rename classes to methods

amqp_transport/src/methods/write_helper.rs

@@ -0,0 +1,198 @@
+use crate::error::TransError;
+use crate::methods::generated::{
+    Bit, Long, Longlong, Longstr, Octet, Short, Shortstr, Table, Timestamp,
+};
+use crate::methods::FieldValue;
+use anyhow::Context;
+use std::io::Write;
+
+pub fn octet<W: Write>(value: Octet, writer: &mut W) -> Result<(), TransError> {
+    writer.write_all(&[value])?;
+    Ok(())
+}
+
+pub fn short<W: Write>(value: Short, writer: &mut W) -> Result<(), TransError> {
+    writer.write_all(&value.to_be_bytes())?;
+    Ok(())
+}
+
+pub fn long<W: Write>(value: Long, writer: &mut W) -> Result<(), TransError> {
+    writer.write_all(&value.to_be_bytes())?;
+    Ok(())
+}
+
+pub fn longlong<W: Write>(value: Longlong, writer: &mut W) -> Result<(), TransError> {
+    writer.write_all(&value.to_be_bytes())?;
+    Ok(())
+}
+
+pub fn bit<W: Write>(value: &[Bit], writer: &mut W) -> Result<(), TransError> {
+    // accumulate bits into bytes, starting from the least significant bit in each byte
+
+    // how many bits have already been packed into `current_buf`
+    let mut already_filled = 0;
+    let mut current_buf = 0u8;
+
+    for &bit in value {
+        if already_filled >= 8 {
+            writer.write_all(&[current_buf])?;
+            current_buf = 0;
+            already_filled = 0;
+        }
+
+        let new_bit = (u8::from(bit)) << already_filled;
+        current_buf |= new_bit;
+        already_filled += 1;
+    }
+
+    if already_filled > 0 {
+        writer.write_all(&[current_buf])?;
+    }
+
+    Ok(())
+}
+
+pub fn shortstr<W: Write>(value: Shortstr, writer: &mut W) -> Result<(), TransError> {
+    let len = u8::try_from(value.len()).context("shortstr too long")?;
+    writer.write_all(&[len])?;
+    writer.write_all(value.as_bytes())?;
+
+    Ok(())
+}
+
+pub fn longstr<W: Write>(value: Longstr, writer: &mut W) -> Result<(), TransError> {
+    let len = u32::try_from(value.len()).context("longstr too long")?;
+    writer.write_all(&len.to_be_bytes())?;
+    writer.write_all(value.as_slice())?;
+
+    Ok(())
+}
+
+// this appears to be unused right now, but it could be used in `Basic` things?
+#[allow(dead_code)]
+pub fn timestamp<W: Write>(value: Timestamp, writer: &mut W) -> Result<(), TransError> {
+    writer.write_all(&value.to_be_bytes())?;
+    Ok(())
+}
+
+pub fn table<W: Write>(table: Table, writer: &mut W) -> Result<(), TransError> {
+    let mut table_buf = Vec::new();
+
+    for (field_name, value) in table {
+        shortstr(field_name, &mut table_buf)?;
+        field_value(value, &mut table_buf)?;
+    }
+
+    let len = u32::try_from(table_buf.len()).context("table too big")?;
+    writer.write_all(&len.to_be_bytes())?;
+    writer.write_all(&table_buf)?;
+
+    Ok(())
+}
+
+fn field_value<W: Write>(value: FieldValue, writer: &mut W) -> Result<(), TransError> {
+    match value {
+        FieldValue::Boolean(bool) => {
+            writer.write_all(&[b't', u8::from(bool)])?;
+        }
+        FieldValue::ShortShortInt(int) => {
+            writer.write_all(b"b")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::ShortShortUInt(int) => {
+            writer.write_all(&[b'B', int])?;
+        }
+        FieldValue::ShortInt(int) => {
+            writer.write_all(b"U")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::ShortUInt(int) => {
+            writer.write_all(b"u")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::LongInt(int) => {
+            writer.write_all(b"I")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::LongUInt(int) => {
+            writer.write_all(b"i")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::LongLongInt(int) => {
+            writer.write_all(b"L")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::LongLongUInt(int) => {
+            writer.write_all(b"l")?;
+            writer.write_all(&int.to_be_bytes())?;
+        }
+        FieldValue::Float(float) => {
+            writer.write_all(b"f")?;
+            writer.write_all(&float.to_be_bytes())?;
+        }
+        FieldValue::Double(float) => {
+            writer.write_all(b"d")?;
+            writer.write_all(&float.to_be_bytes())?;
+        }
+        FieldValue::DecimalValue(scale, long) => {
+            writer.write_all(&[b'D', scale])?;
+            writer.write_all(&long.to_be_bytes())?;
+        }
+        FieldValue::ShortString(str) => {
+            writer.write_all(b"s")?;
+            shortstr(str, writer)?;
+        }
+        FieldValue::LongString(str) => {
+            writer.write_all(b"S")?;
+            longstr(str, writer)?;
+        }
+        FieldValue::FieldArray(array) => {
+            writer.write_all(b"A")?;
+            let len = u32::try_from(array.len()).context("array too long")?;
+            writer.write_all(&len.to_be_bytes())?;
+
+            for element in array {
+                field_value(element, writer)?;
+            }
+        }
+        FieldValue::Timestamp(time) => {
+            writer.write_all(b"T")?;
+            writer.write_all(&time.to_be_bytes())?;
+        }
+        FieldValue::FieldTable(value) => {
+            writer.write_all(b"F")?;
+            table(value, writer)?;
+        }
+        FieldValue::Void => {
+            writer.write_all(b"V")?;
+        }
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn pack_few_bits() {
+        let bits = [true, false, true];
+
+        let mut buffer = [0u8; 1];
+        super::bit(&bits, &mut buffer.as_mut_slice()).unwrap();
+
+        assert_eq!(buffer, [0b00000101])
+    }
+
+    #[test]
+    fn pack_many_bits() {
+        let bits = [
+            /* first 8 */
+            true, true, true, true, false, false, false, false, /* second 4 */
+            true, false, true, true,
+        ];
+
+        let mut buffer = [0u8; 2];
+        super::bit(&bits, &mut buffer.as_mut_slice()).unwrap();
+
+        assert_eq!(buffer, [0b00001111, 0b00001101]);
+    }
+}