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davepeck/BinaryDataScanner.h

Created April 27, 2009 04:35
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Revisions

  1. davepeck revised this gist Apr 27, 2009. 1 changed file with 211 additions and 0 deletions.
    211 changes: 211 additions & 0 deletions BinaryDataScanner.m
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,211 @@
    //
    // BinaryDataScanner.m
    //
    // Copyright 2009 Dave Peck <davepeck [at] davepeck [dot] org>. All rights reserved.
    // http://davepeck.org/
    //
    // This class makes it quite a bit easier to read sequential binary files in Objective-C.
    //
    // This code is released under the BSD license. If you use it in your product, please
    // let me know and, if possible, please put me in your credits.
    //


    #import "BinaryDataScanner.h"

    // NS byte order stuff is not useful here -- CF byte order ensures we're always dealing
    // with the right size on either 32 or 64 bit platforms.
    #import <CoreFoundation/CFByteOrder.h>


    @interface BinaryDataScanner (Private)

    -(id)initWithData:(NSData*)data littleEndian:(BOOL)littleEndian defaultEncoding:(NSStringEncoding)defaultEncoding;
    -(void)dealloc;
    -(NSException *)buildScanException;
    -(void)moveBy:(NSUInteger)count;

    @end


    @implementation BinaryDataScanner (Private)

    -(id)initWithData:(NSData*)initData littleEndian:(BOOL)isLittleEndian defaultEncoding:(NSStringEncoding)theDefaultEncoding
    {
    self = [super init];
    if (self != nil)
    {
    data = [initData retain];
    littleEndian = isLittleEndian;
    encoding = theDefaultEncoding;
    current = (const uint8_t *) [data bytes];
    scanRemain = [data length];
    }
    return self;
    }

    -(void)dealloc
    {
    [data release];
    data = nil;
    [super dealloc];
    }

    -(void)moveBy:(NSUInteger)count
    {
    if (scanRemain < count)
    {
    @throw [self buildScanException];
    }

    scanRemain -= count;
    current += count;
    }

    -(NSException *)buildScanException
    {
    return [NSException exceptionWithName:@"OrangeDataScanException" reason:@"Failure scanning desired information from the bytes." userInfo:nil];
    }

    @end


    @implementation BinaryDataScanner

    +(id)binaryDataScannerWithData:(NSData*)data littleEndian:(BOOL)littleEndian defaultEncoding:(NSStringEncoding)defaultEncoding
    {
    return [[[BinaryDataScanner alloc] initWithData:data littleEndian:littleEndian defaultEncoding:defaultEncoding] autorelease];
    }

    -(NSUInteger) remainingBytes
    {
    return scanRemain;
    }

    -(const uint8_t *) currentPointer
    {
    return current;
    }

    -(void) skipBytes:(NSUInteger)count
    {
    [self moveBy:count];
    }

    -(uint8_t) readByte
    {
    const uint8_t *old = current;
    [self moveBy:1];
    return old[0];
    }

    -(uint16_t) readWord
    {
    const uint16_t *word = (const uint16_t *) current;
    [self moveBy:sizeof(uint16_t)];
    if (littleEndian)
    {
    return CFSwapInt16LittleToHost(*word);
    }
    else
    {
    return CFSwapInt16BigToHost(*word);
    }
    }

    -(uint32_t) readDoubleWord
    {
    const uint32_t *dword = (const uint32_t *) current;
    [self moveBy:sizeof(uint32_t)];
    if (littleEndian)
    {
    return CFSwapInt32LittleToHost(*dword);
    }
    else
    {
    return CFSwapInt32BigToHost(*dword);
    }
    }

    -(NSString*) readNullTerminatedString
    {
    return [self readNullTerminatedStringWithEncoding:encoding];
    }

    -(NSString*) readNullTerminatedStringWithEncoding:(NSStringEncoding)overrideEncoding
    {
    return [self readStringUntilDelimiter:0 encoding:overrideEncoding];
    }

    -(NSString*) readStringUntilDelimiter:(uint8_t)delim
    {
    return [self readStringUntilDelimiter:delim encoding:encoding];
    }

