initial commit

8 files changed, 660 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c8cf75a
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+/doc/
+/libs/
+/.crystal/
+/.shards/
+
+
+# Libraries don't need dependency lock
+# Dependencies will be locked in application that uses them
+/shard.lock
+
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..ffc7b6a
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1 @@
+language: crystal
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..3f522c4
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Paul Duncan
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..454410d
--- /dev/null
+++ b/README.md
@@ -0,0 +1,41 @@
+# zip-crystal
+
+TODO: Write a description here
+
+## Installation
+
+
+Add this to your application's `shard.yml`:
+
+```yaml
+dependencies:
+  zip-crystal:
+    github: [your-github-name]/zip-crystal
+```
+
+
+## Usage
+
+
+```crystal
+require "zip-crystal"
+```
+
+
+TODO: Write usage instructions here
+
+## Development
+
+TODO: Write development instructions here
+
+## Contributing
+
+1. Fork it ( https://github.com/[your-github-name]/zip-crystal/fork )
+2. Create your feature branch (git checkout -b my-new-feature)
+3. Commit your changes (git commit -am 'Add some feature')
+4. Push to the branch (git push origin my-new-feature)
+5. Create a new Pull Request
+
+## Contributors
+
+- [[your-github-name]](https://github.com/[your-github-name]) Paul Duncan - creator, maintainer
diff --git a/shard.yml b/shard.yml
new file mode 100644
index 0000000..3a73c95
--- /dev/null
+++ b/shard.yml
@@ -0,0 +1,7 @@
+name: zip-crystal
+version: 0.1.0
+
+authors:
+  - Paul Duncan <pabs@pablotron.org>
+
+license: MIT
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
new file mode 100644
index 0000000..78a7a10
--- /dev/null
+++ b/spec/spec_helper.cr
@@ -0,0 +1,2 @@
+require "spec"
+require "../src/zip-crystal"
diff --git a/spec/zip-crystal_spec.cr b/spec/zip-crystal_spec.cr
new file mode 100644
index 0000000..910b8f4
--- /dev/null
+++ b/spec/zip-crystal_spec.cr
@@ -0,0 +1,9 @@
+require "./spec_helper"
+
+describe Zip::Crystal do
+  # TODO: Write tests
+
+  it "works" do
+    false.should eq(true)
+  end
+end
diff --git a/src/zip.cr b/src/zip.cr
new file mode 100644
index 0000000..ce61e13
--- /dev/null
+++ b/src/zip.cr
@@ -0,0 +1,569 @@
+require "./zip/*"
+
+module Zip
+  VERSION = "0.1.0"
+
+  LE = IO::ByteOrder::LittleEndian
+
+  # 4.4.4 general purpose bit flag: (2 bytes)
+  #
+  # Bit 0: If set, indicates that the file is encrypted.
+  #
+  # (For Method 6 - Imploding)
+  # Bit 1: If the compression method used was type 6,
+  #        Imploding, then this bit, if set, indicates
+  #        an 8K sliding dictionary was used.  If clear,
+  #        then a 4K sliding dictionary was used.
+  #
+  # Bit 2: If the compression method used was type 6,
+  #        Imploding, then this bit, if set, indicates
+  #        3 Shannon-Fano trees were used to encode the
+  #        sliding dictionary output.  If clear, then 2
+  #        Shannon-Fano trees were used.
+  #
+  # (For Methods 8 and 9 - Deflating)
+  # Bit 2  Bit 1
+  #   0      0    Normal (-en) compression option was used.
+  #   0      1    Maximum (-exx/-ex) compression option was used.
+  #   1      0    Fast (-ef) compression option was used.
+  #   1      1    Super Fast (-es) compression option was used.
+  #
+  # (For Method 14 - LZMA)
+  # Bit 1: If the compression method used was type 14,
+  #        LZMA, then this bit, if set, indicates
+  #        an end-of-stream (EOS) marker is used to
+  #        mark the end of the compressed data stream.
+  #        If clear, then an EOS marker is not present
+  #        and the compressed data size must be known
+  #        to extract.
