UInt8 EXC_BAD_ACCESS | unfilteredImage2

本文介绍了UInt8 EXC_BAD_ACCESS的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有一个方法，将添加一个过滤器的图像。这工作得很好，直到几个月前，现在当我尝试使用这种方法的应用程序将崩溃的图像缓冲区。我创建缓冲区并将其设置为图像的数据，稍后访问特定索引会导致访问崩溃。我已经找了一两个小时，现在我确信有一些可以忽略的东西。我觉得有些东西正在被释放，不应该是。我正在使用xcode的ios DP 4预览版，我认为这个问题是从测试版的更新开始的，但我真的不确定。

这是行它位于第一个 for循环的中间附近

  m_PixelBuf [index + 2] = m_PixelBuf [index + 2] / * aRed * /;

通常情况下，它被设置为一个红色，我已经检查过了，它不应该离开缓冲区边界。（void）contrastWithContrast：（float）contrast colorWithColor：（float）color {
drawImage.image =原版的;
UIImage * unfilteredImage2 = [[[UIImage alloc] initWithCGImage：drawImage.image.CGImage] autorelease];
CGImageRef inImage = unfilteredImage2.CGImage;
CGContextRef ctx;
CFDataRef m_DataRef;
m_DataRef = CGDataProviderCopyData（CGImageGetDataProvider（inImage））;
UInt8 * m_PixelBuf =（UInt8 *）CFDataGetBytePtr（m_DataRef）;
int length = CFDataGetLength（m_DataRef）;
NSLog（@Photo Length：％i，length）;
//////对比度///////////
// NSLog（@Contrast：％f，contrast）;
int aRed;
int aGreen;
int aBlue;
for（int index = 0; index< length; index + = 4）{
aRed = m_PixelBuf [index + 2];
aGreen = m_PixelBuf [index + 1];
aBlue = m_PixelBuf [index]; （（aRed-128）*（对比度+100））/ 100）+128;

aRed =如果（aRed ;如果（aRed> 255）aRed = 255;
m_PixelBuf [index + 2] = m_PixelBuf [index + 2] / * aRed * /; //总是在这里崩溃

aGreen =（（（aGreen-128）*（contrast + 100 ））/ 100）+ 128; （aGreen ;如果（aGreen> 255）aGreen = 255;
m_PixelBuf [index + 1] = aGreen; （（（aBlue-128）*（对比度+100））/ 100）+128; b
$ b aBlue =
if（aBlue m_PixelBuf [index] = aBlue; （inImage），

$ b ctx = CGBitmapContextCreate（m_PixelBuf，
）CGImageGetHeight（inImage），
CGImageGetBitPerComponent ，
CGImageGetColorSpace（inImage），
CGImageGetBitmapInfo（inImage））;
CGImageRef imageRef = CGBitmapContextCreateImage（ctx）;
UIImage * rawImage = [[UIImage alloc] initWithCGImage：imageRef];
drawImage.image = rawImage;

[rawImage发行];
CGContextRelease（ctx）;
CFRelease（imageRef）;
CFRelease（m_DataRef）;

unfilteredImage2 = [[[UIImage alloc] initWithCGImage：drawImage.image.CGImage] autorelease];
inImage = unfilteredImage2.CGImage;
m_DataRef = CGDataProviderCopyData（CGImageGetDataProvider（inImage））;
m_PixelBuf =（UInt8 *）CFDataGetBytePtr（m_DataRef）;
length = CFDataGetLength（m_DataRef）;
$ b $ ///////彩色////////////////
（int index = 0; index< length; index + = 4）
{
//蓝
如果（（m_PixelBuf [指数] +（（int）的颜色* 2））> 255）{
m_PixelBuf [索引] = 255; （（m_PixelBuf [index] +（（int）color * 2））< 0）{
m_PixelBuf [index] = 0;
}
else {
m_PixelBuf [index] = m_PixelBuf [index] +（（int）color * 2）;
}

//绿色
如果（（m_PixelBuf [指数+ 1] +（（int）的颜色* 2））> 255）{
m_PixelBuf [ index + 1] = 255; （（m_PixelBuf [index + 1] +（（int）color * 2））< 0）{
m_PixelBuf [index + 1] = 0;
}
else {
m_PixelBuf [index + 1] = m_PixelBuf [index + 1] +（（int）color * 2）;
}

