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Code Issues Wiki Activity

don't use malloc in the rds modulator

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This commit is contained in:
KubaPro010
2025-03-12 15:39:09 +01:00
parent c65a69a328
commit eeace56821
7 changed files with 31 additions and 58 deletions
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2
.vscode/.server-controller-port.log vendored
View File

@@ -1,5 +1,5 @@
{
"port": 13452,
"time": 1741720487844,
"time": 1741789102822,
"version": "0.0.3"
}

6
gen_wave.py
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@@ -57,9 +57,9 @@ outc.write(header)
outh.write(header)
def generate():
offset = int(sample_rate*0.004) # 190 khz = 760 760/10/2 = 38 190000/10/2=9500
count = int(offset / 10**(len(str(offset)) - 1)) # 760 / 100 = 7 38 / 10 = 3
l = int(sample_rate / 1187.5) // 2 # 16/2 = 8 8 / 2 = 4
offset = int(sample_rate*0.004) # 190 khz = 760
count = int(offset / 10**(len(str(offset)) - 1)) # 760 / 100 = 7
l = int(sample_rate / 1187.5) // 2 # 16/2 = 8
if count*l > l*16: raise Exception("Sample rate too small")
print(f"{offset=} {count=} {l=}")

65
src/modulator.c
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@@ -3,20 +3,14 @@
#include "waveforms.h"
#include "modulator.h"
static struct rds_t *rds;
static float **waveform;
static struct rds_t rds;
static float waveform[2][FILTER_SIZE];
void init_rds_objects() {
rds = malloc(sizeof(struct rds_t));
rds->bit_buffer = malloc(BITS_PER_GROUP);
rds->sample_buffer =
malloc(SAMPLE_BUFFER_SIZE * sizeof(float));
waveform = malloc(2 * sizeof(float));
memset(&rds, 0, sizeof(rds));
for (uint8_t i = 0; i < 2; i++) {
// This is the bpsk, so waveform[0] is 0 degrees out of phase but waveform[1] is 180 degrees, bpsk
waveform[i] = malloc(FILTER_SIZE * sizeof(float));
// This is the bpsk, so waveform[0] is 0 degrees out of phase but waveform[1] is 180 degrees, bpsk
for (uint16_t j = 0; j < FILTER_SIZE; j++) {
waveform[i][j] = i ?
+waveform_biphase[j] : -waveform_biphase[j];
@@ -24,18 +18,6 @@ void init_rds_objects() {
}
}
void exit_rds_objects() {
free(rds->sample_buffer);
free(rds->bit_buffer);
free(rds);
for (uint8_t i = 0; i < 2; i++) {
free(waveform[i]);
}
free(waveform);
}
/* Get an RDS sample. This generates the envelope of the waveform using
* pre-generated elementary waveform samples.
*/
@@ -43,40 +25,39 @@ float get_rds_sample() {
uint16_t idx;
float *cur_waveform;
float sample;
if (rds->sample_count == SAMPLES_PER_BIT) {
if (rds.sample_count == SAMPLES_PER_BIT) {
// New Sample
if (rds->bit_pos == BITS_PER_GROUP) {
if (rds.bit_pos == BITS_PER_GROUP) {
// New bit stream
get_rds_bits(rds->bit_buffer);
rds->bit_pos = 0;
get_rds_bits(rds.bit_buffer);
rds.bit_pos = 0;
}
// Differentially encode, so 1111 becomes 1000 and 0001 becomes 0001
rds->cur_bit = rds->bit_buffer[rds->bit_pos++];
rds->prev_output = rds->cur_output;
rds->cur_output = rds->prev_output ^ rds->cur_bit;
rds.cur_bit = rds.bit_buffer[rds.bit_pos++];
rds.prev_output = rds.cur_output;
rds.cur_output = rds.prev_output ^ rds.cur_bit;
idx = rds->in_sample_index;
cur_waveform = waveform[rds->cur_output]; // get the waveform, this is the biphase in a 0/180 degree phase shift
idx = rds.in_sample_index;
cur_waveform = waveform[rds.cur_output]; // get the waveform, this is the biphase in a 0/180 degree phase shift
for (uint16_t i = 0; i < FILTER_SIZE; i++) {
rds->sample_buffer[idx++] += *cur_waveform++;
rds.sample_buffer[idx++] += *cur_waveform++;
if (idx == SAMPLE_BUFFER_SIZE) idx = 0;
}
rds->in_sample_index += SAMPLES_PER_BIT;
if (rds->in_sample_index == SAMPLE_BUFFER_SIZE)
rds->in_sample_index = 0;
rds.in_sample_index += SAMPLES_PER_BIT;
if (rds.in_sample_index == SAMPLE_BUFFER_SIZE)
rds.in_sample_index = 0;
rds->sample_count = 0;
rds.sample_count = 0;
}
rds->sample_count++;
rds.sample_count++;
sample = rds->sample_buffer[rds->out_sample_index];
sample = rds.sample_buffer[rds.out_sample_index];
rds->sample_buffer[rds->out_sample_index++] = 0;
if (rds->out_sample_index == SAMPLE_BUFFER_SIZE)
rds->out_sample_index = 0;
rds.sample_buffer[rds.out_sample_index++] = 0;
if (rds.out_sample_index == SAMPLE_BUFFER_SIZE)
rds.out_sample_index = 0;
return sample;
}

