From f780e7039679da67c291374d660e3d57efb68a9d Mon Sep 17 00:00:00 2001
From: Roland Fredenhagen <dev@modprog.de>
Date: Thu, 16 Nov 2023 02:08:16 +0100
Subject: [PATCH] Add (de)serialization based on Vec, slice, Read and Write
 (#18)

---
 src/de.rs  | 34 +++++++++++++++++++++++++++++++++-
 src/lib.rs | 29 ++++++++++++++++++++++++++---
 src/ser.rs | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 4 deletions(-)

diff --git a/src/de.rs b/src/de.rs
index 64eaea4..ae0ed9d 100644
--- a/src/de.rs
+++ b/src/de.rs
@@ -3,7 +3,7 @@ use alloc::string::{String, ToString};
 use core::fmt::Display;
 use core::ops::Range;
 
-use serde::de::{EnumAccess, MapAccess, SeqAccess, VariantAccess};
+use serde::de::{DeserializeOwned, EnumAccess, MapAccess, SeqAccess, VariantAccess};
 use serde::Deserialize;
 
 use crate::parser::{self, Config, Event, EventKind, Name, Nested, Parser, Primitive};
@@ -1350,6 +1350,38 @@ impl Config {
         deserializer.ensure_eof()?;
         Ok(result)
     }
+
+    pub fn deserialize_from_slice<'de, T: Deserialize<'de>>(
+        self,
+        source: &'de [u8],
+    ) -> Result<T, Error> {
+        let source = match alloc::str::from_utf8(source) {
+            Ok(source) => source,
+            Err(error) => {
+                let end = error
+                    .error_len()
+                    .map(|l| l + error.valid_up_to())
+                    .unwrap_or(source.len());
+                return Err(Error::new(
+                    (error.valid_up_to() + 1)..end,
+                    ErrorKind::InvalidUtf8,
+                ));
+            }
+        };
+        self.deserialize(source)
+    }
+
+    #[cfg(feature = "std")]
+    pub fn deserialize_from_reader<T: DeserializeOwned, R: std::io::Read>(
+        self,
+        mut reader: R,
+    ) -> Result<T, Error> {
+        let mut source = alloc::vec::Vec::new();
+        reader
+            .read_to_end(&mut source)
+            .map_err(|e| Error::new(0..0, ErrorKind::Message(e.to_string())))?;
+        self.deserialize_from_slice(&source)
+    }
 }
 
 struct BetterPeekable<T>
diff --git a/src/lib.rs b/src/lib.rs
index 8b5a6fe..4937a76 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,11 +19,34 @@ pub fn from_str<'de, D: serde::Deserialize<'de>>(source: &'de str) -> Result<D,
     parser::Config::default().deserialize(source)
 }
 
+#[cfg(feature = "serde")]
+pub fn from_slice<'de, D: serde::Deserialize<'de>>(source: &'de [u8]) -> Result<D, de::Error> {
+    parser::Config::default().deserialize_from_slice(source)
+}
+
+#[cfg(all(feature = "serde", feature = "std"))]
+pub fn from_reader<D: serde::de::DeserializeOwned, R: std::io::Read>(
+    reader: R,
+) -> Result<D, de::Error> {
+    parser::Config::default().deserialize_from_reader(reader)
+}
+
 #[cfg(feature = "serde")]
 pub fn to_string<S: serde::Serialize>(value: &S) -> alloc::string::String {
-    let mut serializer = ser::Serializer::default();
-    value.serialize(&mut serializer).expect("infallible");
-    serializer.finish()
+    ser::Config::default().serialize(value)
+}
+
+#[cfg(feature = "serde")]
+pub fn to_vec<S: serde::Serialize>(value: &S) -> alloc::vec::Vec<u8> {
+    ser::Config::default().serialize_to_vec(value)
+}
+
+#[cfg(all(feature = "serde", feature = "std"))]
+pub fn to_writer<S: serde::Serialize, W: std::io::Write>(
+    value: &S,
+    writer: W,
+) -> std::io::Result<usize> {
+    ser::Config::default().serialize_to_writer(value, writer)
 }
 
 #[cfg(feature = "serde")]
diff --git a/src/ser.rs b/src/ser.rs
index f014b96..72576a1 100644
--- a/src/ser.rs
+++ b/src/ser.rs
@@ -469,6 +469,56 @@ impl Config {
         value.serialize(&mut serializer).expect("core::fmt::Error");
         serializer.finish()
     }
+
+    pub fn serialize_to_vec<S: Serialize>(&self, value: &S) -> alloc::vec::Vec<u8> {
+        self.serialize(value).into_bytes()
+    }
+}
+
+#[cfg(feature = "std")]
+mod serialize_writer {
+    use super::*;
+    struct Writer<T> {
+        writer: T,
+        written: usize,
+        error: Option<std::io::Error>,
+    }
+    impl<T: std::io::Write> Write for Writer<T> {
+        fn write_str(&mut self, s: &str) -> core::fmt::Result {
+            match self.writer.write(s.as_bytes()) {
+                Ok(written) => {
+                    self.written += written;
+                    Ok(())
+                }
+                Err(error) => {
+                    assert!(
+                        self.error.is_none(),
+                        "should not have continued on write error"
+                    );
+                    self.error = Some(error);
+                    Err(core::fmt::Error)
+                }
+            }
+        }
+    }
+    impl Config {
+        pub fn serialize_to_writer<S: Serialize, W: std::io::Write>(
+            &self,
+            value: &S,
+            writer: W,
+        ) -> std::io::Result<usize> {
+            let mut writer = Writer {
+                writer,
+                written: 0,
+                error: None,
+            };
+            let mut serializer = Serializer::new(&mut writer, self);
+            value
+                .serialize(&mut serializer)
+                .map_err(|_| writer.error.expect("should store error on error"))?;
+            Ok(writer.written)
+        }
+    }
 }
 
 #[test]