Session() {capn_init_malloc(&capn);}
static int init_fp(struct capn *c, FILE *f, struct capn_stream *z, int packed) {
/*
* Initialize 'c' from the contents of 'f', assuming the message has been
* serialized with the standard framing format. From https://capnproto.org/encoding.html:
*
* When transmitting over a stream, the following should be sent. All integers are unsigned and little-endian.
* (4 bytes) The number of segments, minus one (since there is always at least one segment).
* (N * 4 bytes) The size of each segment, in words.
* (0 or 4 bytes) Padding up to the next word boundary.
* The content of each segment, in order.
*/
struct capn_segment *s = NULL;
uint32_t i, segnum, total = 0;
uint32_t hdr[1024];
uint8_t zbuf[ZBUF_SZ];
char *data = NULL;
capn_init_malloc(c);
/* Read the first four bytes to know how many headers we have */
if (read_fp(&segnum, 4, f, z, zbuf, packed))
goto err;
segnum = capn_flip32(segnum);
if (segnum > 1023)
goto err;
segnum++; /* The wire encoding was zero-based */
/* Read the header list */
if (read_fp(hdr, 8 * (segnum/2) + 4, f, z, zbuf, packed))
goto err;
for (i = 0; i < segnum; i++) {
uint32_t n = capn_flip32(hdr[i]);
if (n > INT_MAX/8 || n > UINT32_MAX/8 || UINT32_MAX - total < n*8)
goto err;
hdr[i] = n*8;
total += hdr[i];
}
/* Allocate space for the data and the capn_segment structs */
s = (struct capn_segment*) calloc(1, total + (sizeof(*s) * segnum));
if (!s)
goto err;
/* Now read the data and setup the capn_segment structs */
data = (char*) (s+segnum);
if (read_fp(data, total, f, z, zbuf, packed))
goto err;
for (i = 0; i < segnum; i++) {
s[i].len = s[i].cap = hdr[i];
s[i].data = data;
data += s[i].len;
capn_append_segment(c, &s[i]);
}
/* Set the entire region to be freed on the last segment */
s[segnum-1].user = s;
return 0;
err:
memset(c, 0, sizeof(*c));
free(s);
return -1;
}
