add string_reader

1 files changed, 277 insertions, 0 deletions

diff --git a/azalea-brigadier/src/string_reader.rs b/azalea-brigadier/src/string_reader.rs
index e69de29b..376cc711 100644
--- a/azalea-brigadier/src/string_reader.rs
+++ b/azalea-brigadier/src/string_reader.rs
@@ -0,0 +1,277 @@
+use crate::immutable_string_reader::ImmutableStringReader;
+use std::str::FromStr;
+
+#[derive(Clone)]
+struct StringReader<'a> {
+    pub string: &'a str,
+    pub cursor: usize,
+}
+
+const SYNTAX_ESCAPE: char = '\\';
+const SYNTAX_DOUBLE_QUOTE: char = '"';
+const SYNTAX_SINGLE_QUOTE: char = '\'';
+
+impl<'a> From<&'a str> for &StringReader<'a> {
+    fn from(string: &'a str) -> &StringReader<'a> {
+        &StringReader { string, cursor: 0 }
+    }
+}
+
+impl ImmutableStringReader for StringReader<'_> {
+    fn remaining_length(&self) -> usize {
+        self.string.len() - self.cursor
+    }
+
+    fn total_length(&self) -> usize {
+        self.string.len()
+    }
+
+    fn get_read(&self) -> &str {
+        &self.string[self.cursor..]
+    }
+
+    fn remaining(&self) -> &str {
+        &self.string[self.cursor..]
+    }
+
+    fn can_read_length(&self, length: usize) -> bool {
+        self.cursor + length <= self.string.len()
+    }
+
+    fn can_read(&self) -> bool {
+        self.can_read_length(1)
+    }
+
+    fn peek(&self) -> char {
+        self.string.chars().nth(self.cursor).unwrap()
+    }
+
+    fn peek_offset(&self, offset: usize) -> char {
+        self.string.chars().nth(self.cursor + offset).unwrap()
+    }
+}
+
+impl StringReader<'_> {
+    fn read(&mut self) -> char {
+        let c = self.peek();
+        self.cursor += 1;
+        c
+    }
+
+    fn skip(&mut self) {
+        self.cursor += 1;
+    }
+
+    fn is_allowed_number(c: char) -> bool {
+        c >= '0' && c <= '9' || c == '.' || c == '-'
+    }
+
+    fn is_quoted_string_start(c: char) -> bool {
+        c == SYNTAX_DOUBLE_QUOTE || c == SYNTAX_SINGLE_QUOTE
+    }
+
+    fn skip_whitespace(&mut self) {
+        while self.can_read() && self.peek().is_whitespace() {
+            self.skip();
+        }
+    }
+
+    fn read_int(&self) -> Result<(), CommandSyntaxException> {
+        let start = self.cursor;
+        while self.can_read() && StringReader::<'_>::is_allowed_number(self.peek()) {
+            self.skip();
+        }
+        let number = &self.string[start..self.cursor];
+        if number.is_empty() {
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_expected_int()
+                .create_with_context(self));
+        }
+        let result = i32::from_str(number);
+        if result.is_err() {
+            self.cursor = start;
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_invalid_int()
+                .create_with_context(self, number));
+        }
+
+        Ok(())
+    }
+
+    fn read_long(&self) -> Result<(), CommandSyntaxException> {
+        let start = self.cursor;
+        while self.can_read() && StringReader::<'_>::is_allowed_number(self.peek()) {
+            self.skip();
+        }
+        let number = &self.string[start..self.cursor];
+        if number.is_empty() {
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_expected_long()
+                .create_with_context(self));
+        }
+        let result = i64::from_str(number);
+        if result.is_err() {
+            self.cursor = start;
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_invalid_long()
+                .create_with_context(self, number));
+        }
+
+        Ok(())
+    }
+
+    fn read_double(&self) -> Result<(), CommandSyntaxException> {
+        let start = self.cursor;
+        while self.can_read() && StringReader::<'_>::is_allowed_number(self.peek()) {
+            self.skip();
+        }
+        let number = &self.string[start..self.cursor];
+        if number.is_empty() {
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_expected_double()
+                .create_with_context(self));
+        }
+        let result = f64::from_str(number);
+        if result.is_err() {
+            self.cursor = start;
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_invalid_double()
+                .create_with_context(self, number));
+        }
+
+        Ok(())
+    }
+
+    fn read_float(&self) -> Result<(), CommandSyntaxException> {
+        let start = self.cursor;
+        while self.can_read() && StringReader::<'_>::is_allowed_number(self.peek()) {
+            self.skip();
+        }
+        let number = &self.string[start..self.cursor];
+        if number.is_empty() {
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_expected_float()
+                .create_with_context(self));
+        }
+        let result = f32::from_str(number);
+        if result.is_err() {
+            self.cursor = start;
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_invalid_float()
+                .create_with_context(self, number));
+        }
+
+        Ok(())
+    }
+
+    fn is_allowed_in_unquoted_string(c: char) -> bool {
+        c >= '0' && c <= '9'
+            || c >= 'A' && c <= 'Z'
+            || c >= 'a' && c <= 'z'
+            || c == '_'
+            || c == '-'
+            || c == '.'
