Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2
   3static int nr_entries;
   4static const char *base_name;
   5static const char unpack_usage[] = "git-unpack-objects basename";
   6
   7struct pack_entry {
   8        unsigned int offset;
   9        unsigned char sha1[20];
  10};
  11
  12static struct pack_entry **pack_list;
  13
  14static void *map_file(const char *suffix, unsigned long *sizep)
  15{
  16        static char pathname[PATH_MAX];
  17        unsigned long len;
  18        int fd;
  19        struct stat st;
  20        void *map;
  21
  22        len = snprintf(pathname, PATH_MAX, "%s.%s", base_name, suffix);
  23        if (len >= PATH_MAX)
  24                die("bad pack base-name");
  25        fd = open(pathname, O_RDONLY);
  26        if (fd < 0 || fstat(fd, &st))
  27                die("unable to open '%s'", pathname);
  28        len = st.st_size;
  29        if (!len)
  30                die("bad pack file '%s'", pathname);
  31        map = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
  32        if (-1 == (int)(long)map)
  33                die("unable to mmap '%s'", pathname);
  34        close(fd);
  35        *sizep = len;
  36        return map;
  37}
  38
  39static int sort_by_offset(const void *_a, const void *_b)
  40{
  41        struct pack_entry *a = *(struct pack_entry **)_a;
  42        struct pack_entry *b = *(struct pack_entry **)_b;
  43        unsigned int o1, o2;
  44
  45        o1 = ntohl(a->offset);
  46        o2 = ntohl(b->offset);
  47        return o1 < o2 ? -1 : 1;
  48}
  49
  50static int check_index(void *index, unsigned long idx_size)
  51{
  52        unsigned int *array = index;
  53        unsigned int nr;
  54        int i;
  55
  56        if (idx_size < 4*256)
  57                return error("index file too small");
  58        nr = 0;
  59        for (i = 0; i < 256; i++) {
  60                unsigned int n = ntohl(array[i]);
  61                if (n < nr)
  62                        return error("non-monotonic index");
  63                nr = n;
  64        }
  65        if (idx_size != 4*256 + nr * 24) {
  66                printf("idx_size=%d, expected %d (%d)\n", idx_size, 4*256 + nr * 24, nr);
  67                return error("wrong index file size");
  68        }
  69
  70        nr_entries = nr;
  71        pack_list = xmalloc(nr * sizeof(struct pack_entry *));
  72        for (i = 0; i < nr; i++)
  73                pack_list[i] = index + 4*256 + i*24;
  74
  75        qsort(pack_list, nr, sizeof(*pack_list), sort_by_offset);
  76
  77        printf("%d entries\n", nr);
  78        return 0;
  79}
  80
  81int main(int argc, char **argv)
  82{
  83        int i;
  84        unsigned long idx_size, pack_size;
  85        void *index, *pack;
  86
  87        for (i = 1 ; i < argc; i++) {
  88                const char *arg = argv[i];
  89
  90                if (*arg == '-') {
  91                        /* Maybe we'll have some flags here some day.. */
  92                        usage(unpack_usage);
  93                }
  94                if (base_name)
  95                        usage(unpack_usage);
  96                base_name = arg;
  97        }
  98        if (!base_name)
  99                usage(unpack_usage);
 100        index = map_file("idx", &idx_size);
 101        pack = map_file("pack", &pack_size);
 102        if (check_index(index, idx_size) < 0)
 103                die("bad index file");
 104        return 0;
 105}