Merge f6549cee26 into deac7df80a

runtime/lua/vim/text.lua

@@ -2,6 +2,17 @@
 
 local M = {}
 
+local alphabet = '0123456789ABCDEF'
+local lookup = {} ---@type table<integer|string, integer|string>
+do
+  for i = 1, #alphabet do
+    local char = alphabet:sub(i, i)
+    lookup[i - 1] = char
+    lookup[char] = i - 1
+    lookup[char:lower()] = i - 1
+  end
+end
+
 --- Hex encode a string.
 ---
 --- @param str string String to encode
@@ -9,7 +20,9 @@ local M = {}
 function M.hexencode(str)
   local enc = {} ---@type string[]
   for i = 1, #str do
-    enc[i] = string.format('%02X', str:byte(i, i + 1))
+    local byte = str:byte(i)
+    enc[#enc + 1] = lookup[math.floor(byte / 16)] --[[@as string]]
+    enc[#enc + 1] = lookup[byte % 16] --[[@as string]]
   end
   return table.concat(enc)
 end
@@ -26,8 +39,12 @@ function M.hexdecode(enc)
 
   local str = {} ---@type string[]
   for i = 1, #enc, 2 do
-    local n = assert(tonumber(enc:sub(i, i + 1), 16))
-    str[#str + 1] = string.char(n)
+    local u = lookup[enc:sub(i, i)] --[[@as integer]]
+    local l = lookup[enc:sub(i + 1, i + 1)] --[[@as integer]]
+    if not u or not l then
+      return nil, 'string must contain only hex characters'
+    end
+    str[#str + 1] = string.char(u * 16 + l)
   end
   return table.concat(str), nil
 end

test/functional/lua/text_spec.lua

@@ -26,5 +26,21 @@ describe('vim.text', function()
       eq(output, vim.text.hexencode(input))
       eq(input, vim.text.hexdecode(output))
     end)
+
+    it('errors on invalid input', function()
+      -- Odd number of hex characters
+      do
+        local res, err = vim.text.hexdecode('ABC')
+        eq(nil, res)
+        eq('string must have an even number of hex characters', err)
+      end
+
+      -- Non-hexadecimal input
+      do
+        local res, err = vim.text.hexdecode('nothex')
+        eq(nil, res)
+        eq('string must contain only hex characters', err)
+      end
+    end)
   end)
 end)