OOSystemDescriptionManager.m

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/*
 
OOPlanetDescriptionManager.h
 
Singleton class responsible for planet description data.
 
Oolite
Copyright (C) 2004-2013 Giles C Williams and contributors
 
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.
 
*/
 
#import "OOSystemDescriptionManager.h"
#import "OOStringParsing.h"
#import "OOCollectionExtractors.h"
#import "OOTypes.h"
#import "PlayerEntity.h"
#import "Universe.h"
#import "ResourceManager.h"
 
// character sequence which can't be in property name, system key or layer
// and is highly unlikely to be in a manifest identifier
static NSString * const kOOScriptedChangeJoiner = @"~|~";
 
// likely maximum number of planetinfo properties to be applied to a system
// just for efficiency - no harm in exceeding it
#define OO_LIKELY_PROPERTIES_PER_SYSTEM 50
 
@interface OOSystemDescriptionManager (OOPrivate)
- (void) setProperties:(NSDictionary *)properties inDescription:(OOSystemDescriptionEntry *)desc;
- (NSDictionary *) calculatePropertiesForSystemKey:(NSString *)key;
- (void) updateCacheEntry:(NSUInteger)i;
- (void) updateCacheEntry:(NSUInteger)i forProperty:(NSString *)property;
- (id) getProperty:(NSString *)property forSystemKey:(NSString *)key withUniversal:(BOOL)universal;
/* some planetinfo properties have two ways to specify
 * need to get the one with higher layer (if they're both at the same layer,
 * go with property1) */
- (id) getProperty:(NSString *)property1 orProperty:(NSString *)property2 forSystemKey:(NSString *)key withUniversal:(BOOL)universal;
 
- (void) saveScriptedChangeToProperty:(NSString *)property forSystemKey:(NSString *)key andLayer:(OOSystemLayer)layer toValue:(id)value fromManifest:(NSString *)manifest;
 
@end
 
static NSString *kOOSystemLayerProperty = @"layer";
 
@implementation OOSystemDescriptionManager
 
- (id) init
{
    self = [super init];
    if (self != nil)
    {
        universalProperties = [[NSMutableDictionary alloc] initWithCapacity:OO_LIKELY_PROPERTIES_PER_SYSTEM];
        interstellarSpace = [[OOSystemDescriptionEntry alloc] init];
        // assume specific interstellar settings are rare
        systemDescriptions = [[NSMutableDictionary alloc] initWithCapacity:OO_SYSTEM_CACHE_LENGTH+20];
        for (NSUInteger i=0;i<OO_SYSTEM_CACHE_LENGTH;i++)
        {
            propertyCache[i] = [[NSMutableDictionary alloc] initWithCapacity:OO_LIKELY_PROPERTIES_PER_SYSTEM];
            // hub count of 24 is considerably higher than occurs in
            // standard planetinfo
            neighbourCache[i] = [[NSMutableArray alloc] initWithCapacity:24];
        }
        propertiesInUse = [[NSMutableSet alloc] initWithCapacity:OO_LIKELY_PROPERTIES_PER_SYSTEM];
        scriptedChanges = [[NSMutableDictionary alloc] initWithCapacity:64];
    }
    return self;
}
 
- (void) dealloc
{
    DESTROY(universalProperties);
    DESTROY(interstellarSpace);
    DESTROY(systemDescriptions);
    for (NSUInteger i=0;i<OO_SYSTEM_CACHE_LENGTH;i++)
    {
        DESTROY(propertyCache[i]);
        DESTROY(neighbourCache[i]);
    }
    DESTROY(propertiesInUse);
    DESTROY(scriptedChanges);
    [super dealloc];
}
 
 
- (void) buildRouteCache
{
    NSUInteger i,j,k,jIndex,kIndex;
    // firstly, cache all coordinates
    for (i=0;i<OO_SYSTEM_CACHE_LENGTH;i++)
    {
        coordinatesCache[i] = PointFromString([propertyCache[i] oo_stringForKey:@"coordinates"]);
    }
    // now for each system find its neighbours
    for (i=0;i<OO_GALAXIES_AVAILABLE;i++)
    {
        // one galaxy at a time
        for (j=0;j<OO_SYSTEMS_PER_GALAXY;j++)
        {
            jIndex = j+(i*OO_SYSTEMS_PER_GALAXY);
            for (k=j+1;k<OO_SYSTEMS_PER_GALAXY;k++)
            {
                kIndex = k+(i*OO_SYSTEMS_PER_GALAXY);
                if (distanceBetweenPlanetPositions(coordinatesCache[jIndex].x,coordinatesCache[jIndex].y,coordinatesCache[kIndex].x,coordinatesCache[kIndex].y) <= MAX_JUMP_RANGE)
                {
                    // arrays are of system number only
                    [neighbourCache[jIndex] addObject:[NSNumber numberWithUnsignedInteger:k]];
                    [neighbourCache[kIndex] addObject:[NSNumber numberWithUnsignedInteger:j]];
                }
            }
        }
    }
 
