create elementary functions for utf8

snowmerak · snowmerak · commit 8929a3e3886c · 2022-03-31T21:43:05.000+09:00
diff --git a/src/rust/src/utf8.rs b/src/rust/src/utf8.rs
@@ -0,0 +1,188 @@
+
+pub fn length_of(string: String) -> usize {
+    let mut count = 0;
+    let mut cur = 0;
+
+    for c in string.as_bytes() {
+        if cur == 0 {
+            if (c & 0b10000000) == 0 {
+                count += 1;
+                cur = 0;
+                continue;
+            }
+            if (c & 0b11100000) == 0b11000000 {
+                count += 1;
+                cur = 1;
+                continue;
+            }
+            if (c & 0b11110000) == 0b11100000 {
+                count += 1;
+                cur = 2;
+                continue;
+            }
+            if (c & 0b11111000) == 0b11110000 {
+                count += 1;
+                cur = 3;
+                continue;
+            }
+        }
+        cur -= 1;
+    }
+
+    count
+}
+
+pub fn validate(string: String) -> bool {
+    let mut cur = 0;
+    let mut count = 0;
+
+    for c in string.as_bytes() {
+        if cur == 0 {
+            if (c & 0b10000000) == 0 {
+                count += 1;
+                cur = 0;
+                continue;
+            }
+            if (c & 0b11100000) == 0b11000000 {
+                count += 1;
+                cur = 1;
+                continue;
+            }
+            if (c & 0b11110000) == 0b11100000 {
+                count += 1;
+                cur = 2;
+                continue;
+            }
+            if (c & 0b11111000) == 0b11110000 {
+                count += 1;
+                cur = 3;
+                continue;
+            }
+        }
+        if (c & 0b11000000) != 0b10000000 {
+            return false;
+        }
+        if count == 0 {
+            return false; 
+        }
+        cur -= 1;
+    }
+
+    true
+}
+
+pub fn convert_utf8_from(string: String) -> Vec<u32> {
+    let mut count = 0;
+    let mut step = 0;
+    let mut result = vec![];
+
+    if !validate(string.clone()) {
+        return result;
+    }
+
+    let mut temp = 0;
+    for c in string.as_bytes() {
+        if count == 0 {
+            if (c & 0b10000000) == 0 {
+                result.push(temp);
+                temp = (*c as u32) & 0b01111111;
+                count = 0;
+                step = 2;
+                continue;
+            }
+            if (c & 0b11100000) == 0b11000000 {
+                result.push(temp);
+                temp = (*c as u32) & 0b00011111;
+                temp = temp << 6;
+                count = 1;
+                step = 2;
+                continue;
+            }
+            if (c & 0b11110000) == 0b11100000 {
+                result.push(temp);
+                temp = (*c as u32) & 0b00001111;
+                temp = temp << 12;
+                count = 2;
+                step = 2;
+                continue;
+            }
+            if (c & 0b11111000) == 0b11110000 {
+                result.push(temp);
+                temp = (*c as u32) & 0b00000111;
+                temp = temp << 18;
+                count = 3;
+                step = 2;
+                continue;
+            }
+        }
+        count -= 1;
+        step -= 1;
+        temp |= ((*c as u32) & 0b00111111) << (step * 6);
+    }
+    result.push(temp);
+
+    if let Some(x) = result.first() {
+        if *x == 0 {
+            result.remove(0);
+        }
+    }
+    if let Some(x) = result.last() {
+        if *x == 0 {
+            result.pop();
+        }
+    }
+
+    result
+}
+
+pub fn convert_utf8_to(vec: Vec<u32>) -> String {
+    let mut result = Vec::new();
+    
+    for v in vec {
+        println!("{:?}", v);
+        if v <= 0x0000007F {
+            result.push(v as u8);
+            continue;
+        }
+        if v <= 0x000007FF {
+            result.push((((v >> 6) & 0b00011111) | 0b11000000) as u8);
+            result.push(((v & 0b00111111) | 0b10000000) as u8);
+            continue;
+        }
+        if v <= 0x0000FFFF {
+            result.push((((v >> 12) & 0b00001111) | 0b11100000) as u8);
+            result.push((((v >> 6) & 0b00111111) | 0b10000000) as u8);
+            result.push(((v & 0b00111111) | 0b10000000) as u8);
+            continue;
+        }
+        if v <= 0x0010FFFF {
+            result.push((((v >> 18) & 0b00000111) | 0b11110000) as u8);
+            result.push(((v >> 12) & 0b00111111) as u8);
+            result.push(((v >> 6) & 0b00111111) as u8);
+            result.push(((v >> 0) & 0b00111111) as u8);
+            continue;
+        }
+    }
+
+    match String::from_utf8(result) {
+        Ok(x) => x,
+        Err(_) => String::from(""),
+    }
+}
+
+#[test]
+fn test() {
+    let a = "가".to_string();
+    for i in a.as_bytes() {
+        print!("{:#010b} ", i);
+    }
+    println!();
+    let c = convert_utf8_from(a.clone());
+    println!("{:?}", c);
+    let s = convert_utf8_to(c);
+    for i in s.as_bytes() {
+        print!("{:#010b} ", i);
+    }
+    println!();
+    println!("{}", s);
+}
