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-rw-r--r--cdb_make.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/cdb_make.c b/cdb_make.c
new file mode 100644
index 0000000..6d1bd03
--- /dev/null
+++ b/cdb_make.c
@@ -0,0 +1,153 @@
+/* Public domain. */
+
+#include "readwrite.h"
+#include "seek.h"
+#include "error.h"
+#include "alloc.h"
+#include "cdb.h"
+#include "cdb_make.h"
+
+int cdb_make_start(struct cdb_make *c,int fd)
+{
+ c->head = 0;
+ c->split = 0;
+ c->hash = 0;
+ c->numentries = 0;
+ c->fd = fd;
+ c->pos = sizeof c->final;
+ buffer_init(&c->b,write,fd,c->bspace,sizeof c->bspace);
+ return seek_set(fd,c->pos);
+}
+
+static int posplus(struct cdb_make *c,uint32 len)
+{
+ uint32 newpos = c->pos + len;
+ if (newpos < len) { errno = error_nomem; return -1; }
+ c->pos = newpos;
+ return 0;
+}
+
+int cdb_make_addend(struct cdb_make *c,unsigned int keylen,unsigned int datalen,uint32 h)
+{
+ struct cdb_hplist *head;
+
+ head = c->head;
+ if (!head || (head->num >= CDB_HPLIST)) {
+ head = (struct cdb_hplist *) alloc(sizeof(struct cdb_hplist));
+ if (!head) return -1;
+ head->num = 0;
+ head->next = c->head;
+ c->head = head;
+ }
+ head->hp[head->num].h = h;
+ head->hp[head->num].p = c->pos;
+ ++head->num;
+ ++c->numentries;
+ if (posplus(c,8) == -1) return -1;
+ if (posplus(c,keylen) == -1) return -1;
+ if (posplus(c,datalen) == -1) return -1;
+ return 0;
+}
+
+int cdb_make_addbegin(struct cdb_make *c,unsigned int keylen,unsigned int datalen)
+{
+ char buf[8];
+
+ if (keylen > 0xffffffff) { errno = error_nomem; return -1; }
+ if (datalen > 0xffffffff) { errno = error_nomem; return -1; }
+
+ uint32_pack(buf,keylen);
+ uint32_pack(buf + 4,datalen);
+ if (buffer_putalign(&c->b,buf,8) == -1) return -1;
+ return 0;
+}
+
+int cdb_make_add(struct cdb_make *c,char *key,unsigned int keylen,char *data,unsigned int datalen)
+{
+ if (cdb_make_addbegin(c,keylen,datalen) == -1) return -1;
+ if (buffer_putalign(&c->b,key,keylen) == -1) return -1;
+ if (buffer_putalign(&c->b,data,datalen) == -1) return -1;
+ return cdb_make_addend(c,keylen,datalen,cdb_hash(key,keylen));
+}
+
+int cdb_make_finish(struct cdb_make *c)
+{
+ char buf[8];
+ int i;
+ uint32 len;
+ uint32 u;
+ uint32 memsize;
+ uint32 count;
+ uint32 where;
+ struct cdb_hplist *x;
+ struct cdb_hp *hp;
+
+ for (i = 0;i < 256;++i)
+ c->count[i] = 0;
+
+ for (x = c->head;x;x = x->next) {
+ i = x->num;
+ while (i--)
+ ++c->count[255 & x->hp[i].h];
+ }
+
+ memsize = 1;
+ for (i = 0;i < 256;++i) {
+ u = c->count[i] * 2;
+ if (u > memsize)
+ memsize = u;
+ }
+
+ memsize += c->numentries; /* no overflow possible up to now */
+ u = (uint32) 0 - (uint32) 1;
+ u /= sizeof(struct cdb_hp);
+ if (memsize > u) { errno = error_nomem; return -1; }
+
+ c->split = (struct cdb_hp *) alloc(memsize * sizeof(struct cdb_hp));
+ if (!c->split) return -1;
+
+ c->hash = c->split + c->numentries;
+
+ u = 0;
+ for (i = 0;i < 256;++i) {
+ u += c->count[i]; /* bounded by numentries, so no overflow */
+ c->start[i] = u;
+ }
+
+ for (x = c->head;x;x = x->next) {
+ i = x->num;
+ while (i--)
+ c->split[--c->start[255 & x->hp[i].h]] = x->hp[i];
+ }
+
+ for (i = 0;i < 256;++i) {
+ count = c->count[i];
+
+ len = count + count; /* no overflow possible */
+ uint32_pack(c->final + 8 * i,c->pos);
+ uint32_pack(c->final + 8 * i + 4,len);
+
+ for (u = 0;u < len;++u)
+ c->hash[u].h = c->hash[u].p = 0;
+
+ hp = c->split + c->start[i];
+ for (u = 0;u < count;++u) {
+ where = (hp->h >> 8) % len;
+ while (c->hash[where].p)
+ if (++where == len)
+ where = 0;
+ c->hash[where] = *hp++;
+ }
+
+ for (u = 0;u < len;++u) {
+ uint32_pack(buf,c->hash[u].h);
+ uint32_pack(buf + 4,c->hash[u].p);
+ if (buffer_putalign(&c->b,buf,8) == -1) return -1;
+ if (posplus(c,8) == -1) return -1;
+ }
+ }
+
+ if (buffer_flush(&c->b) == -1) return -1;
+ if (seek_begin(c->fd) == -1) return -1;
+ return buffer_putflush(&c->b,c->final,sizeof c->final);
+}