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/* vim: set sw=8 ts=8 sts=8 noet: */
/* capn-stream.c
*
* Copyright (C) 2013 James McKaskill
*
* This software may be modified and distributed under the terms
* of the MIT license. See the LICENSE file for details.
*/
#include "capnp_c.h"
#include "capnp_priv.h"
#include <string.h>
#ifndef min
static unsigned min(unsigned a, unsigned b) { return (a < b) ? a : b; }
#endif
int capn_deflate(struct capn_stream* s) {
if (s->avail_in % 8) {
return CAPN_MISALIGNED;
}
while (s->avail_in) {
int i;
size_t sz;
uint8_t hdr = 0;
uint8_t *p;
if (!s->avail_out)
return CAPN_NEED_MORE;
if (s->raw > 0) {
sz = min(s->raw, min(s->avail_in, s->avail_out));
memcpy(s->next_out, s->next_in, sz);
s->next_out += sz;
s->next_in += sz;
s->avail_out -= sz;
s->avail_in -= sz;
s->raw -= sz;
continue;
}
if (s->avail_in < 8)
return CAPN_NEED_MORE;
sz = 0;
for (i = 0; i < 8; i++) {
if (s->next_in[i]) {
sz ++;
hdr |= 1 << i;
}
}
switch (sz) {
case 0:
if (s->avail_out < 2)
return CAPN_NEED_MORE;
s->next_out[0] = 0;
for (sz = 1; sz < min(s->avail_in/8, 256); sz++) {
if (((uint64_t*) s->next_in)[sz] != 0) {
break;
}
}
s->next_out[1] = (uint8_t) (sz-1);
s->next_in += sz*8;
s->avail_in -= sz*8;
s->next_out += 2;
s->avail_out -= 2;
continue;
case 8:
if (s->avail_out < 10)
return CAPN_NEED_MORE;
s->next_out[0] = 0xFF;
memcpy(s->next_out+1, s->next_in, 8);
s->next_in += 8;
s->avail_in -= 8;
s->raw = min(s->avail_in, 256*8);
if ((p = (uint8_t*) memchr(s->next_in, 0, s->raw)) != NULL) {
s->raw = (p - s->next_in) & ~7;
}
s->next_out[9] = (uint8_t) (s->raw/8);
s->next_out += 10;
s->avail_out -= 10;
continue;
default:
if (s->avail_out < 1U + sz)
return CAPN_NEED_MORE;
*(s->next_out++) = hdr;
for (i = 0; i < 8; i++) {
if (s->next_in[i]) {
*(s->next_out++) = s->next_in[i];
}
}
s->avail_out -= sz + 1;
s->next_in += 8;
s->avail_in -= 8;
continue;
}
}
return 0;
}
int capn_inflate(struct capn_stream* s) {
while (s->avail_out) {
int i;
size_t sz;
uint8_t hdr;
uint8_t *wr;
if (s->avail_buf && s->avail_out >= s->avail_buf) {
memcpy(s->next_out, s->inflate_buf, s->avail_buf);
s->next_out += s->avail_buf;
s->avail_out -= s->avail_buf;
s->avail_buf = 0;
if (!s->avail_out)
return 0;
}
if (s->avail_buf && s->avail_out < s->avail_buf) {
memcpy(s->next_out, s->inflate_buf, s->avail_out);
memmove(s->inflate_buf, s->inflate_buf + s->avail_out,
s->avail_buf - s->avail_out);
s->avail_buf -= s->avail_out;
s->avail_out = 0;
return 0;
}
if (s->zeros > 0) {
sz = min(s->avail_out, s->zeros);
memset(s->next_out, 0, sz);
s->next_out += sz;
s->avail_out -= sz;
s->zeros -= sz;
continue;
}
if (s->raw > 0) {
if (s->avail_in == 0)
return CAPN_NEED_MORE;
sz = min(min(s->avail_out, s->raw), s->avail_in);
memcpy(s->next_out, s->next_in, sz);
s->next_in += sz;
s->next_out += sz;
s->avail_in -= sz;
s->avail_out -= sz;
s->raw -= sz;
continue;
}
if (s->avail_in == 0)
return 0;
else if (s->avail_in < 2)
return CAPN_NEED_MORE;
switch (s->next_in[0]) {
case 0xFF:
/* 0xFF is followed by 8 bytes raw, followed by
* a byte with length in words to read raw */
if (s->avail_in < 10)
return CAPN_NEED_MORE;
memcpy(s->inflate_buf, s->next_in+1, 8);
s->avail_buf = 8;
s->raw = s->next_in[9] * 8;
s->next_in += 10;
s->avail_in -= 10;
continue;
case 0x00:
/* 0x00 is followed by a single byte indicating
* the count of consecutive zero value words
* minus 1 */
s->zeros = (s->next_in[1] + 1) * 8;
s->next_in += 2;
s->avail_in -= 2;
continue;
default:
hdr = s->next_in[0];
sz = 0;
for (i = 0; i < 8; i++) {
if (hdr & (1 << i))
sz++;
}
if (s->avail_in < 1U + sz)
return CAPN_NEED_MORE;
s->next_in += 1;
wr = s->inflate_buf;
for (i = 0; i < 8; i++) {
if (hdr & (1 << i)) {
*wr++ = *s->next_in++;
} else {
*wr++ = 0;
}
}
s->avail_buf = 8;
s->avail_in -= 1 + sz;
continue;
}
}
return 0;
}
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