Files
libblkmaker/blkmaker.c
2012-09-04 04:46:34 +00:00

97 lines
2.4 KiB
C

#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <blkmaker.h>
#include <blktemplate.h>
static inline
void my_htole32(unsigned char *buf, uint32_t n) {
buf[0] = (n >> 0) % 256;
buf[1] = (n >> 8) % 256;
buf[2] = (n >> 16) % 256;
buf[3] = (n >> 24) % 256;
}
bool (*blkmk_sha256_impl)(void *, const void *, size_t) = NULL;
static
bool dblsha256(void *hash, const void *data, size_t datasz) {
return blkmk_sha256_impl(hash, data, datasz) && blkmk_sha256_impl(hash, hash, 32);
}
static
bool build_merkle_root(unsigned char *mrklroot_out, blktemplate_t *tmpl) {
if (!tmpl->cbtxn)
return false;
size_t hashcount = tmpl->txncount + 1;
unsigned char hashes[(hashcount + 1) * 32];
if (!dblsha256(&hashes[0], tmpl->cbtxn->data, tmpl->cbtxn->datasz))
return false;
for (int i = 0; i < tmpl->txncount; ++i)
if (!dblsha256(&hashes[32 * (i + 1)], tmpl->txns[i].data, tmpl->txns[i].datasz))
return false;
while (hashcount > 1)
{
if (hashcount % 2)
{
memcpy(&hashes[32 * hashcount], &hashes[32 * (hashcount - 1)], 32);
++hashcount;
}
for (int i = 0; i < hashcount; i += 2)
// This is where we overlap input and output, on the first pair
if (!dblsha256(&hashes[i / 2 * 32], &hashes[32 * i], 64))
return false;
hashcount /= 2;
}
memcpy(mrklroot_out, &hashes[0], 32);
return true;
}
size_t blkmk_get_data(blktemplate_t *tmpl, void *buf, size_t bufsz, time_t usetime, int16_t *out_expire) {
if (!(blkmk_time_left(tmpl, usetime) && blkmk_work_left(tmpl)))
return 0;
if (bufsz < 76)
return 76;
unsigned char *cbuf = buf;
my_htole32(&cbuf[0], tmpl->version);
memcpy(&cbuf[4], &tmpl->prevblk, 32);
if (!build_merkle_root(&cbuf[36], tmpl))
return 0;
blktime_t timehdr = tmpl->curtime + difftime(usetime, tmpl->_time_rcvd);
if (timehdr > tmpl->maxtime)
timehdr = tmpl->maxtime;
my_htole32(&cbuf[68], timehdr);
memcpy(&cbuf[72], &tmpl->diffbits, 4);
// TODO: set *out_expire if provided
// TEMPORARY HACK:
memcpy(tmpl->_mrklroot, &cbuf[36], 32);
return 76;
}
blktime_diff_t blkmk_time_left(const blktemplate_t *tmpl, time_t nowtime) {
double age = difftime(nowtime, tmpl->_time_rcvd);
if (age >= tmpl->expires)
return 0;
return tmpl->expires - age;
}
unsigned long blkmk_work_left(const blktemplate_t *tmpl) {
// TODO
// TEMPORARY HACK
return (tmpl->version && !tmpl->_mrklroot[0]) ? 1 : 0;
return BLKMK_UNLIMITED_WORK_COUNT;
}