Current code only supports files up to 2GB in size

[jwkblades]

As it currently stands, the code only supports files up to 2GB in size, as it relies on read being able to return the entire file length in a single call. This also assumes that the underlying device is ready and capable of returning the entire file in a single shot. Both can be untrue under certain conditions.

Here is a quick patch to allow reading more than 2GB in size (just for the diff side of things currently):

index 628f1c1..481f00f 100644
--- a/bsdiff.c
+++ b/bsdiff.c
@@ -373,6 +373,19 @@ static int bz2_write(struct bsdiff_stream* stream, const void* buffer, int size)
        return 0;
 }
 
+static off_t readFileTo(int fd, off_t size, uint8_t* buf)
+{
+       off_t bytesRead = 0;
+       int inc = 0;
+       while (bytesRead < size)
+       {
+               inc = read(fd, buf + bytesRead, size - bytesRead);
+               if (inc > 0) bytesRead += inc;
+               else break;
+       }
+       return bytesRead;
+}
+
 int main(int argc,char *argv[])
 {
        int fd;
@@ -397,7 +410,7 @@ int main(int argc,char *argv[])
                ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
                ((old=malloc(oldsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0) ||
-               (read(fd,old,oldsize)!=oldsize) ||
+               (readFileTo(fd,oldsize,old)!=oldsize) ||
                (close(fd)==-1)) err(1,"%s",argv[1]);
 
 
@@ -407,7 +420,7 @@ int main(int argc,char *argv[])
                ((newsize=lseek(fd,0,SEEK_END))==-1) ||
                ((new=malloc(newsize+1))==NULL) ||
                (lseek(fd,0,SEEK_SET)!=0) ||
-               (read(fd,new,newsize)!=newsize) ||
+               (readFileTo(fd,newsize,new)!=newsize) ||
                (close(fd)==-1)) err(1,"%s",argv[2]);
 
        /* Create the patch file */