From 0262ded968ece38cff5cb80626299155ef040228 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Thu, 18 Nov 2021 23:14:47 +0000
Subject: add fuzzer input generator

---
 tests/helpers/mod.rs | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

(limited to 'tests')

diff --git a/tests/helpers/mod.rs b/tests/helpers/mod.rs
index 20de2d4..d3dd05d 100644
--- a/tests/helpers/mod.rs
+++ b/tests/helpers/mod.rs
@@ -289,3 +289,62 @@ fn hex_char(c: u8) -> Result<u8, String> {
 pub fn hex(upper: u8, lower: u8) -> Result<u8, String> {
     Ok(hex_char(upper)? * 16 + hex_char(lower)?)
 }
+
+#[allow(dead_code)]
+pub fn unhex(s: &[u8]) -> Vec<u8> {
+    let mut ret = vec![];
+    let mut i = 0;
+    while i < s.len() {
+        if s[i] == b'\\' {
+            match s[i + 1] {
+                b'\\' => {
+                    ret.push(b'\\');
+                    i += 2;
+                }
+                b'x' => {
+                    let upper = s[i + 2];
+                    let lower = s[i + 3];
+                    ret.push(hex(upper, lower).unwrap());
+                    i += 4;
+                }
+                b'u' => {
+                    assert_eq!(s[i + 2], b'{');
+                    let mut digits = vec![];
+                    let mut j = i + 3;
+                    while s[j] != b'}' {
+                        digits.push(s[j]);
+                        j += 1;
+                    }
+                    let digits: Vec<_> = digits
+                        .iter()
+                        .copied()
+                        .skip_while(|x| x == &b'0')
+                        .collect();
+                    let digits = String::from_utf8(digits).unwrap();
+                    let codepoint = u32::from_str_radix(&digits, 16).unwrap();
+                    let c = char::try_from(codepoint).unwrap();
+                    let mut bytes = [0; 4];
+                    ret.extend(c.encode_utf8(&mut bytes).bytes());
+                    i = j + 1;
+                }
+                b'r' => {
+                    ret.push(0x0d);
+                    i += 2;
+                }
+                b'n' => {
+                    ret.push(0x0a);
+                    i += 2;
+                }
+                b't' => {
+                    ret.push(0x09);
+                    i += 2;
+                }
+                _ => panic!("invalid escape"),
+            }
+        } else {
+            ret.push(s[i]);
+            i += 1;
+        }
+    }
+    ret
+}
-- 
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