}
 
 
- (void) setUniversalProperties:(NSDictionary *)properties
{
    [universalProperties addEntriesFromDictionary:properties];
    [propertiesInUse addObjectsFromArray:[properties allKeys]];
    for (NSUInteger i = 0; i<OO_SYSTEM_CACHE_LENGTH; i++)
    {
        [self updateCacheEntry:i];
    }
}
 
 
- (void) setInterstellarProperties:(NSDictionary *)properties
{
    [self setProperties:properties inDescription:interstellarSpace];
}
 
 
- (void) setProperties:(NSDictionary *)properties forSystemKey:(NSString *)key
{
    OOSystemDescriptionEntry *desc = [systemDescriptions objectForKey:key];
    if (desc == nil)
    {
        // create it
        desc = [[[OOSystemDescriptionEntry alloc] init] autorelease];
        [systemDescriptions setObject:desc forKey:key];
    }
    [self setProperties:properties inDescription:desc];
    [propertiesInUse addObjectsFromArray:[properties allKeys]];
 
    NSArray  *tokens = ScanTokensFromString(key);
    if ([tokens count] == 2 && [tokens oo_unsignedIntegerAtIndex:0] < OO_GALAXIES_AVAILABLE && [tokens oo_unsignedIntegerAtIndex:1] < OO_SYSTEMS_PER_GALAXY)
    {
        OOGalaxyID g = [tokens oo_unsignedIntegerAtIndex:0];
        OOSystemID s = [tokens oo_unsignedIntegerAtIndex:1];
        NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
        if (index >= OO_SYSTEM_CACHE_LENGTH)
        {
            OOLog(@"system.description.error",@"'%@' is an invalid system key. This is an internal error. Please report it.",key);
        }
        else
        {
            [self updateCacheEntry:index];
        }
    }
}
 
 
- (void) setProperty:(NSString *)property forSystemKey:(NSString *)key andLayer:(OOSystemLayer)layer toValue:(id)value fromManifest:(NSString *)manifest
{
    OOSystemDescriptionEntry *desc = [systemDescriptions objectForKey:key];
    if (desc == nil)
    {
        // create it
        desc = [[[OOSystemDescriptionEntry alloc] init] autorelease];
        [systemDescriptions setObject:desc forKey:key];
    }
    [desc setProperty:property forLayer:layer toValue:value];
    [propertiesInUse addObject:property];
 
    NSArray  *tokens = ScanTokensFromString(key);
    if ([tokens count] == 2 && [tokens oo_unsignedIntegerAtIndex:0] < OO_GALAXIES_AVAILABLE && [tokens oo_unsignedIntegerAtIndex:1] < OO_SYSTEMS_PER_GALAXY)
    {
        [self saveScriptedChangeToProperty:property forSystemKey:key andLayer:layer toValue:value fromManifest:manifest];
    
        OOGalaxyID g = [tokens oo_unsignedIntegerAtIndex:0];
        OOSystemID s = [tokens oo_unsignedIntegerAtIndex:1];
        NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
        if (index >= OO_SYSTEM_CACHE_LENGTH)
        {
            OOLog(@"system.description.error",@"'%@' is an invalid system key. This is an internal error. Please report it.",key);
        }
        else
        {
            [self updateCacheEntry:index forProperty:property];
        }
    }
    // for interstellar updates, save but don't update cache
    else if ([tokens count] == 4 && [tokens oo_unsignedIntegerAtIndex:1] < OO_GALAXIES_AVAILABLE && [tokens oo_unsignedIntegerAtIndex:2] < OO_SYSTEMS_PER_GALAXY && [tokens oo_unsignedIntegerAtIndex:3] < OO_SYSTEMS_PER_GALAXY)
    {
        [self saveScriptedChangeToProperty:property forSystemKey:key andLayer:layer toValue:value fromManifest:manifest];
    }
}
 
