From 75916ea0ddd77f646339b16e17628cc75924ba44 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Fri, 22 Dec 2023 22:16:26 +0200
Subject: [PATCH] Convert awkard floats to hex

---
 src/preserves/private/texts.nim | 35 ++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/preserves/private/texts.nim b/src/preserves/private/texts.nim
index 862d674..247d659 100644
--- a/src/preserves/private/texts.nim
+++ b/src/preserves/private/texts.nim
@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: ☭ Emery Hemingway
 # SPDX-License-Identifier: Unlicense
 
-import std/[base64, json, options, sets, sequtils, streams, strutils, tables, typetraits]
+import std/[base64, endians, json, math, options, sets, sequtils, streams, strutils, tables, typetraits]
 import ./values
 
 proc `$`*(s: Symbol): string =
@@ -33,6 +33,8 @@ proc `$`*(s: Symbol): string =
         result.add(c)
     result.add('|')
 
+const hexAlphabet = "0123456789abcdef"
+
 type TextMode* = enum textPreserves, textJson
 
 proc writeText*[E](stream: Stream; pr: Preserve[E]; mode = textPreserves) =
@@ -44,10 +46,30 @@ proc writeText*[E](stream: Stream; pr: Preserve[E]; mode = textPreserves) =
     of false: write(stream, "#f")
     of true: write(stream, "#t")
   of pkFloat:
-    write(stream, $pr.float)
-    write(stream, 'f')
+    case pr.float.classify:
+    of fcNormal, fcZero, fcNegZero:
+      write(stream, $pr.float)
+      write(stream, 'f')
+    else:
+      var buf: array[4, byte]
+      bigEndian32(addr buf[0], addr pr.float)
+      write(stream, "#xf\"")
+      for b in buf:
+        write(stream, hexAlphabet[b shr 4])
+        write(stream, hexAlphabet[b and 0xf])
+      write(stream, '"')
   of pkDouble:
-    write(stream, $pr.double)
+    case pr.double.classify:
+    of fcNormal, fcZero, fcNegZero:
+      write(stream, $pr.double)
+    else:
+      var buf: array[8, byte]
+      bigEndian64(addr buf[0], addr pr.double)
+      write(stream, "#xd\"")
+      for b in buf:
+        write(stream, hexAlphabet[b shr 4])
+        write(stream, hexAlphabet[b and 0xf])
+      write(stream, '"')
   of pkRegister:
     write(stream, $pr.register)
   of pkBigInt:
@@ -65,11 +87,10 @@ proc writeText*[E](stream: Stream; pr: Preserve[E]; mode = textPreserves) =
         write(stream, base64.encode(pr.bytes))
         write(stream, ']')
       else:
-        const alphabet = "0123456789abcdef"
         write(stream, "#x\"")
         for b in pr.bytes:
-          write(stream, alphabet[int(b shr 4)])
-          write(stream, alphabet[int(b and 0xf)])
+          write(stream, hexAlphabet[b.int shr 4])
+          write(stream, hexAlphabet[b.int and 0xf])
         write(stream, '"')
   of pkSymbol:
     let sym = pr.symbol.string