# File lib/arr-pm/file/header.rb, line 36 def read # TODO(sissel): update the comments here to reflect learnings about rpm # internals # At this point assume we've read and consumed the lead and signature. #len = @rpm.signature.index_length + @rpm.signature # # header size is # ( @rpm.signature.index_length * size of a header entry ) # + @rpm.signature.data_length # # header 'entries' are an # int32 (tag id), int32 (tag type), int32 (offset), uint32 (count) # # len = sizeof(il) + sizeof(dl) + (il * sizeof(struct entryInfo_s)) + dl; # See rpm's header.c, the headerLoad method function for reference. # Header always starts with HEADER_MAGIC + index_count(2bytes) + # data_length(2bytes) data = @file.read(HEADER_HEADER_LENGTH).unpack("a8NN") # TODO(sissel): @index_count is really a count, rename? @magic, @index_count, @data_length = data validate @index_size = @index_count * TAG_ENTRY_SIZE tag_data = @file.read(@index_size) data = @file.read(@data_length) (0 ... @index_count).each do |i| offset = i * TAG_ENTRY_SIZE entry_data = tag_data[i * TAG_ENTRY_SIZE, TAG_ENTRY_SIZE] entry = entry_data.unpack("NNNN") entry << data tag = ::RPM::File::Tag.new(*entry) @tags << tag end # each index @length = HEADER_HEADER_LENGTH + @index_size + @data_length end