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-rw-r--r--src/zip.cr172
1 files changed, 93 insertions, 79 deletions
diff --git a/src/zip.cr b/src/zip.cr
index 5c2acfb..9fb416e 100644
--- a/src/zip.cr
+++ b/src/zip.cr
@@ -4,6 +4,13 @@ require "zlib"
module Zip
VERSION = "0.1.0"
+ MAGIC = {
+ cdr_header: 0x02014b50_u32,
+ cdr_footer: 0x06054b50_u32,
+ file_header: 0x04034b50_u32,
+ file_footer: 0x08074b50_u32,
+ }
+
LE = IO::ByteFormat::LittleEndian
# 4.4.4 general purpose bit flag: (2 bytes)
@@ -142,14 +149,14 @@ module Zip
class Error < Exception
end
- module Util
- def self.write_time(io : IO, time : Time) : UInt64
+ module TimeHelper
+ def write_time(io : IO, time : Time) : UInt32
# TODO
0_u32.to_u16.to_io(io, LE)
0_u32.to_u16.to_io(io, LE)
# return number of bytes written
- 4_u64
+ 4_u32
end
end
@@ -162,12 +169,12 @@ module Zip
end
end
- module NoneCompressor
+ module NoneCompressionHelper
def compress_none(src_io, dst_io)
crc = 0_u32
buf = Bytes.new(4096)
- src_len = 0_u64
+ src_len = 0_u32
while ((len = src_io.read(buf)) > 0)
# TODO: crc32
@@ -181,11 +188,11 @@ module Zip
end
end
- module DeflateCompressor
+ module DeflateCompressionHelper
def compress_deflate(src_io, dst_io)
crc = 0_u32
- src_len = 0_u64
- dst_len = 0_u64
+ src_len = 0_u32
+ dst_len = 0_u32
# create buffer and intermediate memory io
buf = Bytes.new(4096)
@@ -217,8 +224,9 @@ module Zip
end
class WriterEntry
- include NoneCompressor
- include DeflateCompressor
+ include TimeHelper
+ include NoneCompressionHelper
+ include DeflateCompressionHelper
# TODO version needed to extract and header flags
# (used for header and central header)
@@ -226,7 +234,7 @@ module Zip
GENERAL_FLAGS = GeneralFlags.flags(FOOTER, EFS)
def initialize(
- @pos : UInt64,
+ @pos : UInt32,
@path : String,
@io : IO,
@method : CompressionMethod = CompressionMethod::DEFLATE,
@@ -234,11 +242,11 @@ module Zip
@comment : String = "",
)
@crc = 0_u32
- @src_len = 0_u64
- @dst_len = 0_u64
+ @src_len = 0_u32
+ @dst_len = 0_u32
end
- def to_s(dst_io) : UInt64
+ def to_s(dst_io) : UInt32
# write header
r = write_header(dst_io, @path, @method, @time)
@@ -269,14 +277,12 @@ module Zip
# extra field (variable size)
#
- HEADER_MAGIC = 0x04034b50_u32
-
private def write_header(
io : IO,
path : String,
method : CompressionMethod,
time : Time,
- ) : UInt64
+ ) : UInt32
# get path length, in bytes
path_len = path.bytesize
@@ -285,23 +291,26 @@ module Zip
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)
+ # write magic (u32), version needed (u16), flags (u16), and
+ # compression method (u16)
+ MAGIC[:file_header].to_io(io, LE)
VERSION_NEEDED.to_u16.to_io(io, LE)
GENERAL_FLAGS.to_u16.to_io(io, LE)
method.to_u16.to_io(io, LE)
- # write time
- Util.write_time(io, time)
+ # write time (u32)
+ write_time(io, time)
- # crc, compressed size, uncompressed size
+ # crc (u32), compressed size (u32), uncompressed size (u32)
# (these will be populated in the footer)
0_u32.to_io(io, LE)
0_u32.to_io(io, LE)
0_u32.to_io(io, LE)
+
+ # write file path length (u16)
path_len.to_u16.to_io(io, LE)
- # write extras field length
+ # write extras field length (u16)
extras_len = 0_u32
extras_len.to_u16.to_io(io, LE)
@@ -312,7 +321,7 @@ module Zip
# TODO: implement this
# return number of bytes written
- 30_u64 + path_len + extras_len
+ 30_u32 + path_len + extras_len
end
private def write_body(dst_io : IO)
@@ -335,22 +344,22 @@ module Zip
# 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)
+ src_len : UInt32,
+ dst_len : UInt32,
+ ) : UInt32
+ # write magic (u32)
+ MAGIC[:file_footer].to_io(io, LE)
+
+ # write crc (u32), compressed size (u32), and full size (u32)
crc.to_io(io, LE)
dst_len.to_io(io, LE)
src_len.to_io(io, LE)
# return number of bytes written
- 16_u64
+ 16_u32
end
#
@@ -376,23 +385,21 @@ module Zip
# 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)
+ ) : UInt32