+  #
+  # Note:  Bits 1 and 2 are undefined if the compression
+  #        method is any other.
+  #
+  # Bit 3: If this bit is set, the fields crc-32, compressed 
+  #        size and uncompressed size are set to zero in the 
+  #        local header.  The correct values are put in the 
+  #        data descriptor immediately following the compressed
+  #        data.  (Note: PKZIP version 2.04g for DOS only 
+  #        recognizes this bit for method 8 compression, newer 
+  #        versions of PKZIP recognize this bit for any 
+  #        compression method.)
+  #
+  # Bit 4: Reserved for use with method 8, for enhanced
+  #        deflating. 
+  #
+  # Bit 5: If this bit is set, this indicates that the file is 
+  #        compressed patched data.  (Note: Requires PKZIP 
+  #        version 2.70 or greater)
+  #
+  # Bit 6: Strong encryption.  If this bit is set, you MUST
+  #        set the version needed to extract value to at least
+  #        50 and you MUST also set bit 0.  If AES encryption
+  #        is used, the version needed to extract value MUST 
+  #        be at least 51. See the section describing the Strong
+  #        Encryption Specification for details.  Refer to the 
+  #        section in this document entitled "Incorporating PKWARE 
+  #        Proprietary Technology into Your Product" for more 
+  #        information.
+  #
+  # Bit 7: Currently unused.
+  #
+  # Bit 8: Currently unused.
+  #
+  # Bit 9: Currently unused.
+  #
+  # Bit 10: Currently unused.
+  #
+  # Bit 11: Language encoding flag (EFS).  If this bit is set,
+  #         the filename and comment fields for this file
+  #         MUST be encoded using UTF-8. (see APPENDIX D)
+  #
+  # Bit 12: Reserved by PKWARE for enhanced compression.
+  #
+  # Bit 13: Set when encrypting the Central Directory to indicate 
+  #         selected data values in the Local Header are masked to
+  #         hide their actual values.  See the section describing 
+  #         the Strong Encryption Specification for details.  Refer
+  #         to the section in this document entitled "Incorporating 
+  #         PKWARE Proprietary Technology into Your Product" for 
+  #         more information.
+  #
+  # Bit 14: Reserved by PKWARE.
+  #
+  # Bit 15: Reserved by PKWARE.
+  #
+  @[Flags]
+  enum GeneralFlags
+    WEAK_ENCRYPTION
+    COMPRESSION_OPTION_1
+    COMPRESSION_OPTION_2
+    FOOTER
+    RESERVED_4
+    PATCH
+    STRONG_ENCRYPTION
+    RESERVED_7
+    RESERVED_8
+    RESERVED_9
+    RESERVED_10
+    EFS
+    RESERVED_12
+    MASKED_VALUES
+    RESERVED_14
+    RESERVED_15
+  end
+
+  enum CompressionMethod
+    NONE = 0            # Stored (no compression)
+    SHRUNK = 1          # Shrunk
+    REDUCED_1 = 2       # Reduced with compression factor 1
+    REDUCED_2 = 3       # Reduced with compression factor 2
+    REDUCED_3 = 4       # Reduced with compression factor 3
+    REDUCED_4 = 5       # Reduced with compression factor 4
+    IMPLODED = 6        # Imploded
+    # Tokenized = 7       # Reserved for Tokenizing compression algorithm
+    DEFLATE = 8         # Deflated
+    DEFLATE64 = 9       # Enhanced Deflating using Deflate64(tm)
+    TERSE_OLD = 10      # PKWARE Data Compression Library Imploding (old IBM TERSE)
+    # RESERVED_11 = 11    # Reserved by PKWARE
+    BZIP2 = 12          # BZIP2
+    # RESERVED_13 = 13  # Reserved by PKWARE
+    LZMA = 14           # LZMA (EFS)
+    # RESERVED_15 = 15    # Reserved by PKWARE
+    # RESERVED_16 = 16    # Reserved by PKWARE
+    # RESERVED_17 = 17    # Reserved by PKWARE
+    TERSE = 18          # IBM TERSE (new)
+    LZ77 = 19           # IBM LZ77 z Architecture (PFS)
+    WAVPACK = 97        # WavPack compressed data
+    PPMD = 98           # PPMd version I, Rev 1
+  end
+
+  # FIXME: should this have a better class?
