new plumbing package (#118)

* plumbing: now core was renamed to core, and formats and clients moved inside

1 files changed, 0 insertions, 181 deletions

diff --git a/formats/packfile/delta.go b/formats/packfile/delta.go
deleted file mode 100644
index d08f969..0000000
--- a/formats/packfile/delta.go
+++ /dev/null
@@ -1,181 +0,0 @@
-package packfile
-
-import (
-	"io/ioutil"
-
-	"gopkg.in/src-d/go-git.v4/core"
-)
-
-// See https://github.com/git/git/blob/49fa3dc76179e04b0833542fa52d0f287a4955ac/delta.h
-// https://github.com/git/git/blob/c2c5f6b1e479f2c38e0e01345350620944e3527f/patch-delta.c,
-// and https://github.com/tarruda/node-git-core/blob/master/src/js/delta.js
-// for details about the delta format.
-
-const deltaSizeMin = 4
-
-// ApplyDelta writes to taget the result of applying the modification deltas in delta to base.
-func ApplyDelta(target, base core.Object, delta []byte) error {
-	r, err := base.Reader()
-	if err != nil {
-		return err
-	}
-
-	w, err := target.Writer()
-	if err != nil {
-		return err
-	}
-
-	src, err := ioutil.ReadAll(r)
-	if err != nil {
-		return err
-	}
-
-	dst := PatchDelta(src, delta)
-	target.SetSize(int64(len(dst)))
-
-	if _, err := w.Write(dst); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-// PatchDelta returns the result of applying the modification deltas in delta to src.
-func PatchDelta(src, delta []byte) []byte {
-	if len(delta) < deltaSizeMin {
-		return nil
-	}
-
-	srcSz, delta := decodeLEB128(delta)
-	if srcSz != uint(len(src)) {
-		return nil
-	}
-
-	targetSz, delta := decodeLEB128(delta)
-	remainingTargetSz := targetSz
-
-	var dest []byte
-	var cmd byte
-	for {
-		cmd = delta[0]
-		delta = delta[1:]
-		if isCopyFromSrc(cmd) {
-			var offset, sz uint
-			offset, delta = decodeOffset(cmd, delta)
-			sz, delta = decodeSize(cmd, delta)
-			if invalidSize(sz, targetSz) ||
-				invalidOffsetSize(offset, sz, srcSz) {
-				break
-			}
-			dest = append(dest, src[offset:offset+sz]...)
-			remainingTargetSz -= sz
-		} else if isCopyFromDelta(cmd) {
-			sz := uint(cmd) // cmd is the size itself
-			if invalidSize(sz, targetSz) {
-				break
-			}
-			dest = append(dest, delta[0:sz]...)
-			remainingTargetSz -= sz
-			delta = delta[sz:]
-		} else {
-			return nil
-		}
-
-		if remainingTargetSz <= 0 {
-			break
-		}
-	}
-
-	return dest
-}
-
-// Decodes a number encoded as an unsigned LEB128 at the start of some
-// binary data and returns the decoded number and the rest of the
-// stream.
-//
-// This must be called twice on the delta data buffer, first to get the
-// expected source buffer size, and again to get the target buffer size.
-func decodeLEB128(input []byte) (uint, []byte) {
-	var num, sz uint
-	var b byte
-	for {
-		b = input[sz]
-		num |= (uint(b) & payload) << (sz * 7) // concats 7 bits chunks
-		sz++
-
-		if uint(b)&continuation == 0 || sz == uint(len(input)) {
-			break
-		}
-	}
-
-	return num, input[sz:]
-}
-
-const (
-	payload      = 0x7f // 0111 1111
-	continuation = 0x80 // 1000 0000
-)
-
-func isCopyFromSrc(cmd byte) bool {
-	return (cmd & 0x80) != 0
-}
-
-func isCopyFromDelta(cmd byte) bool {
-	return (cmd&0x80) == 0 && cmd != 0
-}
-
-func decodeOffset(cmd byte, delta []byte) (uint, []byte) {
-	var offset uint
-	if (cmd & 0x01) != 0 {
-		offset = uint(delta[0])
-		delta = delta[1:]
-	}
-	if (cmd & 0x02) != 0 {
-		offset |= uint(delta[0]) << 8
-		delta = delta[1:]
-	}
-	if (cmd & 0x04) != 0 {
-		offset |= uint(delta[0]) << 16
-		delta = delta[1:]
-	}
-	if (cmd & 0x08) != 0 {
-		offset |= uint(delta[0]) << 24
-		delta = delta[1:]
-	}
-
-	return offset, delta
-}
-
-func decodeSize(cmd byte, delta []byte) (uint, []byte) {
-	var sz uint
-	if (cmd & 0x10) != 0 {
-		sz = uint(delta[0])
-		delta = delta[1:]
-	}
-	if (cmd & 0x20) != 0 {
-		sz |= uint(delta[0]) << 8
-		delta = delta[1:]
-	}
-	if (cmd & 0x40) != 0 {
-		sz |= uint(delta[0]) << 16
-		delta = delta[1:]
-	}
-	if sz == 0 {
-		sz = 0x10000
-	}
-
-	return sz, delta
-}
-
-func invalidSize(sz, targetSz uint) bool {
-	return sz > targetSz
-}
-
-func invalidOffsetSize(offset, sz, srcSz uint) bool {
-	return sumOverflows(offset, sz) ||
-		offset+sz > srcSz
-}
-
-func sumOverflows(a, b uint) bool {
-	return a+b < a
-}