argv_strided_float64array

Convert a Node-API value representing a strided array to a double-precision floating-point array.

Installation

npm install @stdlib/napi-argv-strided-float64array

Usage

var headerDir = require( '@stdlib/napi-argv-strided-float64array' );

headerDir

Absolute file path for the directory containing header files for C APIs.

var dir = headerDir;
// returns <string>

Examples

var headerDir = require( '@stdlib/napi-argv-strided-float64array' );

console.log( headerDir );
// => <string>

C APIs

Usage

#include "stdlib/napi/argv_strided_float64array.h"

stdlib_napi_argv_strided_float64array( env, N, stride, value, **data, *message1, *message2, *err )

Converts a Node-API value representing a strided array to a double-precision floating-point array.

#include "stdlib/napi/argv_strided_float64array.h"
#include <node_api.h>
#include <stdint.h>

static napi_value addon( napi_env env, napi_callback_info info ) {
    napi_value value;

    // ...

    int64_t N = 100;
    int64_t stride = 1;

    // ...

    double *X;
    napi_value err;
    napi_status status = stdlib_napi_argv_strided_float64array( env, N, stride, value, &X, "Must be a typed array.", "Must have sufficient elements.", &err );
    assert( status == napi_ok );
    if ( err != NULL ) {
        assert( napi_throw( env, err ) == napi_ok );
        return NULL;
    }

    // ...
}

The function accepts the following arguments:

• env: [in] napi_env environment under which the function is invoked.
• N: [in] int64_t number of indexed elements.
• stride: [in] int64_t stride length.
• value: [in] napi_value Node-API value.
• data: [out] double** pointer for returning a reference to the output array.
• message1: [in] char* error message if a value is not a Float64Array.
• message2: [in] char* error message if a value has insufficient elements.
• err: [out] napi_value* pointer for storing a JavaScript error. If not provided a number, the function sets err with a JavaScript error; otherwise, err is set to NULL.

napi_status stdlib_napi_argv_strided_float64array( const napi_env env, const int64_t N, const int64_t stride, const napi_value value, double **data, const char *message1, const char *message2, napi_value *err );

The function returns a napi_status status code indicating success or failure (returns napi_ok if success).

STDLIB_NAPI_ARGV_STRIDED_FLOAT64ARRAY( env, X, N, stride, argv, index )

Macro for converting an add-on callback argument to a strided double-precision floating-point array.

#include "stdlib/napi/argv_strided_float64array.h"
#include "stdlib/napi_argv_int64.h"
#include "stdlib/napi/argv.h"
#include <node_api.h>
#include <stdint.h>

static void fcn( const int64_t N, const double *X, const int64_t strideX, double *Y, const int64_t strideY ) {
    int64_t i;
    for ( i = 0; i < N; i++ ) {
        Y[ i*strideY ] = X[ i*strideX ];
    }
}

// ...

static napi_value addon( napi_env env, napi_callback_info info ) {
    // Retrieve add-on callback arguments:
    STDLIB_NAPI_ARGV( env, info, argv, argc, 5 );

    // Convert the number of indexed elements to a C type:
    STDLIB_NAPI_ARGV_INT64( env, N, argv, 0 );

    // Convert the stride arguments to C types:
    STDLIB_NAPI_ARGV_INT64( env, strideX, argv, 2 );
    STDLIB_NAPI_ARGV_INT64( env, strideY, argv, 4 );

    // Convert the arrays a C types:
    STDLIB_NAPI_ARGV_STRIDED_FLOAT64ARRAY( env, X, N, strideX, argv, 1 );
    STDLIB_NAPI_ARGV_STRIDED_FLOAT64ARRAY( env, Y, N, strideY, argv, 3 );

    // ...

    fcn( N, X, strideX, Y, strideY );
}

The macro expects the following arguments:

• env: environment under which the callback is invoked.
• X: output variable name for the array.
• N: number of indexed elements.
• stride: stride length.
• argv: name of the variable containing add-on callback arguments.
• index: argument index.

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.