+ MAGIC[:cdr_header].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_u16.to_io(io, LE)
# write time
- Util.write_time(io, @time)
+ write_time(io, @time)
@crc.to_io(io, LE)
@dst_len.to_io(io, LE)
@@ -402,10 +409,11 @@ module Zip
path_len = @path.bytesize
path_len.to_u16.to_io(io, LE)
- # write extras field length
+ # write extras field length (u16)
extras_len = 0_u32
extras_len.to_u16.to_io(io, LE)
+ # write comment field length (u16)
comment_len = @comment.bytesize
comment_len.to_u16.to_io(io, LE)
@@ -415,10 +423,10 @@ module Zip
# write file attributes (internal, external)
# TODO
0_u32.to_u16.to_io(io, LE)
- 0_u32.to_u16.to_io(io, LE)
+ 0_u32.to_io(io, LE)
# write local header offset
- @pos.to_u32.to_io(io, LE)
+ @pos.to_io(io, LE)
# write path field
@path.to_s(io)
@@ -430,10 +438,7 @@ module Zip
@comment.to_s(io)
# return number of bytes written
- 30_u64 + path_len + extras_len
-
- # TODO
- 0_u64
+ 46_u32 + path_len + extras_len + comment_len
end
end
@@ -441,7 +446,7 @@ module Zip
class Writer
def initialize(
@io : IO,
- @pos : UInt64 = 0,
+ @pos : UInt32 = 0,
@comment : String = "",
@version : UInt32 = 0,
)
@@ -458,7 +463,7 @@ module Zip
raise "already closed" if closed?
end
- def bytes_written : UInt64
+ def bytes_written : UInt32
# return total number of bytes written
@src_pos - @pos
end
@@ -474,7 +479,7 @@ module Zip
end
# write zip footer
- write_footer(cdr_pos)
+ @pos += write_footer(cdr_pos, @pos - cdr_pos)
# flag as closed
@closed = true
@@ -489,7 +494,7 @@ module Zip
method : CompressionMethod = CompressionMethod::DEFLATE,
time : Time = Time.now,
comment : String = "",
- ) : UInt64
+ ) : UInt32
# cache input position
src_pos = @pos
@@ -522,7 +527,7 @@ module Zip
method : CompressionMethod = CompressionMethod::DEFLATE,
time : Time = Time.now,
comment : String = "",
- ) : UInt64
+ ) : UInt32
add(path, MemoryIO.new(body), method, time, comment)
end
@@ -532,7 +537,7 @@ module Zip
method : CompressionMethod = CompressionMethod::DEFLATE,
time : Time = Time.now,
comment : String = "",
- ) : UInt64
+ ) : UInt32
File.open(file_path, "rb") do |io|
add(path, io, method, time, comment)
end
@@ -540,52 +545,61 @@ module Zip
# 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)
- # write magic (u32), disk num (u16), start footer disk (u16)
- FOOTER_MAGIC.to_io(@io, LE)
+ # * 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)
+
+ private def write_footer(
+ cdr_pos : UInt32,
+ cdr_len : UInt32,
+ ) : UInt32
+ # write magic (u32)
+ MAGIC[:cdr_footer].to_io(@io, LE)
+
+ # write disk num (u16) and footer start disk (u16)
0_u32.to_u16.to_io(@io, LE)
0_u32.to_u16.to_io(@io, LE)
- # write num entries (u16) / total entries (u16)
+ # write num entries (u16) and total entries (u16)
num_entries = @entries.size
num_entries.to_u16.to_io(@io, LE)
num_entries.to_u16.to_io(@io, LE)
- # write offset (u32)
- (cdr_pos - @src_pos).to_u32.to_io(@io, LE)
+ # write cdr offset (u32) and cdr length (u32)
+ cdr_len.to_io(@io, LE)
cdr_pos.to_io(@io, LE)
+ # get comment length (u16)
+ comment_len = @comment.bytesize
+
# write comment length (u16) and comment
- @comment.bytesize.to_u16.to_io(@io, LE)
+ comment_len.to_u16.to_io(@io, LE)
@comment.to_s(@io)
+
+ # return number of bytes written
+ 22_u32 + comment_len
end
end
def self.write(
io : IO,
- pos : UInt64 = 0_u64,
+ pos : UInt32 = 0_u32,
comment : String = "",
version : UInt32 = 0_u32,
&cb : Writer -> \
- ) : UInt64
- r = 0_u64
+ ) : UInt32
+ r = 0_u32
begin
w = Writer.new(io, pos, comment, version)
cb.call(w)
@@ -602,11 +616,11 @@ module Zip
def self.write(
path : String,
- pos : UInt64 = 0_u64,
+ pos : UInt32 = 0_u32,
comment : String = "",
version : UInt32 = 0_u32,
&cb : Writer -> \
- ) : UInt64
+ ) : UInt32
File.open(path, "wb") do |io|
write(io, pos, comment, version, &cb)
end
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-18 12:21:20 +0000