示例#1
0
/*@
   PetscBinaryWrite - Writes to a binary file.

   Not Collective

   Input Parameters:
+  fd     - the file
.  p      - the buffer
.  n      - the number of items to write
.  type   - the type of items to read (PETSC_INT, PETSC_DOUBLE or PETSC_SCALAR)
-  istemp - PETSC_FALSE if buffer data should be preserved, PETSC_TRUE otherwise.

   Level: advanced

   Notes: 
   PetscBinaryWrite() uses byte swapping to work on all machines; the files
   are written using big-endian ordering to the file. On small-endian machines the numbers
   are converted to the big-endian format when they are written to disk.
   When PETSc is config/configure.py with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   The Buffer p should be read-write buffer, and not static data.
   This way, byte-swapping is done in-place, and then the buffer is
   written to the file.
   
   This routine restores the original contents of the buffer, after 
   it is written to the file. This is done by byte-swapping in-place 
   the second time. If the flag istemp is set to PETSC_TRUE, the second
   byte-swapping operation is not done, thus saving some computation,
   but the buffer corrupted is corrupted.

   Because byte-swapping may be done on the values in data it cannot be declared const

   Concepts: files^writing binary
   Concepts: binary files^writing

.seealso: PetscBinaryRead(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(), 
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode PETSC_DLLEXPORT PetscBinaryWrite(int fd,void *p,PetscInt n,PetscDataType type,PetscTruth istemp)
{
  char           *pp = (char*)p;
  int            err,wsize;
  size_t         m = (size_t)n,maxblock=65536;
#if !defined(PETSC_WORDS_BIGENDIAN)
  PetscErrorCode ierr;
  void           *ptmp = p; 
#endif

  PetscFunctionBegin;
  if (n < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Trying to write a negative amount of data %D",n);
  if (!n) PetscFunctionReturn(0);

  if (type == PETSC_INT)          m *= sizeof(PetscInt);
  else if (type == PETSC_SCALAR)  m *= sizeof(PetscScalar);
  else if (type == PETSC_DOUBLE)  m *= sizeof(double);
  else if (type == PETSC_SHORT)   m *= sizeof(short);
  else if (type == PETSC_CHAR)    m *= sizeof(char);
  else if (type == PETSC_ENUM)    m *= sizeof(PetscEnum);
  else if (type == PETSC_TRUTH)   m *= sizeof(PetscTruth);
  else if (type == PETSC_LOGICAL) m = PetscBTLength(m)*sizeof(char);
  else SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Unknown type");

#if !defined(PETSC_WORDS_BIGENDIAN)
  ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
#endif

  while (m) {
    wsize = (m < maxblock) ? m : maxblock;
    err = write(fd,pp,wsize);
    if (err < 0 && errno == EINTR) continue;
    if (err != wsize) SETERRQ(PETSC_ERR_FILE_WRITE,"Error writing to file.");
    m -= wsize;
    pp += wsize;
  }

#if !defined(PETSC_WORDS_BIGENDIAN)
  if (!istemp) {
    ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
  }
#endif
  PetscFunctionReturn(0);
}
示例#2
0
/*@
   PetscBinaryRead - Reads from a binary file.

   Not Collective

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

   Output Parameters:
.  p - the buffer



   Level: developer

   Notes: 
   PetscBinaryRead() uses byte swapping to work on all machines; the files
   are written to file ALWAYS using big-endian ordering. On small-endian machines the numbers
   are converted to the small-endian format when they are read in from the file.
   When PETSc is config/configure.py with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   Concepts: files^reading binary
   Concepts: binary files^reading

.seealso: PetscBinaryWrite(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(),
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode PETSC_DLLEXPORT PetscBinaryRead(int fd,void *p,PetscInt n,PetscDataType type)
{
  int               wsize,err;
  size_t            m = (size_t) n,maxblock = 65536;
  char              *pp = (char*)p;
#if !defined(PETSC_WORDS_BIGENDIAN)
  PetscErrorCode    ierr;
  void              *ptmp = p; 
#endif

