From bfa244c8fa87827fae286e474fa015b1c214ea7f Mon Sep 17 00:00:00 2001
From: Pete Matsyburka <pete@docuseal.com>
Date: Mon, 19 May 2025 14:06:37 +0300
Subject: [PATCH] add ico and bmp support

---
 lib/load_bmp.rb                               | 170 ++++++++++++++
 lib/load_ico.rb                               | 209 ++++++++++++++++++
 lib/submissions/generate_audit_trail.rb       |   2 +-
 .../generate_result_attachments.rb            |  29 ++-
 4 files changed, 403 insertions(+), 7 deletions(-)
 create mode 100644 lib/load_bmp.rb
 create mode 100644 lib/load_ico.rb

diff --git a/lib/load_bmp.rb b/lib/load_bmp.rb
new file mode 100644
index 00000000..b5ea074a
--- /dev/null
+++ b/lib/load_bmp.rb
@@ -0,0 +1,170 @@
+# frozen_string_literal: true
+
+module LoadBmp
+  module_function
+
+  # rubocop:disable Metrics
+  def call(bmp_bytes)
+    bmp_bytes = bmp_bytes.b
+
+    header_data = parse_bmp_headers(bmp_bytes)
+
+    raw_pixel_data_from_file = extract_raw_pixel_data_blob(
+      bmp_bytes,
+      header_data[:pixel_data_offset],
+      header_data[:bmp_stride],
+      header_data[:height]
+    )
+
+    final_pixel_data = prepare_unpadded_pixel_data_string(
+      raw_pixel_data_from_file,
+      header_data[:bpp],
+      header_data[:width],
+      header_data[:height],
+      header_data[:bmp_stride]
+    )
+
+    bands = header_data[:bpp] / 8
+
+    unless header_data[:bpp] == 24 || header_data[:bpp] == 32
+      raise ArgumentError, "Conversion for #{header_data[:bpp]}-bpp BMP not implemented."
+    end
+
+    image = Vips::Image.new_from_memory(final_pixel_data, header_data[:width], header_data[:height], bands, :uchar)
+
+    image = image.flip(:vertical) if header_data[:orientation] == -1
+
+    image_rgb =
+      if bands == 3
+        Vips::Image.bandjoin([image[2], image[1], image[0]])
+      elsif bands == 4
+        Vips::Image.bandjoin([image[2], image[1], image[0], image[3]])
+      else
+        image
+      end
+
+    if image_rgb.interpretation == :multiband || image_rgb.interpretation == :'b-w'
+      image_rgb = image_rgb.copy(interpretation: :srgb)
+    end
+
+    image_rgb
+  end
+
+  def parse_bmp_headers(bmp_bytes)
+    raise ArgumentError, 'BMP data too short for file header (14 bytes).' if bmp_bytes.bytesize < 14
+
+    signature, pixel_data_offset = bmp_bytes.unpack('a2@10L<')
+
+    raise ArgumentError, "Not a valid BMP file (invalid signature 'BM')." if signature != 'BM'
+
+    raise ArgumentError, 'BMP data too short for info header size field (4 bytes).' if bmp_bytes.bytesize < (14 + 4)
+
+    info_header_size = bmp_bytes.unpack1('@14L<')
+
+    min_expected_info_header_size = 40
+
+    if info_header_size < min_expected_info_header_size
+      raise ArgumentError,
+            "Unsupported BMP info header size: #{info_header_size}. Expected at least #{min_expected_info_header_size}."
+    end
+
+    header_and_info_header_min_bytes = 14 + min_expected_info_header_size
+
+    if bmp_bytes.bytesize < header_and_info_header_min_bytes
+      raise ArgumentError,
+            'BMP data too short for essential BITMAPINFOHEADER fields ' \
+            "(requires #{header_and_info_header_min_bytes} bytes total)."
+    end
+
+    _header_size_check, width, raw_height_from_header, planes, bpp, compression =
+      bmp_bytes.unpack('@14L<l<l<S<S<L<')
+
+    height = 0
+    orientation = -1
+
+    if raw_height_from_header.negative?
+      height = -raw_height_from_header
+      orientation = 1
+    else
+      height = raw_height_from_header
+    end
+
+    raise ArgumentError, 'BMP width must be positive.' if width <= 0
+    raise ArgumentError, 'BMP height must be positive.' if height <= 0
+
+    if compression != 0
+      raise ArgumentError,
+            "Unsupported BMP compression type: #{compression}. Only uncompressed (0) is supported."
+    end
+
+    unless [24, 32].include?(bpp)
+      raise ArgumentError, "Unsupported BMP bits per pixel: #{bpp}. Only 24-bit and 32-bit are supported."
+    end
+
+    raise ArgumentError, "Unsupported BMP planes: #{planes}. Expected 1." if planes != 1
+
+    bytes_per_pixel = bpp / 8
+    row_size_unpadded = width * bytes_per_pixel
+    bmp_stride = (row_size_unpadded + 3) & ~3
+
+    {
+      width:,
+      height:,
+      bpp:,
+      pixel_data_offset:,
+      bmp_stride:,
+      orientation:
+    }
+  end
+
+  def extract_raw_pixel_data_blob(bmp_bytes, pixel_data_offset, bmp_stride, height)
+    expected_pixel_data_size = bmp_stride * height
+
+    if pixel_data_offset + expected_pixel_data_size > bmp_bytes.bytesize
+      actual_available = bmp_bytes.bytesize - pixel_data_offset
+      actual_available = 0 if actual_available.negative?
