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Determine buffer size needed without encoding. #51

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Determine buffer size needed without encoding. #51

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7 changes: 5 additions & 2 deletions include/cn-cbor/cn-cbor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -265,10 +265,13 @@ void cn_cbor_free(cn_cbor* cb CBOR_CONTEXT);
/**
* Write a CBOR value and all of the child values.
*
* @param[in] buf The buffer into which to write
* @param[in] buf The buffer into which to write. May be NULL to
* determine the necessary size.
* @param[in] buf_offset The offset (in bytes) from the beginning of the buffer
* to start writing at
* @param[in] buf_size The total length (in bytes) of the buffer
* @param[in] buf_size The total length (in bytes) of the buffer. If buf is
* NULL, this is an upper limit and may be 0 to specify
* no limit.
* @param[in] cb [description]
* @return -1 on fail, or number of bytes written
*/
Expand Down
19 changes: 15 additions & 4 deletions src/cn-encoder.c
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Expand Up @@ -41,12 +41,20 @@ typedef struct _write_state
}

#define write_byte_and_data(b, data, sz) \
ws->buf[ws->offset++] = (b); \
memcpy(ws->buf+ws->offset, (data), (sz)); \
if(ws->buf) { \
ws->buf[ws->offset++] = (b); \
memcpy(ws->buf+ws->offset, (data), (sz)); \
} else { \
ws->offset++; \
} \
ws->offset += sz;

#define write_byte(b) \
ws->buf[ws->offset++] = (b); \
if(ws->buf) { \
ws->buf[ws->offset++] = (b); \
} else { \
ws->offset++; \
}

#define write_byte_ensured(b) \
ensure_writable(1); \
Expand Down Expand Up @@ -249,7 +257,9 @@ void _encoder_visitor(const cn_cbor *cb, int depth, void *context)
case CN_CBOR_BYTES:
CHECK(_write_positive(ws, cb->type, cb->length));
ensure_writable(cb->length);
memcpy(ws->buf+ws->offset, cb->v.str, cb->length);
if (ws->buf) {
memcpy(ws->buf+ws->offset, cb->v.str, cb->length);
}
ws->offset += cb->length;
break;

Expand Down Expand Up @@ -302,6 +312,7 @@ ssize_t cn_cbor_encoder_write(uint8_t *buf,
const cn_cbor *cb)
{
cn_write_state ws = { buf, buf_offset, buf_size };
if (!ws.buf && ws.size <= 0) { ws.size = (ssize_t)(((size_t)-1) / 2); }
_visit(cb, _encoder_visitor, _encoder_breaker, &ws);
if (ws.offset < 0) { return -1; }
return ws.offset - buf_offset;
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13 changes: 13 additions & 0 deletions test/cbor_test.c
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Expand Up @@ -116,6 +116,7 @@ CTEST(cbor, parse)
size_t i;
unsigned char encoded[1024];
ssize_t enc_sz;
ssize_t enc_sz2;

for (i=0; i<sizeof(tests)/sizeof(char*); i++) {
ASSERT_TRUE(parse_hex(tests[i], &b));
Expand All @@ -125,7 +126,9 @@ CTEST(cbor, parse)
ASSERT_EQUAL(err.err, CN_CBOR_NO_ERROR);
ASSERT_NOT_NULL(cb);

enc_sz2 = cn_cbor_encoder_write(NULL, 0, sizeof(encoded), cb);
enc_sz = cn_cbor_encoder_write(encoded, 0, sizeof(encoded), cb);
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If #49 is merged, the size passed here could change to enc_sz2 to also test that.

ASSERT_EQUAL(enc_sz, enc_sz2);
ASSERT_DATA(b.ptr, b.sz, encoded, enc_sz);
free(b.ptr);
cn_cbor_free(cb CONTEXT_NULL);
Expand Down Expand Up @@ -164,6 +167,7 @@ CTEST(cbor, parse_normalize)
size_t i;
unsigned char encoded[1024];
ssize_t enc_sz;
ssize_t enc_sz2;

for (i=0; i<sizeof(basic_tests)/sizeof(char*); i+=2) {
ASSERT_TRUE(parse_hex(basic_tests[i], &b));
Expand All @@ -174,7 +178,9 @@ CTEST(cbor, parse_normalize)
ASSERT_EQUAL(err.err, CN_CBOR_NO_ERROR);
ASSERT_NOT_NULL(cb);

enc_sz2 = cn_cbor_encoder_write(NULL, 0, sizeof(encoded), cb);
enc_sz = cn_cbor_encoder_write(encoded, 0, sizeof(encoded), cb);
ASSERT_EQUAL(enc_sz, enc_sz2);
ASSERT_DATA(b2.ptr, b2.sz, encoded, enc_sz);
free(b.ptr);
free(b2.ptr);
Expand All @@ -195,7 +201,9 @@ CTEST(cbor, parse_normalize)
ASSERT_NULL(cb);
#endif /* CBOR_NO_FLOAT */

/* enc_sz2 = cn_cbor_encoder_write(NULL, 0, sizeof(encoded), cb); */
/* enc_sz = cn_cbor_encoder_write(encoded, 0, sizeof(encoded), cb); */
/* ASSERT_EQUAL(enc_sz, enc_sz2); */
/* ASSERT_DATA(b2.ptr, b2.sz, encoded, enc_sz); */
free(b.ptr);
free(b2.ptr);
Expand Down Expand Up @@ -258,13 +266,16 @@ CTEST(cbor, float)
size_t i;
unsigned char encoded[1024];
ssize_t enc_sz;
ssize_t enc_sz2;

for (i=0; i<sizeof(tests)/sizeof(char*); i++) {
ASSERT_TRUE(parse_hex(tests[i], &b));
cb = cn_cbor_decode(b.ptr, b.sz CONTEXT_NULL, &err);
ASSERT_NOT_NULL(cb);

enc_sz2 = cn_cbor_encoder_write(NULL, 0, sizeof(encoded), cb);
enc_sz = cn_cbor_encoder_write(encoded, 0, sizeof(encoded), cb);
ASSERT_EQUAL(enc_sz, enc_sz2);
ASSERT_DATA(b.ptr, b.sz, encoded, enc_sz);

free(b.ptr);
Expand Down Expand Up @@ -446,6 +457,8 @@ CTEST(cbor, create_encode)
ASSERT_NOT_NULL(cdata);

ASSERT_TRUE(cn_cbor_mapput_int(map, 0, cdata, CONTEXT_NULL_COMMA NULL));
enc_sz = cn_cbor_encoder_write(NULL, 0, sizeof(encoded), map);
ASSERT_EQUAL(7, enc_sz);
enc_sz = cn_cbor_encoder_write(encoded, 0, sizeof(encoded), map);
ASSERT_EQUAL(7, enc_sz);
}