我正在运行以下代码
void blur(int height, int width, RGBTRIPLE image[height][width])
{
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
int div = 1;
if ( j + 1 < width - 1 && j + 1 > 0)
{
div++;
}
else
{
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
}
if ( i + 1 < height - 1 && i + 1 > 0)
{
div++;
}
else
{
image[i + 1][j].rgbtRed = 0;
image[i + 1][j].rgbtRed = 0;
image[i + 1][j].rgbtRed = 0;
}
if ( j + 1 < width - 1 && j + 1 > 0 && i + 1 < height - 1 && i + 1 > 0)
{
div++;
}
else
{
image[i + 1][j + 1].rgbtRed = 0;
image[i + 1][j + 1].rgbtRed = 0;
image[i + 1][j + 1].rgbtRed = 0;
}
if ( i - 1 < height - 1 && i - 1 > 0)
{
div++;
}
else
{
image[i - 1][j].rgbtRed = 0;
image[i - 1][j].rgbtRed = 0;
image[i - 1][j].rgbtRed = 0;
}
if ( i - 1 < height - 1 && i - 1 > 0 && j + 1 < width - 1 && j + 1 > 0)
{
div++;
}
else
{
image[i - 1][j + 1].rgbtRed = 0;
image[i - 1][j + 1].rgbtRed = 0;
image[i - 1][j + 1].rgbtRed = 0;
}
if ( j - 1 < width - 1 && j - 1 > 0)
{
div++;
}
else
{
image[i][j - 1].rgbtRed = 0;
image[i][j - 1].rgbtRed = 0;
image[i][j - 1].rgbtRed = 0;
}
if ( j - 1 < width - 1 && j - 1 > 0 && i + 1 < height - 1 && i + 1 > 0)
{
div++;
}
else
{
image[i + 1][j - 1].rgbtRed = 0;
image[i + 1][j - 1].rgbtRed = 0;
image[i + 1][j - 1].rgbtRed = 0;
}
if ( j - 1 < width - 1 && j - 1 > 0 && i - 1 < height - 1 && i - 1 > 0)
{
div++;
}
else
{
image[i - 1][j - 1].rgbtRed = 0;
image[i - 1][j - 1].rgbtRed = 0;
image[i - 1][j - 1].rgbtRed = 0;
}
int averageR = (float)(image[i][j].rgbtRed + image[i][j + 1].rgbtRed + image[i][j - 1].rgbtRed + image[i + 1][j].rgbtRed + image[i - 1][j].rgbtRed + image[i + 1][j + 1].rgbtRed + image[i + 1][j - 1].rgbtRed + image[i - 1][j + 1].rgbtRed + image[i + 1][j - 1].rgbtRed) / div;
int averageG = (float)(image[i][j].rgbtGreen + image[i][j + 1].rgbtGreen + image[i][j - 1].rgbtGreen + image[i + 1][j].rgbtGreen + image[i - 1][j].rgbtGreen + image[i + 1][j + 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen + image[i - 1][j + 1].rgbtGreen + image[i + 1][j - 1].rgbtGreen) / div;
int averageB = (float)(image[i][j].rgbtBlue + image[i][j + 1].rgbtBlue + image[i][j - 1].rgbtBlue + image[i + 1][j].rgbtBlue + image[i - 1][j].rgbtBlue + image[i + 1][j + 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue + image[i - 1][j + 1].rgbtBlue + image[i + 1][j - 1].rgbtBlue) / div;
image[i][j].rgbtRed = round(averageR);
image[i][j].rgbtGreen = round(averageG);
image[i][j].rgbtBlue = round(averageB);
}
}
return;
}
不幸的是，每次我尝试在模糊部分运行它时，都会显示以下消息：
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==8771==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x7f7a4ec2890a (pc 0x000000427faa bp 0x7ffd07cd9170 sp 0x7ffd07cd7560 T8771)
==8771==The signal is caused by a WRITE memory access.
#0 0x427fa9 (/home/ubuntu/pset4/filter/filter+0x427fa9)
#1 0x4232b1 (/home/ubuntu/pset4/filter/filter+0x4232b1)
#2 0x7f7a4db1bb96 (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
#3 0x402dd9 (/home/ubuntu/pset4/filter/filter+0x402dd9)
UndefinedBehaviorSanitizer can not provide additional info.
==8771==ABORTING
知道这可能是什么吗？
答案 0 :(得分：1)
您正在访问image二维数组的边界。
这发生在几个方面。
考虑循环：
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
}
}
i和j是可以分别从0和height以及0和width变化的索引。
但是对于这两个循环，您都可以访问此限制之外的内容。例如，如果j = width-1：
if ( j + 1 < width - 1 && j + 1 > 0)
{
div++;
}
else
{
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
}
第一个条件不能为width-1+1 > width -1，因此您将进入else部分，您将在其中访问
image[i][width].rgbtRed = 0;
那是越界的！
每当i = height-1：image[i + 1][j]之类的行将访问
image[height][j].rgbtRed = 0;
这也超出了范围。
超出范围访问数组会导致未定义的行为，这就是您的消毒器检测到的结果。
注意：尽管它与您要查找的错误无关，但您可能还想更正以下错误：
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
image[i][j + 1].rgbtRed = 0;
以及整个功能的类似部分。请注意，只有 Red 级别受到影响（三次！）；我想您打算还影响 Green 和 Blue 。
为您实现整个功能将超出此问题的范围，但是我将尝试建议如何进行操作。
对于每个像素，您当前
div++）边缘的元素 但是，是什么迫使您对所有元素进行求和？仅对实际上有用的元素求和！您已经有一个执行此总和的正确位置：这是您递增div的位置。
类似的东西：
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
int div = 1;
int curRedSum = 0, curGReenSum = 0, curBlueSum = 0;
if ( j + 1 < width - 1 && j + 1 > 0)
{
div++;
curRedSum += image[i][j + 1].rgbtRed;
curGreenSum += image[i][j + 1].rgbtGreen;
curBlueSum += image[i][j + 1].rgbtBlue;
}
if ( i + 1 < height - 1 && i + 1 > 0)
{
div++;
curRedSum += image[i+1][j].rgbtRed;
curGreenSum += image[i+1][j].rgbtGreen;
curBlueSum += image[i+1][j].rgbtBlue;
}
/* ... */
float averageR = (float)(curRedSum / ( float )div );
float averageG = (float)(curGreenSum / ( float )div );
float averageB = (float)(curBlueSum / ( float )div );
image[i][j].rgbtRed = round(averageR); // Shouldn't this assignemnt be performed on a copy of the image?
image[i][j].rgbtGreen = round(averageG); // Shouldn't this assignemnt be performed on a copy of the image?
image[i][j].rgbtBlue = round(averageB); // Shouldn't this assignemnt be performed on a copy of the image?
}
}
免责声明：该建议仅是一个提示。我不保证无需任何进一步调整即可编译和运行。