+      raise ArgumentError,
+            "Pixel data segment (offset #{pixel_data_offset}, expected size #{expected_pixel_data_size}) " \
+            "exceeds BMP file size (#{bmp_bytes.bytesize}). " \
+            "Only #{actual_available} bytes available after offset."
+    end
+
+    raw_pixel_data_from_file = bmp_bytes.byteslice(pixel_data_offset, expected_pixel_data_size)
+
+    if raw_pixel_data_from_file.nil? || raw_pixel_data_from_file.bytesize < expected_pixel_data_size
+      raise ArgumentError,
+            "Extracted pixel data is smaller (#{raw_pixel_data_from_file&.bytesize || 0} bytes) " \
+            "than expected (#{expected_pixel_data_size} bytes based on stride and height)."
+    end
+
+    raw_pixel_data_from_file
+  end
+
+  def prepare_unpadded_pixel_data_string(raw_pixel_data_from_file, bpp, width, height, bmp_stride)
+    bytes_per_pixel = bpp / 8
+    actual_row_width_bytes = width * bytes_per_pixel
+
+    unpadded_rows = Array.new(height)
+    current_offset_in_blob = 0
+
+    height.times do |i|
+      if current_offset_in_blob + actual_row_width_bytes > raw_pixel_data_from_file.bytesize
+        raise ArgumentError,
+              "Not enough data in pixel blob for row #{i}. Offset #{current_offset_in_blob}, " \
+              "row width #{actual_row_width_bytes}, blob size #{raw_pixel_data_from_file.bytesize}"
+      end
+
+      unpadded_row_slice = raw_pixel_data_from_file.byteslice(current_offset_in_blob, actual_row_width_bytes)
+
+      if unpadded_row_slice.nil? || unpadded_row_slice.bytesize < actual_row_width_bytes
+        raise ArgumentError, "Failed to slice a full unpadded row from pixel data blob for row #{i}."
+      end
+
+      unpadded_rows[i] = unpadded_row_slice
+      current_offset_in_blob += bmp_stride
+    end
+
+    unpadded_rows.join
+  end
+  # rubocop:enable Metrics
+end
diff --git a/lib/load_ico.rb b/lib/load_ico.rb
new file mode 100644
index 00000000..2c48d766
--- /dev/null
+++ b/lib/load_ico.rb
@@ -0,0 +1,209 @@
+# frozen_string_literal: true
+
+module LoadIco
+  BI_RGB = 0
+
+  module_function
+
+  # rubocop:disable Metrics
+  def call(ico_bytes)
+    io = StringIO.new(ico_bytes)
+    _reserved, type, count = io.read(6)&.unpack('S<S<S<')
+
+    raise ArgumentError, 'Unable to load' unless type == 1 && count&.positive?
+
+    ico_entries_parsed = []
+
+    count.times do
+      entry_bytes = io.read(16)
+
+      raise ArgumentError, 'Unable to load' unless entry_bytes && entry_bytes.bytesize == 16
+
+      width_byte, height_byte, _num_colors_palette, _rsvd_entry, _planes_icon_entry, bpp_icon_entry,
+      img_data_size, img_data_offset = entry_bytes.unpack('CCCCS<S<L<L<')
+
+      width = width_byte.zero? ? 256 : width_byte
+      height = height_byte.zero? ? 256 : height_byte
+      sort_bpp = bpp_icon_entry.zero? ? 32 : bpp_icon_entry
+
+      ico_entries_parsed << {
+        width: width, height: height,
+        sort_bpp: sort_bpp,
+        size: img_data_size, offset: img_data_offset
+      }
+    end
+
+    best_entry = ico_entries_parsed.min_by { |e| [-e[:width] * e[:height], -e[:sort_bpp]] }
+
+    raise ArgumentError, 'Unable to load' unless best_entry
+
+    io.seek(best_entry[:offset])
+    image_data_bytes = io.read(best_entry[:size])
+
+    raise ArgumentError, 'Unable to load' unless image_data_bytes && image_data_bytes.bytesize == best_entry[:size]
+
+    image = load_image_entry(image_data_bytes, best_entry[:width], best_entry[:height])
+
+    raise ArgumentError, 'Unable to load' unless image
+
+    image
+  end
+
+  def load_image_entry(image_data_bytes, ico_entry_width, ico_entry_height)
+    dib_io = StringIO.new(image_data_bytes)
+
+    dib_header_size_arr = dib_io.read(4)&.unpack('L<')
+    return nil unless dib_header_size_arr
+
+    dib_header_size = dib_header_size_arr.first
+    return nil unless dib_header_size && dib_header_size >= 40
+
+    dib_params_bytes = dib_io.read(36)
+    return nil unless dib_params_bytes && dib_params_bytes.bytesize == 36
+
+    dib_width, dib_actual_height_field, dib_planes, dib_bpp,
+    dib_compression, _dib_image_size, _xpels, _ypels,
+    dib_clr_used, _dib_clr_important = dib_params_bytes.unpack('l<l<S<S<L<L<l<l<L<L<')
+
+    return nil unless dib_width && dib_actual_height_field && dib_planes && dib_bpp && dib_compression && dib_clr_used
+    return nil unless dib_width == ico_entry_width
+
+    image_pixel_height = ico_entry_height
+
+    expected_dib_height_no_mask = image_pixel_height
+    expected_dib_height_with_mask = image_pixel_height * 2
+    actual_dib_pixel_rows_abs = dib_actual_height_field.abs
+
+    unless actual_dib_pixel_rows_abs == expected_dib_height_no_mask ||