  PetscFunctionBegin;
  if (!n) PetscFunctionReturn(0);

  if (type == PETSC_INT)          m *= sizeof(PetscInt);
  else if (type == PETSC_SCALAR)  m *= sizeof(PetscScalar);
  else if (type == PETSC_DOUBLE)  m *= sizeof(double);
  else if (type == PETSC_SHORT)   m *= sizeof(short);
  else if (type == PETSC_CHAR)    m *= sizeof(char);
  else if (type == PETSC_ENUM)    m *= sizeof(PetscEnum);
  else if (type == PETSC_TRUTH)   m *= sizeof(PetscTruth);
  else if (type == PETSC_LOGICAL) m  = PetscBTLength(m)*sizeof(char);
  else SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Unknown type");
  
  while (m) {
    wsize = (m < maxblock) ? m : maxblock;
    err = read(fd,pp,wsize);
    if (err < 0 && errno == EINTR) continue;
    if (!err && wsize > 0) SETERRQ(PETSC_ERR_FILE_READ,"Read past end of file");
    if (err < 0) SETERRQ1(PETSC_ERR_FILE_READ,"Error reading from file, errno %d",errno);
    m  -= err;
    pp += err;
  }
#if !defined(PETSC_WORDS_BIGENDIAN)
  ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
#endif

  PetscFunctionReturn(0);
}
示例#3
0
文件: sysio.c 项目: petsc/petsc
/*@
   PetscBinaryWrite - Writes to a binary file.

   Not Collective

   Input Parameters:
+  fd     - the file
.  p      - the buffer
.  n      - the number of items to write
.  type   - the type of items to read (PETSC_INT, PETSC_DOUBLE or PETSC_SCALAR)
-  istemp - PETSC_FALSE if buffer data should be preserved, PETSC_TRUE otherwise.

   Level: advanced

   Notes:
   PetscBinaryWrite() uses byte swapping to work on all machines; the files
   are written using big-endian ordering to the file. On small-endian machines the numbers
   are converted to the big-endian format when they are written to disk.
   When PETSc is ./configure with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   If running with __float128 precision the output is in __float128 unless one uses the -binary_write_double option

   The Buffer p should be read-write buffer, and not static data.
   This way, byte-swapping is done in-place, and then the buffer is
   written to the file.

   This routine restores the original contents of the buffer, after
   it is written to the file. This is done by byte-swapping in-place
   the second time. If the flag istemp is set to PETSC_TRUE, the second
   byte-swapping operation is not done, thus saving some computation,
   but the buffer is left corrupted.

   Because byte-swapping may be done on the values in data it cannot be declared const

   Concepts: files^writing binary
   Concepts: binary files^writing

.seealso: PetscBinaryRead(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(),
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode  PetscBinaryWrite(int fd,void *p,PetscInt n,PetscDataType type,PetscBool  istemp)
{
  char           *pp = (char*)p;
  int            err,wsize;
  size_t         m = (size_t)n,maxblock=65536;
  PetscErrorCode ierr;
  void           *ptmp = p;
  char           *fname = NULL;
#if defined(PETSC_USE_REAL___FLOAT128)
  PetscBool      writedouble = PETSC_FALSE;
  double         *ppp;
  PetscReal      *pv;
  PetscInt       i;
#endif
  PetscDataType  wtype = type;

  PetscFunctionBegin;
  if (n < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Trying to write a negative amount of data %D",n);
  if (!n) PetscFunctionReturn(0);

  if (type == PETSC_FUNCTION) {
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    const char *fnametmp;
#endif
    m     = 64;
    fname = (char*)malloc(m*sizeof(char));
    if (!fname) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_MEM,"Cannot allocate space for function name");
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    if (n > 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Can only binary view a single function at a time");
    ierr = PetscFPTFind(*(void**)p,&fnametmp);CHKERRQ(ierr);
    ierr = PetscStrncpy(fname,fnametmp,m);CHKERRQ(ierr);
#else
    ierr = PetscStrncpy(fname,"",m);CHKERRQ(ierr);
#endif
    wtype = PETSC_CHAR;
    pp    = (char*)fname;
    ptmp  = (void*)fname;
  }

