==n) return 1;
m = m->next;
} while (m);
return 0;
}
static int check_invariant (const Hash *t, int filled) {
Node *n;
for (n=t->node; n<t->firstfree; n++) {
TObject *key = &n->key;
LUA_ASSERT(ttype(key) == LUA_T_NIL || n == luaH_mainposition(t, key),
"all elements before firstfree are empty or in their main positions");
}
if (!filled)
LUA_ASSERT(ttype(&(n++)->key) == LUA_T_NIL, "firstfree must be empty");
else
LUA_ASSERT(n == t->node, "table cannot have empty places");
for (; n<t->node+t->size; n++) {
TObject *key = &n->key;
Node *mp = luaH_mainposition(t, key);
LUA_ASSERT(ttype(key) != LUA_T_NIL,
"cannot exist empty elements after firstfree");
LUA_ASSERT(n == mp || luaH_mainposition(t, &mp->key) == mp,
"either an element or its colliding element is in its main position");
LUA_ASSERT(listfind(mp,n), "element is in its main position list");
}
return 1;
}
#endif
/*
** the rehash is done in two stages: first, we insert only the elements whose
** main position is free, to avoid needless collisions. In the second stage,
** we insert the other elements.
*/
static void rehash (Hash *t) { static void rehash (Hash *t) {
const int nold = nhash(t); int oldsize = t->size;
Node *const vold = nodevector(t); Node *nold = t->node;
const int nnew = newsize(t);
int i; int i;
nodevector(t) = hashnodecreate(nnew); LUA_ASSERT(check_invariant(t, 1), "invalid table");
nhash(t) = nnew; L->nblocks -= gcsize(oldsize);
nuse(t) = 0; setnodevector(t, newsize(t)); /* create new array of nodes */
for (i=0; i<nold; i++) { /* first loop; set only elements that can go in their main positions */
Node *n = vold+i; for (i=0; i<oldsize; i++) {
if (ttype(val(n)) != LUA_T_NIL) { Node *old = nold+i;
*luaH_present(t, ref(n)) = *n; /* copy old node to new hash */ if (ttype(&old->val) == LUA_T_NIL)
nuse(t)++; old->next = NULL; /* `remove' it for next loop */
else {
Node *mp = luaH_mainposition(t, &old->key); /* new main position */
if (ttype(&mp->key) == LUA_T_NIL) { /* is it empty? */
mp->key = old->key; /* put element there */
mp->val = old->val;
old->next = NULL; /* `remove' it for next loop */
}
else /* it will be copied in next loop */
old->next = mp; /* to be used in next loop */
} }
} }
L->nblocks += gcsize(nnew)-gcsize(nold); /* update `firstfree' */
luaM_free(vold); while (ttype(&t->firstfree->key) != LUA_T_NIL) t->firstfree--;
} /* second loop; update elements with colision */
for (i=0; i<oldsize; i++) {
Node *old = nold+i;
void luaH_set (Hash *t, const TObject *ref, const TObject *val) { if (old->next) { /* wasn't already `removed'? */
Node *const n = luaH_present(t, ref); Node *mp = old->next; /* main position */
*val(n) = *val; Node *e = t->firstfree; /* actual position */
if (ttype(ref(n)) == LUA_T_NIL) { /* new node? */ e->key = old->key; /* put element in the free position */
*ref(n) = *ref; /* set key */ e->val = old->val;
nuse(t)++; /* count it */ e->next = mp->next; /* chain actual position in main position's list */
if ((long)nuse(t)*3L > (long)nhash(t)*2L) /* check size */ mp->next = e;
rehash(t); do { /* update `firstfree' */
t->firstfree--;
} while (ttype(&t->firstfree->key) != LUA_T_NIL);
}
} }
LUA_ASSERT(check_invariant(t, 0), "invalid table");
luaM_free(nold); /* free old array */
} }
int luaH_pos (const Hash *t, const TObject *r) { /*
Node *const n = luaH_present(t, r); ** sets a pair key-value in a hash table; first, check whether key is
luaL_arg_check(ttype(val(n)) != LUA_T_NIL, 2, "key not found"); ** already present; if not, check whether key's main position is free;
return n-(t->node); ** if not, check whether colliding node is in its main position or not;
** if it is not, move colliding node to an empty place and put new pair
** in its main position; otherwise (colliding node is in its main position),
** new pair goes to an empty position.
** Tricky point: the only place where an old element is moved is when
** we move the colliding node to an empty place; nevertheless, its old
** value is still in that position until we set the value for the new
** pair; therefore, even when `val' points to an element of this table
** (this happens when we use `luaH_move'), there is no problem.
*/
void luaH_set (Hash *t, const TObject *key, const TObject *val) {
Node *mp = luaH_mainposition(t, key);
Node *n = mp;
do { /* check whether `key' is somewhere in the chain */
if (luaO_equalObj(key, &n->key)) {
n->val = *val; /* update value */
return; /* that's all */
}
else n = n->next;
} while (n);
/* `key' not found; must insert it */
if (ttype(&mp->key) != LUA_T_NIL) { /* main position is not free? */
Node *othern; /* main position of colliding node */
n = t->firstfree; /* get a free place */
/* is colliding node out of its main position? (can only happens if
its position if after "firstfree") */
if (mp > n && (othern=luaH_mainposition(t, &mp->key)) != mp) {
/* yes; move colliding node into free position */
while (othern->next != mp) othern = othern->next; /* find previous */
othern->next = n; /* redo the chain with `n' in place of `mp' */
*n = *mp; /* copy colliding node into free pos. (mp->next also goes) */
mp->next = NULL; /* now `mp' is free */
}
else { /* colliding node is in its own main position */
/* new node will go into free position */
n->next = mp->next; /* chain new position */
mp->next = n;
mp = n;
}
}
mp->key = *key;
mp->val = *val;
for (;;) { /* check free places */
if (ttype(&(t->firstfree)->key) == LUA_T_NIL)
return; /* OK; table still has a free place */
else if (t->firstfree == t->node) break; /* cannot decrement from here */
else (t->firstfree)--;
}
rehash(t); /* no more free places */
} }
void luaH_setint (Hash *t, int ref, const TObject *val) { void luaH_setint (Hash *t, int key, const TObject *val) {
TObject index; TObject index;
ttype(&index) = LUA_T_NUMBER; ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = ref; nvalue(&index) = key;
luaH_set(t, &index, val); luaH_set(t, &index, val);
} }
TObject *luaH_getint (const Hash *t, int ref) { const TObject *luaH_getint (const Hash *t, int key) {
TObject index; TObject index;
ttype(&index) = LUA_T_NUMBER; ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = ref; nvalue(&index) = key;
return luaH_get(t, &index); return luaH_get(t, &index);
} }