 
- (void) saveScriptedChangeToProperty:(NSString *)property forSystemKey:(NSString *)key andLayer:(OOSystemLayer)layer toValue:(id)value fromManifest:(NSString *)manifest
{
    // if OXP doesn't have a manifest, cancel saving the change
    if (manifest == nil)
    {
        return;
    }
//  OOLog(@"saving change",@"%@ %@ %@ %d",manifest,key,property,layer);
    NSArray *overrideKey = [NSArray arrayWithObjects:manifest,key,property,[[NSNumber numberWithInt:layer] stringValue],nil];
    // Obj-C copes with NSArray keys to dictionaries fine, but the
    // plist format doesn't, so they can't be saved.
    NSString *overrideKeyStr = [overrideKey componentsJoinedByString:kOOScriptedChangeJoiner];
    if (value != nil)
    {
        [scriptedChanges setObject:value forKey:overrideKeyStr];
    }
    else
    {
        [scriptedChanges removeObjectForKey:overrideKeyStr];
    }
}
 
 
- (void) importScriptedChanges:(NSDictionary *)scripted
{
    NSArray *key = nil;
    NSString *keyStr = nil;
    NSString *manifest = nil;
    foreachkey(keyStr, scripted)
    {
        key = [keyStr componentsSeparatedByString:kOOScriptedChangeJoiner];
        if ([key count] == 4)
        {
            manifest = [key oo_stringAtIndex:0];
            if ([ResourceManager manifestForIdentifier:manifest] != nil)
            {
//              OOLog(@"importing",@"%@ -> %@",keyStr,[scripted objectForKey:keyStr]);
                [self setProperty:[key oo_stringAtIndex:2]
                     forSystemKey:[key oo_stringAtIndex:1]
                         andLayer:[key oo_intAtIndex:3]
                          toValue:[scripted objectForKey:keyStr]
                     fromManifest:manifest];
                // and doing this set stores it into the manager's copy
                // of scripted changes
                // this means in theory we could import more than one
            }
            // else OXP not installed, do not load
        }
        else
        {
            OOLog(@"systemManager.import",@"Key '%@' has unexpected format - skipping",keyStr);
        }
    }
 
}
 
 
// import of the old local_planetinfo_overrides dictionary
- (void) importLegacyScriptedChanges:(NSDictionary *)scripted
{
    NSString *systemKey = nil;
    NSString *propertyKey = nil;
    NSString *defaultManifest = @"org.oolite.oolite";
    
    foreachkey(systemKey,scripted)
    {
        NSDictionary *legacyChanges = [scripted oo_dictionaryForKey:systemKey];
        if ([legacyChanges objectForKey:@"sun_gone_nova"] != nil)
        {
            // then this is a change to import even if we don't know
            // if the OXP is still installed
            foreachkey (propertyKey, legacyChanges)
            {
                [self setProperty:propertyKey
                     forSystemKey:systemKey
                         andLayer:OO_LAYER_OXP_DYNAMIC
                          toValue:[legacyChanges objectForKey:propertyKey]
                     fromManifest:defaultManifest];
            }
            /* Fix for older savegames not having a larger sun radius
             * property set from the Nova mission. */
            id sr = [self getProperty:@"sun_radius" forSystemKey:systemKey];
            float sr_num = [sr floatValue];
            if (sr_num < 600000) {
                // fix sun radius values
                [self setProperty:@"sun_radius"
                     forSystemKey:systemKey
                         andLayer:OO_LAYER_OXP_DYNAMIC
                          toValue:[NSNumber numberWithFloat:sr_num+600000.0f]
                     fromManifest:defaultManifest];
            }
        }
    }
 
}
 
 
- (NSDictionary *) exportScriptedChanges
{
    return [[scriptedChanges copy] autorelease];
}
 
