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lvm2/lib/report
Tony Asleson 91f737383c lvm2app: Add signed numerical property values
Currently lvm2app properties have the following structure:

typedef struct lvm_property_value {
        uint32_t is_settable:1;
        uint32_t is_string:1;
        uint32_t is_integer:1;
        uint32_t is_valid:1;
        uint32_t padding:28;
        union {
                const char *string;
                uint64_t integer;
        } value;
} lvm_property_value_t;

which assumes that numerical values were in the range of 0 to 2**64-1.  However,
some of the properties were 'signed', like LV major/minor numbers and some
reserved values for properties that represent percentages.  Thus when the
values were retrieved they were in two's complement notation.  So for a -1
major number the API user would get a value of 18446744073709551615.  The
API user could cast the returned value to an int64_t to handle this, but that
requires the API developer to look at the source code and determine when it
should be done.

This change modifies the return property structure to:

typedef struct lvm_property_value {
        uint32_t is_settable:1;
        uint32_t is_string:1;
        uint32_t is_integer:1;
        uint32_t is_valid:1;
        uint32_t is_signed:1;
        uint32_t padding:27;
        union {
                const char *string;
                uint64_t integer;
                int64_t signed_integer;
        } value;
} lvm_property_value_t;

With this addition the API user can interrogate that the value is numerical,
(is_integer = 1) and subsequently check if it's signed (is_signed = 1) too.
If signed, then the API developer should use the union's signed_integer to
avoid casting.

This change maintains backwards compatibility as the structure size remains
unchanged and integer value remains unchanged.  Only the additional bit
taken from the pad is utilized.

Bugzilla reference:
https://bugzilla.redhat.com/show_bug.cgi?id=838257

Signed-off-by: Tony Asleson <tasleson@redhat.com>
2015-05-06 08:51:04 -05:00
..
columns-devtypes.h reporting: Add devtypes command. 2013-09-18 01:09:15 +01:00
columns.h lvm2app: Add signed numerical property values 2015-05-06 08:51:04 -05:00
properties.c lvm2app: Add signed numerical property values 2015-05-06 08:51:04 -05:00
properties.h report: select: refactor: move str_list to libdm 2014-06-17 16:27:20 +02:00
report.c lvm2app: Add signed numerical property values 2015-05-06 08:51:04 -05:00
report.h cleanup: replace static struct processing_handle initializer with common init_processing_handle 2015-02-13 11:26:57 +01:00
values.h select: fix matching reserved values while <,<=,>,>= is used in selection criteria 2015-04-24 09:48:57 +02:00