Fix off-by-one in offset_from_vma

[Bo98]

Consider the following ELF file:

Program Headers:
  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
[...]
  LOAD           0x02cfa8 0x000000000002dfa8 0x000000000002dfa8 0x001580 0x002058 RW  0x1000
  LOAD           0x03e000 0x0000000000030000 0x0000000000030000 0x0097c0 0x0097c0 RW  0x1000
[...]

Before this pull request, offset_from_vma(0x30000) would return 0x2F000 which is a part of the first segment when it instead should be the first offset of the latter segment, i.e. 0x3E000.

This was due to the default size of zero. vma_in? searches from the offset inclusive to the offset + size exclusive. When size = 0 the starting offset is counted as exclusive and thus uses the first segment. For correct calculations, the minimum range must be 1.

[david942j]

Thank you for the fix!