 
- (NSDictionary *) getPropertiesForCurrentSystem
{
    OOSystemID s = [UNIVERSE currentSystemID];
    if (s >= 0)
    {
        NSUInteger index = ([PLAYER galaxyNumber] * OO_SYSTEMS_PER_GALAXY) + s;
        if (index >= OO_SYSTEM_CACHE_LENGTH)
        {
            OOLog(@"system.description.error",@"'%lu' is an invalid system index for the current system. This is an internal error. Please report it.",index);
            return [NSDictionary dictionary];
        }
        return propertyCache[index];
    }
    else
    {
        OOLog(@"system.description.error", @"%@", @"getPropertiesForCurrentSystem called while player in interstellar space. This is an internal error. Please report it.");
        // this shouldn't be called for interstellar space
        return [NSDictionary dictionary];
    }
}
 
 
- (NSDictionary *) getPropertiesForSystemKey:(NSString *)key
{
    NSArray  *tokens = ScanTokensFromString(key);
    if ([tokens count] == 2 && [tokens oo_unsignedIntegerAtIndex:0] < OO_GALAXIES_AVAILABLE && [tokens oo_unsignedIntegerAtIndex:1] < OO_SYSTEMS_PER_GALAXY)
    {
        OOGalaxyID g = [tokens oo_unsignedIntegerAtIndex:0];
        OOSystemID s = [tokens oo_unsignedIntegerAtIndex:1];
        NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
        if (index >= OO_SYSTEM_CACHE_LENGTH)
        {
            OOLog(@"system.description.error",@"'%@' is an invalid system key. This is an internal error. Please report it.",key);
            return [NSDictionary dictionary];
        }
        return propertyCache[index];
    }
    // interstellar spaces aren't cached
    return [self calculatePropertiesForSystemKey:key];
}
 
 
- (NSDictionary *) getPropertiesForSystem:(OOSystemID)s inGalaxy:(OOGalaxyID)g
{
    NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
    if (index >= OO_SYSTEM_CACHE_LENGTH)
    {
        OOLog(@"system.description.error",@"'%u, %u' is an invalid system. This is an internal error. Please report it.",g,s);
        return [NSDictionary dictionary];
    }
    return propertyCache[index];
}
 
 
- (id) getProperty:(NSString *)property forSystemKey:(NSString *)key
{
    return [self getProperty:property forSystemKey:key withUniversal:YES];
}
 
- (id) getProperty:(NSString *)property forSystem:(OOSystemID)s inGalaxy:(OOGalaxyID)g
{
    if (s < 0)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return nil;
    }
    NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
    if (index >= OO_SYSTEM_CACHE_LENGTH)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return nil;
    }
    return [propertyCache[index] objectForKey:property];
}
 
 
- (id) getProperty:(NSString *)property forSystemKey:(NSString *)key withUniversal:(BOOL)universal
{
    OOSystemDescriptionEntry *desc = nil;
    if (EXPECT_NOT([key isEqualToString:@"interstellar"]))
    {
        desc = interstellarSpace;
    }
    else
    {
        desc = [systemDescriptions objectForKey:key];
    }
    if (desc == nil)
    {
        return nil;
    }
    id result = nil;
    result = [desc getProperty:property forLayer:OO_LAYER_OXP_PRIORITY];
    if (result == nil)
    {
        result = [desc getProperty:property forLayer:OO_LAYER_OXP_DYNAMIC];
    }
    if (result == nil)
    {
        result = [desc getProperty:property forLayer:OO_LAYER_OXP_STATIC];
    }
    if (result == nil && universal)
    {
        result = [universalProperties objectForKey:property];
    }
    if (result == nil)
    {
        result = [desc getProperty:property forLayer:OO_LAYER_CORE];
    }
    return result;
}
 
 
- (id) getProperty:(NSString *)property1 orProperty:(NSString *)property2 forSystemKey:(NSString *)key withUniversal:(BOOL)universal
{
    OOSystemDescriptionEntry *desc = [systemDescriptions objectForKey:key];
    if (desc == nil)
    {
        return nil;
    }
    id result = nil;
    result = [desc getProperty:property1 forLayer:OO_LAYER_OXP_PRIORITY];
    if (result == nil)
    {
        result = [desc getProperty:property2 forLayer:OO_LAYER_OXP_PRIORITY];
    }
    if (result == nil)
    {
        result = [desc getProperty:property1 forLayer:OO_LAYER_OXP_DYNAMIC];
    }
    if (result == nil)
    {
        result = [desc getProperty:property2 forLayer:OO_LAYER_OXP_DYNAMIC];
    }
    if (result == nil)
    {
        result = [desc getProperty:property1 forLayer:OO_LAYER_OXP_STATIC];
    }
    if (result == nil)
    {
        result = [desc getProperty:property2 forLayer:OO_LAYER_OXP_STATIC];
    }
    if (universal)
    {
        if (result == nil)
        {
            result = [universalProperties objectForKey:property1];
        }
        if (result == nil)
        {
            result = [universalProperties objectForKey:property2];
        }
    }
    if (result == nil)
    {
        result = [desc getProperty:property1 forLayer:OO_LAYER_CORE];
    }
    if (result == nil)
    {
        result = [desc getProperty:property2 forLayer:OO_LAYER_CORE];
    }
    return result;
}
 
