diff options
Diffstat (limited to 'src/lib/capnp-c/capn-stream.cc')
| -rw-r--r-- | src/lib/capnp-c/capn-stream.cc | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/src/lib/capnp-c/capn-stream.cc b/src/lib/capnp-c/capn-stream.cc new file mode 100644 index 0000000..135d1b2 --- /dev/null +++ b/src/lib/capnp-c/capn-stream.cc @@ -0,0 +1,217 @@ +/* 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; +} + |