Save an array to a binary file. More...

Functions

AFAPI int saveArray (const char *key, const array &arr, const char *filename, const bool append=false)
 
AFAPI af_err af_save_array (int *index, const char *key, const af_array arr, const char *filename, const bool append)
 

Detailed Description

Save an array to a binary file.

The saveArray and readArray functions are designed to provide store and read access to arrays using files written to disk.

The format of the file (version 1) is as follows:

Header:

Description Data Type Size (Bytes) Detailed Desc
Version Char 1 ArrayFire File Format Version for future use. Currently set to 1
Array Count Int 4 No. of Arrays stored in file

Per Array:

Description Data Type Size (Bytes) Detailed Desc
Length of Key String Int 4 No. of characters (excluding null ending) in the key string
Key Char [] length Key of the Array. Used when reading from file
Offset Int64 8 No of bytes between offset and start of next array
Array Type Char 1 Type corresponding to af_dtype enum
Dims (4 values) Int64 4 * 8 = 32 Dimensions of the Array
Data Type sizeof(Type) * dims.elements() Actual data of the array

The offset is equal to 1 byte (type) + 32 bytes (dims) + size of data.

An file with 2 arrays would look like (representative)

1
2
Array 1 Key Length
Array 1 Key
Array 1 Offset
Array 1 Type
Array 1 Dims
Array 1 Data
Array 2 Key Length
Array 2 Key
Array 2 Offset
Array 2 Type
Array 2 Dims
Array 2 Data

Save array allows you to append any number of Arrays to the same file using the append argument. If the append argument is false, then the contents of the file are discarded and new array is written anew.

On each append, the array counter in the header is incremented and the new array is written to the end of the file. This function does not check if the tag is unique or not.

Function Documentation

◆ af_save_array()

AFAPI af_err af_save_array ( int *  index,
const char *  key,
const af_array  arr,
const char *  filename,
const bool  append 
)
Parameters
[out]indexis the index location of the array in the file
[in]keyis an expression used as tag/key for the array during readArray()
[in]arris the array to be written
[in]filenameis the path to the location on disk
[in]appendis used to append to an existing file when true and create or overwrite an existing file when false

◆ saveArray()

AFAPI int af::saveArray ( const char *  key,
const array arr,
const char *  filename,
const bool  append = false 
)
Parameters
[in]keyis an expression used as tag/key for the array during readArray
[in]arris the array to be written
[in]filenameis the path to the location on disk
[in]appendis used to append to an existing file when true and create or overwrite an existing file when false
Returns
index of the saved array in the file