//红色
如果（（m_PixelBuf [指数+ 2] +（（int）的颜色* 2））> 255）{
m_PixelBuf [ index + 2] = 255; （（m_PixelBuf [index + 2] +（（int）color * 2））< 0）{
m_PixelBuf [index + 2] = 0;
}
else {
m_PixelBuf [index + 2] = m_PixelBuf [index + 2] +（（int）color * 2）;
}

// m_PixelBuf [index + 3] = 255; // Alpha
}

ctx = CGBitmapContextCreate（m_PixelBuf，
CGImageGetHeight（inImage），
CGImageGetBitsPerComponent（inImage），
CGImageGetBytesPerRow（inImage），
CGImageGetColorSpace（inImage），
CGImageGetBitmapInfo（inImage）） ;
imageRef = CGBitmapContextCreateImage（ctx）;
rawImage = [[UIImage alloc] initWithCGImage：imageRef];
drawImage.image = rawImage;
[rawImage发行];
CGContextRelease（ctx）;
CFRelease（imageRef）;
CFRelease（m_DataRef）;
//drawImage.image = unfilteredImage2;
willUpdate = YES;

$ b

对于任何额外的评论/信息抱歉我只是复制了整个方法。 / p>

谢谢，

Storealutes

解决方案

我有同样的问题。
您应该使用下面的代码来获取像素缓冲区的指针，而不是CFDataGetBytePtr（）。

$ p codeGImageRef cgImage = originalImage。 CGImage;
size_t width = CGImageGetWidth（cgImage）;
size_t height = CGImageGetHeight（cgImage）;
$ b $ char * buffer =（char *）malloc（sizeof（char）* width * height * 4）;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB（）;
CGContextRef cgContext = CGBitmapContextCreate（buffer，width，height，8，width * 4，colorSpace，kCGImageAlphaPremultipliedLast）;
CGContextSetBlendMode（cgContext，kCGBlendModeCopy）;
CGContextDrawImage（cgContext，CGRectMake（0.0f，0.0f，width，height），cgImage）;

free（buffer）;
CGContextRelease（cgContext）;
CGColorSpaceRelease（colorSpace）;

I have a method that will add a filter to an image. This worked fine until a couple of months ago, now when I try to use this method the application will crash on the images buffer. I create the buffer and set it to the image's data, accessing the specific index later causes a bad access crash. I have looked for the past hour or two, and now I am convinced there is something im overlooking. I think something is being released that should not be. I am using the ios DP 4 preview of xcode, and I think this problem started with the update to the beta, but I am really not sure.

This is the line it crashes on located near the middle of the first for loop

    m_PixelBuf[index+2] = m_PixelBuf[index+2]/*aRed*/;

Normally it is set to aRed Which I have checked, and it should not go out of the buffers boundaries.

    -(void)contrastWithContrast:(float )contrast colorWithColor:(float )color{
    drawImage.image = original;
    UIImage * unfilteredImage2 = [[[UIImage alloc]initWithCGImage:drawImage.image.CGImage]    autorelease];
    CGImageRef inImage = unfilteredImage2.CGImage;
    CGContextRef ctx;
    CFDataRef m_DataRef;
    m_DataRef = CGDataProviderCopyData(CGImageGetDataProvider(inImage));
    UInt8 * m_PixelBuf  = (UInt8 *) CFDataGetBytePtr(m_DataRef);
    int length = CFDataGetLength(m_DataRef);
    NSLog(@"Photo Length: %i",length);
    //////Contrast/////////////
    //NSLog(@"Contrast:%f",contrast);
    int aRed;
    int aGreen;
    int aBlue;
    for (int index = 0; index < length; index += 4){
    aRed = m_PixelBuf[index+2];
    aGreen = m_PixelBuf[index+1];
    aBlue = m_PixelBuf[index];

    aRed = (((aRed-128)*(contrast+100) )/100) + 128;
    if (aRed < 0) aRed = 0; if (aRed>255) aRed=255;
    m_PixelBuf[index+2] = m_PixelBuf[index+2]/*aRed*/;//Always crashes here

