From f4ad61665c75d1d19462bfd67439f9d0f8788a8b Mon Sep 17 00:00:00 2001
From: Alberto Restifo <alberto@restifo.dev>
Date: Fri, 24 Apr 2020 15:59:16 +0200
Subject: [PATCH] Parse time

---
 spec/cbor/from_cbor_spec.cr |  7 +++++++
 src/cbor/decoder.cr         | 39 ++++++++++++++++++++++++++++++++++++-
 src/cbor/from_cbor.cr       | 24 +++++++++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/spec/cbor/from_cbor_spec.cr b/spec/cbor/from_cbor_spec.cr
index 73ddde4..fc818ca 100644
--- a/spec/cbor/from_cbor_spec.cr
+++ b/spec/cbor/from_cbor_spec.cr
@@ -9,7 +9,14 @@ describe "CBOR helpers on basic types" do
       {UInt32, Bytes[0x1a, 0x00, 0x0f, 0x42, 0x40], 1000000},
       {UInt64, Bytes[0x1b, 0x00, 0x00, 0x00, 0xe8, 0xd4, 0xa5, 0x10, 0x00], 1000000000000},
       {Int8, Bytes[0x29], -10},
+      {Bool, Bytes[0xf4], false},
+      {Bool, Bytes[0xf5], true},
       {Bytes, Bytes[0x44, 0x01, 0x02, 0x03, 0x04], Bytes[0x01, 0x02, 0x03, 0x04]},
+      {Time,
+       Bytes[0xc0, 0x74, 0x32, 0x30, 0x31, 0x33, 0x2d, 0x30, 0x33, 0x2d, 0x32, 0x31, 0x54, 0x32, 0x30, 0x3a, 0x30, 0x34, 0x3a, 0x30, 0x30, 0x5a],
+       Time::Format::RFC_3339.parse("2013-03-21T20:04:00Z")},
+      {Time, Bytes[0xc1, 0x1a, 0x51, 0x4b, 0x67, 0xb0], Time.unix(1363896240)},
+      {Time, Bytes[0xc1, 0xfb, 0x41, 0xd4, 0x52, 0xd9, 0xec, 0x20, 0x00, 0x00], Time.unix_ms((1363896240.5 * 1000).to_i)},
     ]
 
     tests.each do |tt|
diff --git a/src/cbor/decoder.cr b/src/cbor/decoder.cr
index ffbc18a..7c97a13 100644
--- a/src/cbor/decoder.cr
+++ b/src/cbor/decoder.cr
@@ -24,15 +24,52 @@ class CBOR::Decoder
     read_type(Token::IntT) { |token| token.value }
   end
 
+  def read_float
+    read_type(Token::FloatT) { |token| token.value }
+  end
+
+  def read_num
+    case token = @current_token
+    when Token::IntT, Token::FloatT
+      token.value
+    else
+      unexpected_token(token, "Token::IntT or Token::FloatT")
+    end
+  end
+
   def read_bytes
     read_type(Token::BytesT) { |token| token.value }
   end
 
+  def read_tag : Tag
+    read_type(Token::TagT) { |token| token.value }
+  end
+
+  def read_bool : Bool
+    read_type(Token::SimpleValueT) do |token|
+      case token.value
+      when SimpleValue::False
+        false
+      when SimpleValue::True
+        true
+      else
+        unexpected_token(token, "SimpleValue::True or SimpleValue::False")
+      end
+    end
+  end
+
   private def finish_token!
     @current_token = @lexer.next_token
   end
 
-  private macro read_type(type, finish_token = true, &block)
+  private macro read_type(type, finish_token = true, ignore_tag = true, &block)
+    # Skip the tag unless the token we want to read is a tag
+    {% if type != Token::TagT && ignore_tag %}
+      if @current_token.is_a?(Token::TagT)
+        finish_token!
+      end
+    {% end %}
+
     case token = @current_token
     when {{type}}
       {% if finish_token %}finish_token!{% end %}
diff --git a/src/cbor/from_cbor.cr b/src/cbor/from_cbor.cr
index cf6e905..7a88aee 100644
--- a/src/cbor/from_cbor.cr
+++ b/src/cbor/from_cbor.cr
@@ -19,6 +19,30 @@ end
 
 {% end %}
 
+def Bool.new(decoder : CBOR::Decoder)
+  decoder.read_bool
+end
+
 def Slice.new(decoder : CBOR::Decoder)
   decoder.read_bytes.to_slice
 end
+
+# Reads the CBOR values a time. The value must be surrounded by a time tag as
+# specified by [Section 2.4.1 of RFC 7049][1].
+#
+# [1]: https://tools.ietf.org/html/rfc7049#section-2.4.1
+def Time.new(decoder : CBOR::Decoder)
+  case tag = decoder.read_tag
+  when CBOR::Tag::RFC3339Time
+    Time::Format::RFC_3339.parse(decoder.read_string)
+  when CBOR::Tag::EpochTime
+    case num = decoder.read_num
+    when Int
+      Time.unix(num)
+    when Float
+      Time.unix_ms((num * 1000).to_i)
+    end
+  else
+    raise CBOR::ParseError.new("Expected tag to have value 0 or 1, got #{tag.value.to_s}")
+  end
+end