+            || c == '+'
+    }
+
+    fn read_unquoted_string(&self) -> &str {
+        let start = self.cursor;
+        while self.can_read() && StringReader::<'_>::is_allowed_in_unquoted_string(self.peek()) {
+            self.skip();
+        }
+        &self.string[start..self.cursor]
+    }
+
+    fn read_quoted_string(&self) -> Result<&str, CommandSyntaxException> {
+        if !self.can_read() {
+            return "";
+        }
+        let next = self.peek();
+        if !StringReader::<'_>::is_quoted_string_start(next) {
+            return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                .reader_expected_start_of_quote()
+                .create_with_context(self));
+        }
+        self.skip();
+        self.read_string_until(next)
+    }
+
+    fn read_string_until(&self, terminator: char) -> Result<String, CommandSynatxException> {
+        let result = String::new();
+        let mut escaped = false;
+        while self.can_read() {
+            let c = self.read();
+            if escaped {
+                if c == terminator || c == SYNTAX_ESCAPE {
+                    result.push(c);
+                    escaped = false;
+                } else {
+                    self.cursor -= 1;
+                    return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+                        .reader_invalid_escape()
+                        .create_with_context(self, c));
+                }
+            } else if c == SYNTAX_ESCAPE {
+                escaped = true;
+            } else if c == terminator {
+                return Ok(result);
+            } else {
+                result.push(c);
+            }
+        }
+
+        Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+            .reader_expected_end_of_quote()
+            .create_with_context(self))
+    }
+
+    fn read_string(&self) -> Result<String, CommandSyntaxException> {
+        // if (!canRead()) {
+        //     return "";
+        // }
+        // final char next = peek();
+        // if (isQuotedStringStart(next)) {
+        //     skip();
+        //     return readStringUntil(next);
+        // }
+        // return readUnquotedString();
+        if !self.can_read() {
+            return Ok(String::new());
+        }
+        let next = self.peek();
+        if StringReader::<'_>::is_quoted_string_start(next) {
+            self.skip();
+            return self.read_string_until(next);
+        }
+        Ok(self.read_unquoted_string().to_string())
+    }
+
+	fn read_boolean(&self) -> Result<bool, CommandSyntaxException> {
+		let start = self.cursor;
+		let value = self.read_string()?;
+		if value.is_empty() {
+			return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+				.reader_expected_bool()
+				.create_with_context(self));
+		}
+
+		if value == "true" {
+			return Ok(true);
+		} else if value == "false" {
+			return Ok(false);
+		} else {
+			self.cursor = start;
+			return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+				.reader_invalid_bool()
+				.create_with_context(self, value));
+		}
+	}
+
+	fn expect(&self, c: char) -> Result<(), CommandSyntaxException> {
+		if !self.can_read() || self.peek() != c {
+			return Err(CommandSyntaxException::BUILT_IN_EXCEPTIONS
+				.reader_expected_symbol()
+				.create_with_context(self, c));
+		}
+		self.skip();
+	}