Merge pull request #17020 from seandewar/vim-8.1.2342

vim-patch:8.1.{2342,2343,2356,2357},8.2.0233: `rand` and `srand`

1 files changed, 157 insertions, 0 deletions

diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 50030f2994..b96ff50787 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -22,6 +22,7 @@
 #include "nvim/eval/encode.h"
 #include "nvim/eval/executor.h"
 #include "nvim/eval/funcs.h"
+#include "nvim/eval/typval.h"
 #include "nvim/eval/userfunc.h"
 #include "nvim/ex_cmds2.h"
 #include "nvim/ex_docmd.h"
@@ -6978,6 +6979,162 @@ static void f_py3eval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   script_host_eval("python3", argvars, rettv);
 }
 
+static void init_srand(uint32_t *const x)
+  FUNC_ATTR_NONNULL_ALL
+{
+#ifndef MSWIN
+  static int dev_urandom_state = NOTDONE;  // FAIL or OK once tried
+
+  if (dev_urandom_state != FAIL) {
+    const int fd = os_open("/dev/urandom", O_RDONLY, 0);
+    struct {
+      union {
+        uint32_t number;
+        char bytes[sizeof(uint32_t)];
+      } contents;
+    } buf;
+
+    // Attempt reading /dev/urandom.
+    if (fd == -1) {
+      dev_urandom_state = FAIL;
+    } else {
+      buf.contents.number = 0;
+      if (read(fd, buf.contents.bytes, sizeof(uint32_t)) != sizeof(uint32_t)) {
+        dev_urandom_state = FAIL;
+      } else {
+        dev_urandom_state = OK;
+        *x = buf.contents.number;
+      }
+      os_close(fd);
+    }
+  }
+  if (dev_urandom_state != OK) {
+    // Reading /dev/urandom doesn't work, fall back to time().
+#endif
+    *x = time(NULL);
+#ifndef MSWIN
+  }
+#endif
+}
+
+static inline uint32_t splitmix32(uint32_t *const x)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_ALWAYS_INLINE
+{
+  uint32_t z = (*x += 0x9e3779b9);
+  z = (z ^ (z >> 16)) * 0x85ebca6b;
+  z = (z ^ (z >> 13)) * 0xc2b2ae35;
+  return z ^ (z >> 16);
+}
+
+static inline uint32_t shuffle_xoshiro128starstar(uint32_t *const x, uint32_t *const y,
+                                                  uint32_t *const z, uint32_t *const w)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_ALWAYS_INLINE
+{
+#define ROTL(x, k) ((x << k) | (x >> (32 - k)))
+  const uint32_t result = ROTL(*y * 5, 7) * 9;
+  const uint32_t t = *y << 9;
+  *z ^= *x;
+  *w ^= *y;
+  *y ^= *z;
+  *x ^= *w;
+  *z ^= t;
+  *w = ROTL(*w, 11);
+#undef ROTL
+  return result;
+}
+
+/// "rand()" function
+static void f_rand(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  uint32_t result;
+
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    static uint32_t gx, gy, gz, gw;
+    static bool initialized = false;
+
+    // When no argument is given use the global seed list.
+    if (!initialized) {
+      // Initialize the global seed list.
+      uint32_t x;
+      init_srand(&x);
+
+      gx = splitmix32(&x);
+      gy = splitmix32(&x);
+      gz = splitmix32(&x);
+      gw = splitmix32(&x);
+      initialized = true;
+    }
+
+    result = shuffle_xoshiro128starstar(&gx, &gy, &gz, &gw);
+  } else if (argvars[0].v_type == VAR_LIST) {
+    list_T *const l = argvars[0].vval.v_list;
+    if (tv_list_len(l) != 4) {
+      goto theend;
+    }
+
+    typval_T *const tvx = TV_LIST_ITEM_TV(tv_list_find(l, 0L));
+    typval_T *const tvy = TV_LIST_ITEM_TV(tv_list_find(l, 1L));
+    typval_T *const tvz = TV_LIST_ITEM_TV(tv_list_find(l, 2L));
+    typval_T *const tvw = TV_LIST_ITEM_TV(tv_list_find(l, 3L));
+    if (tvx->v_type != VAR_NUMBER) {
+      goto theend;
+    }
+    if (tvy->v_type != VAR_NUMBER) {
+      goto theend;
+    }
+    if (tvz->v_type != VAR_NUMBER) {
+      goto theend;
+    }
+    if (tvw->v_type != VAR_NUMBER) {
+      goto theend;
+    }
+    uint32_t x = tvx->vval.v_number;
+    uint32_t y = tvy->vval.v_number;
+    uint32_t z = tvz->vval.v_number;
+    uint32_t w = tvw->vval.v_number;
+
+    result = shuffle_xoshiro128starstar(&x, &y, &z, &w);
+
+    tvx->vval.v_number = (varnumber_T)x;
+    tvy->vval.v_number = (varnumber_T)y;
+    tvz->vval.v_number = (varnumber_T)z;
+    tvw->vval.v_number = (varnumber_T)w;
+  } else {
+    goto theend;
+  }
+
+  rettv->v_type = VAR_NUMBER;
+  rettv->vval.v_number = (varnumber_T)result;
+  return;
+
+theend:
+  semsg(_(e_invarg2), tv_get_string(&argvars[0]));
+  rettv->v_type = VAR_NUMBER;
+  rettv->vval.v_number = -1;
+}
+
+/// "srand()" function
+static void f_srand(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  uint32_t x = 0;
+
+  tv_list_alloc_ret(rettv, 4);
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    init_srand(&x);
+  } else {
+    bool error = false;
+    x = tv_get_number_chk(&argvars[0], &error);
+    if (error) {
+      return;
+    }
+  }
+
+  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
+  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
+  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
+  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
+}
+
 /// "perleval()" function
 static void f_perleval(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {