5 // gets the address of an object representing a C pointer, with the
6 // intention of storing the pointer across code which may potentially GC.
7 char* factor_vm::pinned_alien_offset(cell obj) {
10 alien* ptr = untag<alien>(obj);
11 if (to_boolean(ptr->expired))
12 general_error(ERROR_EXPIRED, obj, false_object);
13 if (to_boolean(ptr->base))
14 type_error(ALIEN_TYPE, obj);
15 return (char*)ptr->address;
20 type_error(ALIEN_TYPE, obj);
21 return NULL; // can't happen
27 cell factor_vm::allot_alien(cell delegate_, cell displacement) {
28 if (displacement == 0)
31 data_root<object> delegate(delegate_, this);
32 data_root<alien> new_alien(allot<alien>(sizeof(alien)), this);
34 if (TAG(delegate_) == ALIEN_TYPE) {
35 tagged<alien> delegate_alien = delegate.as<alien>();
36 displacement += delegate_alien->displacement;
37 new_alien->base = delegate_alien->base;
39 new_alien->base = delegate.value();
41 new_alien->displacement = displacement;
42 new_alien->expired = false_object;
43 new_alien->update_address();
45 return new_alien.value();
49 cell factor_vm::allot_alien(cell address) {
50 return allot_alien(false_object, address);
53 // make an alien pointing at an offset of another alien
55 void factor_vm::primitive_displaced_alien() {
56 cell alien = ctx->pop();
57 cell displacement = to_cell(ctx->pop());
63 ctx->push(allot_alien(alien, displacement));
66 type_error(ALIEN_TYPE, alien);
71 // address of an object representing a C pointer. Explicitly throw an error
72 // if the object is a byte array, as a sanity check.
73 // Allocates memory (from_unsigned_cell can allocate)
74 void factor_vm::primitive_alien_address() {
75 ctx->replace(from_unsigned_cell((cell)pinned_alien_offset(ctx->peek())));
78 // pop ( alien n ) from datastack, return alien's address plus n
79 void* factor_vm::alien_pointer() {
80 fixnum offset = to_fixnum(ctx->pop());
81 return alien_offset(ctx->pop()) + offset;
84 // define words to read/write values at an alien address
85 #define DEFINE_ALIEN_ACCESSOR(name, type, from, to) \
86 VM_C_API void primitive_alien_##name(factor_vm * parent) { \
87 parent->ctx->push(parent->from(*(type*)(parent->alien_pointer()))); \
89 VM_C_API void primitive_set_alien_##name(factor_vm * parent) { \
90 type* ptr = (type*)parent->alien_pointer(); \
91 type value = (type)parent->to(parent->ctx->pop()); \
95 EACH_ALIEN_PRIMITIVE(DEFINE_ALIEN_ACCESSOR)
97 // open a native library and push a handle
99 void factor_vm::primitive_dlopen() {
100 data_root<byte_array> path(ctx->pop(), this);
102 data_root<dll> library(allot<dll>(sizeof(dll)), this);
103 library->path = path.value();
104 ffi_dlopen(library.untagged());
105 ctx->push(library.value());
108 // look up a symbol in a native library
110 void factor_vm::primitive_dlsym() {
111 data_root<object> library(ctx->pop(), this);
112 data_root<byte_array> name(ctx->peek(), this);
115 symbol_char* sym = name->data<symbol_char>();
117 if (to_boolean(library.value())) {
118 dll* d = untag_check<dll>(library.value());
120 if (d->handle == NULL)
121 ctx->replace(false_object);
123 ctx->replace(allot_alien(ffi_dlsym(d, sym)));
125 ctx->replace(allot_alien(ffi_dlsym(NULL, sym)));
128 // look up a symbol in a native library
130 void factor_vm::primitive_dlsym_raw() {
131 data_root<object> library(ctx->pop(), this);
132 data_root<byte_array> name(ctx->peek(), this);
135 symbol_char* sym = name->data<symbol_char>();
137 if (to_boolean(library.value())) {
138 dll* d = untag_check<dll>(library.value());
140 if (d->handle == NULL)
141 ctx->replace(false_object);
143 ctx->replace(allot_alien(ffi_dlsym_raw(d, sym)));
145 ctx->replace(allot_alien(ffi_dlsym_raw(NULL, sym)));
148 // close a native library handle
149 void factor_vm::primitive_dlclose() {
150 dll* d = untag_check<dll>(ctx->pop());
151 if (d->handle != NULL)
155 void factor_vm::primitive_dll_validp() {
156 cell library = ctx->peek();
157 if (to_boolean(library))
158 ctx->replace(tag_boolean(untag_check<dll>(library)->handle != NULL));
160 ctx->replace(special_objects[OBJ_CANONICAL_TRUE]);
163 // gets the address of an object representing a C pointer
164 char* factor_vm::alien_offset(cell obj) {
166 case BYTE_ARRAY_TYPE:
167 return untag<byte_array>(obj)->data<char>();
169 return (char*)untag<alien>(obj)->address;
173 type_error(ALIEN_TYPE, obj);
174 return NULL; // can't happen