Besides application, GNUstep also support library, bundle and tool. Here is the demonstration of them. I'll write a regular expression library, which will be used by a tool.
Library is very simple. It's just a collection of classes. Unix usually have a built-in posix regular expression engine. Here, I wrap it into a library.
GNUmakefile
include $(GNUSTEP_MAKEFILES)/common.make LIBRARY_NAME = libRegEx libRegEx_OBJC_FILES = RegEx.m libRegEx_HEADERS = RegEx.h # The Headers that are to be installed libRegEx_HEADER_FILES = RegEx.h libRegEx_HEADER_FILES_DIR = . libRegEx_HEADER_FILES_INSTALL_DIR = RegEx include $(GNUSTEP_MAKEFILES)/library.make
That's almost the same as the GNUmakefile for application. It use LIBRARY_NAME instead APP_NAME. libRegEx_HEADER_FILES is the files to be installed as headers. libRegEx_HEADER_FILES_DIR is where the header files are in the source code. libRegEx_HEADER_FILES_INSTALL_DIR is where the headers to be install. Once this library is installed, the headers should be in GNUstep/Local/Library/Headers/RegEx/. There is a document for GNUstep Makefiles Package
Then here is a source code of RegEx class, which use C library
RegEx.h
#ifndef _RegEx_H_
#define _RegEx_H_
#include <Foundation/Foundation.h>
#include <regex.h>
@interface RegExPattern : NSObject
{
regex_t *preg;
/* Mask could be regex options. For example: REG_ICASE, REG_NEWLINE*/
unsigned int _mask;
}
+ (RegExPattern *) regexPattern: (NSString *) pattern;
- (id) initWithPattern: (NSString *) pattern options: (unsigned int) mask;
- (regex_t *) pattern;
@end
@interface RegExParser: NSObject
{
}
/* The return range is related to the whole string.
* Not related to the given range.
*/
+ (NSRange) rangeOfString:(NSString *) pattern
inString: (NSString *) string;
+ (NSRange) rangeOfPattern: (RegExPattern *) pattern
inString: (NSString *) string;
+ (NSRange) rangeOfString: (NSString *) pattern
inString: (NSString *) string
range: (NSRange) range;
+ (NSRange) rangeOfPattern: (RegExPattern *) pattern
inString: (NSString *) string
range: (NSRange) range;
@end
#endif /* _RegEx_H_ */
RegEx.m
#include "RegEx.h"
@implementation RegExPattern
+ (RegExPattern *) regexPattern: (NSString *) pattern
{
id object = [[RegExPattern alloc] initWithPattern: pattern
options: REG_EXTENDED];
return AUTORELEASE(object);
}
- (void) dealloc
{
regfree(preg);
free(preg); /* Not sure about this */
[super dealloc];
}
- (id) initWithPattern: (NSString *) pattern options: (unsigned int) mask
{
int result;
char errbuf[255];
_mask = mask;
preg = malloc(sizeof(regex_t));
result = regcomp(preg, [pattern cString], mask);
if (result != 0)
{
regerror(result, preg, errbuf, 255);
NSLog(@"RegEx Error: Couldn't compile regex %@: %s", pattern, errbuf);
regfree(preg);
return nil;
}
self = [super init];
return self;
}
- (regex_t *) pattern
{
return preg;
}
@end
static regmatch_t pmatch[1];
static char errbuf[255];
@implementation RegExParser
+ (NSRange) rangeOfString:(NSString *) pattern
inString: (NSString *) string
{
return [RegExParser rangeOfString: pattern
inString: string
range: NSMakeRange(0, [string length])];
}
+ (NSRange) rangeOfPattern: (RegExPattern *) pattern
inString: (NSString *) string
{
return [RegExParser rangeOfPattern: pattern
inString: string
range: NSMakeRange(0, [string length])];
}
+ (NSRange) rangeOfString: (NSString *) pattern
inString: (NSString *) string
range: (NSRange) range;
{
return [RegExParser rangeOfPattern: [RegExPattern regexPattern: pattern]
inString: string
range: range];
}
+ (NSRange) rangeOfPattern: (RegExPattern *) pattern
inString: (NSString *) string
range: (NSRange) range
{
int result;
int location, length;
int mask = 0;
/* Considering the situation of beginning line */
if (range.location != 0)
mask = mask | REG_NOTBOL;
if ((range.location + range.length) != [string length])
mask = mask | REG_NOTEOL;
result = regexec([pattern pattern],
[[string substringWithRange: range] cString],
1, pmatch, mask);
if (result != 0)
{
if (result != REG_NOMATCH)
{
regerror(result, [pattern pattern], errbuf, 255);
NSLog(@"RegEx Error: Couldn't match RegEx %s", errbuf);
}
return NSMakeRange(NSNotFound, 0);
}
location = range.location + pmatch->rm_so;
length = pmatch->rm_eo - pmatch->rm_so;
return NSMakeRange(location, length);
}
@end
There is nothing special in the RegEx source code. Just use C library from Objective-C source. After compilation and installation, I can use it as library.
