diff options
Diffstat (limited to 'src/H5Zshuffle.c')
| -rw-r--r-- | src/H5Zshuffle.c | 153 |
1 files changed, 93 insertions, 60 deletions
diff --git a/src/H5Zshuffle.c b/src/H5Zshuffle.c index 61dcc4f..ffd676f 100644 --- a/src/H5Zshuffle.c +++ b/src/H5Zshuffle.c @@ -9,73 +9,106 @@ #include "H5Eprivate.h" #include "H5MMprivate.h" #include "H5Zprivate.h" -#include <stdio.h> #ifdef H5_HAVE_FILTER_SHUFFLE -size_t H5Z_filter_shuffle(unsigned flags, - size_t cd_nelmts, - const unsigned cd_values[], - size_t nbytes, - size_t *buf_size,void **buf) { - - size_t i; - size_t j; - size_t k; - size_t ret_value = 0; - size_t byte_pos; - size_t bytesoftype; - void* dest = NULL; - char* _src; - char* _des; - char* _dest; - size_t numofelements; - - bytesoftype=cd_values[0]; - numofelements=nbytes/bytesoftype; - _src =(char*)(*buf); +/* Interface initialization */ +#define PABLO_MASK H5Z_shuffle_mask +#define INTERFACE_INIT NULL +static int interface_initialize_g = 0; - dest = malloc((size_t)nbytes); - _dest =(char*)dest; + +/*------------------------------------------------------------------------- + * Function: H5Z_filter_shuffle + * + * Purpose: Implement an I/O filter which "de-interlaces" a block of data + * by putting all the bytes in a byte-position for each element + * together in the block. For example, for 4-byte elements stored + * as: 012301230123, shuffling will store them as: 000111222333 + * Usually, the bytes in each byte position are more related to + * each other and putting them together will increase compression. + * + * Return: Success: + * + * Failure: + * + * Programmer: Kent Yang + * Wednesday, November 13, 2002 + * + * Modifications: + * Quincey Koziol, November 13, 2002 + * Cleaned up code. + * + *------------------------------------------------------------------------- + */ +size_t +H5Z_filter_shuffle(unsigned flags, size_t cd_nelmts, + const unsigned cd_values[], size_t nbytes, + size_t *buf_size, void **buf) +{ + void *dest = NULL; /* Buffer to deposit [un]shuffled bytes into */ + unsigned char *_src; /* Alias for source buffer */ + unsigned char *_dest; /* Alias for destination buffer */ + unsigned bytesoftype; /* Number of bytes per element */ + size_t numofelements; /* Number of elements in buffer */ + size_t i,j; /* Local index variables */ + size_t ret_value; /* Return value */ + + FUNC_ENTER_NOAPI(H5Z_filter_shuffle, 0); + + /* Check arguments */ + if (cd_nelmts!=1 || cd_values[0]==0) + HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, 0, "invalid shuffle parameters"); + + /* Get the number of bytes per element from the parameter block */ + bytesoftype=cd_values[0]; + + /* Don't do anything for 1-byte elements */ + if(bytesoftype>1) { + /* Compute the number of elements in buffer */ + numofelements=nbytes/bytesoftype; + + /* Allocate the destination buffer */ + if (NULL==(dest = H5MM_malloc(nbytes))) + HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0, "memory allocation failed for shuffle buffer"); + + if(flags & H5Z_FLAG_REVERSE) { + /* Get the pointer to the source buffer */ + _src =(unsigned char *)(*buf); + + /* Input; unshuffle */ + for(i=0; i<bytesoftype; i++) { + _dest=((unsigned char *)dest)+i; + for(j=0; j<numofelements; j++) { + *_dest=*_src++; + _dest+=bytesoftype; + } /* end for */ + } /* end for */ + } /* end if */ + else { + /* Get the pointer to the destination buffer */ + _dest =(unsigned char *)dest; - j = 0; - k = 0; - if(flags & H5Z_FLAG_REVERSE) { - for(i=0;i<nbytes;i++) { - byte_pos = 1 +j *numofelements; - if(byte_pos > nbytes) { - k++; - j=0; - byte_pos=1; - } - *(_dest+i)=*((char*)(_src+byte_pos-1+k)); - j++; - } - free(*buf); - *buf = dest; - dest = NULL; - *buf_size=nbytes; - ret_value = nbytes; - } + /* Output; shuffle */ + for(i=0; i<bytesoftype; i++) { + _src=((unsigned char *)(*buf))+i; + for(j=0; j<numofelements; j++) { + *_dest++=*_src; + _src+=bytesoftype; + } /* end for */ + } /* end for */ + } /* end else */ - else { - for (i=0;i<nbytes;i++){ - byte_pos = 1+j * bytesoftype; - if(byte_pos >nbytes) { - k++; - j=0; - byte_pos = 1; - } + /* Set the buffer information to return */ + H5MM_xfree(*buf); + *buf = dest; + *buf_size=nbytes; + } /* end else */ - *(_dest+i)=*(_src+byte_pos-1+k); - j++; - } - free(*buf); - *buf = dest; - dest = NULL; - *buf_size=nbytes; - ret_value = nbytes; - } + /* Set the return value */ + ret_value = nbytes; +done: + FUNC_LEAVE (ret_value); } #endif /*H5_HAVE_FILTER_SHUFFLE */ |