path: root/builtin
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authorJunio C Hamano <>2013-04-13 18:56:41 (GMT)
committerJunio C Hamano <>2013-06-07 17:02:12 (GMT)
commita84b794ad0622103cae98639d7176b2451dc6f92 (patch)
tree4e8ee29ad0a408fc47ff7281e492c83d0f3e7e52 /builtin
parent66eb375d3d334efa3f467775a5f2a647c131c4b1 (diff)
commit-slab: introduce a macro to define a slab for new type
Introduce a header file to define a macro that can define the struct type, initializer, accessor and cleanup functions to manage a commit slab. Update the "indegree" topological sort facility using it. To associate 32 flag bits with each commit, you can write: define_commit_slab(flag32, uint32); to declare "struct flag32" type, define an instance of it with struct flag32 flags; and initialize it by calling init_flag32(&flags); After that, a call to flag32_at() function uint32 *fp = flag32_at(&flags, commit); will return a pointer pointing at a uint32 for that commit. Once you are done with these flags, clean them up with clear_flag32(&flags); Callers that cannot hard-code how wide the data to be associated with the commit be at compile time can use the "_with_stride" variant to initialize the slab. Suppose you want to give one bit per existing ref, and paint commits down to find which refs are descendants of each commit. Saying typedef uint32 bits320[5]; define_commit_slab(flagbits, bits320); at compile time will still limit your code with hard-coded limit, because you may find that you have more than 320 refs at runtime. The code can declare a commit slab "struct flagbits" like this instead: define_commit_slab(flagbits, unsigned char); struct flagbits flags; and initialize it by: nrefs = ... count number of refs ... init_flagbits_with_stride(&flags, (nrefs + 7) / 8); so that unsigned char *fp = flagbits_at(&flags, commit); will return a pointer pointing at an array of 40 "unsigned char"s associated with the commit, once you figure out nrefs is 320 at runtime. Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'builtin')
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