#if defined(PETSC_USE_REAL___FLOAT128)
  ierr = PetscOptionsGetBool(NULL,NULL,"-binary_write_double",&writedouble,NULL);CHKERRQ(ierr);
  /* If using __float128 precision we still write in doubles to file */
  if ((type == PETSC_SCALAR || type == PETSC_REAL) && writedouble) {
    wtype = PETSC_DOUBLE;
    ierr = PetscMalloc1(n,&ppp);CHKERRQ(ierr);
    pv = (PetscReal*)pp;
    for (i=0; i<n; i++) {
      ppp[i] = (double) pv[i];
    }
    pp   = (char*)ppp;
    ptmp = (char*)ppp;
  }
#endif

  if (wtype == PETSC_INT)          m *= sizeof(PetscInt);
  else if (wtype == PETSC_SCALAR)  m *= sizeof(PetscScalar);
  else if (wtype == PETSC_REAL)    m *= sizeof(PetscReal);
  else if (wtype == PETSC_DOUBLE)  m *= sizeof(double);
  else if (wtype == PETSC_FLOAT)   m *= sizeof(float);
  else if (wtype == PETSC_SHORT)   m *= sizeof(short);
  else if (wtype == PETSC_LONG)    m *= sizeof(long);
  else if (wtype == PETSC_CHAR)    m *= sizeof(char);
  else if (wtype == PETSC_ENUM)    m *= sizeof(PetscEnum);
  else if (wtype == PETSC_BOOL)    m *= sizeof(PetscBool);
  else if (wtype == PETSC_INT64)   m *= sizeof(PetscInt64);
  else if (wtype == PETSC_BIT_LOGICAL) m = PetscBTLength(m)*sizeof(char);
  else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown type");

  if (!PetscBinaryBigEndian()) {ierr = PetscByteSwap(ptmp,wtype,n);CHKERRQ(ierr);}

  while (m) {
    wsize = (m < maxblock) ? m : maxblock;
    err   = write(fd,pp,wsize);
    if (err < 0 && errno == EINTR) continue;
    if (err != wsize) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_FILE_WRITE,"Error writing to file total size %d err %d wsize %d",(int)n,(int)err,(int)wsize);
    m  -= wsize;
    pp += wsize;
  }

  if (!istemp) {
    if (!PetscBinaryBigEndian()) {ierr = PetscByteSwap(ptmp,wtype,n);CHKERRQ(ierr);}
  }
  if (type == PETSC_FUNCTION) {
    free(fname);
  }
#if defined(PETSC_USE_REAL___FLOAT128)
  if ((type == PETSC_SCALAR || type == PETSC_REAL) && writedouble) {
    ierr = PetscFree(ppp);CHKERRQ(ierr);
  }
#endif
  PetscFunctionReturn(0);
}
示例#4
0
文件: sysio.c 项目: petsc/petsc
/*@C
   PetscBinaryRead - Reads from a binary file.

   Not Collective

   Input Parameters:
+  fd - the file descriptor
.  num  - the maximum number of items to read
-  type - the type of items to read (PETSC_INT, PETSC_REAL, PETSC_SCALAR, etc.)

   Output Parameters:
+  data - the buffer
-  count - the number of items read, optional



   Level: developer

   Notes:
   If count is not provided and the number of items read is less than
   the maximum number of items to read, then this routine errors.

