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Make SC16Q11-nodc conversions table-based for speed.

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Add a mechanism for converters to initialize tables on demand.
Move UC8 table setup to the new lazy-setup path.
Fix uc8 lookup table allocation size.
This commit is contained in:
Oliver Jowett 2017-01-27 21:58:12 +00:00
parent 8a41bcb730
commit 417cda7061
4 changed files with 252 additions and 88 deletions
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20
dump1090.c
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@ -129,7 +129,7 @@ void modesInitConfig(void) {
//=========================================================================
//
void modesInit(void) {
int i, q;
int i;
pthread_mutex_init(&Modes.data_mutex,NULL);
pthread_cond_init(&Modes.data_cond,NULL);
@ -139,8 +139,7 @@ void modesInit(void) {
// Allocate the various buffers used by Modes
Modes.trailing_samples = (MODES_PREAMBLE_US + MODES_LONG_MSG_BITS + 16) * 1e-6 * Modes.sample_rate;
if ( ((Modes.maglut = (uint16_t *) malloc(sizeof(uint16_t) * 256 * 256) ) == NULL) ||
((Modes.log10lut = (uint16_t *) malloc(sizeof(uint16_t) * 256 * 256) ) == NULL) )
if ( ((Modes.log10lut = (uint16_t *) malloc(sizeof(uint16_t) * 256 * 256) ) == NULL) )
{
fprintf(stderr, "Out of memory allocating data buffer.\n");
exit(1);
@ -184,21 +183,6 @@ void modesInit(void) {
if (Modes.net_sndbuf_size > (MODES_NET_SNDBUF_MAX))
{Modes.net_sndbuf_size = MODES_NET_SNDBUF_MAX;}
// compute UC8 magnitude lookup table
for (i = 0; i <= 255; i++) {
for (q = 0; q <= 255; q++) {
float fI, fQ, magsq;
fI = (i - 127.5) / 127.5;
fQ = (q - 127.5) / 127.5;
magsq = fI * fI + fQ * fQ;
if (magsq > 1)
magsq = 1;
Modes.maglut[le16toh((i*256)+q)] = (uint16_t) round(sqrtf(magsq) * 65535.0);
}
}
// Prepare the log10 lookup table: 100log10(x)
Modes.log10lut[0] = 0; // poorly defined..
for (i = 1; i <= 65535; i++) {