xref: /petsc/src/sys/classes/viewer/impls/socket/mex-scripts/bread.c (revision 3b751433063d81e134f7574f65c0d235a4700d16)

#include <petscsys.h>
#include <../src/sys/classes/viewer/impls/socket/socket.h>

/*
   TAKEN from src/sys/fileio/sysio.c The swap byte routines are
  included here because the MATLAB programs that use this do NOT
  link to the PETSc libraries.
*/
#include <errno.h>
#if defined(PETSC_HAVE_UNISTD_H)
  #include <unistd.h>
#endif

/*
  SYByteSwapInt - Swap bytes in an integer
*/
static void SYByteSwapInt(int *buff, PetscCount n)
{
  int   tmp;
  char *ptr1, *ptr2 = (char *)&tmp;
  for (PetscCount j = 0; j < n; j++) {
    ptr1 = (char *)(buff + j);
    for (PetscCount i = 0; i < sizeof(int); i++) ptr2[i] = ptr1[sizeof(int) - 1 - i];
    buff[j] = tmp;
  }
}
/*
  SYByteSwapShort - Swap bytes in a short
*/
static void SYByteSwapShort(short *buff, PetscCount n)
{
  short tmp;
  char *ptr1, *ptr2 = (char *)&tmp;
  for (PetscCount j = 0; j < n; j++) {
    ptr1 = (char *)(buff + j);
    for (PetscCount i = 0; i < sizeof(short); i++) ptr2[i] = ptr1[sizeof(int) - 1 - i];
    buff[j] = tmp;
  }
}
/*
  SYByteSwapScalar - Swap bytes in a double
  Complex is dealt with as if array of double twice as long.
*/
static void SYByteSwapScalar(PetscScalar *buff, PetscCount n)
{
  double tmp, *buff1 = (double *)buff;
  char  *ptr1, *ptr2 = (char *)&tmp;
#if defined(PETSC_USE_COMPLEX)
  n *= 2;
#endif
  for (PetscCount j = 0; j < n; j++) {
    ptr1 = (char *)(buff1 + j);
    for (PetscCount i = 0; i < sizeof(double); i++) ptr2[i] = ptr1[sizeof(double) - 1 - i];
    buff1[j] = tmp;
  }
}

#define PETSC_MEX_ERROR(a) \
  { \
    fprintf(stdout, "sread: %s \n", a); \
    return PETSC_ERR_SYS; \
  }

// PetscClangLinter pragma disable: -fdoc.*
/*
  PetscBinaryRead - Reads from a socket, called from MATLAB

  Input Parameters:
+ fd   - the file
. n    - the number of items to read
- type - the type of items to read (PETSC_INT or PETSC_SCALAR)

  Output Parameter:
. p - the buffer

  Notes:
  does byte swapping to work on all machines.
*/
PetscErrorCode PetscBinaryRead(int fd, void *p, PetscCount n, PetscInt *dummy, PetscDataType type)
{
  int        maxblock, err;
  char      *pp   = (char *)p;
  PetscCount ntmp = n, wsize;
  void      *ptmp = p;

  maxblock = 65536;
  if (type == PETSC_INT) n *= sizeof(int);
  else if (type == PETSC_SCALAR) n *= sizeof(PetscScalar);
  else if (type == PETSC_SHORT) n *= sizeof(short);
  else if (type == PETSC_CHAR) n *= sizeof(char);
  else PETSC_MEX_ERROR("PetscBinaryRead: Unknown type");

  while (n) {
    wsize = (n < maxblock) ? n : maxblock;
    err   = (int)read(fd, pp, (int)wsize);
    if (err < 0 && errno == EINTR) continue;
    if (!err && wsize > 0) return 1;
    if (err < 0) PETSC_MEX_ERROR("Error reading from socket\n");
    n -= err;
    pp += err;
  }

  if (!PetscBinaryBigEndian()) {
    if (type == PETSC_INT) SYByteSwapInt((int *)ptmp, ntmp);
    else if (type == PETSC_SCALAR) SYByteSwapScalar((PetscScalar *)ptmp, ntmp);
    else if (type == PETSC_SHORT) SYByteSwapShort((short *)ptmp, ntmp);
  }
  return 0;
}

/*
    PetscBinaryWrite - Writes to a socket, called from MATLAB

  Input Parameters:
+   fd - the file
.   n  - the number of items to read
.   p - the data
-   type - the type of items to read (PETSC_INT or PETSC_SCALAR)

  Notes:
    does byte swapping to work on all machines.
*/
PetscErrorCode PetscBinaryWrite(int fd, const void *p, PetscCount n, PetscDataType type)
{
  int        maxblock, err = 0, retv = 0;
  char      *pp   = (char *)p;
  PetscCount ntmp = n;
  void      *ptmp = (void *)p;
  PetscCount wsize;

  maxblock = 65536;
  if (type == PETSC_INT) n *= sizeof(int);
  else if (type == PETSC_SCALAR) n *= sizeof(PetscScalar);
  else if (type == PETSC_SHORT) n *= sizeof(short);
  else if (type == PETSC_CHAR) n *= sizeof(char);
  else PETSC_MEX_ERROR("PetscBinaryRead: Unknown type");

  if (!PetscBinaryBigEndian()) {
    /* make sure data is in correct byte ordering before sending  */
    if (type == PETSC_INT) SYByteSwapInt((int *)ptmp, ntmp);
    else if (type == PETSC_SCALAR) SYByteSwapScalar((PetscScalar *)ptmp, ntmp);
    else if (type == PETSC_SHORT) SYByteSwapShort((short *)ptmp, ntmp);
  }

  while (n) {
    wsize = (n < maxblock) ? n : maxblock;
    err   = (int)write(fd, pp, (int)wsize);
    if (err < 0 && errno == EINTR) continue;
    if (!err && wsize > 0) {
      retv = 1;
      break;
    };
    if (err < 0) break;
    n -= err;
    pp += err;
  }

  if (!PetscBinaryBigEndian()) {
    /* swap the data back if we swapped it before sending it */
    if (type == PETSC_INT) SYByteSwapInt((int *)ptmp, ntmp);
    else if (type == PETSC_SCALAR) SYByteSwapScalar((PetscScalar *)ptmp, ntmp);
    else if (type == PETSC_SHORT) SYByteSwapShort((short *)ptmp, ntmp);
  }

  if (err < 0) PETSC_MEX_ERROR("Error writing to socket\n");
  return retv;
}