treat cfg->bc as a null-ending string, #191 #192

src/mcx_core.h

@@ -182,7 +182,7 @@ typedef struct  __align__(16) KernelParams {
     unsigned int srcnum;               /**< total number of source patterns */
     unsigned int nphase;               /**< number of samples for inverse-cdf, will be added by 2 to include -1 and 1 on the two ends */
     float omega;                       /**< modulation angular frequency (2*pi*f), in rad/s, for FD/RF replay */
-    unsigned char bc[12];              /**< boundary conditions */
+    unsigned char bc[12];              /**< boundary condition flags, copy the first 12 chars from cfg->bc without the terminating NULL */
 } MCXParam;
 
 void mcx_run_simulation(Config* cfg, GPUInfo* gpu);

src/mcx_utils.h

@@ -258,7 +258,7 @@ typedef struct MCXConfig {
     float* dx;                   /**< anisotropic voxel spacing for x-axis */
     float* dy;                   /**< anisotropic voxel spacing for y-axis */
     float* dz;                   /**< anisotropic voxel spacing for z-axis */
-    char bc[13];                 /**<boundary condition flag for [-x,-y,-z,+x,+y,+z, det(-x,-y,-z,+x,+y,+z)] */
+    char bc[13];                 /**<boundary condition flag for [-x,-y,-z,+x,+y,+z, det(-x,-y,-z,+x,+y,+z)], last element is always NULL for string termination */
     unsigned int nphase;         /**< number of samples for inverse-cdf, will be added by 2 to include -1 and 1 on the two ends */
     float* invcdf;               /**< equal-space sampled inversion of CDF(cos(theta)) for the phase function of the zenith angle */
 } Config;

src/mcxlab.cpp

@@ -1063,8 +1063,7 @@ void mcx_set_field(const mxArray* root, const mxArray* item, int idx, Config* cf
             mexErrMsgTxt("the 'bc' field must be a non-empty string");
         }
 
-        mxGetString(item, cfg->bc, len + 1);
-        cfg->bc[len] = '\0';
+        mxGetString(item, cfg->bc, len + 1); // copy the string, plus the ending NULL, max 13 char
         printf("mcx.bc='%s';\n", cfg->bc);
     } else if (strcmp(name, "detphotons") == 0) {
         arraydim = mxGetDimensions(item);

src/pmcx.cpp

@@ -726,7 +726,7 @@ void parse_config(const py::dict& user_cfg, Config& mcx_config) {
             throw py::value_error("the 'bc' field must be a non-empty string / have no more than 12 characters.");
         }
 
-        strncpy(mcx_config.bc, bc_string.c_str(), bc_string.size());
+        strncpy(mcx_config.bc, bc_string.c_str(), bc_string.size() + 1); // copy the string, plus the ending NULL, max 13 char
     }
 
     if (user_cfg.contains("detphotons")) {