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authorAdam Carpenter <gitlab@53hor.net>2019-07-09 15:14:04 -0400
committerAdam Carpenter <gitlab@53hor.net>2019-07-09 15:14:04 -0400
commit7e8ee5ed9cad6484e9f13f81731b102ced58402e (patch)
tree5395402ab07bbb5a659dbd68c701e22a1227202f /meap/meap-code/ch6/ch6-memscan-1/src/main.rs
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Diffstat (limited to 'meap/meap-code/ch6/ch6-memscan-1/src/main.rs')
-rwxr-xr-xmeap/meap-code/ch6/ch6-memscan-1/src/main.rs14
1 files changed, 14 insertions, 0 deletions
diff --git a/meap/meap-code/ch6/ch6-memscan-1/src/main.rs b/meap/meap-code/ch6/ch6-memscan-1/src/main.rs
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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