6
src/modulator.h
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@@ -1,8 +1,8 @@
/* RDS signal context */
typedef struct rds_t {
uint8_t *bit_buffer; /* BITS_PER_GROUP */
uint8_t bit_buffer[BITS_PER_GROUP];
uint8_t bit_pos;
float *sample_buffer; /* SAMPLE_BUFFER_SIZE */
float sample_buffer[SAMPLE_BUFFER_SIZE];
uint8_t prev_output;
uint8_t cur_output;
uint8_t cur_bit;
@@ -12,5 +12,3 @@ typedef struct rds_t {
} rds_t;
extern void init_rds_objects();
extern void exit_rds_objects();

4
src/rds.c
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@@ -547,10 +547,6 @@ void init_rds_encoder(struct rds_params_t rds_params) {
init_rds_objects();
}
void exit_rds_encoder() {
exit_rds_objects();
}
void set_rds_pi(uint16_t pi_code) {
rds_data.pi = pi_code;
}

3
src/rds.h
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@@ -11,7 +11,7 @@
#define GROUP_LENGTH 4
#define BITS_PER_GROUP (GROUP_LENGTH * (BLOCK_SIZE + POLY_DEG))
#define RDS_SAMPLE_RATE 9500
#define SAMPLES_PER_BIT 8
#define SAMPLES_PER_BIT 8 // (1/1187.5)*RDS_SAMPLE_RATE
#define FILTER_SIZE 24
#define SAMPLE_BUFFER_SIZE (SAMPLES_PER_BIT + FILTER_SIZE)
@@ -263,7 +263,6 @@ typedef struct rds_oda_t {
#endif
extern void init_rds_encoder(struct rds_params_t rds_params);
extern void exit_rds_encoder();
extern void get_rds_bits(uint8_t *bits);
extern void set_rds_pi(uint16_t pi_code);
extern void set_rds_ecc(uint8_t ecc);

3
src/rds95.c
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@@ -206,7 +206,7 @@ int main(int argc, char **argv) {
int pulse_error;
float mpx_buffer[NUM_MPX_FRAMES];
static float mpx_buffer[NUM_MPX_FRAMES];
while(!stop_rds) {
for (size_t i = 0; i < NUM_MPX_FRAMES; i++) {
@@ -227,7 +227,6 @@ exit:
}
pthread_attr_destroy(&attr);
exit_rds_encoder();
pa_simple_free(device);
return 0;