~luxferre/nntrac

9acabe0de87eef95c2b54accc7a493a21b359da4 — Luxferre 3 months ago 5bd1524
improved prng
2 files changed, 8 insertions(+), 6 deletions(-)

M README.md
M nntrac.c
M README.md => README.md +1 -1
@@ 85,7 85,7 @@ Name|Args|Implemented?|UTF-8 safe?|Meaning
- `sf`: store (raw) file. 3 arguments: `#(sf,fname,form)`. Stores the raw value from `form` into a named file. The value is always written in its entirety (the form pointer is ignored) and segment gap bytes, if there are any, are written "as is". Returns a null value. The form doesn't get deleted from the internal form storage. The file is fully overwritten if it already exists.
- `ff`: fetch (raw) file. 3 arguments: `#(ff,fname,form)`. Reads a raw string from the named file into `form`. Returns null value (check the target form afterwards).
- `tm`: local/UTC/Epoch time. 2 or 3 arguments: `#(tl,fmt[,U])`. Returns the local (or UTC, if the third parameter `U` is specified) time formatted according to the strftime-compatible `fmt` string or `E` format. If the format string is just `E` (Epoch), returns the amount of seconds since 00:00:00 UTC, January 1, 1970.
- `rn`: random number. 3 arguments: `#(rn,n1,n2)`. Returns a (pseudo-)random integer number in the range `n1` (included) to `n2` (not included). Implemented using the xorshift64 algorithm.
- `rn`: random number. 3 arguments: `#(rn,n1,n2)`. Returns a (pseudo-)random integer number in the range `n1` (included) to `n2` (not included). Implemented using the double-pass xorshift64* algorithm.
- `os`: run an OS command. 2 arguments: `#(os,cmd)`. Runs a command in the external OS shell (the one determined by the `system()` C call) and returns the command exit code. The output is not captured.

For self-contained nntrac environments that have no external shell (or the shell is nntrac itself), you can disable the `os` primitive by building nntrac with the `-DNNT_NO_EXTSHELL` flag.

M nntrac.c => nntrac.c +7 -5
@@ 1061,9 1061,11 @@ char *prim_tm(char *arglist, char *res, int *reslen) {
}

static unsigned long long nnt_rngs; /* PRNG state*/    
unsigned long long xorshift64() {
  nnt_rngs^=(nnt_rngs<<13);nnt_rngs^=(nnt_rngs>>7);nnt_rngs^=(nnt_rngs<<17);
  return nnt_rngs;
unsigned long long xorshift64s() {
  nnt_rngs^=(nnt_rngs>>12);nnt_rngs^=(nnt_rngs<<25);nnt_rngs^=(nnt_rngs>>27);
  unsigned long long inter = (nnt_rngs * 0x2545F4914F6CDD1DULL) >> 32;
  nnt_rngs^=(nnt_rngs>>12);nnt_rngs^=(nnt_rngs<<25);nnt_rngs^=(nnt_rngs>>27);
  return (inter << 32) | ((nnt_rngs * 0x2545F4914F6CDD1DULL) & 0xFFFFFFFF);
}

/* [new] rn primitive: (pseudo)random number */


@@ 1073,7 1075,7 @@ char *prim_rn(char *arglist, char *res, int *reslen) {
       *tos = strtok(NULL, NNT_ADEL_S);
  long long a = (froms == NULL) ? 0 : snum(froms),
            b = (tos == NULL) ? ARITH_LIMIT : snum(tos);
  res = n2s(a == b ? a : (a + xorshift64() % (b - a)), res, reslen);
  res = n2s(a == b ? a : (a + xorshift64s() % (b - a)), res, reslen);
  return res;
}



@@ 1081,7 1083,7 @@ char *prim_rn(char *arglist, char *res, int *reslen) {
void nnt_init() {
  nnt_forms = malloc(0); /* init the forms table */
  nnt_primitives = malloc(0); /* init the primitives table */
  nnt_rngs = time(NULL); xorshift64(); /* init the PRNG */
  nnt_rngs = time(NULL); xorshift64s(); /* init the PRNG */
  nnt_regprimitive("ps", &prim_ps);
  nnt_regprimitive("rc", &prim_rc);
  nnt_regprimitive("rs", &prim_rs);