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);
16 return (char*)ptr->address;
21 type_error(ALIEN_TYPE, obj);
22 return NULL; // can't happen
28 cell factor_vm::allot_alien(cell delegate_, cell displacement) {
29 if (displacement == 0)
32 data_root<object> delegate(delegate_, this);
33 data_root<alien> new_alien(allot<alien>(sizeof(alien)), this);
35 if (TAG(delegate_) == ALIEN_TYPE) {
36 tagged<alien> delegate_alien = delegate.as<alien>();
37 displacement += delegate_alien->displacement;
38 new_alien->base = delegate_alien->base;
40 new_alien->base = delegate.value();
42 new_alien->displacement = displacement;
43 new_alien->expired = false_object;
44 new_alien->update_address();
46 return new_alien.value();
50 cell factor_vm::allot_alien(cell address) {
51 return allot_alien(false_object, address);
54 // make an alien pointing at an offset of another alien
56 void factor_vm::primitive_displaced_alien() {
57 cell alien = ctx->pop();
58 cell displacement = to_cell(ctx->pop());
64 ctx->push(allot_alien(alien, displacement));
67 type_error(ALIEN_TYPE, alien);
72 // address of an object representing a C pointer. Explicitly throw an error
73 // if the object is a byte array, as a sanity check.
74 // Allocates memory (from_unsigned_cell can allocate)
75 void factor_vm::primitive_alien_address() {
76 ctx->replace(from_unsigned_cell((cell)pinned_alien_offset(ctx->peek())));
79 // pop ( alien n ) from datastack, return alien's address plus n
80 void* factor_vm::alien_pointer() {
81 fixnum offset = to_fixnum(ctx->pop());
82 return alien_offset(ctx->pop()) + offset;
85 // define words to read/write values at an alien address
86 #define DEFINE_ALIEN_ACCESSOR(name, type, from, to) \
87 VM_C_API void primitive_alien_##name(factor_vm * parent) { \
88 parent->ctx->push(parent->from(*(type*)(parent->alien_pointer()))); \
90 VM_C_API void primitive_set_alien_##name(factor_vm * parent) { \
91 type* ptr = (type*)parent->alien_pointer(); \
92 type value = (type)parent->to(parent->ctx->pop()); \
96 EACH_ALIEN_PRIMITIVE(DEFINE_ALIEN_ACCESSOR)
98 // open a native library and push a handle
100 void factor_vm::primitive_dlopen() {
101 data_root<byte_array> path(ctx->pop(), this);
103 data_root<dll> library(allot<dll>(sizeof(dll)), this);
104 library->path = path.value();
105 ffi_dlopen(library.untagged());
106 ctx->push(library.value());
109 // look up a symbol in a native library
111 void factor_vm::primitive_dlsym() {
112 data_root<object> library(ctx->pop(), this);
113 data_root<byte_array> name(ctx->peek(), this);
116 symbol_char* sym = name->data<symbol_char>();
118 if (to_boolean(library.value())) {
119 dll* d = untag_check<dll>(library.value());
121 if (d->handle == NULL)
122 ctx->replace(false_object);
124 ctx->replace(allot_alien(ffi_dlsym(d, sym)));
126 ctx->replace(allot_alien(ffi_dlsym(NULL, sym)));
129 // look up a symbol in a native library
131 void factor_vm::primitive_dlsym_raw() {
132 data_root<object> library(ctx->pop(), this);
133 data_root<byte_array> name(ctx->peek(), this);
136 symbol_char* sym = name->data<symbol_char>();
138 if (to_boolean(library.value())) {
139 dll* d = untag_check<dll>(library.value());
141 if (d->handle == NULL)
142 ctx->replace(false_object);
144 ctx->replace(allot_alien(ffi_dlsym_raw(d, sym)));
146 ctx->replace(allot_alien(ffi_dlsym_raw(NULL, sym)));
149 // close a native library handle
150 void factor_vm::primitive_dlclose() {
151 dll* d = untag_check<dll>(ctx->pop());
152 if (d->handle != NULL)
156 void factor_vm::primitive_dll_validp() {
157 cell library = ctx->peek();
158 if (to_boolean(library))
159 ctx->replace(tag_boolean(untag_check<dll>(library)->handle != NULL));
161 ctx->replace(special_objects[OBJ_CANONICAL_TRUE]);
164 // gets the address of an object representing a C pointer
165 char* factor_vm::alien_offset(cell obj) {
167 case BYTE_ARRAY_TYPE:
168 return untag<byte_array>(obj)->data<char>();
170 return (char*)untag<alien>(obj)->address;
174 type_error(ALIEN_TYPE, obj);
175 return NULL; // can't happen