combine char bytes to 32 bit int

Suppose you have byte array and that array is aligned on 32 bit boundary. Then you may write to that array with incrementing pointer to char, but read with incrementing pointer to int. This way you'll get LE packed words, like:

...
// You did not tell you platform, for C6x every array is at least 4B aligned
// Check your environment.

char buf[MANY];

char * pc = (char *) &buf[0];
int  * pi = ( int *) &buf[0];

*pc++ = ingress_byte; // this way write to buf and move pointer
// next after whole buffer reception or after n*4 bytes received
// read your 32-bit data as
destination = *pi++;