Actual source code: memc.c

petsc-3.8.0 2017-09-26
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  2: /*
  3:     We define the memory operations here. The reason we just do not use
  4:   the standard memory routines in the PETSc code is that on some machines
  5:   they are broken.

  7: */
  8:  #include <petscsys.h>
  9:  #include <petscbt.h>
 10: #include <../src/sys/utils/ftn-kernels/fcopy.h>
 11: #if defined(PETSC_HAVE_STRING_H)
 12: #include <string.h>
 13: #endif

 15: /*@
 16:    PetscMemcmp - Compares two byte streams in memory.

 18:    Not Collective

 20:    Input Parameters:
 21: +  str1 - Pointer to the first byte stream
 22: .  str2 - Pointer to the second byte stream
 23: -  len  - The length of the byte stream
 24:          (both str1 and str2 are assumed to be of length len)

 26:    Output Parameters:
 27: .   e - PETSC_TRUE if equal else PETSC_FALSE.

 29:    Level: intermediate

 31:    Note:
 32:    This routine is anologous to memcmp()
 33: @*/
 34: PetscErrorCode  PetscMemcmp(const void *str1,const void *str2,size_t len,PetscBool  *e)
 35: {
 36:   int r;

 39:   if (len > 0 && !str1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"Trying to compare at a null pointer");
 40:   if (len > 0 && !str2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"Trying to compare at a null pointer");
 41:   r = memcmp((char*)str1,(char*)str2,len);
 42:   if (!r) *e = PETSC_TRUE;
 43:   else    *e = PETSC_FALSE;
 44:   return(0);
 45: }

 47: /*@
 48:    PetscMemmove - Copies n bytes, beginning at location b, to the space
 49:    beginning at location a. Copying  between regions that overlap will
 50:    take place correctly.

 52:    Not Collective

 54:    Input Parameters:
 55: +  b - pointer to initial memory space
 56: -  n - length (in bytes) of space to copy

 58:    Output Parameter:
 59: .  a - pointer to copy space

 61:    Level: intermediate

 63:    Note:
 64:    This routine is analogous to memmove().

 66:    Since b can overlap with a, b cannot be declared as const

 68:    Concepts: memory^copying with overlap
 69:    Concepts: copying^memory with overlap

 71: .seealso: PetscMemcpy()
 72: @*/
 73: PetscErrorCode  PetscMemmove(void *a,void *b,size_t n)
 74: {
 76:   if (n > 0 && !a) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"Trying to copy to null pointer");
 77:   if (n > 0 && !b) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"Trying to copy from a null pointer");
 78: #if !defined(PETSC_HAVE_MEMMOVE)
 79:   if (a < b) {
 80:     if (a <= b - n) memcpy(a,b,n);
 81:     else {
 82:       memcpy(a,b,(int)(b - a));
 83:       PetscMemmove(b,b + (int)(b - a),n - (int)(b - a));
 84:     }
 85:   } else {
 86:     if (b <= a - n) memcpy(a,b,n);
 87:     else {
 88:       memcpy(b + n,b + (n - (int)(a - b)),(int)(a - b));
 89:       PetscMemmove(a,b,n - (int)(a - b));
 90:     }
 91:   }
 92: #else
 93:   memmove((char*)(a),(char*)(b),n);
 94: #endif
 95:   return(0);
 96: }