15
ltable.h
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: ltable.h,v 1.12 1999/08/16 20:52:00 roberto Exp roberto $ ** $Id: ltable.h,v 1.13 1999/10/04 17:51:04 roberto Exp roberto $
** Lua tables (hash) ** Lua tables (hash)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -11,20 +11,19 @@
#define node(t,i) (&(t)->node[i]) #define node(t,i) (&(t)->node[i])
#define ref(n) (&(n)->ref) #define key(n) (&(n)->key)
#define val(n) (&(n)->val) #define val(n) (&(n)->val)
#define nhash(t) ((t)->nhash)
#define luaH_get(t,ref) (val(luaH_present((t), (ref))))
#define luaH_move(t,from,to) (luaH_setint(t, to, luaH_getint(t, from))) #define luaH_move(t,from,to) (luaH_setint(t, to, luaH_getint(t, from)))
Hash *luaH_new (int nhash); Hash *luaH_new (int nhash);
void luaH_free (Hash *t); void luaH_free (Hash *t);
Node *luaH_present (const Hash *t, const TObject *key); const TObject *luaH_get (const Hash *t, const TObject *key);
void luaH_set (Hash *t, const TObject *ref, const TObject *val); void luaH_set (Hash *t, const TObject *key, const TObject *val);
int luaH_pos (const Hash *t, const TObject *r); int luaH_pos (const Hash *t, const TObject *r);
void luaH_setint (Hash *t, int ref, const TObject *val); void luaH_setint (Hash *t, int key, const TObject *val);
TObject *luaH_getint (const Hash *t, int ref); const TObject *luaH_getint (const Hash *t, int key);
unsigned long luaH_hash (const TObject *key); /* exported only for debugging */
#endif #endif

4
lvm.c
View File

@@ -1,5 +1,5 @@
/* /*
** $Id: lvm.c,v 1.61 1999/09/06 13:55:09 roberto Exp roberto $ ** $Id: lvm.c,v 1.62 1999/09/17 16:53:54 roberto Exp roberto $
** Lua virtual machine ** Lua virtual machine
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@@ -107,7 +107,7 @@ void luaV_gettable (void) {
int tg = table->value.a->htag; int tg = table->value.a->htag;
im = luaT_getim(tg, IM_GETTABLE); im = luaT_getim(tg, IM_GETTABLE);
if (ttype(im) == LUA_T_NIL) { /* and does not have a "gettable" method */ if (ttype(im) == LUA_T_NIL) { /* and does not have a "gettable" method */
TObject *h = luaH_get(avalue(table), table+1); const TObject *h = luaH_get(avalue(table), table+1);
if (ttype(h) == LUA_T_NIL && if (ttype(h) == LUA_T_NIL &&
(ttype(im=luaT_getim(tg, IM_INDEX)) != LUA_T_NIL)) { (ttype(im=luaT_getim(tg, IM_INDEX)) != LUA_T_NIL)) {
/* result is nil and there is an "index" tag method */ /* result is nil and there is an "index" tag method */