1 files changed, 68 insertions, 0 deletions
diff --git a/lua/colorizer/parser/rgba_hex.lua b/lua/colorizer/parser/rgba_hex.lua
new file mode 100644
index 0000000..0f16fbe
--- /dev/null
+++ b/lua/colorizer/parser/rgba_hex.lua
@@ -0,0 +1,68 @@
+---Helper function to parse argb
+local bit = require "bit"
+local floor, min = math.floor, math.min
+local band, rshift, lshift = bit.band, bit.rshift, bit.lshift
+
+local utils = require "colorizer.utils"
+local byte_is_alphanumeric = utils.byte_is_alphanumeric
+local byte_is_hex = utils.byte_is_hex
+local parse_hex = utils.parse_hex
+
+local parser = {}
+
+---parse for #rrggbbaa and return rgb hex.
+-- a format used in android apps
+---@param line string: line to parse
+---@param i number: index of line from where to start parsing
+---@param opts table: Containing minlen, maxlen, valid_lengths
+---@return number|nil: index of line where the hex value ended
+---@return string|nil: rgb hex value
+function parser.rgba_hex_parser(line, i, opts)
+  local minlen, maxlen, valid_lengths = opts.minlen, opts.maxlen, opts.valid_lengths
+  local j = i + 1
+  if #line < j + minlen - 1 then
+    return
+  end
+
+  if i > 1 and byte_is_alphanumeric(line:byte(i - 1)) then
+    return
+  end
+
+  local n = j + maxlen
+  local alpha
+  local v = 0
+
+  while j <= min(n, #line) do
+    local b = line:byte(j)
+    if not byte_is_hex(b) then
+      break
+    end
+    if j - i >= 7 then
+      alpha = parse_hex(b) + lshift(alpha or 0, 4)
+    else
+      v = parse_hex(b) + lshift(v, 4)
+    end
+    j = j + 1
+  end
+
+  if #line >= j and byte_is_alphanumeric(line:byte(j)) then
+    return
+  end
+
+  local length = j - i
+  if length ~= 4 and length ~= 7 and length ~= 9 then
+    return
+  end
+
+  if alpha then
+    alpha = tonumber(alpha) / 255
+    local r = floor(band(rshift(v, 16), 0xFF) * alpha)
+    local g = floor(band(rshift(v, 8), 0xFF) * alpha)
+    local b = floor(band(v, 0xFF) * alpha)
+    local rgb_hex = string.format("%02x%02x%02x", r, g, b)
+    return 9, rgb_hex
+  end
+  return (valid_lengths[length - 1] and length), line:sub(i + 1, i + length - 1)
+end
+
+return parser.rgba_hex_parser