+           actual_dib_pixel_rows_abs == expected_dib_height_with_mask
+      return nil
+    end
+
+    return nil unless dib_planes == 1
+    return nil unless dib_compression == BI_RGB
+    return nil unless [1, 4, 8, 24, 32].include?(dib_bpp)
+
+    has_and_mask = (actual_dib_pixel_rows_abs == expected_dib_height_with_mask) && (dib_bpp < 32)
+
+    dib_io.seek(dib_header_size, IO::SEEK_SET)
+
+    palette = []
+    if dib_bpp <= 8
+      num_palette_entries = dib_clr_used.zero? ? (1 << dib_bpp) : dib_clr_used
+      num_palette_entries.times do
+        palette_color_bytes = dib_io.read(4)
+        return nil unless palette_color_bytes && palette_color_bytes.bytesize == 4
+
+        b, g, r, _a_reserved = palette_color_bytes.unpack('CCCC')
+        palette << [r, g, b, 255]
+      end
+    end
+
+    xor_mask_data_offset = dib_io.pos
+    xor_scanline_stride = (((dib_width * dib_bpp) + 31) / 32) * 4
+
+    and_mask_data_offset = 0
+    and_scanline_stride = 0
+    if has_and_mask
+      and_mask_data_offset = xor_mask_data_offset + (image_pixel_height * xor_scanline_stride)
+      and_scanline_stride = (((dib_width * 1) + 31) / 32) * 4
+    end
+
+    flat_rgba_pixels = []
+
+    (0...image_pixel_height).each do |y_row|
+      y_dib_row = image_pixel_height - 1 - y_row
+
+      dib_io.seek(xor_mask_data_offset + (y_dib_row * xor_scanline_stride))
+      xor_scanline_bytes = dib_io.read(xor_scanline_stride)
+      min_xor_bytes_needed = ((dib_width * dib_bpp) + 7) / 8
+      return nil unless xor_scanline_bytes && xor_scanline_bytes.bytesize >= min_xor_bytes_needed
+
+      and_mask_bits_for_row = []
+      if has_and_mask
+        dib_io.seek(and_mask_data_offset + (y_dib_row * and_scanline_stride))
+        and_mask_scanline_bytes = dib_io.read(and_scanline_stride)
+        min_and_bytes_needed = ((dib_width * 1) + 7) / 8
+        return nil unless and_mask_scanline_bytes && and_mask_scanline_bytes.bytesize >= min_and_bytes_needed
+
+        (0...dib_width).each do |x_pixel|
+          byte_index = x_pixel / 8
+          bit_index_in_byte = 7 - (x_pixel % 8)
+          byte_val = and_mask_scanline_bytes.getbyte(byte_index)
+          and_mask_bits_for_row << ((byte_val >> bit_index_in_byte) & 1)
+        end
+      end
+
+      (0...dib_width).each do |x_pixel|
+        r = 0
+        g = 0
+        b = 0
+        a = 255
+
+        case dib_bpp
+        when 32
+          offset = x_pixel * 4
+          blue = xor_scanline_bytes.getbyte(offset)
+          green = xor_scanline_bytes.getbyte(offset + 1)
+          red = xor_scanline_bytes.getbyte(offset + 2)
+          alpha_val = xor_scanline_bytes.getbyte(offset + 3)
+          r = red
+          g = green
+          b = blue
+          a = alpha_val
+        when 24
+          offset = x_pixel * 3
+          blue = xor_scanline_bytes.getbyte(offset)
+          green = xor_scanline_bytes.getbyte(offset + 1)
+          red = xor_scanline_bytes.getbyte(offset + 2)
+          r = red
+          g = green
+          b = blue
+        when 8
+          idx = xor_scanline_bytes.getbyte(x_pixel)
+          r_p, g_p, b_p, a_p = palette[idx] || [0, 0, 0, 0]
+          r = r_p
+          g = g_p
+          b = b_p
+          a = a_p
+        when 4
+          byte_val = xor_scanline_bytes.getbyte(x_pixel / 2)
+          idx = (x_pixel.even? ? (byte_val >> 4) : (byte_val & 0x0F))
+          r_p, g_p, b_p, a_p = palette[idx] || [0, 0, 0, 0]
+          r = r_p
+          g = g_p
+          b = b_p
+          a = a_p
+        when 1
+          byte_val = xor_scanline_bytes.getbyte(x_pixel / 8)
+          idx = (byte_val >> (7 - (x_pixel % 8))) & 1
+          r_p, g_p, b_p, a_p = palette[idx] || [0, 0, 0, 0]
+          r = r_p
+          g = g_p
+          b = b_p
+          a = a_p
+        end
+
+        if has_and_mask && !and_mask_bits_for_row.empty?
+          a = and_mask_bits_for_row[x_pixel] == 1 ? 0 : 255
+        end
+        flat_rgba_pixels.push(r, g, b, a)
+      end
+    end
+
+    pixel_data_string = flat_rgba_pixels.pack('C*')
+
+    expected_bytes = dib_width * image_pixel_height * 4
+
+    return nil unless pixel_data_string.bytesize == expected_bytes && expected_bytes.positive?
+
+    Vips::Image.new_from_memory(
+      pixel_data_string,
+      dib_width,
+      image_pixel_height,
+      4,
+      :uchar
+    )
+  end
+  # rubocop:enable Metrics
+end
diff --git a/lib/submissions/generate_audit_trail.rb b/lib/submissions/generate_audit_trail.rb
index ecfe9b84..32622049 100644
--- a/lib/submissions/generate_audit_trail.rb
+++ b/lib/submissions/generate_audit_trail.rb
@@ -309,7 +309,7 @@ module Submissions
 
