Remove dependency on base64 - close #177

rb/build_dist.rb

@@ -1,7 +1,10 @@
 #!/usr/bin/env ruby
 
-require "fileutils"
+require "base64"
 require "digest/md5"
+require "fileutils"
+require "stringio"
+require "zlib"
 
 if File.read("lib/rscons/version.rb") =~ /VERSION = "(.+)"/
   VERSION = $1
@@ -68,11 +71,15 @@ license = File.read("LICENSE.txt").gsub(/^(.*?)$/) do |line|
   end
 end
 
-require "zlib"
-require "base64"
 compressed_script = Zlib::Deflate.deflate(stripped.join)
+hash = Digest::MD5.hexdigest(compressed_script)
 encoded_compressed_script = Base64.encode64(compressed_script).gsub("\n", "")
-hash = Digest::MD5.hexdigest(encoded_compressed_script)
+encoded_compressed_script_io = StringIO.new(encoded_compressed_script)
+commented_encoded_compressed_script = ""
+until encoded_compressed_script_io.eof?
+  line = encoded_compressed_script_io.read(64)
+  commented_encoded_compressed_script += "##{line}\n"
+end
 
 FileUtils.rm_rf(DIST)
 FileUtils.mkdir_p(DIST)
@@ -82,25 +89,53 @@ File.open("#{DIST}/#{PROG_NAME}", "wb", 0755) do |fh|
 
 #{license}
 
+BASE64CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+
+def base64_decode(s)
+  out = ""
+  v = 0
+  bits = 0
+  s.each_char do |c|
+    if cv = BASE64CHARS.index(c)
+      v = (v << 6) | cv
+      bits += 6
+    elsif c == "="
+      break
+    end
+    if bits >= 8
+      out += (v >> (bits - 8)).chr
+      v &= 0xFFFFFFFF >> (32 - (bits - 8))
+      bits -= 8
+    end
+  end
+  out
+end
+
 script = File.join(File.dirname(__FILE__), ".rscons-#{VERSION}-#{hash}.rb")
 unless File.exist?(script)
-  if File.read(__FILE__, mode: "rb") =~ /^#==>(.*)/
+  if File.read(__FILE__, mode: "rb") =~ /^#==>(.*)/m
     require "zlib"
-    require "base64"
     encoded_compressed = $1
-    unescaped_compressed = Base64.decode64(encoded_compressed)
-    inflated = Zlib::Inflate.inflate(unescaped_compressed)
+    compressed = base64_decode(encoded_compressed)
+    if ENV["rscons_dist_specs"]
+      require "digest/md5"
+      if Digest::MD5.hexdigest(compressed) != "#{hash}"
+        raise "Hash mismatch when decompressing rscons executable"
+      end
+    end
+    inflated = Zlib::Inflate.inflate(compressed)
     File.open(script, "wb") do |fh|
       fh.write(inflated)
     end
   else
-    raise "Could not decompress."
+    raise "Error expanding rscons executable"
   end
 end
 load script
 if __FILE__ == $0
   Rscons::Cli.new.run(ARGV)
 end
-#==>#{encoded_compressed_script}
+#==>
+#{commented_encoded_compressed_script}
 EOF
 end