| Message ID | 87af80d75efe782e9edb47f214e0521f50a9cf56.1368474222.git.mst@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 13 May 2013 21:01, Michael S. Tsirkin <mst@redhat.com> wrote: > Sometimes we need to pass ranges around, add a > handy structure for this purpose. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > include/qemu/range.h | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/include/qemu/range.h b/include/qemu/range.h > index 3502372..4bcd346 100644 > --- a/include/qemu/range.h > +++ b/include/qemu/range.h > @@ -1,6 +1,28 @@ > #ifndef QEMU_RANGE_H > #define QEMU_RANGE_H > > +#include <inttypes.h> > + > +/* > + * Operations on 64 address ranges. missing "bit" ? > + * Notes: > + * - ranges must not wrap around 0, but can include the last byte ~0x0LL. > + * - this can not represent a full 0 to ~0x0LL range. > + */ > + > +/* A structure representing a range of addresses. */ > +struct Range { > + uint64_t begin; /* First byte of the range, or 0 if empty. */ > + uint64_t end; /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */ > +}; > +typedef struct Range Range; > + > +/* verify that range is not empty and does not overlap */ Doesn't overlap what? Why isn't an empty range valid? The struct definition above says it's OK. > +static inline bool range_valid(struct Range *range) > +{ > + return range->begin + 1 <= range->end; > +} I note that memory.c defines its own concept of an AddrRange. thanks -- PMM
On Mon, May 13, 2013 at 09:20:08PM +0100, Peter Maydell wrote: > On 13 May 2013 21:01, Michael S. Tsirkin <mst@redhat.com> wrote: > > Sometimes we need to pass ranges around, add a > > handy structure for this purpose. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > include/qemu/range.h | 22 ++++++++++++++++++++++ > > 1 file changed, 22 insertions(+) > > > > diff --git a/include/qemu/range.h b/include/qemu/range.h > > index 3502372..4bcd346 100644 > > --- a/include/qemu/range.h > > +++ b/include/qemu/range.h > > @@ -1,6 +1,28 @@ > > #ifndef QEMU_RANGE_H > > #define QEMU_RANGE_H > > > > +#include <inttypes.h> > > + > > +/* > > + * Operations on 64 address ranges. > > missing "bit" ? > > > + * Notes: > > + * - ranges must not wrap around 0, but can include the last byte ~0x0LL. > > + * - this can not represent a full 0 to ~0x0LL range. > > + */ > > + > > +/* A structure representing a range of addresses. */ > > +struct Range { > > + uint64_t begin; /* First byte of the range, or 0 if empty. */ > > + uint64_t end; /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */ > > +}; > > +typedef struct Range Range; > > + > > +/* verify that range is not empty and does not overlap */ > > Doesn't overlap what? I meant wrap around there. > Why isn't an empty range valid? > The struct definition above says it's OK. Yes it's a bad name. Should be range_non_empty or something. > > +{ > > + return range->begin + 1 <= range->end; > > +} > > I note that memory.c defines its own concept of an AddrRange. > > thanks > -- PMM Good point, maybe I'll reuse that or just use two 64 bit fields explicitly.
diff --git a/include/qemu/range.h b/include/qemu/range.h index 3502372..4bcd346 100644 --- a/include/qemu/range.h +++ b/include/qemu/range.h @@ -1,6 +1,28 @@ #ifndef QEMU_RANGE_H #define QEMU_RANGE_H +#include <inttypes.h> + +/* + * Operations on 64 address ranges. + * Notes: + * - ranges must not wrap around 0, but can include the last byte ~0x0LL. + * - this can not represent a full 0 to ~0x0LL range. + */ + +/* A structure representing a range of addresses. */ +struct Range { + uint64_t begin; /* First byte of the range, or 0 if empty. */ + uint64_t end; /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */ +}; +typedef struct Range Range; + +/* verify that range is not empty and does not overlap */ +static inline bool range_valid(struct Range *range) +{ + return range->begin + 1 <= range->end; +} + /* Get last byte of a range from offset + length. * Undefined for ranges that wrap around 0. */ static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
Sometimes we need to pass ranges around, add a handy structure for this purpose. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- include/qemu/range.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)