               image =
                 begin
-                  Vips::Image.new_from_buffer(attachment.download, '').autorot
+                  Submissions::GenerateResultAttachments.load_vips_image(attachment).autorot
                 rescue Vips::Error
                   next unless attachment.content_type.starts_with?('image/')
                   next if attachment.byte_size.zero?
diff --git a/lib/submissions/generate_result_attachments.rb b/lib/submissions/generate_result_attachments.rb
index 0a5da813..de8e055f 100644
--- a/lib/submissions/generate_result_attachments.rb
+++ b/lib/submissions/generate_result_attachments.rb
@@ -11,6 +11,9 @@ module Submissions
                   'Helvetica'
                 end
 
+    ICO_REGEXP = %r{\Aimage/(?:x-icon|vnd\.microsoft\.icon)\z}
+    BMP_REGEXP = %r{\Aimage/(?:bmp|x-bmp|x-ms-bmp)\z}
+
     FONT_BOLD_NAME = if File.exist?(FONT_BOLD_PATH)
                        FONT_BOLD_PATH
                      else
@@ -250,9 +253,7 @@ module Submissions
           when ->(type) { type == 'signature' && (with_signature_id || field.dig('preferences', 'reason_field_uuid')) }
             attachment = submitter.attachments.find { |a| a.uuid == value }
 
