Include README code in examples/

examples/readme.rs

@@ -0,0 +1,82 @@
+use base64::decode;
+use cryptostream::{read, write};
+// openssl::Cipher is re-exported as cryptostream::Cipher
+use cryptostream::Cipher;
+use std::io::prelude::*;
+
+fn main() {
+    f1();
+    f2();
+}
+
+fn f1() {
+    // This is the cipher text, base64-encoded to avoid any whitespace munging. In this
+    // contrived example, we are using a binary `Vec<u8>` as the `Read` source containing
+    // the encrypted data; in practice it could be a binary file, a network stream, or
+    // anything else.
+    let src: Vec<u8> = decode(concat!(
+        "vuU+0SXFWQLu8vl/o1WzmPCmf7x/O6ToGQ162Aq2CHxcnc/ax/Q8nTbRlNn0OSPrFuE3yDdO",
+        "VC35RmwtUIlxKIkWbnxJpRF5yRJvVByQgWX1qLW8DfMjRp7gVaFNv4qr7G65M6hbSx6hGJXv",
+        "Q6s1GiFwi91q0V17DI79yVrINHCXdBnUOqeLGfJ05Edu+39EQNYn4dky7VdgTP2VYZE7Vw==",
+    ))
+    .unwrap();
+    let key: Vec<_> = decode("kjtbxCPw3XPFThb3mKmzfg==").unwrap();
+    let iv: Vec<_> = decode("dB0Ej+7zWZWTS5JUCldWMg==").unwrap();
+
+    // The source can be anything implementing `Read`. In this case, a simple &[u8] slice.
+    let mut decryptor =
+        read::Decryptor::new(src.as_slice(), Cipher::aes_128_cbc(), &key, &iv).unwrap();
+
+    let mut decrypted = [0u8; 1024]; // a buffer to decrypt into
+    let mut bytes_decrypted = 0;
+
+    loop {
+        // Just read from the `Decryptor` as if it were any other `Read` impl,
+        // the decryption takes place automatically.
+        let read_count = decryptor.read(&mut decrypted[bytes_decrypted..]).unwrap();
+        bytes_decrypted += read_count;
+        if read_count == 0 {
+            break;
+        }
+    }
+
+    println!("{}", String::from_utf8_lossy(&decrypted));
+}
+
+fn f2() {
+    // Starting again with the same encrypted bytestream, encoded as base64:
+    let src: Vec<u8> = decode(concat!(
+        "vuU+0SXFWQLu8vl/o1WzmPCmf7x/O6ToGQ162Aq2CHxcnc/ax/Q8nTbRlNn0OSPrFuE3yDdO",
+        "VC35RmwtUIlxKIkWbnxJpRF5yRJvVByQgWX1qLW8DfMjRp7gVaFNv4qr7G65M6hbSx6hGJXv",
+        "Q6s1GiFwi91q0V17DI79yVrINHCXdBnUOqeLGfJ05Edu+39EQNYn4dky7VdgTP2VYZE7Vw=="
+    ))
+    .unwrap();
+    let key: Vec<_> = decode("kjtbxCPw3XPFThb3mKmzfg==").unwrap();
+    let iv: Vec<_> = decode("dB0Ej+7zWZWTS5JUCldWMg==").unwrap();
+
+    // The destination can be any object implementing `Write`: in this case, a `Vec<u8>`.
+    let mut decrypted = Vec::new();
+
+    // When a `cryptostream` is dropped, all buffers are flushed and it is automatically
+    // finalized. We can either call `drop()` on the cryptostream or put its usage in a
+    // separate scope.
+    {
+        let mut decryptor =
+            write::Decryptor::new(&mut decrypted, Cipher::aes_128_cbc(), &key, &iv).unwrap();
+
+        let mut bytes_decrypted = 0;
+
+        while bytes_decrypted != src.len() {
+            // Just write encrypted ciphertext to the `Decryptor` instance as if it were any
+            // other `Write` impl. Decryption takes place automatically.
+            let write_count = decryptor.write(&src[bytes_decrypted..]).unwrap();
+            bytes_decrypted += write_count;
+        }
+    }
+
+    // The underlying `Write` instance is only guaranteed to contain the complete and
+    // finalized contents after the cryptostream is either explicitly finalized with a
+    // call to `Cryptostream::finish()` or when it's dropped (either at the end of a scope
+    // or via an explicit call to `drop()`, whichever you prefer).
+    println!("{}", String::from_utf8_lossy(&decrypted));
+}