diff options
Diffstat (limited to 'internal/gitdiff/base85.go')
| -rw-r--r-- | internal/gitdiff/base85.go | 91 |
1 files changed, 0 insertions, 91 deletions
diff --git a/internal/gitdiff/base85.go b/internal/gitdiff/base85.go deleted file mode 100644 index 86db117..0000000 --- a/internal/gitdiff/base85.go +++ /dev/null @@ -1,91 +0,0 @@ -package gitdiff - -import ( - "fmt" -) - -var ( - b85Table map[byte]byte - b85Alpha = []byte( - "0123456789" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "!#$%&()*+-;<=>?@^_`{|}~", - ) -) - -func init() { - b85Table = make(map[byte]byte) - for i, c := range b85Alpha { - b85Table[c] = byte(i) - } -} - -// base85Decode decodes Base85-encoded data from src into dst. It uses the -// alphabet defined by base85.c in the Git source tree. src must contain at -// least len(dst) bytes of encoded data. -func base85Decode(dst, src []byte) error { - var v uint32 - var n, ndst int - for i, b := range src { - if b, ok := b85Table[b]; ok { - v = 85*v + uint32(b) - n++ - } else { - return fmt.Errorf("invalid base85 byte at index %d: 0x%X", i, src[i]) - } - if n == 5 { - rem := len(dst) - ndst - for j := 0; j < 4 && j < rem; j++ { - dst[ndst] = byte(v >> 24) - ndst++ - v <<= 8 - } - v = 0 - n = 0 - } - } - if n > 0 { - return fmt.Errorf("base85 data terminated by underpadded sequence") - } - if ndst < len(dst) { - return fmt.Errorf("base85 data underrun: %d < %d", ndst, len(dst)) - } - return nil -} - -// base85Encode encodes src in Base85, writing the result to dst. It uses the -// alphabet defined by base85.c in the Git source tree. -func base85Encode(dst, src []byte) { - var di, si int - - encode := func(v uint32) { - dst[di+0] = b85Alpha[(v/(85*85*85*85))%85] - dst[di+1] = b85Alpha[(v/(85*85*85))%85] - dst[di+2] = b85Alpha[(v/(85*85))%85] - dst[di+3] = b85Alpha[(v/85)%85] - dst[di+4] = b85Alpha[v%85] - } - - n := (len(src) / 4) * 4 - for si < n { - encode(uint32(src[si+0])<<24 | uint32(src[si+1])<<16 | uint32(src[si+2])<<8 | uint32(src[si+3])) - si += 4 - di += 5 - } - - var v uint32 - switch len(src) - si { - case 3: - v |= uint32(src[si+2]) << 8 - fallthrough - case 2: - v |= uint32(src[si+1]) << 16 - fallthrough - case 1: - v |= uint32(src[si+0]) << 24 - encode(v) - } -} - -// base85Len returns the length of n bytes of Base85 encoded data. -func base85Len(n int) int { - return (n + 3) / 4 * 5 -} |
