//------------------------------------------------------------------------------
// GB_macrofy_bytes: create a single scalar from an array of bytes
//------------------------------------------------------------------------------

// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2023, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

//------------------------------------------------------------------------------

// When the macro is used, sizeof (ztype) must be the same as nbytes.

#include "GB.h"
#include "GB_stringify.h"

void GB_macrofy_bytes
(
    FILE *fp,               // file to write macros, assumed open already
    // input:
    const char *Name,       // all-upper-case name
    const char *variable,   // variable to declaer
    const char *type_name,  // name of the type
    const uint8_t *value,   // array of size nbytes
    size_t nbytes,
    bool is_identity        // true for the identity value
)
{

    bool same = (nbytes > 0) ;
    for (int k = 0 ; k < nbytes ; k++)
    { 
        same = same && (value [0] == value [k]) ;
    }

    if (same)
    { 
        // all bytes are the same; use memset
        fprintf (fp,
            "#define GB_DECLARE_%s(%s) %s %s ; "
            "memset (&%s, 0x%02x, %d)\n",
            Name, variable, type_name, variable,
            variable, value [0], (int) nbytes) ;
    }
    else
    {
        // not all bytes are the same; use memcpy
        fprintf (fp,
            "#define GB_DECLARE_%s(%s) %s %s ; \\\n"
            "{ \\\n"
            "    const uint8_t bytes [%d] = \\\n"
            "    { \\\n"
            "        ",
            Name, variable, type_name, variable, (int) nbytes) ;
        for (int k = 0 ; k < nbytes ; k++)
        {
            fprintf (fp, "0x%02x", (int) (value [k])) ;
            if (k < nbytes-1)
            { 
                fprintf (fp, ", ") ;
                if (k > 0 && k % 8 == 7) fprintf (fp, "\\\n        ") ;
            }
        }
        // finalize the array and use memcpy to initialize the scalar
        fprintf (fp,
            "  \\\n"
            "    } ; \\\n"
            "    memcpy (&%s, bytes, %d) ; \\\n"
            "}\n",
            variable, (int) nbytes) ;
    }

    if (same && is_identity)
    { 
        // all the bytes of the identity value are the same
        fprintf (fp, "#define GB_HAS_IDENTITY_BYTE 1\n") ;
        fprintf (fp, "#define GB_IDENTITY_BYTE 0x%02x\n", (int) value [0]) ;
    }
}