size_t readfull(int f, T ** buf) {
off_t sz = lseek(f, 0, SEEK_END);
lseek(f, 0, SEEK_SET);
*buf = (char*)malloc(sz);
preada(f, *buf, sz, 0);
return sz;
}
inline U read_val() {
if (blockptr + sizeof(U) > block + blocklen) {
// Read
blocklen = std::min(blocksize, total_to_process - fpos);
preada(fd, block, blocklen, fpos);
blockptr = block;
}
U res = *((U*)blockptr);
blockptr += sizeof(U);
fpos += sizeof(U);
return res;
}
void read_compressed(int f, T * tbuf, size_t nbytes) {
#ifndef GRAPHCHI_DISABLE_COMPRESSION
unsigned char * buf = (unsigned char*)tbuf;
int ret;
unsigned have;
z_stream strm;
int CHUNK = (int) std::max((size_t)4096 * 1024, nbytes);
size_t fsize = lseek(f, 0, SEEK_END);
unsigned char * in = (unsigned char *) malloc(fsize);
lseek(f, 0, SEEK_SET);
/* allocate inflate state */
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
ret = inflateInit(&strm);
if (ret != Z_OK)
assert(false);
/* decompress until deflate stream ends or end of file */
do {
ssize_t a = 0;
do {
a = read(f, in + strm.avail_in, fsize - strm.avail_in); //fread(in, 1, CHUNK, source);
strm.avail_in += (int) a;
IASSERT(a != (ssize_t)(-1));
} while (a > 0);
if (strm.avail_in == 0)
break;
strm.next_in = in;
/* run inflate() on input until output buffer not full */
do {
strm.avail_out = CHUNK;
strm.next_out = buf;
ret = inflate(&strm, Z_NO_FLUSH);
IASSERT(ret != Z_STREAM_ERROR); /* state not clobbered */
switch (ret) {
case Z_NEED_DICT:
ret = Z_DATA_ERROR; /* and fall through */
case Z_DATA_ERROR:
case Z_MEM_ERROR:
assert(false);
}
have = CHUNK - strm.avail_out;
buf += have;
} while (strm.avail_out == 0);
/* done when inflate() says it's done */
} while (ret != Z_STREAM_END);
// std::cout << "Read: " << (buf - (unsigned char*)tbuf) << std::endl;
/* clean up and return */
(void)inflateEnd(&strm);
free(in);
#else
preada(f, tbuf, nbytes, 0);
#endif
}
