Create variable amount of struct objects inside a struct (C) - c

Question

I haven't written any C for more than a decade, but here I am...
I want to be able to create and access the following items of a data structure:
FilterCoefficients[0].TargetSampleNum = 0;
FilterCoefficients[0].SourceWeights[0].Weight = 0.812;
FilterCoefficients[0].SourceWeights[0].SourceSampleNum = 0;
FilterCoefficients[0].SourceWeights[1].Weight = 0.153;
FilterCoefficients[0].SourceWeights[1].SourceSampleNum = 1;
FilterCoefficients[1].TargetSampleNum = 1;
FilterCoefficients[1].SourceWeights[0].Weight = 0.352;
FilterCoefficients[1].SourceWeights[0].SourceSampleNum = 0;
FilterCoefficients[1].SourceWeights[1].Weight = 0.721;
FilterCoefficients[1].SourceWeights[1].SourceSampleNum = 1;
[...]
The indices have to be dynamically allocated (amount of needed space changes during runtime). I am attempting to create said data structure with the following:
typedef struct SampleWeight_t
{
unsigned long SourceSampleNum;
double Weight;
} SampleWeight;
typedef struct FilterCoefficients_t
{
unsigned long TargetSampleNum;
SampleWeight* SourceWeights;
} FilterCoefficients;
However, I am having difficulties creating the structure. I am getting Break Point exceptions when malloc-ing or free-ing the structure.
FilterCoefficients* FilterCoefficients;
SampleWeight* SampleWeight;
FilterCoefficients = malloc(sizeof(FilterCoefficients) * target_width);
if (FilterCoefficients == NULL) {
//errhandler
}
for (int i = 0; i < target_width; i++) {
FilterCoefficients[i].SourceWeights = malloc(sizeof(SampleWeight) * (int)ceil(scalingFactorWidth * window_width)); // **exception usually here**
if (FilterCoefficients[i].SourceWeights == NULL) {
//errhandler
}
FilterCoefficients[i].TargetSampleNum = i;
for (int j = i - filter_width; j < i + filter_width; j++) {
FilterCoefficients[i].SourceWeights[j + filter_width].Weight = bilinear_filter(0.5 + scalingFactorWidth2 * (j - 0.5));
if (j > 0) {
FilterCoefficients[i].SourceWeights[j + filter_width].SourceSampleNum = j;
}
else {
FilterCoefficients[i].SourceWeights[j + filter_width].SourceSampleNum = 0;
}
}
}
for (int i = 0; i < target_width; i++) {
free(FilterCoefficients[i].SourceWeights); // **exception usually here**
}
free(FilterCoefficients);
Any help which is gonna point me to a solution is appreciated.

Answer 1

This compiles and executes. I had to simplify.
#include <stdio.h>
#include <stdlib.h>
typedef struct SampleWeight_t
{
unsigned long SourceSampleNum;
double Weight;
} SampleWeight;
typedef struct FilterCoefficients_t
{
unsigned long TargetSampleNum;
SampleWeight* SourceWeights;
} FilterCoefficients;
int main ( void) {
FilterCoefficients* FilterCoeff;
int window_width = 35;
int target_width = 55;
FilterCoeff = malloc(sizeof(FilterCoefficients) * target_width);
if (FilterCoeff == NULL) {
//errhandler
}
for (int i = 0; i < target_width; i++) {
FilterCoeff[i].SourceWeights = malloc(sizeof(SampleWeight) * window_width);
if (FilterCoeff[i].SourceWeights == NULL) {
//errhandler
}
FilterCoeff[i].TargetSampleNum = i;
for (int j = 0; j < window_width; j++) {
FilterCoeff[i].SourceWeights[j].Weight = i * j;
if (j > 0) {
FilterCoeff[i].SourceWeights[j].SourceSampleNum = j;
}
else {
FilterCoeff[i].SourceWeights[j].SourceSampleNum = 0;
}
}
}
for (int i = 0; i < target_width; i++) {
free(FilterCoeff[i].SourceWeights); // **exception usually here**
}
free(FilterCoeff);
}