ardour/livetrax
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somewhat better solution to prev commit.

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parse up to 32bit VLQs, match smf_format_vlq()
This commit is contained in:
Robin Gareus 2015-12-27 03:40:48 +01:00
parent 2c197fd89a
commit 8d45eecd45
2 changed files with 12 additions and 13 deletions
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15
libs/evoral/src/Event.cpp
View File

@ -38,23 +38,16 @@ init_event_id_counter(event_id_t n)
event_id_t
next_event_id ()
{
/* libsmf supports reading variable-length data up to 4 bytes only.
* so we wrap around at 2^(4 * 7) - 1
*
* interestingly enough libsmf happily writes data longer than that, but then
* fails to load it in ./libs/evoral/src/libsmf/smf_load.c:237
* g_critical("SMF error: Variable Length Quantities longer than four bytes are not supported yet.");
/* TODO: handle 31bit overflow , event_id_t is an int32_t,
* and libsmf only supports loading uint32_t vlq's, see smf_extract_vlq()
*
* event-IDs only have to be unique per .mid file.
* Previously (Ardour 4.2ish) Ardour re-generated those IDs when loading the
* file but that lead to .mid files being modified on every load/save.
*
* For now just assume that by the time 2^28 is reached, files with low ids have vanished.
* There is only one user who managed to get to 268 million events so far.
* quite a feat: id-counter="6483089" event-counter="276390506"
* Eventually a proper solution will have to be implemented.
* current user-record: is event-counter="276390506" (just abov 2^28)
*/
return g_atomic_int_add (&_event_id_counter, 1) & 268435455;
return g_atomic_int_add (&_event_id_counter, 1);
}
#ifdef EVORAL_EVENT_ALLOC

10
libs/evoral/src/libsmf/smf_load.c
View File

@ -214,13 +214,19 @@ smf_extract_vlq(const unsigned char *buf, const size_t buffer_length, uint32_t *
{
uint32_t val = 0;
const unsigned char *c = buf;
int i = 0;
for (;;) {
for (;; ++i) {
if (c >= buf + buffer_length) {
g_critical("End of buffer in extract_vlq().");
return (-1);
}
if (i == 4 && (val & 0xfe000000)) {
g_critical("SMF error: Variable Length Quantities longer than four bytes are not supported yet.");
return (-2);
}
val = (val << 7) + (*c & 0x7F);
if (*c & 0x80)
@ -233,7 +239,7 @@ smf_extract_vlq(const unsigned char *buf, const size_t buffer_length, uint32_t *
*value = val;
*len = c - buf + 1;
if (*len > 4) {
if (*len > 5) {
g_critical("SMF error: Variable Length Quantities longer than four bytes are not supported yet.");
return (-2);
}