Function Open

index/read.go:97–112

(file string)

const postEntrySize = 3 + 4 + 4

func Open(file string) *Index {
	mm := mmap(file)
	if len(mm.d) < 4*4+len(trailerMagic) || string(mm.d[len(mm.d)-len(trailerMagic):]) != trailerMagic {
		corrupt()
	}
	n := uint32(len(mm.d) - len(trailerMagic) - 5*4)
	ix := &Index{data: mm}
	ix.pathData = ix.uint32(n)
	ix.nameData = ix.uint32(n + 4)
	ix.postData = ix.uint32(n + 8)
	ix.nameIndex = ix.uint32(n + 12)
	ix.postIndex = ix.uint32(n + 16)
	ix.numName = int((ix.postIndex-ix.nameIndex)/4) - 1
	ix.numPost = int((n - ix.postIndex) / postEntrySize)
	return ix
}

// slice returns the slice of index data starting at the given byte offset.
// If n >= 0, the slice must have length at least n and is truncated to length n.