 
- (void) setProperties:(NSDictionary *)properties inDescription:(OOSystemDescriptionEntry *)desc
{
    OOSystemLayer layer = [properties oo_unsignedIntForKey:kOOSystemLayerProperty defaultValue:OO_LAYER_OXP_STATIC];
    if (layer > OO_LAYER_OXP_PRIORITY)
    {
        OOLog(@"system.description.error",@"Layer %u is not a valid layer number in system information.",layer);
        layer = OO_LAYER_OXP_PRIORITY;
    }
    NSString *key = nil;
    foreachkey(key, properties)
    {
        if (![key isEqualToString:kOOSystemLayerProperty])
        {
            [propertiesInUse addObject:key];
            [desc setProperty:key forLayer:layer toValue:[properties objectForKey:key]];
        }
    }
}
 
 
- (NSDictionary *) calculatePropertiesForSystemKey:(NSString *)key
{
    NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:OO_LIKELY_PROPERTIES_PER_SYSTEM];
    NSString *property = nil;
    id val = nil;
    BOOL interstellar = [key hasPrefix:@"interstellar:"];
    foreach (property, propertiesInUse)
    {
        // don't use universal properties on interstellar specific regions
        val = [self getProperty:property forSystemKey:key withUniversal:!interstellar];
 
        if (val != nil)
        {
            [dict setObject:val forKey:property];
        }
        else if (interstellar)
        {
            // interstellar is always overridden by specific regions
            // universal properties for interstellar get picked up here
            val = [self getProperty:property forSystemKey:@"interstellar"];
            if (val != nil)
            {
                [dict setObject:val forKey:property];
            }
        }
    }
    return dict;
}
 
 
- (void) updateCacheEntry:(NSUInteger)i
{
    NSAssert(i < OO_SYSTEM_CACHE_LENGTH,@"Invalid cache entry number");
    NSString *key = [NSString stringWithFormat:@"%lu %lu",i/OO_SYSTEMS_PER_GALAXY,i%OO_SYSTEMS_PER_GALAXY];
    NSDictionary *current = [self calculatePropertiesForSystemKey:key];
 
    [propertyCache[i] removeAllObjects];
    [propertyCache[i] addEntriesFromDictionary:current];
}
 
 
- (void) updateCacheEntry:(NSUInteger)i forProperty:(NSString *)property
{
    NSAssert(i < OO_SYSTEM_CACHE_LENGTH,@"Invalid cache entry number");
    NSString *key = [NSString stringWithFormat:@"%lu %lu",i/OO_SYSTEMS_PER_GALAXY,i%OO_SYSTEMS_PER_GALAXY];
    id current = [self getProperty:property forSystemKey:key];
    if (current == nil)
    {
        [propertyCache[i] removeObjectForKey:property];
    }
    else
    {
        [propertyCache[i] setObject:current forKey:property];
    }
}
 
 
- (NSPoint) getCoordinatesForSystem:(OOSystemID)s inGalaxy:(OOGalaxyID)g
{
    if (s < 0)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return (NSPoint){0,0};
    }
    NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
    if (index >= OO_SYSTEM_CACHE_LENGTH)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return (NSPoint){0,0};
    }
    return coordinatesCache[index];
}
 
 
- (NSArray *) getNeighbourIDsForSystem:(OOSystemID)s inGalaxy:(OOGalaxyID)g
{
    if (s < 0)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return nil;
    }
    NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
    if (index >= OO_SYSTEM_CACHE_LENGTH)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return nil;
    }
 
    return neighbourCache[index];
}
 
 
- (Random_Seed) getRandomSeedForCurrentSystem
{
    if ([UNIVERSE currentSystemID] < 0)
    {
        return kNilRandomSeed;
    }
    else
    {
        OOSystemID s = [UNIVERSE currentSystemID];
        NSUInteger index = ([PLAYER galaxyNumber] * OO_SYSTEMS_PER_GALAXY) + s;
        if (index >= OO_SYSTEM_CACHE_LENGTH)
        {
            OOLog(@"system.description.error",@"'%lu' is an invalid system index for the current system. This is an internal error. Please report it.",(unsigned long)index);
            return kNilRandomSeed;
        }
        return RandomSeedFromString([propertyCache[index] oo_stringForKey:@"random_seed"]);
    }
}
 
