/* Force a lazy pair. NB: When an error occurs during forcing, we release the lock of the pair, so that the pair can be forced again. However, the generator has already caused some side-effect before the error, so the next forcing may not yield a correct next value. Another plausible option is to mark the pair 'unforcible' permanently, by lp->owner == (AO_t)2, and let subsequent attempt of forcing the pair fail. */ ScmObj Scm_ForceLazyPair(volatile ScmLazyPair *lp) { static const struct timespec req = {0, 1000000}; struct timespec rem; ScmVM *vm = Scm_VM(); do { if (AO_compare_and_swap_full(&lp->owner, 0, SCM_WORD(vm))) { /* Here we own the lazy pair. */ ScmObj item = lp->item; /* Calling generator might change VM state, so we protect incomplete stack frame if there's any. */ int extra_frame_pushed = Scm__VMProtectStack(vm); SCM_UNWIND_PROTECT { ScmObj val = Scm_ApplyRec0(lp->generator); ScmObj newgen = (vm->numVals == 1)? lp->generator : vm->vals[0]; vm->numVals = 1; /* make sure the extra val won't leak out */ if (SCM_EOFP(val)) { lp->item = SCM_NIL; lp->generator = SCM_NIL; } else { ScmObj newlp = Scm_MakeLazyPair(val, newgen); lp->item = newlp; lp->generator = SCM_NIL; } AO_nop_full(); SCM_SET_CAR(lp, item); /* We don't need barrier here. */ lp->owner = (AO_t)1; } SCM_WHEN_ERROR { lp->owner = (AO_t)0; /*NB: See above about error handling*/ SCM_NEXT_HANDLER; } SCM_END_PROTECT; if (extra_frame_pushed) { Scm__VMUnprotectStack(vm); } return SCM_OBJ(lp); /* lp is now an (extended) pair */ } /* Check if we're already working on forcing this pair. Unlike force/delay, We don't allow recursive forcing of lazy pair. Since generators are supposed to be called every time to yield a new value, so it is ambiguous what value should be returned if a generator calls itself recursively. */ if (lp->owner == SCM_WORD(vm)) { /* NB: lp->owner will be reset by the original caller of the generator. */ Scm_Error("Attempt to recursively force a lazy pair."); } /* Somebody's already working on forcing. Let's wait for it to finish, or to abort. */ while (SCM_HTAG(lp) == 7 && lp->owner != 0) { nanosleep(&req, &rem); } } while (lp->owner == 0); /* we retry if the previous owner abandoned. */
/* If OBJ is a primitive object (roughly, immediate or number), write it to PORT. Assumes the caller locks the PORT. Returns the # of characters written, or #f if OBJ is not a primitive object. */ ScmObj Scm__WritePrimitive(ScmObj obj, ScmPort *port, ScmWriteContext *ctx) { #define CASE_ITAG_RET(obj, str) \ case SCM_ITAG(obj): \ Scm_PutzUnsafe(str, -1, port); \ return SCM_MAKE_INT(sizeof(str)-1); if (SCM_IMMEDIATEP(obj)) { switch (SCM_ITAG(obj)) { CASE_ITAG_RET(SCM_FALSE, "#f"); CASE_ITAG_RET(SCM_TRUE, "#t"); CASE_ITAG_RET(SCM_NIL, "()"); CASE_ITAG_RET(SCM_EOF, "#<eof>"); CASE_ITAG_RET(SCM_UNDEFINED, "#<undef>"); CASE_ITAG_RET(SCM_UNBOUND, "#<unbound>"); default: Scm_Panic("write: unknown itag object: %08x", SCM_WORD(obj)); } } else if (SCM_INTP(obj)) { char buf[SPBUFSIZ]; int k = snprintf(buf, SPBUFSIZ, "%ld", SCM_INT_VALUE(obj)); Scm_PutzUnsafe(buf, -1, port); return SCM_MAKE_INT(k); } else if (SCM_CHARP(obj)) { size_t k = write_char(SCM_CHAR_VALUE(obj), port, ctx); return SCM_MAKE_INT(k); } else if (SCM_NUMBERP(obj)) { return SCM_MAKE_INT(Scm_PrintNumber(port, obj, NULL)); } return SCM_FALSE; }
/* If OBJ is a primitive object (roughly, immediate or number), write it to PORT. Assumes the caller locks the PORT. Returns the # of characters written, or #f if OBJ is not a primitive object. */ ScmObj Scm__WritePrimitive(ScmObj obj, ScmPort *port, ScmWriteContext *ctx) { const ScmWriteControls *wp = Scm_GetWriteControls(ctx, port->writeState); #define CASE_ITAG_RET(obj, str) \ case SCM_ITAG(obj): \ Scm_PutzUnsafe(str, -1, port); \ return SCM_MAKE_INT(sizeof(str)-1); if (SCM_IMMEDIATEP(obj)) { switch (SCM_ITAG(obj)) { CASE_ITAG_RET(SCM_FALSE, "#f"); CASE_ITAG_RET(SCM_TRUE, "#t"); CASE_ITAG_RET(SCM_NIL, "()"); CASE_ITAG_RET(SCM_EOF, "#<eof>"); CASE_ITAG_RET(SCM_UNDEFINED, "#<undef>"); CASE_ITAG_RET(SCM_UNBOUND, "#<unbound>"); default: Scm_Panic("write: unknown itag object: %08x", SCM_WORD(obj)); } } else if (SCM_INTP(obj) && wp->printBase == 10 && !wp->printRadix) { /* Shortcut to avoid allocation */ char buf[SPBUFSIZ]; int k = snprintf(buf, SPBUFSIZ, "%ld", SCM_INT_VALUE(obj)); Scm_PutzUnsafe(buf, -1, port); return SCM_MAKE_INT(k); } else if (SCM_CHARP(obj)) { size_t k = write_char(SCM_CHAR_VALUE(obj), port, ctx); return SCM_MAKE_INT(k); } else if (SCM_NUMBERP(obj)) { ScmNumberFormat fmt; Scm_NumberFormatInit(&fmt); fmt.radix = wp->printBase; if (wp->printRadix) fmt.flags |= SCM_NUMBER_FORMAT_ALT_RADIX; return SCM_MAKE_INT(Scm_PrintNumber(port, obj, &fmt)); } /* PVREF only appears in pattern temlate in the current macro expander. It will be go away once we rewrite the expander. */ else if (SCM_PVREF_P(obj)) { char buf[SPBUFSIZ]; int k = snprintf(buf, SPBUFSIZ, "#<pvar %ld.%ld>", SCM_PVREF_LEVEL(obj), SCM_PVREF_COUNT(obj)); Scm_PutzUnsafe(buf, -1, port); return SCM_MAKE_INT(k); } return SCM_FALSE; }
/* General hash function */ u_long Scm_Hash(ScmObj obj) { u_long hashval; if (!SCM_PTRP(obj)) { SMALL_INT_HASH(hashval, (u_long)SCM_WORD(obj)); return hashval; } else if (SCM_NUMBERP(obj)) { return Scm_EqvHash(obj); } else if (SCM_STRINGP(obj)) { goto string_hash; } else if (SCM_PAIRP(obj)) { u_long h = 0, h2; ScmObj cp; SCM_FOR_EACH(cp, obj) { h2 = Scm_Hash(SCM_CAR(cp)); h = COMBINE(h, h2); } h2 = Scm_Hash(cp); h = COMBINE(h, h2); return h; } else if (SCM_VECTORP(obj)) {
/* Trick: The hashtable contains positive integer after the walk pass. If we emit a reference tag N, we replace the entry's value to -N, so that we can distinguish whether we've already emitted the object or not. */ static void write_rec(ScmObj obj, ScmPort *port, ScmWriteContext *ctx) { char numbuf[50]; /* enough to contain long number */ ScmObj stack = SCM_NIL; ScmWriteState *st = port->writeState; ScmHashTable *ht = (st? st->sharedTable : NULL); int stack_depth = 0; #define PUSH(elt) \ do { \ stack = Scm_Cons(elt, stack); \ if (!ht && ++stack_depth > STACK_LIMIT) { \ Scm_Error("write recursed too deeply; " \ "maybe a circular structure?"); \ } \ } while (0) #define POP() \ do { \ stack = SCM_CDR(stack); \ if (ht) stack_depth--; \ } while (0) for (;;) { write1: if (ctx->flags & WRITE_LIMITED) { if (port->src.ostr.length >= ctx->limit) return; } /* number may be heap allocated, but we don't use srfi-38 notation. */ if (!SCM_PTRP(obj) || SCM_NUMBERP(obj)) { if (SCM_FALSEP(Scm__WritePrimitive(obj, port, ctx))) { Scm_Panic("write: got a bogus object: %08x", SCM_WORD(obj)); } goto next; } if ((SCM_STRINGP(obj) && SCM_STRING_SIZE(obj) == 0) || (SCM_VECTORP(obj) && SCM_VECTOR_SIZE(obj) == 0)) { /* we don't put a reference tag for these */ write_general(obj, port, ctx); goto next; } if (ht) { ScmObj e = Scm_HashTableRef(ht, obj, SCM_MAKE_INT(1)); long k = SCM_INT_VALUE(e); if (k <= 0) { /* This object is already printed. */ snprintf(numbuf, 50, "#%ld#", -k); Scm_PutzUnsafe(numbuf, -1, port); goto next; } else if (k > 1) { /* This object will be seen again. Put a reference tag. */ ScmWriteState *s = port->writeState; snprintf(numbuf, 50, "#%d=", s->sharedCounter); Scm_HashTableSet(ht, obj, SCM_MAKE_INT(-s->sharedCounter), 0); s->sharedCounter++; Scm_PutzUnsafe(numbuf, -1, port); } } /* Writes aggregates */ if (SCM_PAIRP(obj)) { /* special case for quote etc. NB: we need to check if we've seen SCM_CDR(obj), otherwise we'll get infinite recursion for the case like (cdr '#1='#1#). */ if (SCM_PAIRP(SCM_CDR(obj)) && SCM_NULLP(SCM_CDDR(obj)) && (!ht || SCM_FALSEP(Scm_HashTableRef(ht, SCM_CDR(obj), SCM_FALSE)))){ const char *prefix = NULL; if (SCM_CAR(obj) == SCM_SYM_QUOTE) { prefix = "'"; } else if (SCM_CAR(obj) == SCM_SYM_QUASIQUOTE) { prefix = "`"; } else if (SCM_CAR(obj) == SCM_SYM_UNQUOTE) { prefix = ","; } else if (SCM_CAR(obj) == SCM_SYM_UNQUOTE_SPLICING) { prefix = ",@"; } if (prefix) { Scm_PutzUnsafe(prefix, -1, port); obj = SCM_CADR(obj); goto write1; } } /* normal case */ Scm_PutcUnsafe('(', port); PUSH(Scm_Cons(SCM_TRUE, SCM_CDR(obj))); obj = SCM_CAR(obj); goto write1; } else if (SCM_VECTORP(obj)) { Scm_PutzUnsafe("#(", -1, port); PUSH(Scm_Cons(SCM_MAKE_INT(1), obj)); obj = SCM_VECTOR_ELEMENT(obj, 0); goto write1; } else { /* string or user-defined object */ write_general(obj, port, ctx); goto next; } next: while (SCM_PAIRP(stack)) { ScmObj top = SCM_CAR(stack); SCM_ASSERT(SCM_PAIRP(top)); if (SCM_INTP(SCM_CAR(top))) { /* we're processing a vector */ ScmObj v = SCM_CDR(top); int i = SCM_INT_VALUE(SCM_CAR(top)); int len = SCM_VECTOR_SIZE(v); if (i == len) { /* we've done this vector */ Scm_PutcUnsafe(')', port); POP(); } else { Scm_PutcUnsafe(' ', port); obj = SCM_VECTOR_ELEMENT(v, i); SCM_SET_CAR(top, SCM_MAKE_INT(i+1)); goto write1; } } else { /* we're processing a list */ ScmObj v = SCM_CDR(top); if (SCM_NULLP(v)) { /* we've done with this list */ Scm_PutcUnsafe(')', port); POP(); } else if (!SCM_PAIRP(v)) { Scm_PutzUnsafe(" . ", -1, port); obj = v; SCM_SET_CDR(top, SCM_NIL); goto write1; } else if (ht && !SCM_EQ(Scm_HashTableRef(ht, v, SCM_MAKE_INT(1)), SCM_MAKE_INT(1))) { /* cdr part is shared */ Scm_PutzUnsafe(" . ", -1, port); obj = v; SCM_SET_CDR(top, SCM_NIL); goto write1; } else { Scm_PutcUnsafe(' ', port); obj = SCM_CAR(v); SCM_SET_CDR(top, SCM_CDR(v)); goto write1; } } } break; } #undef PUSH #undef POP }
