CODEWITHSUNDEEP
cfilebinary
sfi
sfi

Reputation: 146

C binary file handling as an array

I would like to access a file as you would an array, rather than use fopen() and fgetc()/fputc() etc.

I'm looking for a method that will give me a pointer to the file which I can then treat as a big string(EOF terminated or a given length, whatever), I want the whole file in memory and need fast access to specific sections.

Is this possible? If so could you recommend a method? I'm also curious why this is not the default way of accessing files in c, is it because files are not generally stored in contiguous memory?

thanks for your help.

Upvotes: 0

Views: 245

Answers (1)

cnicutar
cnicutar

Reputation: 182619

You are looking for something called memory-mapped files. For example, if you're on Unix, look for mmap.

fd = open(...);    
p = mmap(NULL, buf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);

/* Use `p` like a pointer to some memory and fstat to find size. */

If you're on Win32 look for CreateFileMapping and MapViewOfFile.

Upvotes: 3

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