+  class Error < Exception
+  end
+
+  # TODO
+  class Reader
+    def initialize(path : String)
+    end
+
+    def initialize(io : IO)
+    end
+  end
+
+  module NoneCompressor
+    def self.compress_none(src_io, dst_io)
+      crc = 0_u32
+
+      buf = Bytes.new(4096)
+      src_len = 0_u64
+
+      while ((len = src_io.read(buf)) > 0)
+        # TODO: crc32
+
+        dst_io.write((len < buf.size) ? Bytes.new(buf, len) : len)
+        src_len += len
+      end
+
+      # return results
+      { crc, src_len, dst_len }
+    end
+  end
+
+  module DeflateCompressor
+    def self.compress_deflate(src_io, dst_io)
+      crc = 0_u32
+      src_len = 0_u64
+      dst_len = 0_u64
+
+      # create buffer and intermediate memory io
+      buf = Bytes.new(4096)
+      mem_io = MemoryIO.new(4096)
+
+      Zlib::Deflate::Deflate.new(
+        output:     mem_io,
+        sync_close: false,
+      ) do |zlib_io|
+        while ((len = src_io.read(buf)) > 0)
+          # TODO: crc32
+
+          # compress bytes to memory io
+          zlib_io.write((len < buf.size) ? Bytes.new(buf, len) : buf)
+          src_len += len
+
+          # write compressed bytes to dst_io
+          dst_io.write(Bytes.new(mem_io.buffer, mem_io.pos))
+          dst_len += mem_io.pos
+
+          # clear memio
+          mem_io.rewind
+        end
+      end
+
+      # return results
+      { crc, src_len, dst_len }
+    end
+  end
+
+  class WriterEntry
+    include NoneCompressor
+    include DeflateCompressor
+
+    # TODO version needed to extract and header flags
+    # (used for header and central header)
+    VERSION_NEEDED = 0_u32
+    GENERAL_FLAGS = GeneralFlags.flags(FOOTER, EFS)
+
+    def initialize(
+      @pos      : UInt64,
+      @path     : String, 
+      @io       : IO,
+      @method   : CompressionMethod = CompressionMethod::DEFLATE,
+      @time     : Time = Time.now,
+      @comment  : String? = nil,
+    )
+      @crc = 0_u32
+      @src_len = 0_u64
+      @dst_len = 0_u64
+    end
+
+    def to_s(dst_io) : UInt64
+      # write header
+      r = write_header(dst_io)
+
+      # write body
+      @crc, @src_len, @dst_len = write_body(dst_io)
+      r += dst_len
+
+      # write footer
+      r += write_footer(dst_io, crc, src_len, dst_len)
+
+      # return number of bytes written
+      r
+    end
+
+    #
+    # local file header signature     4 bytes  (0x04034b50)
+    # version needed to extract       2 bytes
+    # general purpose bit flag        2 bytes
+    # compression method              2 bytes
+    # last mod file time              2 bytes
+    # last mod file date              2 bytes
+    # crc-32                          4 bytes
+    # compressed size                 4 bytes
+    # uncompressed size               4 bytes
+    # file name length                2 bytes
+    # extra field length              2 bytes
+    # file name (variable size)
+    # extra field (variable size)
+    #
+
+    HEADER_MAGIC = 0x04034b50_u32
+
+    private def write_header(
+      io      : IO,
+      path    : String,
+      method  : CompressionMethod,
+      time    : Time,
+    ) : UInt64
+      # get path length, in bytes
+      path_len = path.bytesize
+
+      # check file path
+      raise "empty file path" if path_len == 0
+      raise "file path too long" if path_len >= UInt16::MAX
+      raise "file path contains leading slash" if path[0] == '/'
+
+      # write magic, version needed, flags, and compression method
+      HEADER_MAGIC.to_io(io, LE)
+      VERSION_NEEDED.to_u16.to_io(io, LE)
+      GENERAL_FLAGS.to_u16.to_io(io, LE)
+      method.to_io(io, LE)
+
+      # TODO: write time
+      # encode(time, io)
+
+      # crc, compressed size, uncompressed size
+      0_u32.to_io(io, LE)
+      0_u32.to_io(io, LE)
+      0_u32.to_io(io, LE)
+      path_len.to_u16.to_io(io, LE)
+
+      # write extras field length
+      extras_len = 0_u32