   PetscBinaryRead() uses byte swapping to work on all machines; the files
   are written to file ALWAYS using big-endian ordering. On small-endian machines the numbers
   are converted to the small-endian format when they are read in from the file.
   When PETSc is ./configure with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   Concepts: files^reading binary
   Concepts: binary files^reading

.seealso: PetscBinaryWrite(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(),
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode  PetscBinaryRead(int fd,void *data,PetscInt num,PetscInt *count,PetscDataType type)
{
  size_t            typesize, m = (size_t) num, n = 0, maxblock = 65536;
  char              *p = (char*)data;
#if defined(PETSC_USE_REAL___FLOAT128)
  PetscBool         readdouble = PETSC_FALSE;
  double            *pdouble;
#endif
  void              *ptmp = data;
  char              *fname = NULL;
  PetscErrorCode    ierr;

  PetscFunctionBegin;
  if (count) *count = 0;
  if (num < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Trying to read a negative amount of data %D",num);
  if (!num) PetscFunctionReturn(0);

  if (type == PETSC_FUNCTION) {
    m     = 64;
    type  = PETSC_CHAR;
    fname = (char*)malloc(m*sizeof(char));
    p     = (char*)fname;
    ptmp  = (void*)fname;
    if (!fname) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_MEM,"Cannot allocate space for function name");
  }
  if (type == PETSC_BIT_LOGICAL) m = PetscBTLength(m);

  ierr = PetscDataTypeGetSize(type,&typesize);CHKERRQ(ierr);

#if defined(PETSC_USE_REAL___FLOAT128)
  ierr = PetscOptionsGetBool(NULL,NULL,"-binary_read_double",&readdouble,NULL);CHKERRQ(ierr);
  /* If using __float128 precision we still read in doubles from file */
  if ((type == PETSC_REAL || type == PETSC_COMPLEX) && readdouble) {
    PetscInt cnt = num * ((type == PETSC_REAL) ? 1 : 2);
    ierr = PetscMalloc1(cnt,&pdouble);CHKERRQ(ierr);
    p = (char*)pdouble;
    typesize /= 2;
  }
#endif

  m *= typesize;

  while (m) {
    size_t len = (m < maxblock) ? m : maxblock;
    int    ret = (int)read(fd,p,len);
    if (ret < 0 && errno == EINTR) continue;
    if (!ret && len > 0) break; /* Proxy for EOF */
    if (ret < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_FILE_READ,"Error reading from file, errno %d",errno);
    m -= ret;
    p += ret;
    n += ret;
  }
  if (m && !count) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FILE_READ,"Read past end of file");

  num = (PetscInt)(n/typesize); /* Should we require `n % typesize == 0` ? */
  if (count) *count = num;      /* TODO: This is most likely wrong for PETSC_BIT_LOGICAL */

#if defined(PETSC_USE_REAL___FLOAT128)
  if ((type == PETSC_REAL || type == PETSC_COMPLEX) && readdouble) {
    PetscInt  i, cnt = num * ((type == PETSC_REAL) ? 1 : 2);
    PetscReal *preal = (PetscReal*)data;
    if (!PetscBinaryBigEndian()) {ierr = PetscByteSwapDouble(pdouble,cnt);CHKERRQ(ierr);}
    for (i=0; i<cnt; i++) preal[i] = pdouble[i];
    ierr = PetscFree(pdouble);CHKERRQ(ierr);
    PetscFunctionReturn(0);
  }
#endif

  if (!PetscBinaryBigEndian()) {ierr = PetscByteSwap(ptmp,type,num);CHKERRQ(ierr);}

  if (type == PETSC_FUNCTION) {
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    ierr = PetscDLSym(NULL,fname,(void**)data);CHKERRQ(ierr);
#else
    *(void**)data = NULL;
#endif
    free(fname);
  }
  PetscFunctionReturn(0);
}
示例#5
0
文件: sysio.c 项目: pombredanne/petsc
/*@
   PetscBinaryWrite - Writes to a binary file.

   Not Collective

   Input Parameters:
+  fd     - the file
.  p      - the buffer
.  n      - the number of items to write
.  type   - the type of items to read (PETSC_INT, PETSC_DOUBLE or PETSC_SCALAR)
-  istemp - PETSC_FALSE if buffer data should be preserved, PETSC_TRUE otherwise.

   Level: advanced

   Notes:
   PetscBinaryWrite() uses byte swapping to work on all machines; the files
   are written using big-endian ordering to the file. On small-endian machines the numbers
   are converted to the big-endian format when they are written to disk.
   When PETSc is ./configure with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   The Buffer p should be read-write buffer, and not static data.
   This way, byte-swapping is done in-place, and then the buffer is
   written to the file.

