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(Objective-C) Compress Large Binary File in BlocksCompresses a large binary file in blocks. Note: This example requires Chilkat v11.0.0 or greater.
#import <CkoFileAccess.h> #import <CkoCompression.h> BOOL success = NO; // This example assumes the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. CkoFileAccess *facSrc = [[CkoFileAccess alloc] init]; CkoFileAccess *facDest = [[CkoFileAccess alloc] init]; // Open a large binary file for reading. success = [facSrc OpenForRead: @"qa_data/bmp/big.bmp"]; if (success == NO) { NSLog(@"%@",facSrc.LastErrorText); return; } // If we compress in 64K chunks, find out how many blocks there will be. int blockSize = 65536; int numBlocks = [[facSrc GetNumBlocks: [NSNumber numberWithInt: blockSize]] intValue]; // Open an output file for the compressed data. success = [facDest OpenForWrite: @"c:/temp/qa_output/compressedBmp.dat"]; if (success == NO) { NSLog(@"%@",facDest.LastErrorText); return; } CkoCompression *compress = [[CkoCompression alloc] init]; compress.Algorithm = @"deflate"; NSData fileBytes; NSData compressedBytes; // Assuming numBlocks > 1 compress.FirstChunk = YES; compress.LastChunk = NO; int i = 0; while (i < numBlocks) { fileBytes = [facSrc ReadBlock: [NSNumber numberWithInt: i] blockSize: [NSNumber numberWithInt: blockSize]]; compressedBytes = [compress CompressBytes: fileBytes]; [facDest FileWrite: compressedBytes]; i = i + 1; compress.FirstChunk = NO; if (i == (numBlocks - 1)) { compress.LastChunk = YES; } } [facSrc FileClose]; [facDest FileClose]; NSLog(@"%@",@"Finished compressing file."); |
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