From 7e8ee5ed9cad6484e9f13f81731b102ced58402e Mon Sep 17 00:00:00 2001
From: Adam Carpenter <gitlab@53hor.net>
Date: Tue, 9 Jul 2019 15:14:04 -0400
Subject: Init.
---
meap/meap-code/ch5/ch5-q/Cargo.lock | 127 ++++++++++++++++++++++++++++++++++++
meap/meap-code/ch5/ch5-q/Cargo.toml | 7 ++
meap/meap-code/ch5/ch5-q/src/lib.rs | 76 +++++++++++++++++++++
3 files changed, 210 insertions(+)
create mode 100755 meap/meap-code/ch5/ch5-q/Cargo.lock
create mode 100755 meap/meap-code/ch5/ch5-q/Cargo.toml
create mode 100755 meap/meap-code/ch5/ch5-q/src/lib.rs
(limited to 'meap/meap-code/ch5/ch5-q')
diff --git a/meap/meap-code/ch5/ch5-q/Cargo.lock b/meap/meap-code/ch5/ch5-q/Cargo.lock
new file mode 100755
index 0000000..3ac932f
--- /dev/null
+++ b/meap/meap-code/ch5/ch5-q/Cargo.lock
@@ -0,0 +1,127 @@
+[root]
+name = "ch5-q"
+version = "0.1.0"
+dependencies = [
+ "num 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "bitflags"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "fuchsia-zircon"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "fuchsia-zircon-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "fuchsia-zircon-sys"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "num"
+version = "0.1.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-bigint 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-complex 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-integer 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-iter 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-rational 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-bigint"
+version = "0.1.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-integer 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.1.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-iter"
+version = "0.1.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-integer 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.1.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-bigint 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-integer 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.1.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "rand"
+version = "0.3.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "fuchsia-zircon 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rustc-serialize"
+version = "0.3.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[metadata]
+"checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
+"checksum fuchsia-zircon 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f6c0581a4e363262e52b87f59ee2afe3415361c6ec35e665924eb08afe8ff159"
+"checksum fuchsia-zircon-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "43f3795b4bae048dc6123a6b972cadde2e676f9ded08aef6bb77f5f157684a82"
+"checksum libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)" = "5ba3df4dcb460b9dfbd070d41c94c19209620c191b0340b929ce748a2bcd42d2"
+"checksum num 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "a311b77ebdc5dd4cf6449d81e4135d9f0e3b153839ac90e648a8ef538f923525"
+"checksum num-bigint 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "8fd0f8dbb4c0960998958a796281d88c16fbe68d87b1baa6f31e2979e81fd0bd"
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+"checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
diff --git a/meap/meap-code/ch5/ch5-q/Cargo.toml b/meap/meap-code/ch5/ch5-q/Cargo.toml
new file mode 100755
index 0000000..ffd0826
--- /dev/null
+++ b/meap/meap-code/ch5/ch5-q/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "ch5-q"
+version = "0.1.0"
+authors = ["Tim McNamara <code@timmcnamara.co.nz>"]
+
+[dependencies]
+num = "*"
\ No newline at end of file
diff --git a/meap/meap-code/ch5/ch5-q/src/lib.rs b/meap/meap-code/ch5/ch5-q/src/lib.rs
new file mode 100755
index 0000000..d05ca3a
--- /dev/null
+++ b/meap/meap-code/ch5/ch5-q/src/lib.rs
@@ -0,0 +1,76 @@
+/// Q1_7 - single byte representation of a fixed point number with range [-1, 1].
+/// The name refers to the Texas Instrument representation
+///
+/// References:
+/// - English Wikipedia: "Q (number format)" https://en.wikipedia.org/wiki/Q_(number_format)
+#[derive(Debug,Clone,Copy,PartialEq,Eq)]
+pub struct Q7(i8); // tuple struct holding a i8 value
+
+impl From<f64> for Q7 {
+ fn from (n: f64) -> Self {
+ if n >= 1.0 { // out of bounds numbers are coerced to the maximum of the range
+ Q7(127)
+ } else if n <= -1.0 {
+ Q7(-128)
+ } else {
+ Q7((n * 128.0) as i8) // 128 == (2 ** 7) == pow(2,7)
+ }
+ }
+}
+
+impl From<Q7> for f64 {
+ fn from(n: Q7) -> f64 {
+ (n.0 as f64) * 2f64.powf(-7.0) // 0.0078125// (2 ** -7) // pow(2, -7)
+ }
+}
+
+impl From<f32> for Q7 {
+ fn from (n: f32) -> Self {
+ Q7::from(n as f64) // conversion from f32 to f64 works perfectly
+ }
+}
+
+impl From<Q7> for f32 {
+ fn from(n: Q7) -> f32 {
+ f64::from(n) as f32 // conversion from f64 to f32 can result in undefined behavior,
+ // but not here as f32 can represent all values representable by Q7
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn out_of_bounds() {
+ assert_eq!(Q7::from(10.), Q7::from(1.));
+ assert_eq!(Q7::from(-10.), Q7::from(-1.));
+ }
+
+ #[test]
+ fn f32_to_q7() {
+ let n1: f32 = 0.7;
+ let q1 = Q7::from(n1);
+
+ let n2 = -0.4;
+ let q2 = Q7::from(n2);
+
+ let n3 = 123.0;
+ let q3 = Q7::from(n3);
+
+ assert_eq!(q1, Q7(89));
+ assert_eq!(q2, Q7(-51));
+ assert_eq!(q3, Q7(127));
+ }
+
+ #[test]
+ fn q7_to_f32() {
+ let q1 = Q7::from(0.7);
+ let n1 = f32::from(q1);
+ assert_eq!(n1, 0.6953125);
+
+ let q2 = Q7::from(n1); // numbers that can be represented exactly by Q7
+ let n2 = f32::from(q2); // can survive the transition between Q7 and f32
+ assert_eq!(n1, n2);
+ }
+}
--
cgit v1.2.3