   This routine restores the original contents of the buffer, after
   it is written to the file. This is done by byte-swapping in-place
   the second time. If the flag istemp is set to PETSC_TRUE, the second
   byte-swapping operation is not done, thus saving some computation,
   but the buffer is left corrupted.

   Because byte-swapping may be done on the values in data it cannot be declared const

   Concepts: files^writing binary
   Concepts: binary files^writing

.seealso: PetscBinaryRead(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(),
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode  PetscBinaryWrite(int fd,void *p,PetscInt n,PetscDataType type,PetscBool  istemp)
{
  char           *pp = (char*)p;
  int            err,wsize;
  size_t         m = (size_t)n,maxblock=65536;
  PetscErrorCode ierr;
#if !defined(PETSC_WORDS_BIGENDIAN)
  void           *ptmp = p;
#endif
  char           *fname = NULL;

  PetscFunctionBegin;
  if (n < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Trying to write a negative amount of data %D",n);
  if (!n) PetscFunctionReturn(0);

  if (type == PETSC_FUNCTION) {
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    const char *fnametmp;
#endif
    m     = 64;
    fname = (char*)malloc(m*sizeof(char));
    if (!fname) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_MEM,"Cannot allocate space for function name");
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    if (n > 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Can only binary view a single function at a time");
    ierr = PetscFPTFind(*(void**)p,&fnametmp);CHKERRQ(ierr);
    ierr = PetscStrncpy(fname,fnametmp,m);CHKERRQ(ierr);
#else
    ierr = PetscStrncpy(fname,"",m);CHKERRQ(ierr);
#endif
    type = PETSC_CHAR;
    pp   = (char*)fname;
#if !defined(PETSC_WORDS_BIGENDIAN)
    ptmp = (void*)fname;
#endif
  }

  if (type == PETSC_INT)          m *= sizeof(PetscInt);
  else if (type == PETSC_SCALAR)  m *= sizeof(PetscScalar);
  else if (type == PETSC_DOUBLE)  m *= sizeof(double);
  else if (type == PETSC_FLOAT)   m *= sizeof(float);
  else if (type == PETSC_SHORT)   m *= sizeof(short);
  else if (type == PETSC_CHAR)    m *= sizeof(char);
  else if (type == PETSC_ENUM)    m *= sizeof(PetscEnum);
  else if (type == PETSC_BOOL)   m *= sizeof(PetscBool);
  else if (type == PETSC_BIT_LOGICAL) m = PetscBTLength(m)*sizeof(char);
  else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown type");

#if !defined(PETSC_WORDS_BIGENDIAN)
  ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
#endif

  while (m) {
    wsize = (m < maxblock) ? m : maxblock;
    err   = write(fd,pp,wsize);
    if (err < 0 && errno == EINTR) continue;
    if (err != wsize) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_FILE_WRITE,"Error writing to file total size %d err %d wsize %d",(int)n,(int)err,(int)wsize);
    m  -= wsize;
    pp += wsize;
  }

#if !defined(PETSC_WORDS_BIGENDIAN)
  if (!istemp) {
    ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
  }
#endif
  if (type == PETSC_FUNCTION) {
    free(fname);
  }
  PetscFunctionReturn(0);
}
示例#6
0
文件: sysio.c 项目: pombredanne/petsc
/*@
   PetscBinaryRead - Reads from a binary file.

   Not Collective

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

   Output Parameters:
.  p - the buffer



   Level: developer

   Notes:
   PetscBinaryRead() uses byte swapping to work on all machines; the files
   are written to file ALWAYS using big-endian ordering. On small-endian machines the numbers
   are converted to the small-endian format when they are read in from the file.
   When PETSc is ./configure with --with-64bit-indices the integers are written to the
   file as 64 bit integers, this means they can only be read back in when the option --with-64bit-indices
   is used.