+      extras_len.to_u16.to_io(io, LE)
+
+      # write path field
+      path.to_s(io)
+
+      # write extra fields
+      # TODO: implement this
+
+      # return number of bytes written
+      30_u64 + path_len + extras_len
+    end
+
+    private def write_body(dst_io : IO)
+      case @method
+      when CompressionMethod::NONE
+        compress_none(@io, dst_io)
+      when CompressionMethod::DEFLATE
+        compress_deflate(@io, dst_io)
+      else
+        raise Error, "unsupported compression method"
+      end
+    end
+
+    #  4.3.9  Data descriptor:
+    #       MAGIC = 0x08074b50              4 bytes
+    #       crc-32                          4 bytes
+    #       compressed size                 4 bytes
+    #       uncompressed size               4 bytes
+    #
+    # 4.3.9.3 Although not originally assigned a signature, the value 
+    # 0x08074b50 has commonly been adopted as a signature value 
+
+    FOOTER_MAGIC = 0x08074b50_u32
+
+    private def write_footer(
+      io      : IO,
+      crc     : UInt32,
+      src_len : UInt64,
+      dst_len : UInt64,
+    ) : UInt64
+      # write footer
+      FOOTER_MAGIC.to_io(io, LE)
+      crc.to_io(io, LE)
+      dst_len.to_io(io, LE)
+      src_len.to_io(io, LE)
+
+      # return number of bytes written
+      16_u64
+    end
+
+    #
+    # central file header signature   4 bytes  (0x02014b50)
+    # version made by                 2 bytes
+    # version needed to extract       2 bytes
+    # general purpose bit flag        2 bytes
+    # compression method              2 bytes
+    # last mod file time              2 bytes
+    # last mod file date              2 bytes
+    # crc-32                          4 bytes
+    # compressed size                 4 bytes
+    # uncompressed size               4 bytes
+    # file name length                2 bytes
+    # extra field length              2 bytes
+    # file comment length             2 bytes
+    # disk number start               2 bytes
+    # internal file attributes        2 bytes
+    # external file attributes        4 bytes
+    # relative offset of local header 4 bytes
+    # 
+    # file name (variable size)
+    # extra field (variable size)
+    # file comment (variable size)
+
+    CENTRAL_MAGIC = 0x02014b50_u32
+
+    # TODO: version made by, if unspecified
+    CENTRAL_VERSION_MADE_BY = 0_u32
+
+    def write_central(
+      io      : IO,
+      version : UInt32 = CENTRAL_VERSION_MADE_BY
+    ) : UInt64
+      CENTRAL_MAGIC.to_io(io, LE)
+      version.to_u16.to_io(io, LE)
+      VERSION_NEEDED.to_u16.to_io(io, LE)
+      GENERAL_FLAGS.to_u16.to_io(io, LE)
+      @method.to_io(io, LE)
+
+      # TODO: write time
+      # encode(time, io)
+
+      @crc.to_io(io, LE)
+      @dst_len.to_io(io, LE)
+      @src_len.to_io(io, LE)
+      
+      # get path length and write it
+      path_len = path.bytesize
+      path_len.to_u16.to_io(io, LE)
+
+      # write extras field length
+      extras_len = 0_u32
+      extras_len.to_u16.to_io(io, LE)
+
+      comment_len = @comment.bytesize
+      comment_len.to_u16.to_io(io, LE)
+
+      # write disk number
+      0_u32.to_u16.to_io(io, LE)
+
+      # write file attributes (internal, external)
+      # TODO
+      0_u32.to_u16.to_io(io, LE)
+      0_u32.to_u16.to_io(io, LE)
+
+      # write local header offset
+      @pos.to_u32.to_io(io, LE)
+
+      # write path field
+      path.to_s(io)
+
+      # write extra fields
+      # TODO: implement this
+
+      # write comment
+      comment.to_s(io)
+
+      # return number of bytes written
+      30_u64 + path_len + extras_len
+
+      # TODO
+      0_u64
+    end
+
+  end
+
+  class Writer
+    def initialize(
+      @io       : IO,
+      @pos      : UInt64 = 0,
+      @comment  : String = "",
+      @version  : UInt32 = 0,
+    )
+      @entries = [] of WriterEntry
+      @closed = false
+      @src_pos = @pos
+    end
+
+    def closed?
