清空筛选条件
清空筛选条件

fread file with 4 bytes of prepended array size

3 次查看（过去 30 天）
A
A 2012-2-7
编辑： Matthew Phillips 2013-10-3
How do I read in a binary file(fread function) with data that has 4 bytes of data that specify the array size for each group of data. For example if I load the file using fread it would be 100x20 matrix but the first 4 bytes specify the area size(16 bytes). The file should read as 100x16. I'm currently using a for loop to read the file as start at byte 5, read 16, then start at byte 20, read 16, etc. Seems like their should be one line of code that says skip first 4 bytes of each data set. Thank you.
  1 个评论
A
A 2012-2-7
This works, but is it possible to optimize this code:
fseek(fid,4,'bof');
A =(fread(fid,[4,4],'*uint8',0,'n')).';
p=4;
for i= 1:100
p=p+20;
fseek(fid,p,'bof');
temp = (fread(fid,[4,4],'*uint8',0,'n')).';
A = cat(3,temp, A);
end

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Sean de Wolski
Sean de Wolski 2012-2-7
Yes, fseek will be your friend.
  2 个评论
Sean de Wolski
Sean de Wolski 2012-2-7
preallocating A to its final size would be good. Why not just read all of the file in at once and reshape() after?

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Programming 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by