diff options
Diffstat (limited to 'cryptfs')
| -rw-r--r-- | cryptfs/cryptfs_content.go | 39 | ||||
| -rw-r--r-- | cryptfs/log.go | 2 |
2 files changed, 39 insertions, 2 deletions
diff --git a/cryptfs/cryptfs_content.go b/cryptfs/cryptfs_content.go index 4658529..e23d9b5 100644 --- a/cryptfs/cryptfs_content.go +++ b/cryptfs/cryptfs_content.go @@ -77,7 +77,7 @@ func (be *CryptFS) EncryptBlock(plaintext []byte) []byte { return ciphertext } -// Split a plaintext byte range into (possible partial) blocks +// Split a plaintext byte range into (possibly partial) blocks func (be *CryptFS) SplitRange(offset uint64, length uint64) []intraBlock { var b intraBlock var parts []intraBlock @@ -113,6 +113,22 @@ func (be *CryptFS) minu64(x uint64, y uint64) uint64 { return y } +// CiphertextRange - Get byte range in backing ciphertext corresponding +// to plaintext range. Returns a range aligned to ciphertext blocks. +func (be *CryptFS) CiphertextRange(offset uint64, length uint64) (uint64, uint64, int) { + // Decrypting the ciphertext will yield too many plaintext bytes. Skip this number + // of bytes from the front. + skip := offset % be.plainBS + + firstBlockNo := offset / be.plainBS + lastBlockNo := ( offset + length - 1 ) / be.plainBS + + alignedOffset := firstBlockNo * be.cipherBS + alignedLength := (lastBlockNo - firstBlockNo + 1) * be.cipherBS + + return alignedOffset, alignedLength, int(skip) +} + // Get the byte range in the ciphertext corresponding to blocks // (full blocks!) func (be *CryptFS) JoinCiphertextRange(blocks []intraBlock) (uint64, uint64) { @@ -138,3 +154,24 @@ func (be *CryptFS) CropPlaintext(plaintext []byte, blocks []intraBlock) []byte { } return cropped } + +// MergeBlocks - Merge newData into oldData at offset +// New block may be bigger than both newData and oldData +func (be *CryptFS) MergeBlocks(oldData []byte, newData []byte, offset int) []byte { + + // Make block of maximum size + out := make([]byte, be.plainBS) + + // Copy old and new data into it + copy(out, oldData) + l := len(newData) + copy(out[offset:offset + l], newData) + + // Crop to length + outLen := len(oldData) + newLen := offset + len(newData) + if outLen < newLen { + outLen = newLen + } + return out[0:outLen] +} diff --git a/cryptfs/log.go b/cryptfs/log.go index f9c46c8..8233529 100644 --- a/cryptfs/log.go +++ b/cryptfs/log.go @@ -15,5 +15,5 @@ func (l logChannel) Printf(format string, args ...interface{}) { } -var Debug = logChannel{false} +var Debug = logChannel{true} var Warn = logChannel{true} |