object.con commit Add "diff-cache" helper program to compare a tree (or commit) with (e74f8f6)
   1#include "object.h"
   2#include "cache.h"
   3#include <stdlib.h>
   4#include <string.h>
   5
   6struct object **objs;
   7int nr_objs;
   8static int obj_allocs;
   9
  10static int find_object(unsigned char *sha1)
  11{
  12        int first = 0, last = nr_objs;
  13
  14        while (first < last) {
  15                int next = (first + last) / 2;
  16                struct object *obj = objs[next];
  17                int cmp;
  18
  19                cmp = memcmp(sha1, obj->sha1, 20);
  20                if (!cmp)
  21                        return next;
  22                if (cmp < 0) {
  23                        last = next;
  24                        continue;
  25                }
  26                first = next+1;
  27        }
  28        return -first-1;
  29}
  30
  31struct object *lookup_object(unsigned char *sha1)
  32{
  33        int pos = find_object(sha1);
  34        if (pos >= 0)
  35                return objs[pos];
  36        return NULL;
  37}
  38
  39void created_object(unsigned char *sha1, struct object *obj)
  40{
  41        int pos = find_object(sha1);
  42
  43        obj->parsed = 0;
  44        memcpy(obj->sha1, sha1, 20);
  45        obj->type = NULL;
  46        obj->refs = NULL;
  47        obj->used = 0;
  48
  49        if (pos >= 0)
  50                die("Inserting %s twice\n", sha1_to_hex(sha1));
  51        pos = -pos-1;
  52
  53        if (obj_allocs == nr_objs) {
  54                obj_allocs = alloc_nr(obj_allocs);
  55                objs = realloc(objs, obj_allocs * sizeof(struct object *));
  56        }
  57
  58        /* Insert it into the right place */
  59        memmove(objs + pos + 1, objs + pos, (nr_objs - pos) * 
  60                sizeof(struct object *));
  61
  62        objs[pos] = obj;
  63        nr_objs++;
  64}
  65
  66void add_ref(struct object *refer, struct object *target)
  67{
  68        struct object_list **pp = &refer->refs;
  69        struct object_list *p;
  70        
  71        while ((p = *pp) != NULL) {
  72                if (p->item == target)
  73                        return;
  74                pp = &p->next;
  75        }
  76
  77        target->used = 1;
  78        p = malloc(sizeof(*p));
  79        p->item = target;
  80        p->next = NULL;
  81        *pp = p;
  82}
  83
  84void mark_reachable(struct object *obj, unsigned int mask)
  85{
  86        struct object_list *p = obj->refs;
  87
  88        /* If we've been here already, don't bother */
  89        if (obj->flags & mask)
  90                return;
  91        obj->flags |= mask;
  92        while (p) {
  93                mark_reachable(p->item, mask);
  94                p = p->next;
  95        }
  96}