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// Package packfile implements encoding and decoding of packfile 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.
//
//
// Source:
// https://www.kernel.org/pub/software/scm/git/docs/v1.7.5/technical/pack-protocol.txt
package packfile
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