diff options
Diffstat (limited to 'cryptfs/intrablock.go')
| -rw-r--r-- | cryptfs/intrablock.go | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/cryptfs/intrablock.go b/cryptfs/intrablock.go index c83976c..faff471 100644 --- a/cryptfs/intrablock.go +++ b/cryptfs/intrablock.go @@ -19,13 +19,13 @@ func (ib *intraBlock) IsPartial() bool { // CiphertextRange - get byte range in ciphertext file corresponding to BlockNo // (complete block) func (ib *intraBlock) CiphertextRange() (offset uint64, length uint64) { - return HEADER_LEN + ib.BlockNo * ib.fs.cipherBS, ib.fs.cipherBS + return ib.fs.BlockNoToCipherOff(ib.BlockNo), ib.fs.cipherBS } // PlaintextRange - get byte range in plaintext corresponding to BlockNo // (complete block) func (ib *intraBlock) PlaintextRange() (offset uint64, length uint64) { - return ib.BlockNo * ib.fs.plainBS, ib.fs.plainBS + return ib.fs.BlockNoToPlainOff(ib.BlockNo), ib.fs.plainBS } // CropBlock - crop a potentially larger plaintext block down to the relevant part @@ -37,3 +37,15 @@ func (ib *intraBlock) CropBlock(d []byte) []byte { } return d[ib.Skip:lenWant] } + +// Ciphertext range corresponding to the sum of all "blocks" (complete blocks) +func (ib *intraBlock) JointCiphertextRange(blocks []intraBlock) (offset uint64, length uint64) { + firstBlock := blocks[0] + lastBlock := blocks[len(blocks)-1] + + offset = ib.fs.BlockNoToCipherOff(firstBlock.BlockNo) + offsetLast := ib.fs.BlockNoToCipherOff(lastBlock.BlockNo) + length = offsetLast + ib.fs.cipherBS - offset + + return offset, length +} |