From a78d06f33aff013490775521e3dba3c42e5de85d Mon Sep 17 00:00:00 2001
From: Alberto Restifo <alberto@restifo.dev>
Date: Fri, 24 Apr 2020 00:05:50 +0200
Subject: [PATCH] Implement floats

---
 README.md              |  7 +++++++
 spec/rfc_spec.cr       | 30 +++++++++++-------------------
 src/cbor/diagnostic.cr | 14 ++++++++++++++
 src/cbor/lexer.cr      |  7 ++++++-
 src/cbor/tag.cr        |  5 +++++
 5 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index 641d04d..89b4d72 100644
--- a/README.md
+++ b/README.md
@@ -9,9 +9,16 @@ in Crystal.
 
 - Full RFC7049 support
 - Full support for diagnostic notation
+- Assign a field to a type base on the CBOR tag
+- Support for a wide range of IANA CBOR Tags
 
 ## Limitations
 
+### Half-precision floating point is not supported
+
+Crystal doesn't have a `Float16` type, so half-precision floating point numbers
+are not supported for the time being.
+
 ### Maximum Array/String array/Bytes array length
 
 The spec allows for the maximum length of arrays, string arrays and bytes array
diff --git a/spec/rfc_spec.cr b/spec/rfc_spec.cr
index 5c32fe7..a0c726f 100644
--- a/spec/rfc_spec.cr
+++ b/spec/rfc_spec.cr
@@ -1,14 +1,6 @@
 require "./spec_helper"
 
 # All those tests have been exported from the RFC7049 appendix A.
-#
-# Some test results have been modified as the tool doesn't support
-# the full diagnostic notation as per RFC.
-#
-# Specifically:
-#
-# * Removed the undescore marking the start of infinite stirngs, bytes and
-#   array. This implementation doesn't expose the difference between the two.
 
 tests = [
   { %(0), "00" },
@@ -32,25 +24,25 @@ tests = [
   # { %(0.0), "f9 00 00" },
   # { %(-0.0), "f9 80 00" },
   # { %(1.0), "f9 3c 00" },
-  # { %(1.1), "fb 3f f1 99 99 99 99 99 9a" },
+  { %(1.1), "fb 3f f1 99 99 99 99 99 9a" },
   # { %(1.5), "f9 3e 00" },
   # { %(65504.0), "f9 7b ff" },
-  # { %(100000.0), "fa 47 c3 50 00" },
-  # { %(3.4028234663852886e+38), "fa 7f 7f ff ff" },
-  # { %(1.0e+300), "fb 7e 37 e4 3c 88 00 75 9c" },
+  { %(100000.0), "fa 47 c3 50 00" },
+  # { %(3.4028234663852886e+38), "fa 7f 7f ff ff" }, TODO: Not precise enough?
+  { %(1.0e+300), "fb 7e 37 e4 3c 88 00 75 9c" },
   # { %(5.960464477539063e-8), "f9 00 01" },
   # { %(0.00006103515625), "f9 04 00" },
   # { %(-4.0), "f9 c4 00" },
-  # { %(-4.1), "fb c0 10 66 66 66 66 66 66" },
+  { %(-4.1), "fb c0 10 66 66 66 66 66 66" },
   # { %(Infinity), "f9 7c 00" },
   # { %(NaN), "f9 7e 00" },
   # { %(-Infinity), "f9 fc 00" },
-  # { %(Infinity), "fa 7f 80 00 00" },
-  # { %(NaN), "fa 7f c0 00 00" },
-  # { %(-Infinity), "fa ff 80 00 00" },
-  # { %(Infinity), "fb 7f f0 00 00 00 00 00 00" },
-  # { %(NaN), "fb 7f f8 00 00 00 00 00 00" },
-  # { %(-Infinity), "fb ff f0 00 00 00 00 00 00" },
+  { %(Infinity), "fa 7f 80 00 00" },
+  { %(NaN), "fa 7f c0 00 00" },
+  { %(-Infinity), "fa ff 80 00 00" },
+  { %(Infinity), "fb 7f f0 00 00 00 00 00 00" },
+  { %(NaN), "fb 7f f8 00 00 00 00 00 00" },
+  { %(-Infinity), "fb ff f0 00 00 00 00 00 00" },
   { %(false), "f4" },
   { %(true), "f5" },
   { %(null), "f6" },
diff --git a/src/cbor/diagnostic.cr b/src/cbor/diagnostic.cr
index befa983..da06286 100644
--- a/src/cbor/diagnostic.cr
+++ b/src/cbor/diagnostic.cr
@@ -54,6 +54,20 @@ class CBOR::Diagnostic
       token.value.to_diagnostic
     when Token::TagT
       "#{token.value.value.to_s}(#{next_value})"
+    when Token::FloatT
+      return "NaN" if token.value.nan?
+      return token.value.to_s if token.value.finite?
+
+      case value = token.value
+      when Float32
+        return "Infinity" if value == Float32::INFINITY
+        "-Infinity"
+      when Float64
+        return "Infinity" if value == Float64::INFINITY
+        "-Infinity"
+      else
+        token.value.to_s
+      end
     else
       token.inspect
     end
diff --git a/src/cbor/lexer.cr b/src/cbor/lexer.cr
index 7233a99..fa60b6f 100644
--- a/src/cbor/lexer.cr
+++ b/src/cbor/lexer.cr
@@ -81,9 +81,14 @@ class CBOR::Lexer
       Token::MapT.new
     when 0xc0..0xdb
       consume_tag(read_size(byte - 0xc0))
-      ##################
     when 0xe0..0xf8
       consume_simple_value(read_size(byte - 0xe0))
+    when 0xf9
+      raise ParseError.new("Half-precision floating points are not supported")
+    when 0xfa
+      Token::FloatT.new(value: read(Float32))
+    when 0xfb
+      Token::FloatT.new(value: read(Float64))
     else
       raise ParseError.new("Unexpected first byte 0x#{byte.to_s(16)}")
     end
diff --git a/src/cbor/tag.cr b/src/cbor/tag.cr
index 79fe467..1d31434 100644
--- a/src/cbor/tag.cr
+++ b/src/cbor/tag.cr
@@ -6,6 +6,10 @@ enum CBOR::Tag : UInt32
   Decimal
   BigFloat
 
+  CSOEEnCrypt = 16
+  CSOEMac
+  CSOESign
+
   ConvertBase64URL = 21
   ConvertBase64
   ConvertBase16
@@ -16,6 +20,7 @@ enum CBOR::Tag : UInt32
   Base64
   RegularExpression
   MimeMessage
+  UUID
 
   CBORMarker = 55799
 end