    aGreen = (((aGreen-128)*(contrast+100) )/100) + 128;
    if (aGreen < 0) aGreen = 0; if (aGreen>255) aGreen=255;
    m_PixelBuf[index+1] = aGreen;

    aBlue = (((aBlue-128)*(contrast+100) )/100) + 128;
    if (aBlue < 0) aBlue = 0; if (aBlue>255) aBlue=255;
    m_PixelBuf[index] = aBlue;
}
ctx = CGBitmapContextCreate(m_PixelBuf,
                            CGImageGetWidth( inImage ),
                            CGImageGetHeight( inImage ),
                            CGImageGetBitsPerComponent(inImage),
                            CGImageGetBytesPerRow(inImage ),
                            CGImageGetColorSpace(inImage ),
                            CGImageGetBitmapInfo(inImage) );
CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage* rawImage = [[UIImage alloc]initWithCGImage:imageRef];
drawImage.image = rawImage;

[rawImage release];
CGContextRelease(ctx);
CFRelease(imageRef);
CFRelease(m_DataRef);

unfilteredImage2 = [[[UIImage alloc]initWithCGImage:drawImage.image.CGImage] autorelease];
inImage = unfilteredImage2.CGImage;
m_DataRef = CGDataProviderCopyData(CGImageGetDataProvider(inImage));
m_PixelBuf = (UInt8 *) CFDataGetBytePtr(m_DataRef);
length = CFDataGetLength(m_DataRef);

///////Color////////////////
for (int index = 0; index < length; index += 4)
{
    //Blue
    if((m_PixelBuf[index] + ((int)color * 2))>255){
        m_PixelBuf[index] = 255;
    }else if((m_PixelBuf[index] + ((int)color * 2))<0){
        m_PixelBuf[index] = 0;
    }
    else{
        m_PixelBuf[index]=m_PixelBuf[index] + ((int)color * 2);
    }

    //Green
    if((m_PixelBuf[index+1] + ((int)color * 2))>255){
        m_PixelBuf[index+1] = 255;
    }else if((m_PixelBuf[index+1] + ((int)color * 2))<0){
        m_PixelBuf[index+1] = 0;
    }
    else{
        m_PixelBuf[index+1]=m_PixelBuf[index+1] + ((int)color * 2);
    }

    //Red
    if((m_PixelBuf[index+2] + ((int)color * 2))>255){
        m_PixelBuf[index+2] = 255;
    }else if((m_PixelBuf[index+2] + ((int)color * 2))<0){
        m_PixelBuf[index+2] = 0;
    }
    else{
        m_PixelBuf[index+2]=m_PixelBuf[index+2] + ((int)color * 2);
    }

    //m_PixelBuf[index+3]=255;//Alpha
}

ctx = CGBitmapContextCreate(m_PixelBuf,
                            CGImageGetWidth( inImage ),
                            CGImageGetHeight( inImage ),
                            CGImageGetBitsPerComponent(inImage),
                            CGImageGetBytesPerRow(inImage ),
                            CGImageGetColorSpace(inImage ),
                            CGImageGetBitmapInfo(inImage) );
imageRef = CGBitmapContextCreateImage (ctx);
rawImage = [[UIImage alloc]initWithCGImage:imageRef];
drawImage.image = rawImage;
[rawImage release];
CGContextRelease(ctx);
CFRelease(imageRef);
CFRelease(m_DataRef);
//drawImage.image = unfilteredImage2;
willUpdate = YES;
}

sorry for any extra comments/info I just copied the whole method in.

Thanks,

Storealutes

解决方案

I had same problem.You should use below code to get pointer to pixel buffer instead of CFDataGetBytePtr().

CGImageRef cgImage = originalImage.CGImage;
size_t width = CGImageGetWidth(cgImage);
size_t height = CGImageGetHeight(cgImage);

char *buffer = (char*)malloc(sizeof(char) * width * height * 4);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef cgContext = CGBitmapContextCreate(buffer, width, height, 8, width * 4, colorSpace, kCGImageAlphaPremultipliedLast);
CGContextSetBlendMode(cgContext, kCGBlendModeCopy);
CGContextDrawImage(cgContext, CGRectMake(0.0f, 0.0f, width, height), cgImage);

free(buffer);
CGContextRelease(cgContext);
CGColorSpaceRelease(colorSpace);

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