   Concepts: files^reading binary
   Concepts: binary files^reading

.seealso: PetscBinaryWrite(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(),
          PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()
@*/
PetscErrorCode  PetscBinaryRead(int fd,void *p,PetscInt n,PetscDataType type)
{
  int               wsize,err;
  size_t            m = (size_t) n,maxblock = 65536;
  char              *pp = (char*)p;
#if defined(PETSC_USE_REAL___FLOAT128)
  PetscBool         readdouble = PETSC_FALSE;
  double            *ppp;
#endif
#if !defined(PETSC_WORDS_BIGENDIAN) || defined(PETSC_USE_REAL___FLOAT128)
  PetscErrorCode    ierr;
#endif
#if !defined(PETSC_WORDS_BIGENDIAN)
  void              *ptmp = p;
#endif
  char              *fname = NULL;

  PetscFunctionBegin;
  if (n < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Trying to write a negative amount of data %D",n);
  if (!n) PetscFunctionReturn(0);

  if (type == PETSC_FUNCTION) {
    m            = 64;
    type         = PETSC_CHAR;
    fname        = (char*) malloc(m*sizeof(char));
    if (!fname) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_MEM,"Cannot allocate space for function name");
    pp           = (char*)fname;
#if !defined(PETSC_WORDS_BIGENDIAN)
    ptmp         = (void*)fname;
#endif
  }

  if (type == PETSC_INT)          m *= sizeof(PetscInt);
  else if (type == PETSC_SCALAR)  m *= sizeof(PetscScalar);
  else if (type == PETSC_DOUBLE)  m *= sizeof(double);
  else if (type == PETSC_FLOAT)   m *= sizeof(float);
  else if (type == PETSC_SHORT)   m *= sizeof(short);
  else if (type == PETSC_CHAR)    m *= sizeof(char);
  else if (type == PETSC_ENUM)    m *= sizeof(PetscEnum);
  else if (type == PETSC_BOOL)   m *= sizeof(PetscBool);
  else if (type == PETSC_BIT_LOGICAL) m  = PetscBTLength(m)*sizeof(char);
  else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Unknown type");

#if defined(PETSC_USE_REAL___FLOAT128)
  ierr = PetscOptionsGetBool(NULL,"-binary_read_double",&readdouble,NULL);CHKERRQ(ierr);
  /* If using __float128 precision we still read in doubles from file */
  if (type == PETSC_SCALAR && readdouble) {
    m    = m/2;
    ierr = PetscMalloc1(n,&ppp);CHKERRQ(ierr);
    pp   = (char*)ppp;
  }
#endif

  while (m) {
    wsize = (m < maxblock) ? m : maxblock;
    err   = read(fd,pp,wsize);
    if (err < 0 && errno == EINTR) continue;
    if (!err && wsize > 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FILE_READ,"Read past end of file");
    if (err < 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_FILE_READ,"Error reading from file, errno %d",errno);
    m  -= err;
    pp += err;
  }

#if defined(PETSC_USE_REAL___FLOAT128)
  if (type == PETSC_SCALAR && readdouble) {
    PetscScalar *pv = (PetscScalar*) p;
    PetscInt    i;
#if !defined(PETSC_WORDS_BIGENDIAN)
    ierr = PetscByteSwapDouble(ppp,n);CHKERRQ(ierr);
#endif
    for (i=0; i<n; i++) pv[i] = ppp[i];
    ierr = PetscFree(ppp);CHKERRQ(ierr);
    PetscFunctionReturn(0);
  }
#endif

#if !defined(PETSC_WORDS_BIGENDIAN)
  ierr = PetscByteSwap(ptmp,type,n);CHKERRQ(ierr);
#endif

  if (type == PETSC_FUNCTION) {
#if defined(PETSC_SERIALIZE_FUNCTIONS)
    ierr = PetscDLSym(NULL,fname,(void**)p);CHKERRQ(ierr);
#else
    *(void**)p = NULL;
#endif
    free(fname);
  }
  PetscFunctionReturn(0);
}