/* Trick: The hashtable contains positive integer after the walk pass. If we emit a reference tag N, we replace the entry's value to -N, so that we can distinguish whether we've already emitted the object or not. */ static void write_rec(ScmObj obj, ScmPort *port, ScmWriteContext *ctx) { char numbuf[50]; /* enough to contain long number */ ScmObj stack = SCM_NIL; ScmWriteState *st = port->writeState; ScmHashTable *ht = (st? st->sharedTable : NULL); const ScmWriteControls *wp = Scm_GetWriteControls(ctx, st); int stack_depth = 0; /* only used when !ht */ #define PUSH(elt) \ do { \ stack = Scm_Cons(elt, stack); \ if (!ht && ++stack_depth > STACK_LIMIT) { \ Scm_Error("write recursed too deeply; " \ "maybe a circular structure?"); \ } \ } while (0) #define POP() \ do { \ stack = SCM_CDR(stack); \ if (!ht) stack_depth--; \ } while (0) #define CHECK_LEVEL() \ do { \ if (st) { \ if (wp->printLevel >= 0 && st->currentLevel >= wp->printLevel) { \ Scm_PutcUnsafe('#', port); \ goto next; \ } else { \ if (st) st->currentLevel++; \ } \ } \ } while (0) for (;;) { write1: if (ctx->flags & WRITE_LIMITED) { if (port->src.ostr.length >= ctx->limit) return; } /* number may be heap allocated, but we don't use srfi-38 notation. */ if (!SCM_PTRP(obj) || SCM_NUMBERP(obj)) { if (SCM_FALSEP(Scm__WritePrimitive(obj, port, ctx))) { Scm_Panic("write: got a bogus object: %08x", SCM_WORD(obj)); } goto next; } if ((SCM_STRINGP(obj) && SCM_STRING_SIZE(obj) == 0) || (SCM_VECTORP(obj) && SCM_VECTOR_SIZE(obj) == 0)) { /* we don't put a reference tag for these */ write_general(obj, port, ctx); goto next; } /* obj is heap allocated and we may use label notation. */ if (ht) { ScmObj e = Scm_HashTableRef(ht, obj, SCM_MAKE_INT(1)); long k = SCM_INT_VALUE(e); if (k <= 0) { /* This object is already printed. */ snprintf(numbuf, 50, "#%ld#", -k); Scm_PutzUnsafe(numbuf, -1, port); goto next; } else if (k > 1) { /* This object will be seen again. Put a reference tag. */ ScmWriteState *s = port->writeState; snprintf(numbuf, 50, "#%d=", s->sharedCounter); Scm_HashTableSet(ht, obj, SCM_MAKE_INT(-s->sharedCounter), 0); s->sharedCounter++; Scm_PutzUnsafe(numbuf, -1, port); } } /* Writes aggregates */ if (SCM_PAIRP(obj)) { CHECK_LEVEL(); /* special case for quote etc. NB: we need to check if we've seen SCM_CDR(obj), otherwise we'll get infinite recursion for the case like (cdr '#1='#1#). */ if (SCM_PAIRP(SCM_CDR(obj)) && SCM_NULLP(SCM_CDDR(obj)) && (!ht || SCM_FALSEP(Scm_HashTableRef(ht, SCM_CDR(obj), SCM_FALSE)))){ const char *prefix = NULL; if (SCM_CAR(obj) == SCM_SYM_QUOTE) { prefix = "'"; } else if (SCM_CAR(obj) == SCM_SYM_QUASIQUOTE) { prefix = "`"; } else if (SCM_CAR(obj) == SCM_SYM_UNQUOTE) { prefix = ","; } else if (SCM_CAR(obj) == SCM_SYM_UNQUOTE_SPLICING) { prefix = ",@"; } if (prefix) { Scm_PutzUnsafe(prefix, -1, port); obj = SCM_CADR(obj); goto write1; } } if (wp->printLength == 0) { /* in this case we don't print the elements at all, so we need to treat this specially. */ Scm_PutzUnsafe("(...)", -1, port); if (st) st->currentLevel--; goto next; } /* normal case */ Scm_PutcUnsafe('(', port); PUSH(Scm_Cons(SCM_TRUE, Scm_Cons(SCM_MAKE_INT(1), SCM_CDR(obj)))); obj = SCM_CAR(obj); goto write1; } else if (SCM_VECTORP(obj)) { CHECK_LEVEL(); if (wp->printLength == 0) { /* in this case we don't print the elements at all, so we need to treat this specially. */ Scm_PutzUnsafe("#(...)", -1, port); if (st) st->currentLevel--; goto next; } Scm_PutzUnsafe("#(", -1, port); PUSH(Scm_Cons(SCM_MAKE_INT(1), obj)); obj = SCM_VECTOR_ELEMENT(obj, 0); goto write1; } else if (Scm_ClassOf(obj)->flags & SCM_CLASS_AGGREGATE) { CHECK_LEVEL(); write_general(obj, port, ctx); if (st) st->currentLevel--; goto next; } else { write_general(obj, port, ctx); goto next; } next: while (SCM_PAIRP(stack)) { ScmObj top = SCM_CAR(stack); SCM_ASSERT(SCM_PAIRP(top)); if (SCM_INTP(SCM_CAR(top))) { /* we're processing a vector */ ScmObj v = SCM_CDR(top); int i = SCM_INT_VALUE(SCM_CAR(top)); int len = SCM_VECTOR_SIZE(v); if (i == len) { /* we've done this vector */ Scm_PutcUnsafe(')', port); POP(); } else if (wp->printLength >= 0 && wp->printLength <= i) { Scm_PutzUnsafe(" ...)", -1, port); POP(); } else { Scm_PutcUnsafe(' ', port); obj = SCM_VECTOR_ELEMENT(v, i); SCM_SET_CAR(top, SCM_MAKE_INT(i+1)); goto write1; } } else { /* we're processing a list */ SCM_ASSERT(SCM_PAIRP(SCM_CDR(top))); long count = SCM_INT_VALUE(SCM_CADR(top)); ScmObj v = SCM_CDDR(top); if (SCM_NULLP(v)) { /* we've done with this list */ Scm_PutcUnsafe(')', port); POP(); } else if (!SCM_PAIRP(v)) { /* Improper list. We treat aggregate types specially, since such object at this position shouldn't increment "level" - its content is regarded as the same level of the current list. */ Scm_PutzUnsafe(" . ", -1, port); if (Scm_ClassOf(v)->flags & SCM_CLASS_AGGREGATE) { if (st) st->currentLevel--; write_rec(v, port, ctx); if (st) st->currentLevel++; Scm_PutcUnsafe(')', port); POP(); } else { obj = v; SCM_SET_CAR(SCM_CDR(top), SCM_MAKE_INT(count+1)); SCM_SET_CDR(SCM_CDR(top), SCM_NIL); goto write1; } } else if (wp->printLength >= 0 && wp->printLength <= count) { /* print-length limit reached */ Scm_PutzUnsafe(" ...)", -1, port); POP(); } else if (ht && !SCM_EQ(Scm_HashTableRef(ht, v, SCM_MAKE_INT(1)), SCM_MAKE_INT(1))) { /* cdr part is shared */ Scm_PutzUnsafe(" . ", -1, port); obj = v; SCM_SET_CAR(SCM_CDR(top), SCM_MAKE_INT(count+1)); SCM_SET_CDR(SCM_CDR(top), SCM_NIL); goto write1; } else { Scm_PutcUnsafe(' ', port); obj = SCM_CAR(v); SCM_SET_CAR(SCM_CDR(top), SCM_MAKE_INT(count+1)); SCM_SET_CDR(SCM_CDR(top), SCM_CDR(v)); goto write1; } } if (st) st->currentLevel--; } break; } #undef PUSH #undef POP #undef CHECK_DEPTH }