 
- (Random_Seed) getRandomSeedForSystem:(OOSystemID)s inGalaxy:(OOGalaxyID)g
{
    if (s < 0)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return kNilRandomSeed;
    }
    NSUInteger index = (g * OO_SYSTEMS_PER_GALAXY) + s;
    if (index >= OO_SYSTEM_CACHE_LENGTH)
    {
        OOLog(@"system.description.error",@"'%d %d' is an invalid system key. This is an internal error. Please report it.",g,s);
        return kNilRandomSeed;
    }
    return RandomSeedFromString([propertyCache[index] oo_stringForKey:@"random_seed"]);
}
 
 
@end
 
 
@interface OOSystemDescriptionEntry (OOPrivate)
- (id) validateProperty:(NSString *)property withValue:(id)value;
@end
 
@implementation OOSystemDescriptionEntry 
 
- (id) init
{
    self = [super init];
    if (self != nil)
    {
        for (NSUInteger i=0;i<OO_SYSTEM_LAYERS;i++)
        {
            layers[i] = [[NSMutableDictionary alloc] initWithCapacity:OO_LIKELY_PROPERTIES_PER_SYSTEM];
        }
    }
    return self;
}
 
 
- (void) dealloc
{
    for (NSUInteger i=0;i<OO_SYSTEM_LAYERS;i++)
    {
        DESTROY(layers[i]);
    }
    [super dealloc];
}
 
 
- (void) setProperty:(NSString *)property forLayer:(OOSystemLayer)layer toValue:(id)value
{
    if (value == nil)
    {
        [layers[layer] removeObjectForKey:property];
    }
    else
    {
        // validate type of object for certain properties
        value = [self validateProperty:property withValue:value];
        // if it's nil now, validation failed and could not be recovered
        // so don't actually set anything
        if (value != nil)
        {
            [layers[layer] setObject:value forKey:property];
        }
    }
}
 
 
- (id) getProperty:(NSString *)property forLayer:(OOSystemLayer)layer
{
    return [layers[layer] objectForKey:property];
}
 
 
/* Mostly the rest of the game gets a system dictionary from
 * [UNIVERSE currentSystemData] or similar, which means that it uses
 * safe methods like oo_stringForKey: - a few things use a direct call
 * to getProperty for various reasons, so need some type validation
 * here instead. */
- (id) validateProperty:(NSString *)property withValue:(id)value
{
    if ([property isEqualToString:@"coordinates"])
    {
        // must be a string with two numbers in it
        // TODO: convert two element arrays
        if (![value isKindOfClass:[NSString class]])
        {
            OOLog(@"system.description.error",@"'%@' is not a valid format for coordinates",value);
            return nil;
        }
        NSArray     *tokens = ScanTokensFromString((NSString *)value);
        if ([tokens count] != 2)
        {
            OOLog(@"system.description.error",@"'%@' is not a valid format for coordinates (must have exactly two numbers)",value);
            return nil;
        }
    } 
    else if ([property isEqualToString:@"radius"] || [property isEqualToString:@"government"]) 
    { 
        // read in a context which expects a string, but it's a string representation of a number
        if (![value isKindOfClass:[NSString class]])
        {
            if ([value isKindOfClass:[NSNumber class]])
            {
                return [value stringValue];
            }
            else
            {
                OOLog(@"system.description.error",@"'%@' is not a valid value for '%@' (string required)",value,property);
                return nil;
            }
        }
    }
    else if ([property isEqualToString:@"inhabitant"] || [property isEqualToString:@"inhabitants"] || [property isEqualToString:@"name"] ) 
    {
        // read in a context which expects a string
        if (![value isKindOfClass:[NSString class]])
        {
            OOLog(@"system.description.error",@"'%@' is not a valid value for '%@' (string required)",value,property);
            return nil;
        }
    }
 
    return value;
}
 
@end