Add support for creating zip files

Basic zip files can be created (or appended to) by supplying the
path to a zip file and either paths to existing files or NSData
objects along with filenames.

SSZipArchive.h

@@ -7,10 +7,25 @@
 //
 
 #import <Foundation/Foundation.h>
+#import "minizip/zip.h"
 
-@interface SSZipArchive : NSObject
+@interface SSZipArchive : NSObject {
+@private
+    NSString *_path;
+    zipFile _zip;    
+}
 
+// Unzip
 + (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination;
 + (BOOL)unzipFileAtPath:(NSString *)path toDestination:(NSString *)destination overwrite:(BOOL)overwrite password:(NSString *)password error:(NSError **)error;
 
+// Zip
++ (BOOL)createZipFileAtPath:(NSString *)path withFilesAtPaths:(NSArray *)filenames;
+
+- (id)initWithPath:(NSString *)path;
+- (BOOL)open;
+- (BOOL)writeFile:(NSString *)path;
+- (BOOL)writeData:(NSData *)data filename:(NSString *)filename;
+- (BOOL)close;
+
 @end

SSZipArchive.m

@@ -148,6 +148,128 @@
 	return success;
 }
 
+#pragma mark - unzip
+
+#define CHUNK 16384
+
++ (BOOL)createZipFileAtPath:(NSString *)path withFilesAtPaths:(NSArray *)paths {
+    
+    BOOL success = NO;
+    
+    SSZipArchive *zipArchive = [[SSZipArchive alloc] initWithPath:path];
+    if ([zipArchive open]) {
+        
+        for (NSString *path in paths) {
+            [zipArchive writeFile:path];
+        }
+        
+        success = [zipArchive close];        
+    }
+    [zipArchive release];
+    
+    return success;
+}
+
+- (id)initWithPath:(NSString *)path
+{
+    self = [super init];
+    if (self) {
+        _path = [path copy];
+        // Initialization code here.
+    }
+    
+    return self;
+}
+
+- (void)dealloc {
+    [_path release];
+    [super dealloc];
+}
+
+- (BOOL)open {
+    
+    NSAssert((_zip == NULL), @"Attempting open an archive which is already open");    
+    
+    _zip = zipOpen([_path UTF8String], APPEND_STATUS_CREATE);
+    
+    return (NULL != _zip);
+}
+
+- (BOOL)writeFile:(NSString *)path {
+    NSAssert((_zip != NULL), @"Attempting to write to an archive which was never opened");     
+    
+    FILE *input = fopen([path UTF8String], "r");
+    if (NULL == input) {
+        return NO;
+    }
+    
+    zipOpenNewFileInZip(_zip, 
+                        [[path lastPathComponent] UTF8String],
+                        NULL, 
+                        NULL, 
+                        0, 
+                        NULL, 
+                        0, 
+                        NULL, 
+                        Z_DEFLATED, 
+                        Z_DEFAULT_COMPRESSION);
+    
+    void *buffer = malloc(CHUNK);
+    unsigned int len = 0;
+    
+    while (!feof(input)) { 
+        len = (unsigned int) fread(buffer, 1, CHUNK, input);            
+        zipWriteInFileInZip(_zip, buffer, len);
+    }
+    
+    zipCloseFileInZip(_zip);
+    
+    free(buffer);    
+    
+    return YES;
+}
+
+- (BOOL)writeData:(NSData *)data filename:(NSString *)filename {
+    NSAssert((_zip != NULL), @"Attempting to write to an archive which was never opened");     
+    NSAssert((data != NULL), @"Nil data"); 
+    
+    zipOpenNewFileInZip(_zip, 
+                        [filename UTF8String],
+                        NULL, 
+                        NULL, 
+                        0, 
+                        NULL, 
+                        0, 
+                        NULL, 
+                        Z_DEFLATED, 
+                        Z_DEFAULT_COMPRESSION);
+    
+    void *buffer = malloc(CHUNK);
+    unsigned int offset = 0;
+    NSUInteger length = [data length];    
+    unsigned int chunk_length;
+    
+    while (offset < length) { 
+        chunk_length = MIN(CHUNK, ((unsigned int) length)-offset);
+        [data getBytes:&buffer range:NSMakeRange(offset, chunk_length)];
+        zipWriteInFileInZip(_zip, buffer, chunk_length);
+        offset += chunk_length;
+    }
+    
+    zipCloseFileInZip(_zip);
+    
+    free(buffer);  
+    
+    return YES;    
+}
+
+- (BOOL)close {    
+    NSAssert((_zip != NULL), @"Attempting to close an archive which was never opened");
+    
+    zipClose(_zip, NULL);
+    
+    return YES;    
+}
 
 #pragma mark - Private
 

Tests/SSZipArchiveTests.m

@@ -11,21 +11,32 @@
 
 @interface SSZipArchiveTests ()
 - (NSString *)_cachesPath;
+- (NSString *)_createOutputPath;
 @end
 
 @implementation SSZipArchiveTests
 
-- (void)testBasicUnzipping {
-	NSString *zipPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestArchive" ofType:@"zip"];
-	NSString *outputPath = [[self _cachesPath] stringByAppendingPathComponent:@"basic"];
+- (void)testBasicZipping {
+	NSString *outputPath = [self _createOutputPath];
+    
+    NSArray *inputPaths = [NSArray arrayWithObjects:
+                           [outputPath stringByAppendingPathComponent:@"Readme.markdown"],
+                           [outputPath stringByAppendingPathComponent:@"LICENSE"],
+                           nil];
+    NSString *archivePath = [outputPath stringByAppendingPathComponent:@"CreatedArchive.zip"];
+    [SSZipArchive createZipFileAtPath:archivePath withFilesAtPaths:inputPaths];
  
 	NSFileManager *fileManager = [NSFileManager defaultManager];        
-	if (![fileManager fileExistsAtPath:outputPath]) {
-		[fileManager createDirectoryAtPath:outputPath withIntermediateDirectories:YES attributes:nil error:nil];
-	}
+	STAssertTrue([fileManager fileExistsAtPath:archivePath], @"Archive created");    
+}
+
+- (void)testBasicUnzipping {
+	NSString *zipPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestArchive" ofType:@"zip"];
+	NSString *outputPath = [self _createOutputPath];
 	
 	[SSZipArchive unzipFileAtPath:zipPath toDestination:outputPath];
 	
+	NSFileManager *fileManager = [NSFileManager defaultManager];    
 	NSString *testPath = [outputPath stringByAppendingPathComponent:@"Readme.markdown"];
 	STAssertTrue([fileManager fileExistsAtPath:testPath], @"Readme unzipped");
 	
@@ -40,6 +51,19 @@
 
 #pragma mark - Private
 
+- (NSString *)_createOutputPath {
+	NSString *outputPath = [[self _cachesPath] stringByAppendingPathComponent:@"basic"];
+    
+	NSFileManager *fileManager = [NSFileManager defaultManager];
+	if (![fileManager fileExistsAtPath:outputPath]) {
+		[fileManager createDirectoryAtPath:outputPath withIntermediateDirectories:YES attributes:nil error:nil];
+	}
+    
+//    NSLog(@"outputPath: %@", outputPath);
+    
+    return outputPath;
+}
+
 - (NSString *)_cachesPath {
 	return [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject]
 			stringByAppendingPathComponent:@"com.samsoffes.ssziparchive.tests"];