diff options
| -rw-r--r-- | src/zip.cr | 127 |
1 files changed, 99 insertions, 28 deletions
@@ -13,6 +13,9 @@ module Zip LE = IO::ByteFormat::LittleEndian + # size of buffers, in bytes + BUFFER_SIZE = 8192 + # 4.4.4 general purpose bit flag: (2 bytes) # # Bit 0: If set, indicates that the file is encrypted. @@ -173,15 +176,21 @@ module Zip def compress_none(src_io, dst_io) crc = 0_u32 - buf = Bytes.new(4096) + buf = Bytes.new(BUFFER_SIZE) src_len = 0_u32 while ((len = src_io.read(buf)) > 0) # build output slice dst_buf = (len < buf.size) ? buf[0, len] : buf + dst_crc = Zlib.crc32(dst_buf) + + # update crc + crc = if crc != 0 + Zlib.crc32_combine(crc, dst_crc, dst_buf.size) + else + Zlib.crc32(dst_buf) + end - # add to crc - crc = (crc != 0) ? Zlib.crc32(dst_buf, crc) : Zlib.crc32(dst_buf) # write to output buffer dst_io.write(dst_buf) @@ -194,41 +203,104 @@ module Zip end module DeflateCompressionHelper + ZALLOC_PROC = LibZ::AllocFunc.new do |data, num_items, size| + GC.malloc(num_items * size) + end + + ZFREE_PROC = LibZ::FreeFunc.new do |data, addr| + GC.free(addr) + end + + ZLIB_VERSION = LibZ.zlibVersion + def compress_deflate(src_io, dst_io) crc = 0_u32 - src_len = 0_u32 - dst_len = 0_u32 - # create buffer and intermediate memory io - buf = Bytes.new(4096) - mem_io = MemoryIO.new(4096) + # create read and compress buffers + src_buf = Bytes.new(BUFFER_SIZE) + dst_buf = Bytes.new(BUFFER_SIZE) - Zlib::Deflate.new( - output: mem_io, - sync_close: false, - ) do |zlib_io| - while ((len = src_io.read(buf)) > 0) - # build output slice - dst_buf = (len < buf.size) ? buf[0, len] : buf - - # add to crc - crc = (crc != 0) ? Zlib.crc32(dst_buf, crc) : Zlib.crc32(dst_buf) + # create deflate stream + z = LibZ::ZStream.new( + zalloc: ZALLOC_PROC, + zfree: ZFREE_PROC, + ) - # compress bytes to memory io - zlib_io.write(dst_buf) - src_len += len + # init stream + err = LibZ.deflateInit2( + pointerof(z), + LibZ::DEFAULT_COMPRESSION, # FIXME: make this configurable + LibZ::Z_DEFLATED, + -15, # raw deflate, window bits = 15 + LibZ::DEF_MEM_LEVEL, + LibZ::Strategy::DEFAULT_STRATEGY, + ZLIB_VERSION, + sizeof(LibZ::ZStream) + ) - # write compressed bytes to dst_io - dst_io.write(Bytes.new(mem_io.buffer, mem_io.pos)) - dst_len += mem_io.pos + # check for error + if err != LibZ::Error::OK + # raise zlib error + raise Zlib::Error.new(err, z) + end - # clear memio - mem_io.rewind + # loop and compress input data + while ((len = src_io.read(src_buf)) > 0) + # build temp slice (if necessary) + tmp_buf = (len < src_buf.size) ? src_buf[0, len] : src_buf + tmp_crc = Zlib.crc32(tmp_buf) + + # update crc + crc = if crc != 0 + Zlib.crc32_combine(crc, tmp_crc, tmp_buf.size) + else + Zlib.crc32(tmp_buf) end + + # set zlib input buffer + z.next_in = tmp_buf.to_unsafe + z.avail_in = tmp_buf.size.to_u32 + + # write compressed data to dst io + write_compressed(dst_io, dst_buf, pointerof(z), false) end + # set zlib input buffer to null + z.next_in = Pointer(UInt8).null + z.avail_in = 0_u32 + + # flush remaining data + write_compressed(dst_io, dst_buf, pointerof(z), true) + + # free stream + LibZ.deflateEnd(pointerof(z)) + # return results - { crc.to_u32, src_len, dst_len } + { crc.to_u32, z.total_in.to_u32, z.total_out.to_u32 } + end + + private def write_compressed( + io : IO, + buf : Bytes, + zp : Pointer(LibZ::ZStream), + flush : Bool, + ) + zf = flush ? LibZ::Flush::FINISH : LibZ::Flush::NO_FLUSH + + loop do + # set zlib output buffer + zp.value.next_out = buf.to_unsafe + zp.value.avail_out = buf.size.to_u32 + + # compress data (TODO: check for error) + LibZ.deflate(zp, zf) + + # write compressed buffer to dst io + len = buf.size - zp.value.avail_out + io.write((len > 0) ? buf[0, len] : buf) + + break if zp.value.avail_out != 0 + end end end @@ -449,7 +521,6 @@ module Zip # return number of bytes written 46_u32 + path_len + extras_len + comment_len end - end class Writer |