decorate.c

   1 /*
   2  * decorate.c - decorate a git object with some arbitrary
   3  * data.
   4  */
   5
   6 #include "git-compat-util.h"
   7 #include "object.h"
   8 #include "decorate.h"
   9
  10 static unsigned int hash_obj(const struct object *obj, unsigned int n)
  11 {
  12         return oidhash(&obj->oid) % n;
  13 }
  14
  15 static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)
  16 {
  17         struct decoration_entry *entries = n->entries;
  18         unsigned int j = hash_obj(base, n->size);
  19
  20         while (entries[j].base) {
  21                 if (entries[j].base == base) {
  22                         void *old = entries[j].decoration;
  23                         entries[j].decoration = decoration;
  24                         return old;
  25                 }
  26                 if (++j >= n->size)
  27                         j = 0;
  28         }
  29         entries[j].base = base;
  30         entries[j].decoration = decoration;
  31         n->nr++;
  32         return NULL;
  33 }
  34
  35 static void grow_decoration(struct decoration *n)
  36 {
  37         unsigned int i;
  38         unsigned int old_size = n->size;
  39         struct decoration_entry *old_entries = n->entries;
  40
  41         n->size = (old_size + 1000) * 3 / 2;
  42         CALLOC_ARRAY(n->entries, n->size);
  43         n->nr = 0;
  44
  45         for (i = 0; i < old_size; i++) {
  46                 const struct object *base = old_entries[i].base;
  47                 void *decoration = old_entries[i].decoration;
  48
  49                 if (!decoration)
  50                         continue;
  51                 insert_decoration(n, base, decoration);
  52         }
  53         free(old_entries);
  54 }
  55
  56 void *add_decoration(struct decoration *n, const struct object *obj,
  57                 void *decoration)
  58 {
  59         if ((n->nr + 1) > n->size * 2 / 3)
  60                 grow_decoration(n);
  61         return insert_decoration(n, obj, decoration);
  62 }
  63
  64 void *lookup_decoration(struct decoration *n, const struct object *obj)
  65 {
  66         unsigned int j;
  67
  68         /* nothing to lookup */
  69         if (!n->size)
  70                 return NULL;
  71         j = hash_obj(obj, n->size);
  72         for (;;) {
  73                 struct decoration_entry *ref = n->entries + j;
  74                 if (ref->base == obj)
  75                         return ref->decoration;
  76                 if (!ref->base)
  77                         return NULL;
  78                 if (++j == n->size)
  79                         j = 0;
  80         }
  81 }
  82
  83 void clear_decoration(struct decoration *n, void (*free_cb)(void *))
  84 {
  85         if (free_cb) {
  86                 unsigned int i;
  87                 for (i = 0; i < n->size; i++) {
  88                         void *d = n->entries[i].decoration;
  89                         if (d)
  90                                 free_cb(d);
  91                 }
  92         }
  93
  94         FREE_AND_NULL(n->entries);
  95         n->size = n->nr = 0;
  96 }