From 7e8ee5ed9cad6484e9f13f81731b102ced58402e Mon Sep 17 00:00:00 2001 From: Adam Carpenter Date: Tue, 9 Jul 2019 15:14:04 -0400 Subject: Init. --- meap/meap-code/ch6/ch6-memscan-1/src/main.rs | 14 ++++++++++++++ 1 file changed, 14 insertions(+) create mode 100755 meap/meap-code/ch6/ch6-memscan-1/src/main.rs (limited to 'meap/meap-code/ch6/ch6-memscan-1/src/main.rs') diff --git a/meap/meap-code/ch6/ch6-memscan-1/src/main.rs b/meap/meap-code/ch6/ch6-memscan-1/src/main.rs new file mode 100755 index 0000000..b92da20 --- /dev/null +++ b/meap/meap-code/ch6/ch6-memscan-1/src/main.rs @@ -0,0 +1,14 @@ +fn main() { + let mut n_nonzero = 0; + + for i in 0..10000 { + let ptr = i as *const u8; // <1> Convert `i` to a `pass:[*const T]`, a "`raw pointer`" of type `u8`. Raw pointers allow programmers to inspect raw memory addresses. We treat every address as a unit, ignoring the fact that most values span multiple bytes. + let byte_at_addr = unsafe { *ptr }; // <2> _Dereference_ the pointer. That is, read the value at address `i`. Another way of saying this is read the value being pointed to. + + if byte_at_addr != 0 { + n_nonzero += 1; + } + } + + println!("non-zero bytes in memory: {}", n_nonzero); +} \ No newline at end of file -- cgit v1.2.3