1: #ifndef PETSCBT_H
  2: #define PETSCBT_H

  4: #include <petscviewer.h>

  6: /* SUBMANSEC = Sys */

  8: /*S
  9:      PetscBT - PETSc bitarrays, efficient storage of arrays of boolean values

 11:      Level: advanced

 13:      Notes:
 14:      The following routines do not have their own manual pages

 16: .vb
 17:      PetscBTCreate(m,&bt)         - creates a bit array with enough room to hold m values
 18:      PetscBTDestroy(&bt)          - destroys the bit array
 19:      PetscBTMemzero(m,bt)         - zeros the entire bit array (sets all values to false)
 20:      PetscBTSet(bt,index)         - sets a particular entry as true
 21:      PetscBTClear(bt,index)       - sets a particular entry as false
 22:      PetscBTLookup(bt,index)      - returns the value
 23:      PetscBTLookupSet(bt,index)   - returns the value and then sets it true
 24:      PetscBTLookupClear(bt,index) - returns the value and then sets it false
 25:      PetscBTLength(m)             - returns number of bytes in array with m bits
 26:      PetscBTView(m,bt,viewer)     - prints all the entries in a bit array
 27: .ve

 29:     PETSc does not check error flags on `PetscBTLookup()`, `PetcBTLookupSet()`, `PetscBTLength()` because error checking
 30:     would cost hundreds more cycles then the operation.

 32: S*/
 33: typedef char *PetscBT;

 35: /* convert an index i to an index suitable for indexing a PetscBT, such that
 36:  * bt[PetscBTIndex(i)] returns the i'th value of the bt */
 37: static inline size_t PetscBTIndex_Internal(PetscInt index)
 38: {
 39:   return (size_t)index / PETSC_BITS_PER_BYTE;
 40: }

 42: static inline char PetscBTMask_Internal(PetscInt index)
 43: {
 44:   return (char)(1 << index % PETSC_BITS_PER_BYTE);
 45: }

 47: static inline size_t PetscBTLength(PetscInt m)
 48: {
 49:   return (size_t)m / PETSC_BITS_PER_BYTE + 1;
 50: }

 52: static inline PetscErrorCode PetscBTMemzero(PetscInt m, PetscBT array)
 53: {
 54:   return PetscArrayzero(array, PetscBTLength(m));
 55: }

 57: static inline PetscErrorCode PetscBTDestroy(PetscBT *array)
 58: {
 59:   return (*array) ? PetscFree(*array) : 0;
 60: }

 62: static inline PetscErrorCode PetscBTCreate(PetscInt m, PetscBT *array)
 63: {
 64:   return PetscCalloc1(PetscBTLength(m), array);
 65: }

 67: static inline char PetscBTLookup(PetscBT array, PetscInt index)
 68: {
 69:   return array[PetscBTIndex_Internal(index)] & PetscBTMask_Internal(index);
 70: }

 72: static inline PetscErrorCode PetscBTSet(PetscBT array, PetscInt index)
 73: {
 74:   array[PetscBTIndex_Internal(index)] |= PetscBTMask_Internal(index);
 75:   return 0;
 76: }

 78: static inline PetscErrorCode PetscBTNegate(PetscBT array, PetscInt index)
 79: {
 80:   array[PetscBTIndex_Internal(index)] ^= PetscBTMask_Internal(index);
 81:   return 0;
 82: }

 84: static inline PetscErrorCode PetscBTClear(PetscBT array, PetscInt index)
 85: {
 86:   array[PetscBTIndex_Internal(index)] &= (char)~PetscBTMask_Internal(index);
 87:   return 0;
 88: }

 90: static inline char PetscBTLookupSet(PetscBT array, PetscInt index)
 91: {
 92:   const char ret = PetscBTLookup(array, index);
 93:   PetscBTSet(array, index);
 94:   return ret;
 95: }

 97: static inline char PetscBTLookupClear(PetscBT array, PetscInt index)
 98: {
 99:   const char ret = PetscBTLookup(array, index);
100:   PetscBTClear(array, index);
101:   return ret;
102: }

104: static inline PetscErrorCode PetscBTView(PetscInt m, const PetscBT bt, PetscViewer viewer)
105: {
106:   if (m < 1) return 0;
107:   if (!viewer) PetscViewerASCIIGetStdout(PETSC_COMM_SELF, &viewer);
108:   PetscViewerASCIIPushSynchronized(viewer);
109:   for (PetscInt i = 0; i < m; ++i) PetscViewerASCIISynchronizedPrintf(viewer, "%" PetscInt_FMT " %d\n", i, (int)PetscBTLookup(bt, i));
110:   PetscViewerFlush(viewer);
111:   PetscViewerASCIIPopSynchronized(viewer);
112:   return 0;
113: }
114: #endif /* PETSCBT_H */