    -(NSString*) readStringUntilDelimiter:(uint8_t)delim encoding:(NSStringEncoding)overrideEncoding
    {
    const uint8_t *start = current;
    NSUInteger stringLength = 0;

    while (scanRemain > 0 && *current != delim)
    {
    scanRemain -= 1;
    current += 1;
    stringLength += 1;
    }

    if (scanRemain < 1 || *current != delim)
    {
    @throw [self buildScanException];
    }

    // move over the delimiter
    [self moveBy:1];

    NSString *result = [[NSString alloc] initWithBytes:(const void*)start length:stringLength encoding:overrideEncoding];
    return [result autorelease];
    }

    -(NSString*) readStringOfLength:(NSUInteger)count handleNullTerminatorAfter:(BOOL)handleNull
    {
    return [self readStringOfLength:count handleNullTerminatorAfter:handleNull encoding:encoding];
    }

    -(NSString*) readStringOfLength:(NSUInteger)count handleNullTerminatorAfter:(BOOL)handleNull encoding:(NSStringEncoding)overrideEncoding
    {
    const uint8_t *start = current;
    [self moveBy:count];

    if (handleNull)
    {
    const uint8_t *nullTerminator = current;
    [self moveBy:1];
    if (*nullTerminator != 0)
    {
    @throw [self buildScanException];
    }
    }

    NSString *result = [[NSString alloc] initWithBytes:(const void*)start length:count encoding:overrideEncoding];
    return [result autorelease];
    }

    -(NSArray*) readArrayOfNullTerminatedStrings:(NSUInteger)count
    {
    return [self readArrayOfNullTerminatedStrings:count encoding:encoding];
    }

    -(NSArray*) readArrayOfNullTerminatedStrings:(NSUInteger)count encoding:(NSStringEncoding)overrideEncoding
    {
    NSMutableArray *array = [NSMutableArray arrayWithCapacity:count];

    for (NSUInteger i = 0; i < count; i++)
    {
    [array addObject:[self readNullTerminatedStringWithEncoding:overrideEncoding]];
    }

    return [array autorelease];
    }

    @end

  2. davepeck created this gist Apr 27, 2009.
    42 changes: 42 additions & 0 deletions BinaryDataScanner.h
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,42 @@
    //
    // BinaryDataScanner.m
    //
    // Copyright 2009 Dave Peck <davepeck [at] davepeck [dot] org>. All rights reserved.
    // http://davepeck.org/
    //
    // This class makes it quite a bit easier to read sequential binary files in Objective-C.
    //
    // This code is released under the BSD license. If you use it in your product, please
    // let me know and, if possible, please put me in your credits.
    //

    #import <UIKit/UIKit.h>

    @interface BinaryDataScanner : NSObject {
    BOOL littleEndian;
    NSStringEncoding encoding;
    NSData *data;
    const uint8_t *current;
    NSUInteger scanRemain;
    }

    +(id)binaryDataScannerWithData:(NSData*)data littleEndian:(BOOL)littleEndian defaultEncoding:(NSStringEncoding)defaultEncoding;

    -(NSUInteger) remainingBytes;
    -(const uint8_t *) currentPointer;

    -(void) skipBytes:(NSUInteger)count;
    -(uint8_t) readByte;
    -(uint16_t) readWord;
    -(uint32_t) readDoubleWord;
    -(NSString*) readNullTerminatedString;
    -(NSString*) readNullTerminatedStringWithEncoding:(NSStringEncoding)overrideEncoding;
    -(NSString*) readStringUntilDelimiter:(uint8_t)delim;
    -(NSString*) readStringUntilDelimiter:(uint8_t)delim encoding:(NSStringEncoding)overrideEncoding;
    -(NSString*) readStringOfLength:(NSUInteger)count handleNullTerminatorAfter:(BOOL)handleNull;
    -(NSString*) readStringOfLength:(NSUInteger)count handleNullTerminatorAfter:(BOOL)handleNull encoding:(NSStringEncoding)overrideEncoding;
    -(NSArray*) readArrayOfNullTerminatedStrings:(NSUInteger)count;
    -(NSArray*) readArrayOfNullTerminatedStrings:(NSUInteger)count encoding:(NSStringEncoding)overrideEncoding;

    @end