Here is a little tool to test the library, called regex_test
GNUmakefile
include $(GNUSTEP_MAKEFILES)/common.make
TOOL_NAME = regex_test
regex_test_OBJC_FILES = \
main.m
regex_HEADERS =
ADDITIONAL_TOOL_LIBS += -lRegEx
include $(GNUSTEP_MAKEFILES)/tool.make
Again, use TOOL_NAME instead APP_NAME. ADDITIONAL_TOOL_LIBS include the new libRegEx library.
main.m
#include <Foundation/Foundation.h>
#include <RegEx/RegEx.h>
int main (int argc, const char **argv)
{
NSRange range;
NSAutoreleasePool *pool = [NSAutoreleasePool new];
range = [RegExParser rangeOfString: @"middle"
inString: @"head middle end"];
NSLog(@"%@", NSStringFromRange(range));
RELEASE(pool);
return 0;
}
Generally, GNUstep tools are the same as unix commands. You can type the command name directly with correct path environment variable, or you can use opentool to open GNUstep tools. opentool can avoid the problem of paths if any.
If you want to put all the tools, libraries in a project rather than many separated directories, you can use the subproject function of GNUstep-make.
Say I want to put everything in the ~/foo/ directory. Tool is in ~/foo/, and library is in ~/foo/RegEx/. Then the GNUmakefile of this tool can be:
GNUmakefile
include $(GNUSTEP_MAKEFILES)/common.make SUBPROJECTS = RegEx TOOL_NAME = regex_test regex_test_OBJC_FILES = \ main.m regex_HEADERS = ADDITIONAL_TOOL_LIBS += -lRegEx ADDITIONAL_LIB_DIRS += -LRegEx/$(GNUSTEP_OBJ_DIR) include $(GNUSTEP_MAKEFILES)/aggregate.make include $(GNUSTEP_MAKEFILES)/tool.make
SUBPROJECTS indicates the subproject is in the directory RegEx. ADDITIONAL_LIB_DIRS can access the compiled library under the directory RegEx so that I don't need to install the libRegEx first, then compile the tool. aggregate.make told gmake that there are sub-projects so that it will go into the sub-directories.
By doing this, all the source code is under the ~/foo/ directory. Here is the source code:RegEx-1-src.tar.gz
Instead of library, GNUstep support dynamically loaded bundle, which act as plug-in in other applications. Bundles can be loaded anytime, and library has to be linked at compilation.
Now, change the RegEx library into bundle.
GNUmakefile
include $(GNUSTEP_MAKEFILES)/common.make BUNDLE_NAME = RegEx BUNDLE_EXTENSION = .bundle BUNDLE_INSTALL_DIR = $(GNUSTEP_INSTALLATION_DIR)/Library/Bundles RegEx_OBJC_FILES = RegEx.m RegEx_HEADERS = RegEx.h RegEx_PRINCIPAL_CLASS = RegExParser include $(GNUSTEP_MAKEFILES)/bundle.make
Just change LIBRARY to BUNDLE. Most important one is the RegEx_PRINCIPAL_CLASS. You can get the principal class from a bundle without known its name. That's all for the bundle. No change in source code.
You have to access the bundle by its path, then get the class inside either by class name or by principal class. Here is the example:
GNUmakefile
include $(GNUSTEP_MAKEFILES)/common.make SUBPROJECTS = RegEx TOOL_NAME = regex_test regex_test_OBJC_FILES = main.m regex_HEADERS = include $(GNUSTEP_MAKEFILES)/aggregate.make include $(GNUSTEP_MAKEFILES)/tool.make
main.m
#include <Foundation/Foundation.h>
#include <RegEx/RegEx.h>
int main (int argc, const char **argv)
{
NSRange range;
NSAutoreleasePool *pool;
NSArray *paths;
NSFileManager *fileManager;
NSString *path;
NSBundle *bundle;
Class RegExClass;
int i;
pool = [NSAutoreleasePool new];
Search the bundle first
fileManager = [NSFileManager defaultManager];
/* Search for the bundles */
paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,
NSLocalDomainMask, YES);
for (i = 0; i < [paths count]; i++)
{
path = [[paths objectAtIndex: i] stringByAppendingPathComponent: @"Bundles/RegEx.bundle"];
if ([fileManager fileExistsAtPath: path])
break;
}
Get the bundle by its path. Then get the principalClass, which is the regular expression parser.
bundle = [NSBundle bundleWithPath: path]; RegExClass = [bundle principalClass];
Once the class is got, use it as normal class from libraries
range = [RegExClass rangeOfString: @"middle"
inString: @"head middle end"];
NSLog(@"%@", NSStringFromRange(range));
RELEASE(pool);
return 0;
}
Here is the source code: RegEx-2-src.tar.gz
The advantage of bundle is to load it dynamically. For example, if the application can't find the RegEx bundle, it can disable the functions at runtime. In this way, many function can be put into bundle, and depending on which bundle is installed, an application can offer different kind of function. Bundle can also be used as plug-in. For example, an application can have many bundles for different file formats. They only need to share a common header, either using protocal or using the same super class. An application can give a file to all the bundles, and ask which one can handle it. Then use the one to process the file format. The way to install header of bundles is the same as library. Use _HEADER_FILES in GNUmakefile to specify the headers to install.
Bundle is something really useful in GNUstep. You should take some time to read the header of it. You can even have some resources (images, sound) in the bundle.