Add internal utility for zeroing int vectors.

Remove unnecessary branches in related functions.

PiperOrigin-RevId: 562768873
Change-Id: I3964a7a953d95bcd4e29137a7b590be5ffa6e311

src/engine/engine_core_constraint.c

@@ -16,7 +16,6 @@
 
 #include <stdio.h>
 #include <stddef.h>
-#include <string.h>
 
 #include <mujoco/mjdata.h>
 #include <mujoco/mjmacro.h>
@@ -252,7 +251,7 @@ int mj_addConstraint(const mjModel* m, mjData* d,
 
       // copy if not empty
       if (NV) {
-        memcpy(ind + adr[nefc+i], chain, sizeof(int)*NV);
+        mju_copyInt(ind + adr[nefc+i], chain, NV);
         mju_copy(J + adr[nefc+i], jac + i*NV, NV);
       }
     }
@@ -644,11 +643,11 @@ void mj_instantiateEquality(const mjModel* m, mjData* d) {
               // add first or second chain
               if (j == 0) {
                 NV = d->ten_J_rownnz[id[j]];
-                memcpy(chain, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV*sizeof(int));
+                mju_copyInt(chain, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV);
                 mju_copy(jac[j], d->ten_J+d->ten_J_rowadr[id[j]], NV);
               } else {
                 NV2 = d->ten_J_rownnz[id[j]];
-                memcpy(chain2, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV2*sizeof(int));
+                mju_copyInt(chain2, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV2);
                 mju_copy(jac[j], d->ten_J+d->ten_J_rowadr[id[j]], NV2);
               }
             } else {
@@ -1530,10 +1529,10 @@ static inline int mj_ne(const mjModel* m, mjData* d, int* nnz) {
           } else {
             if (!j) {
               NV = d->ten_J_rownnz[id[j]];
-              memcpy(chain, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV*sizeof(int));
+              mju_copyInt(chain, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV);
             } else {
               NV2 = d->ten_J_rownnz[id[j]];
-              memcpy(chain2, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV2*sizeof(int));
+              mju_copyInt(chain2, d->ten_J_colind+d->ten_J_rowadr[id[j]], NV2);
             }
           }
         }

src/engine/engine_io.c

@@ -874,7 +874,7 @@ static void makeDSparse(const mjModel* m, mjData* d) {
   }
 
   // populate colind
-  memcpy(remaining, rownnz, nv * sizeof(int));
+  mju_copyInt(remaining, rownnz, nv);
   for (int i = nv - 1; i >= 0; i--) {
     // init at diagonal
     remaining[i]--;

src/engine/engine_island.c

@@ -16,7 +16,6 @@
 
 #include <stdio.h>
 #include <stddef.h>
-#include <string.h>
 
 #include <mujoco/mjdata.h>
 #include <mujoco/mjmacro.h>
@@ -76,7 +75,7 @@ int mj_floodFill(int* island, int nr, const int* rownnz, const int* rowadr, cons
       island[v] = nisland;
 
       // push adjacent vertices onto stack
-      memcpy(stack + nstack, colind + rowadr[v], rownnz[v]*sizeof(int));
+      mju_copyInt(stack + nstack, colind + rowadr[v], rownnz[v]);
       nstack += rownnz[v];
     }
 

src/engine/engine_solver.c

@@ -464,7 +464,7 @@ void mj_solPGS(const mjModel* m, mjData* d, int maxiter) {
     }
 
     // process state
-    memcpy(oldstate, d->efc_state, nefc*sizeof(int));
+    mju_copyInt(oldstate, d->efc_state, nefc);
     int nactive = dualState(m, d);
     int nchange = 0;
     for (int i=0; i < nefc; i++) {
@@ -680,7 +680,7 @@ void mj_solNoSlip(const mjModel* m, mjData* d, int maxiter) {
     }
 
     // process state
-    memcpy(oldstate, d->efc_state, nefc*sizeof(int));
+    mju_copyInt(oldstate, d->efc_state, nefc);
     int nactive = dualState(m, d);
     int nchange = 0;
     for (int i=0; i < nefc; i++) {
@@ -1314,7 +1314,7 @@ static void HessianCone(const mjModel* m, mjData* d, mjCGContext* ctx) {
         for (int r=0; r < dim; r++) {
           // copy data for this row
           mju_copy(LTJ_row, LTJ+r*nnz, nnz);
-          memcpy(LTJ_ind, d->efc_J_colind+d->efc_J_rowadr[i+r], nnz*sizeof(int));
+          mju_copyInt(LTJ_ind, d->efc_J_colind+d->efc_J_rowadr[i+r], nnz);
 
           // update
           mju_cholUpdateSparse(ctx->Hcone, LTJ_row, nv, 1,
@@ -1476,7 +1476,7 @@ static void HessianIncremental(const mjModel* m, mjData* d,
 
         // scale vec, copy colind
         mju_scl(vec, d->efc_J+adr, mju_sqrt(d->efc_D[i]), nnz);
-        memcpy(vec_ind, d->efc_J_colind+adr, nnz*sizeof(int));
+        mju_copyInt(vec_ind, d->efc_J_colind+adr, nnz);
 
