2 require 'git/raw/internal/object'
3 require 'git/raw/internal/mmap'
8 class PackFormatError < StandardError
19 OffsetStart = FanOutCount * IdxOffsetSize
20 SHA1Start = OffsetStart + OffsetSize
21 EntrySize = OffsetSize + SHA1Size
25 file = file[0...-3] + 'pack'
29 @packfile = File.open(file)
30 @idxfile = File.open(file[0...-4]+'idx')
31 @idx = Mmap.new(@idxfile)
34 FanOutCount.times do |i|
35 pos = @idx[i * IdxOffsetSize,IdxOffsetSize].unpack('N')[0]
37 raise PackFormatError, "pack #@name has discontinuous index #{i}"
56 offset = find_object(sha1)
58 return parse_object(offset)
64 offset = @idx[pos,OffsetSize].unpack('N')[0]
65 sha1 = @idx[pos+OffsetSize,SHA1Size]
72 # unpacking the offset is quite expensive, so
73 # we avoid using #each
76 sha1 = @idx[pos,SHA1Size]
84 first, last = @offsets[slot,2]
86 mid = (first + last) / 2
87 midsha1 = @idx[SHA1Start + mid * EntrySize,SHA1Size]
88 cmp = midsha1 <=> sha1
95 pos = OffsetStart + mid * EntrySize
96 offset = @idx[pos,OffsetSize].unpack('N')[0]
105 def parse_object(offset)
106 data, type = unpack_object(offset)
107 RawObject.new(OBJ_TYPES[type], data)
109 protected :parse_object
111 def unpack_object(offset)
113 @packfile.seek(offset)
115 c = @packfile.read(1)[0]
121 c = @packfile.read(1)[0]
122 size |= ((c & 0x7f) << shift)
128 when OBJ_OFS_DELTA, OBJ_REF_DELTA
129 data, type = unpack_deltified(type, offset, obj_offset, size)
130 when OBJ_COMMIT, OBJ_TREE, OBJ_BLOB, OBJ_TAG
131 data = unpack_compressed(offset, size)
133 raise PackFormatError, "invalid type #{type}"
137 private :unpack_object
139 def unpack_deltified(type, offset, obj_offset, size)
140 @packfile.seek(offset)
141 data = @packfile.read(SHA1Size)
143 if type == OBJ_OFS_DELTA
146 base_offset = c & 0x7f
151 base_offset |= c & 0x7f
153 base_offset = obj_offset - base_offset
156 base_offset = find_object(data)
160 base, type = unpack_object(base_offset)
161 delta = unpack_compressed(offset, size)
162 [patch_delta(base, delta), type]
164 private :unpack_deltified
166 def unpack_compressed(offset, destsize)
168 @packfile.seek(offset)
169 zstr = Zlib::Inflate.new
170 while outdata.size < destsize
171 indata = @packfile.read(4096)
173 raise PackFormatError, 'error reading pack data'
175 outdata += zstr.inflate(indata)
177 if outdata.size > destsize
178 raise PackFormatError, 'error reading pack data'
183 private :unpack_compressed
185 def patch_delta(base, delta)
186 src_size, pos = patch_delta_header_size(delta, 0)
187 if src_size != base.size
188 raise PackFormatError, 'invalid delta data'
191 dest_size, pos = patch_delta_header_size(delta, pos)
193 while pos < delta.size
199 cp_off = delta[pos += 1] if c & 0x01 != 0
200 cp_off |= delta[pos += 1] << 8 if c & 0x02 != 0
201 cp_off |= delta[pos += 1] << 16 if c & 0x04 != 0
202 cp_off |= delta[pos += 1] << 24 if c & 0x08 != 0
203 cp_size = delta[pos += 1] if c & 0x10 != 0
204 cp_size |= delta[pos += 1] << 8 if c & 0x20 != 0
205 cp_size |= delta[pos += 1] << 16 if c & 0x40 != 0
206 cp_size = 0x10000 if cp_size == 0
208 dest += base[cp_off,cp_size]
213 raise PackFormatError, 'invalid delta data'
220 def patch_delta_header_size(delta, pos)
226 raise PackFormatError, 'invalid delta header'
229 size |= (c & 0x7f) << shift
231 end while c & 0x80 != 0
234 private :patch_delta_header_size
242 storage = Git::Internal::PackStorage.new(path)
243 storage.each_sha1 do |sha1|
245 puts "%s %s" % [obj.sha1.unpack('H*'), obj.type]