개요

• 솔라나라에 설명된 어플리케이션에 대해 맨 페이지를 찾아 출력한다.
• MAN 페이지에 대한 설명은 윈디하나의 솔라나라: MAN 페이지을 참고하자.
• svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.

dax_zip(3dax)

dax_zip(3DAX)                DAX Library Functions               dax_zip(3DAX)



NAME
       dax_zip - compress data and create codec

SYNOPSIS
       cc [ flag... ] file... -ldax [ library...]

       #include <dax.h>

       dax_result_t
       dax_zip(dax_context_t *ctx, uint64_t options, dax_vec_t *src, void *buf,
           size_t *buflen, dax_zip_t **codec);

DESCRIPTION
       This  function zips data in src and writes the code word stream to buf.
       The buflen parameter specifies the size of buf in bytes. It returns  an
       encoder  or  decoder  in  codec, which you can pass to libdax functions
       that unzip data. The codec should be destroyed when no longer needed by
       using the dax_zip_free function. It returns the number of bytes written
       to buf in buflen.

   Supported Flags
       DAX_ZIP_HIGH    Derive a codec that yields a higher  compression  ratio
                       for src. This requires more memory and CPU time.



RETURN VALUES
       Returns  the  number  of  code words written to buf in the dax_result_t
       count field and sets the dax_result_t status field to one of  the  fol‐
       lowing values:


       DAX_SUCCESS      Operation completed successfully


       DAX_EINVAL       Invalid argument, detected by libdax


       DAX_ENOMEM       Memory resources unavailable


       DAX_EOVERFLOW    Output  buffer  overflow.  Returns the required buffer
                        size in buflen and modifies buf.


       DAX_ETHREAD      The calling thread did not create ctx


       DAX_EZIP         Cannot compress the data in src. The size of the  com‐
                        pressed  data  plus  the size of the codec exceeds the
                        size of the src data. buf may be modified.



USAGE
       After calling the dax_zip() function, you can create a  dax_vec_t  with
       data pointing to buf, and pass it to the DAX functions that unzip data.

EXAMPLES
       Example 1



         #include <stdio.h>
         #include <stdlib.h>
         #include <strings.h>
         #include <dax.h>

         #define ELEM_BITS(vec) \
             ((vec->format & DAX_BITS) ? \
             vec->elem_width : (8 * vec->elem_width))

         #define VEC_LEN(vec) \
             ((vec->elements * ELEM_BITS(vec) + vec->offset + 7) / 8)

         void compress(dax_context_t *ctx, dax_vec_t *src)
         {
                 dax_result_t res;
                 dax_zip_t *codec;
                 size_t len = VEC_LEN(src);
                 void *buf = memalign(64, len);

                 res = dax_zip(ctx, DAX_ZIP_HIGH, src, buf, &len, &codec);
                 if (res.status == DAX_EOVERFLOW) {
                         printf("data is not compressible.\n");
                         return;
                 }
                 src->data = realloc(buf, len);
                 src->format |= DAX_ZIP;
                 src->codec = codec;
                 src->codewords = res.count;
         }

         void decompress(dax_context_t *ctx, dax_vec_t *src)
         {
                 dax_result_t res;
                 size_t dstlen = DAX_OUTPUT_SIZE(VEC_LEN(src), 8);
                 void *dstbuf = memalign(64, dstlen);
                 dax_vec_t dst = {dstlen, dstbuf, DAX_BYTES, 1};

                 res = dax_extract(ctx, 0, src, &dst);
                 free(src->data);
                 (void) dax_zip_free(ctx, src->codec);
                 src->data = dstbuf;
                 src->format &= ~DAX_ZIP;
                 src->codec = NULL;
         }



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       tab()  box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
       TRIBUTE VALUE _ Availabilitysystem/library _ Interface StabilityCommit‐
       ted


SEE ALSO
       dax_encode(3DAX), dax_extract(3DAX), dax_zip_free(3DAX), libdax(3LIB)

NOTES
       The DAX hardware does not compress the data. Compression is implemented
       in software.


       The zipped format of this function is not the same format supported  by
       the zip(1) command.


       The zipped buf is a contiguous stream of fixed-width code words with no
       padding between each. The codec provides the width  of  the  code  word
       which  can  be 1 to 10 bits wide, and each code word is big endian. The
       code word order increases from left to right (from MSB to  LSB)  within
       each  byte and from low address to high address across bytes. Each code
       word represents a symbol of 1 to 8 bytes in  length.  The  symbols  are
       defined in codec.



Oracle Solaris 11.4               03 Mar 2017                    dax_zip(3DAX)