         // sparse update
         rank = mju_cholUpdateSparse(ctx->H, vec, nv, flag_update,
@@ -1563,7 +1563,7 @@ static void mj_solCGNewton(const mjModel* m, mjData* d, int maxiter, int flg_New
       mju_copy(gradold, ctx.grad, nv);
       mju_copy(Mgradold, ctx.Mgrad, nv);
     }
-    memcpy(oldstate, d->efc_state, nefc*sizeof(int));
+    mju_copyInt(oldstate, d->efc_state, nefc);
     mjtNum oldcost = ctx.cost;
 
     // update

src/engine/engine_support.c

@@ -14,8 +14,6 @@
 
 #include "engine/engine_support.h"
 
-#include <string.h>
-
 #include <mujoco/mjdata.h>
 #include <mujoco/mjmacro.h>
 #include <mujoco/mjmodel.h>
@@ -1161,7 +1159,7 @@ void mj_copyM2DSparse(const mjModel* m, mjData* d, mjtNum* dst, const mjtNum* sr
 
   // init remaining
   int* remaining = mj_stackAllocInt(d, nv);
-  memcpy(remaining, d->D_rownnz, nv * sizeof(int));
+  mju_copyInt(remaining, d->D_rownnz, nv);
 
   // copy data
   for (int i = nv - 1; i >= 0; i--) {

src/engine/engine_util_blas.c

@@ -238,9 +238,7 @@ mjtNum mju_normalize4(mjtNum vec[4]) {
 
 // res = 0
 void mju_zero(mjtNum* res, int n) {
-  if (n > 0) {
-    memset(res, 0, n*sizeof(mjtNum));
-  }
+  memset(res, 0, n*sizeof(mjtNum));
 }
 
 
@@ -256,9 +254,7 @@ void mju_fill(mjtNum* res, mjtNum val, int n) {
 
 // res = vec
 void mju_copy(mjtNum* res, const mjtNum* vec, int n) {
-  if (n > 0) {
-    memcpy(res, vec, n*sizeof(mjtNum));
-  }
+  memcpy(res, vec, n*sizeof(mjtNum));
 }
 
 

src/engine/engine_util_misc.c

@@ -1209,9 +1209,14 @@ int mju_isZero(mjtNum* vec, int n) {
 
 // set integer vector to 0
 void mju_zeroInt(int* res, int n) {
-  if (n > 0) {
-    memset(res, 0, n*sizeof(int));
-  }
+  memset(res, 0, n*sizeof(int));
+}
+
+
+
+// copy int vector vec into res
+void mju_copyInt(int* res, const int* vec, int n) {
+  memcpy(res, vec, n*sizeof(int));
 }
 
 

src/engine/engine_util_misc.h

@@ -122,6 +122,9 @@ MJAPI int mju_isZero(mjtNum* vec, int n);
 // set integer vector to 0
 MJAPI void mju_zeroInt(int* res, int n);
 
+// copy int vector vec into res
+MJAPI void mju_copyInt(int* res, const int* vec, int n);
+
 // standard normal random number generator (optional second number)
 MJAPI mjtNum mju_standardNormal(mjtNum* num2);
 

src/engine/engine_util_solve.c

@@ -16,7 +16,6 @@
 
 #include <math.h>
 #include <stdio.h>
-#include <string.h>
 
 #include <mujoco/mjdata.h>
 #include <mujoco/mjmacro.h>
@@ -592,7 +591,7 @@ void mju_factorLUSparse(mjtNum* LU, int n, int* scratch,
   int* remaining = scratch;
 
   // set remaining = rownnz
-  memcpy(remaining, rownnz, n*sizeof(int));
+  mju_copyInt(remaining, rownnz, n);
 
   // diagonal elements (i,i)
   for (int i=n-1; i >= 0; i--) {

src/engine/engine_util_sparse.c

@@ -273,8 +273,8 @@ int mju_combineSparse(mjtNum* dst, const mjtNum* src, mjtNum a, mjtNum b,
 
   // copy dst into buf
   if (dst_nnz) {
-    memcpy(buf, dst, dst_nnz*sizeof(mjtNum));
-    memcpy(buf_ind, dst_ind, dst_nnz*sizeof(int));
+    mju_copy(buf, dst, dst_nnz);
+    mju_copyInt(buf_ind, dst_ind, dst_nnz);
   }
 
   // prepare to merge buf and src into dst
@@ -599,7 +599,7 @@ void mju_sqrMatTDSparse(mjtNum* res, const mjtNum* mat, const mjtNum* matT,
     // if rowsuper, use the previous row sparsity structure
     if (rowsuperT && i > 0 && rowsuperT[i-1]) {
       res_rownnz[i] = res_rownnz[i-1];
-      memcpy(cols, res_colind+res_rowadr[i-1], res_rownnz[i]*sizeof(int));
+      mju_copyInt(cols, res_colind+res_rowadr[i-1], res_rownnz[i]);
     }
 
     // iterate through each row of M'