formats/packfile: type Hash instead of strings

1 files changed, 0 insertions, 168 deletions

diff --git a/packfile/doc.go b/packfile/doc.go
deleted file mode 100644
index 1fc28da..0000000
--- a/packfile/doc.go
+++ /dev/null
@@ -1,168 +0,0 @@
-package packfile
-
-// Code from:
-// https://github.com/gitchain/gitchain/tree/master/git @ 4c2fabdf9
-//
-// GIT pack format
-// ===============
-//
-// == pack-*.pack files have the following format:
-//
-//    - A header appears at the beginning and consists of the following:
-//
-//      4-byte signature:
-//          The signature is: {'P', 'A', 'C', 'K'}
-//
-//      4-byte version number (network byte order):
-//          GIT currently accepts version number 2 or 3 but
-//          generates version 2 only.
-//
-//      4-byte number of objects contained in the pack (network byte order)
-//
-//      Observation: we cannot have more than 4G versions ;-) and
-//      more than 4G objects in a pack.
-//
-//    - The header is followed by number of object entries, each of
-//      which looks like this:
-//
-//      (undeltified representation)
-//      n-byte type and length (3-bit type, (n-1)*7+4-bit length)
-//      compressed data
-//
-//      (deltified representation)
-//      n-byte type and length (3-bit type, (n-1)*7+4-bit length)
-//      20-byte base object name
-//      compressed delta data
-//
-//      Observation: length of each object is encoded in a variable
-//      length format and is not constrained to 32-bit or anything.
-//
-//   - The trailer records 20-byte SHA1 checksum of all of the above.
-//
-// == Original (version 1) pack-*.idx files have the following format:
-//
-//   - The header consists of 256 4-byte network byte order
-//     integers.  N-th entry of this table records the number of
-//     objects in the corresponding pack, the first byte of whose
-//     object name is less than or equal to N.  This is called the
-//     'first-level fan-out' table.
-//
-//   - The header is followed by sorted 24-byte entries, one entry
-//     per object in the pack.  Each entry is:
-//
-//     4-byte network byte order integer, recording where the
-//     object is stored in the packfile as the offset from the
-//     beginning.
-//
-//     20-byte object name.
-//
-//   - The file is concluded with a trailer:
-//
-//     A copy of the 20-byte SHA1 checksum at the end of
-//     corresponding packfile.
-//
-//     20-byte SHA1-checksum of all of the above.
-//
-// Pack Idx file:
-//
-//     --  +--------------------------------+
-// fanout  | fanout[0] = 2 (for example)    |-.
-// table   +--------------------------------+ |
-//         | fanout[1]                      | |
-//         +--------------------------------+ |
-//         | fanout[2]                      | |
-//         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
-//         | fanout[255] = total objects    |---.
-//     --  +--------------------------------+ | |
-// main        | offset                         | | |
-// index       | object name 00XXXXXXXXXXXXXXXX | | |
-// table       +--------------------------------+ | |
-//         | offset                         | | |
-//         | object name 00XXXXXXXXXXXXXXXX | | |
-//         +--------------------------------+<+ |
-//       .-| offset                         |   |
-//       | | object name 01XXXXXXXXXXXXXXXX |   |
-//       | +--------------------------------+   |
-//       | | offset                         |   |
-//       | | object name 01XXXXXXXXXXXXXXXX |   |
-//       | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   |
-//       | | offset                         |   |
-//       | | object name FFXXXXXXXXXXXXXXXX |   |
-//     --| +--------------------------------+<--+
-// trailer   | | packfile checksum              |
-//       | +--------------------------------+
-//       | | idxfile checksum               |
-//       | +--------------------------------+
-//           .-------.
-//                   |
-// Pack file entry: <+
-//
-//      packed object header:
-//     1-byte size extension bit (MSB)
-//            type (next 3 bit)
-//            size0 (lower 4-bit)
-//         n-byte sizeN (as long as MSB is set, each 7-bit)
-//         size0..sizeN form 4+7+7+..+7 bit integer, size0
-//         is the least significant part, and sizeN is the
-//         most significant part.
-//      packed object data:
-//         If it is not DELTA, then deflated bytes (the size above
-//         is the size before compression).
-//     If it is REF_DELTA, then
-//       20-byte base object name SHA1 (the size above is the
-//         size of the delta data that follows).
-//           delta data, deflated.
-//     If it is OFS_DELTA, then
-//       n-byte offset (see below) interpreted as a negative
-//         offset from the type-byte of the header of the
-//         ofs-delta entry (the size above is the size of
-//         the delta data that follows).
-//       delta data, deflated.
-//
-//      offset encoding:
-//       n bytes with MSB set in all but the last one.
-//       The offset is then the number constructed by
-//       concatenating the lower 7 bit of each byte, and
-//       for n >= 2 adding 2^7 + 2^14 + ... + 2^(7*(n-1))
-//       to the result.
-//
-//
-//
-// == Version 2 pack-*.idx files support packs larger than 4 GiB, and
-//    have some other reorganizations.  They have the format:
-//
-//   - A 4-byte magic number '\377tOc' which is an unreasonable
-//     fanout[0] value.
-//
-//   - A 4-byte version number (= 2)
-//
-//   - A 256-entry fan-out table just like v1.
-//
-//   - A table of sorted 20-byte SHA1 object names.  These are
-//     packed together without offset values to reduce the cache
-//     footprint of the binary search for a specific object name.
-//
-//   - A table of 4-byte CRC32 values of the packed object data.
-//     This is new in v2 so compressed data can be copied directly
-//     from pack to pack during repacking without undetected
-//     data corruption.
-//
-//   - A table of 4-byte offset values (in network byte order).
-//     These are usually 31-bit pack file offsets, but large
-//     offsets are encoded as an index into the next table with
-//     the msbit set.
-//
-//   - A table of 8-byte offset entries (empty for pack files less
-//     than 2 GiB).  Pack files are organized with heavily used
-//     objects toward the front, so most object references should
-//     not need to refer to this table.
-//
-//   - The same trailer as a v1 pack file:
-//
-//     A copy of the 20-byte SHA1 checksum at the end of
-//     corresponding packfile.
-//
-//     20-byte SHA1-checksum of all of the above.
-//
-// From:
-// https://www.kernel.org/pub/software/scm/git/docs/v1.7.5/technical/pack-protocol.txt