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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program 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
* of the License, or (at your option) any later version.
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sci/sci.h"
#include "sci/engine/state.h"
namespace Sci {
reg_t read_selector(SegManager *segMan, reg_t object, Selector selector_id, const char *file, int line) {
ObjVarRef address;
if (lookup_selector(segMan, object, selector_id, &address, NULL) != kSelectorVariable)
return NULL_REG;
else
return *address.getPointer(segMan);
}
void write_selector(SegManager *segMan, reg_t object, Selector selector_id, reg_t value, const char *fname, int line) {
ObjVarRef address;
if ((selector_id < 0) || (selector_id > (int)((SciEngine*)g_engine)->getKernel()->getSelectorNamesSize())) {
warning("Attempt to write to invalid selector %d of"
" object at %04x:%04x (%s L%d).", selector_id, PRINT_REG(object), fname, line);
return;
}
if (lookup_selector(segMan, object, selector_id, &address, NULL) != kSelectorVariable)
warning("Selector '%s' of object at %04x:%04x could not be"
" written to (%s L%d)", ((SciEngine*)g_engine)->getKernel()->getSelectorName(selector_id).c_str(), PRINT_REG(object), fname, line);
else
*address.getPointer(segMan) = value;
}
int invoke_selector(EngineState *s, reg_t object, int selector_id, SelectorInvocation noinvalid, int kfunct,
StackPtr k_argp, int k_argc, const char *fname, int line, int argc, ...) {
va_list argp;
int i;
int framesize = 2 + 1 * argc;
reg_t address;
int slc_type;
StackPtr stackframe = k_argp + k_argc;
stackframe[0] = make_reg(0, selector_id); // The selector we want to call
stackframe[1] = make_reg(0, argc); // Argument count
slc_type = lookup_selector(s->segMan, object, selector_id, NULL, &address);
if (slc_type == kSelectorNone) {
warning("Selector '%s' of object at %04x:%04x could not be invoked (%s L%d)",
((SciEngine*)g_engine)->getKernel()->getSelectorName(selector_id).c_str(), PRINT_REG(object), fname, line);
if (noinvalid == kStopOnInvalidSelector)
error("[Kernel] Not recoverable: VM was halted");
return 1;
}
if (slc_type == kSelectorVariable) // Swallow silently
return 0;
va_start(argp, argc);
for (i = 0; i < argc; i++) {
reg_t arg = va_arg(argp, reg_t);
stackframe[2 + i] = arg; // Write each argument
}
va_end(argp);
// Write "kernel" call to the stack, for debugging:
ExecStack *xstack;
xstack = add_exec_stack_entry(s, NULL_REG, NULL, NULL_REG, k_argc, k_argp - 1, 0, NULL_REG,
s->_executionStack.size()-1, SCI_XS_CALLEE_LOCALS);
xstack->selector = -42 - kfunct; // Evil debugging hack to identify kernel function
xstack->type = EXEC_STACK_TYPE_KERNEL;
// Now commit the actual function:
xstack = send_selector(s, object, object, stackframe, framesize, stackframe);
xstack->sp += argc + 2;
xstack->fp += argc + 2;
run_vm(s, 0); // Start a new vm
s->_executionStack.pop_back(); // Get rid of the extra stack entry
return 0;
}
static int _obj_locate_varselector(SegManager *segMan, Object *obj, Selector slc) {
// Determines if obj explicitly defines slc as a varselector
// Returns -1 if not found
byte *buf;
uint varnum;
if (getSciVersion() < SCI_VERSION_1_1) {
varnum = obj->variable_names_nr;
int selector_name_offset = varnum * 2 + SCRIPT_SELECTOR_OFFSET;
buf = obj->base_obj + selector_name_offset;
} else {
if (!(obj->getInfoSelector().offset & SCRIPT_INFO_CLASS))
obj = segMan->getObject(obj->getSuperClassSelector());
buf = (byte *)obj->base_vars;
varnum = obj->_variables[1].toUint16();
}
for (uint i = 0; i < varnum; i++)
if (READ_LE_UINT16(buf + (i << 1)) == slc) // Found it?
return i; // report success
return -1; // Failed
}
static int _class_locate_funcselector(Object *obj, Selector slc) {
// Determines if obj is a class and explicitly defines slc as a funcselector
// Does NOT say anything about obj's superclasses, i.e. failure may be
// returned even if one of the superclasses defines the funcselector.
int funcnum = obj->methods_nr;
int i;
for (i = 0; i < funcnum; i++)
if (obj->getFuncSelector(i) == slc) // Found it?
return i; // report success
return -1; // Failed
}
static SelectorType _lookup_selector_function(SegManager *segMan, int seg_id, Object *obj, Selector selector_id, reg_t *fptr) {
int index;
// "recursive" lookup
while (obj) {
index = _class_locate_funcselector(obj, selector_id);
if (index >= 0) {
if (fptr) {
*fptr = obj->getFunction(index);
}
return kSelectorMethod;
} else {
seg_id = obj->getSuperClassSelector().segment;
obj = segMan->getObject(obj->getSuperClassSelector());
}
}
return kSelectorNone;
}
SelectorType lookup_selector(SegManager *segMan, reg_t obj_location, Selector selector_id, ObjVarRef *varp, reg_t *fptr) {
Object *obj = segMan->getObject(obj_location);
Object *species;
int index;
bool oldScriptHeader = (getSciVersion() == SCI_VERSION_0_EARLY);
// Early SCI versions used the LSB in the selector ID as a read/write
// toggle, meaning that we must remove it for selector lookup.
if (oldScriptHeader)
selector_id &= ~1;
if (!obj) {
error("lookup_selector(): Attempt to send to non-object or invalid script. Address was %04x:%04x",
PRINT_REG(obj_location));
}
if (obj->isClass())
species = obj;
else
species = segMan->getObject(obj->getSpeciesSelector());
if (!obj) {
error("lookup_selector(): Error while looking up Species class.\nOriginal address was %04x:%04x. Species address was %04x:%04x",
PRINT_REG(obj_location), PRINT_REG(obj->getSpeciesSelector()));
return kSelectorNone;
}
index = _obj_locate_varselector(segMan, obj, selector_id);
if (index >= 0) {
// Found it as a variable
if (varp) {
varp->obj = obj_location;
varp->varindex = index;
}
return kSelectorVariable;
}
return _lookup_selector_function(segMan, obj_location.segment, obj, selector_id, fptr);
}
} // End of namespace Sci
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