iotile-common

object

Utilities.object:base64ToArrayBuffer

Decode a Base 64 encoded string into an ArrayBuffer

object

Utilities.function:copyArrayBuffer

Copy an ArrayBuffer into another one like memcpy

This function is a javascript translation of memcpy. It takes a source and destination ArrayBuffer, an offset into both and a length of bytes to copy. In slicing syntax, this function does the following:

dest[destOffset:destOffset+length] = src[srcOffset:srcOffset+length]

• Exceptions

• {@link type:InsufficientSpaceError InsufficentSpaceError}: If there is not space in the destination buffer to hold the copied data. This function will not expand the size of the destination buffer, so it must already be allocated with enough space for the copied data.

{InsufficientSpaceError} If there is not space in the destination buffer to hold the copied data.

object

Utilities.function:createStreamerSlug

Convert a numeric deviceID and streamer index to an IOTile cloud streamer slug

This function converts a device id like 0x20 and streamer 0 to a string slug of the form: t--XXXX-XXXX-XXXX-XXXX--YYYY

The slug always has the hex string in lowercase. The device id is converted into the XXXX portion and the streamer is converted to the YYYY portion.

object

Utilities.function:delay

Delay for a fixed number of milliseconds

This function wraps setTimeout in a promise API that can be used with async/await.

object

Utilities.function:deviceIDToSlug

Convert a numeric deviceID to an IOTile cloud device slug

This function converts a device id like 0x20 to a string slug of the form: d--XXXX-XXXX-XXXX-XXXX

The slug always has the hex string in lowercase.

object

Utilities.function:endsWith

Check if a string ends with another string

object

Utilities.function:expectedBufferSize

Determine how large a buffer is given its binary format string

This function takes a string describing how fixed width integers are packed into a binary ArrayBuffer and calculates how large the buffer would need to be to contain that many integers of those sizes. It also support packing fixed length strings that must be prefixed with a number like 18s for an exactly 18 character string.

Alignment is not taken into account, so if you are trying to match the alignment of a structure on, e.g. a 32 bit platform, you will need to insert alignment gaps as needed.

See Also

{@link Utilities.function:packArrayBuffer Utilities.packArrayBuffer}

{@link Utilities.function:unpackArrayBuffer Utilities.unpackArrayBuffer}

object

Utilities.function:mapStreamName

Convert a string description of an IOTile variable into a number

This function converts string like 'output 1' into 16 bit integers like 0x5001.

object

Utilities.function:numberToHexString

Convert a number to lowercase hex string

This function takes a number like 0x16 and returns the string '16'. It would also take 0xAF and return 'af'. It will pad the number out to a fixed length using the second length parameter.

The slug always has the hex string in lowercase.

object

Utilities.function:packArrayBuffer

Pack a series of arguments into an ArrayBuffer using a format string

This function is a javascript equivalent of the python struct.pack function. It takes a format string consisting of the letters l, L, B and H and a variable list of numeric arguments. There must be exactly as many arguments as letters in the format string. The format string is used to convert each argument into a little endian binary representation of the number which is serialized into an ArrayBuffer. The resulting ArrayBuffer is returned.

The meaning of each format code is:

• B: An 8 bit wide unsigned integer
• H: A 16 bit wide unsigned integer
• L: A 32 bit wide unsigned integer
• l: A 32 bit wide signed integer
• #s: A fixed length string with length given by the number preceding s, e.g. 5s for a 5 character string. If the string argument is shorter than what is specified, it is padded with null characters.

Exceptions

• **{@link type:ArgumentError} If there is an unknown format string code or the string does not match the number or type of arguments received.

object

Utilities.function:padString

Pad a string by appended a given character until it reaches a fixed length

object

Utilities.function:parseBufferFormatCode

Parse a string format code describing the packing of a binary buffer into an array of entries where each entry has a type code and a count prefix. For example,

"18sH" would turn into [{count: 18, code: 's'}, {count: 8, code: 'H'}]

See Also

{@link Utilities.function:packArrayBuffer Utilities.packArrayBuffer}

{@link Utilities.function:unpackArrayBuffer Utilities.unpackArrayBuffer}

object

Utilities.function:startsWith

Check if a string ends with another string

object

Utilities.function:unpackArrayBuffer

Unpack an ArrayBuffer into a list of numeric values using a format string

This function is a javascript equivalent of the python struct.unpack function. It takes a format string consisting of the letters l, L, B and H and a single ArrayBuffer. The format string is used to decode the ArrayBuffer into a list of numbers assuming that those numbers are encoded into fixed width integers in little endian format in the ArrayBuffer.

The meaning of each format code is:

• B: An 8 bit wide unsigned integer
• H: A 16 bit wide unsigned integer
• L: A 32 bit wide unsigned integer
• l: A 32 bit wide signed integer
• #s: A fixed length string. # should be a decimal number, e.g. 5s or 18s

Exceptions

• **{@link type:ArgumentError} If there is an unknown format string code or the string does not match the data contained inside the ArrayBuffer.