| blob | ||
|---|---|---|
 | Chapter 4. SIMPOL Built-In Types |  |
Blob types are value types and can contain either
.nul, .inf, the empty blob or a
blob value of any size (limited by memory). Blobs are made up of bytes.
To provide for ease of creation, it is possible to assign literal strings
and string variables to a blob using either the equals
= symbol, the .toblob() intrinsic
function, or as part of the
blob.new() method.
Resizes an existing blob. If the blob's size is increased, it is padded with 0's. If it is decreased, the content is truncated.
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| value | None | blob | string | The value to be assigned to the new object. In value types the parameter to the new function is not a named parameter. Specifically in this object the initial parameter can be either a blob, a string that contains no characters greater than character value 255, or the named parameter that follows, which is an initialization size. |
| size | None | integer |
This parameter can be used in place of an initialization value in
order to create a blob with an initial size that has been
initialized with 0 in each byte. This can be useful when
manipulating items that will be eventually placed in a single
buffer and can be far more efficient both in memory and speed than
doing so in other ways. To use this parameter, it is necessary use
it by name in the new() method.
|
| Property | Type | Description |
|---|---|---|
| size | integer | Contains the size of the blob in bytes (octets). |
| type | type | Specifies the integer type object. |
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer |
Contains the starting position for extracting the blob. If the
value of this is .nul or
.inf then the return value will be
.nul.
|
| length | 1 | integer |
Contains the number of bytes to read from the blob. If the value
of this is .nul then the return value will
also be .nul. If it is .inf
then all of the bytes to the end of the blob will be read.
|
Returns an integer from a blob starting at the byte for position
start. If any of the four parameters are equal
to .nul then the result will also be
.nul. If any of the following parameters:
start, lbo, or
signed is equal to .inf
then the result will be .nul.
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer | Returns an integer starting at the position named in this parameter. |
| length | 1 | integer |
The number of bytes to read from the blob to return as an
integer value. If this is equal to .inf, then
all of the bytes will be read to the end of the blob and
interpreted as an integer.
|
| lbo | .true | boolean |
Indicates whether the integer value should be interpreted as
having been stored with the least significant byte first
(.true) or with the most significant byte
first (.false).
|
| signed | .false | boolean | Indicates whether the integer will be interpreted as a signed or unsigned value. |
Returns a string from a blob starting at the byte for position
start for length
characters and taking into consideration the settings for character
size and logical byte order as well as the optional terminator
characters. If any of the first four parameters are equal to
.nul then the result will also be
.nul. If any of the following parameters:
start, charsize,
lbo, or terminator is
equal to .inf then the result will be
.nul.
blobvar.getstring (
integer startlengthcharsizelboterminatorterminatedby
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer | Returns a string starting at the position named in this parameter. |
| length | 1 | integer |
The number of characters to read from the blob. If this is equal
to .inf, then characters will be read to the
end of the blob, or until a terminator is found (see
terminator parameter).
|
| charsize | 2 | integer | The number of bytes per character, which must be greater than 0. |
| lbo | .true | boolean |
Indicates whether characters should be interpreted as having
been stored with the least significant byte first
(.true) or with the most significant byte
first (.false).
|
| terminator | "" | string |
A string made up of all the characters that can terminate the
string being read. As soon as any one character in the string of
terminators is read then reading stops and the string is
returned. if the value of this is .nul then no
characters will terminate the string being read.
|
| terminatedby | no object | string |
This parameter must be an object, not a string value such as a
literal or expression. If the reading of the string is terminated
by finding a character in the terminator
string then that character is returned in the
terminatedby object.
|
Outputs a blob into a blob starting at position
start. It is an error to try and write beyond
the end of the blob.
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer |
Writes a blob beginning at the starting position named in this
parameter. If the value of this is .nul or
.inf then the return value will be
.nul.
|
| blob | None | blob |
Contains the blob to be output. If the value of this is either
.nul or .inf, then no bytes
will be output.
|
Outputs an integer to a blob starting at position
start for length bytes. It is an error to
write past the end of the blob. If either the
start or length
parameter is equal to either .nul or
.inf then a runtime error, "number out of range"
will occur. If the lbo parameter is equal to
either .nul or .inf or the
integer parameter is equal to either
.nul or .inf then no bytes will
be output.
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer | Writes an integer starting at the position named in this parameter. |
| integer | None | integer | The value to output. |
| length | 1 | integer | The number of bytes to write to the blob. |
| lbo | .true | boolean |
Indicates whether the integer value should be stored with the
least significant byte first (.true) or with
the most significant byte first (.false).
|
Outputs a string to a blob starting at the byte for position
start for the length of the string and taking
into consideration the settings for character size and logical byte
order. It is an error to write past the end of the blob. If either of
the following parameters: charsize or
lbo is equal to either .nul
or .inf or if the string
parameter is equal to either .nul or
.inf then no bytes will be output. If the
start is equal to either
.nul or .inf then an error,
number out of range, will be generated.
| Parameter | Default value | Type name | Description |
|---|---|---|---|
| start | 1 | integer | Writes a string to the blob starting at the position named in this parameter. |
| string | None | string | The string to be output. |
| charsize | 2 | integer | The number of bytes per character, which must be greater than 0. |
| lbo | .true | boolean |
Indicates whether characters have been stored with the least
significant byte first (.true) or with the
most significant byte first (.false).
|
| |  | |
| array |  | boolean |