+      @closed
+    end
+
+    private def assert_open
+      raise Error, "already closed" if closed?
+    end
+
+    def bytes_written : UInt64
+      # return total number of bytes written
+      @src_pos - @pos
+    end
+
+    def close
+      assert_open
+
+      # cache cdr position
+      cdr_pos = @pos
+
+      @entries.each do |entry|
+        @pos += entry.to_central(@io)
+      end
+
+      # write zip footer
+      write_footer(cdr_pos)
+
+      # flag as closed
+      @closed = true
+
+      # return total number of bytes written
+      bytes_written
+    end
+
+    def add(
+      path    : String, 
+      io      : IO,
+      method  : CompressionMethod = CompressionMethod::DEFLATE,
+      time    : Time = Time.now,
+      comment : String? = nil,
+    ) : UInt64
+      src_pos = @pos,
+      # make sure writer is still open
+      assert_open
+
+      # create entry
+      entry = WriterEntry.new(
+        pos:      @pos,
+        path:     path,
+        io:       io,
+        method:   method,
+        time:     time,
+        comment:  comment,
+      )
+
+      # add to list of entries
+      @entries << entry
+      
+      # write entry, update offset
+      @pos += entry.to_s(@io)
+
+      # return number of bytes written
+      @pos - src_pos
+    end
+
+    # 4.3.16  End of central directory record:
+    #
+    # end of central dir signature    4 bytes  (0x06054b50)
+    # number of this disk             2 bytes
+    # number of the disk with the
+    # start of the central directory  2 bytes
+    # total number of entries in the
+    # central directory on this disk  2 bytes
+    # total number of entries in
+    # the central directory           2 bytes
+    # size of the central directory   4 bytes
+    # offset of start of central
+    # directory with respect to
+    # the starting disk number        4 bytes
+    # .ZIP file comment length        2 bytes
+    # .ZIP file comment       (variable size)
+
+    FOOTER_MAGIC = 0x06054b50_u32
+
+    private def write_footer(cdr_pos : UInt64)
+      FOOTER_MAGIC.to_io(@io, LE)
+      0_u32.to_u16.to_io(@io, LE)
+      0_u32.to_u16.to_io(@io, LE)
+
+      num_entries = @entries.size
+      num_entries.to_u16.to_io(@io, LE)
+      num_entries.to_u16.to_io(@io, LE)
+
+      (@pos - cdr_pos).to_io(@io, LE)
+      cdr_pos.to_io(@io, LE)
+
+      @comment.bytesize.to_u16.to_io(@io, LE)
+      @comment.to_s(@io)
+    end
+  end
+
+  def self.write(
+    io      : IO, 
+    pos     : UInt64 = 0,
+    comment : String = "", 
+    version : UInt32 = 0,
+    &cb     : Writer -> \
+  ) : UInt64
+    r = 0_u64
+    begin 
+      w = Writer.new(io, pos, comment, version)
+      cb.call(w)
+    ensure
+      w.close unless w.closed?
+      r = w.bytes_written
+    end
+
+    # return total number of bytes written
+    r
+  end
+
+  def self.write(
+    path    : String,
+    pos     : UInt64 = 0,
+    comment : String = "", 
+    version : UInt32 = 0,
+    &cb     : Writer -> \
+  ) : UInt64
+    write(File.open(path, "wb"), pos, comment, version, &cb)
+  end
+end