-            attachments_data_cache[attachment.uuid] ||= attachment.download
-
-            image = Vips::Image.new_from_buffer(attachments_data_cache[attachment.uuid], '').autorot
+            image = load_vips_image(attachment, attachments_data_cache).autorot
 
             reason_value = submitter.values[field.dig('preferences', 'reason_field_uuid')].presence
 
@@ -360,11 +361,9 @@ module Submissions
           when 'image', 'signature', 'initials', 'stamp'
             attachment = submitter.attachments.find { |a| a.uuid == value }
 
-            attachments_data_cache[attachment.uuid] ||= attachment.download
-
             image =
               begin
-                Vips::Image.new_from_buffer(attachments_data_cache[attachment.uuid], '').autorot
+                load_vips_image(attachment, attachments_data_cache).autorot
               rescue Vips::Error
                 next unless attachment.content_type.starts_with?('image/')
                 next if attachment.byte_size.zero?
@@ -804,6 +803,24 @@ module Submissions
       []
     end
 
+    def load_vips_image(attachment, cache = {})
+      cache[attachment.uuid] ||= attachment.download
+
+      data = cache[attachment.uuid]
+
+      if ICO_REGEXP.match?(attachment.content_type)
+        Rollbar.error("Load ICO: #{attachment.uuid}") if defined?(Rollbar)
+
+        LoadIco.call(data)
+      elsif BMP_REGEXP.match?(attachment.content_type)
+        Rollbar.error("Load BMP: #{attachment.uuid}") if defined?(Rollbar)
+
+        LoadBmp.call(data)
+      else
+        Vips::Image.new_from_buffer(data, '')
+      end
+    end
+
     def h
       Rails.application.routes.url_helpers
     end