| Blob Functions | ||
|---|---|---|
 | Chapter 1. Intrinsic Functions |  |
Blob Functions
This section contains the intrinsic functions that are used for working together with blob values.
.inblob()
Prototype
.inblob(
, <sourceblob>
) <searchblob>
Return types
.nul, .inf, integer
Description
Returns the one-based position of the first occurrence of one blob within another. If the subblob is not found then zero is returned.
Parameters
sourceblob
| Type name | Result for an expression of this type in this parameter |
|---|---|
.nul
| The result will be .nul |
.inf
| The result will be .inf, unless the second parameter is
.nul |
blob
| The blob to find the subblob in |
searchblob
| Type name | Result for an expression of this type in this parameter |
|---|---|
.nul
| The result will be .nul |
.inf
| The result will be .inf, unless the first parameter is
.nul |
blob
| The subblob to search for. If this is the empty blob then the return value
will be 0, unless the first parameter is .nul or
.inf
|
.subblob()
Prototype
.subblob(
, <sourceblob>
, <startpos>
) <count>
Return types
.nul, .inf, blob
Description
Extracts bytes a specified number of bytes from a specified position in a blob
Parameters
sourceblob
| Type name | Result for an expression of this type in this parameter |
|---|---|
.nul
| The result will be .nul |
.inf
| The result will be .inf, unless another parameter is
.nul |
blob
| The blob to extract bytes from |
startpos
| Type name | Result for an expression of this type in this parameter |
|---|---|
.nul
| The result will be .nul |
.inf
| If the result will be a blob, then it will be the empty blob, ie. the function behaves as if byte extraction starts at the end of the blob. |
integer
| The one-based position to start extracting bytes from. If this is zero or negative then the start position is the start of the blob. If it is greater than the length of the blob then an empty blob is returned. |
count
| Type name | Result for an expression of this type in this parameter |
|---|---|
.nul
| The result will be .nul |
.inf
| If the result is a blob then all bytes to the end of the blob are extracted |
integer
| The number of bytes to extract. If this is negative no bytes are returned. If it is greater than the length from the start of the extraction to the end of the blob then bytes up to the end of the blob are returned. |