- We define Type Computation Bugs (TCM) as follows:
- An arithmetic expression (over numbers, strings, or pointers) is calculated improperly, or a boolean condition is evaluated improperly.
- Fig. 1 depicts TCM causes, attributes and consequences.
Fig 1. Type Computation Bugs (TCM) Class - click on image for detailed view.
-
The TCM operations are: Calculate and Evaluate. They reflect the improper use of data types in arithmetic calculations and condition evaluations.
| Operation Value | Definition |
|---|---|
| Calculate | Find the result of a numeric, pointer, or string operation. |
| Evaluate | Find the result of a boolean condition (incl. comparison). |
- The graph of causes shows that there are three main causes for declaration bugs: Improper Operation,
Improper Data Value, Improper DataType, and Improper Function.
- An object is declared int, while it should be float.
- A class implements a cloneable or a serializable interface.
- Comparison via = vs. ==.
- Incorrect data type inference.
- Wrong order or number of arguments to a function call.
- Incorrect deep objects comparison implementation.
| Improper Operation | ||
|---|---|---|
| Value | Definition | Examples |
| Wrong | An inappropriate data type is specified; or an inappropriate function/operator is used. | |
| Erroneous | The Type System or a compute function implementation has a bug. | |
| Operands | |
|---|---|
| Concept | Definition |
| Data Value | A numeric, text, pointer/address, or boolean value stored in an object’s memory. |
| Data Type | A set of allowed values and the operations allowed over them. |
| Function | An organized block of code that when called takes in data, processes it, and produces a result(s). |
- The graph of consequences shows Improper DataValue and Type Computation Error as consequences.
| Improper Data Value | |
|---|---|
| Concept | Definition |
| Under Range | Data value is smaller than type’s lower range. |
| Over Range | Data value is larger than type’s upper range. |
| Flipped Sign | Sign bit is overwritten from type related calculation. |
| Wrong Argument Value | Inaccurate input data value; i.e., non-verified for harmed semantics. |
| Wrong Object Resolved Value | Object is resolved from wrong scope. |
| Reference vs. Object | Object’s address instead of object’s data value. |
| Wrong Result | Incorrect value from type conversion or computation. |
| Wrap Around | A moved around-the-clock value over its data type upper or lower range, as it exceeds that range. (Integer Over-/Under-flow is a wrapped-around the upper/lower range integer value; may become very small/large and change to the opposite sign.) |
| Truncated Value | Rightmost bits of value that won’t fit type size are cut off. |
| Distorted Value | Incorrect value (although fits type size) due to sign flip or signed/unsigned and vice versa conversions. |
| Rounded Value | Real number value precision loss. |
| Type Computation Error | |
|---|---|
| Value | Definition |
| Undefined | The Type System cannon represent the computa- tion result (e.g. division by 0). |
- The attributes of TCM are:
| Name | Value | Definition |
|---|---|---|
| Source Code | Codebase | The operation is in programmer’s code – in the application itself. |
| Third Party | The operation is in a third party library. | |
| Standard Library | The operation is in the standard library for a particular programming language. | |
| Compiler/Interpreter | The operation is in the language processor that allows execution or creates executables (compiler, assembler, interpreter). | |
| Data Type Kind | Primitive | Mimics the hardware units and is not built from other data types – e.g. int (long, short, signed), float, double, string, boolean. |
| Structured | Builds of other data types; have members of primitive and/or structured data types – e.g. array, record, struct, union, class, interface. | |
| Mechanism | Function | An organized block of code that when called takes in data, processes it, and returns a result. |
| Operator | A function with a symbolic name that implements a mathematical, relational or logical operation. | |
| Method | A member function of an OOP class. | |
| Lambda Expression | An anonymous function, implemented within another function. | |
| Procedure | A function with a void return type |
|
| Data Value Kind | Numeric | A number stored in an object’s memory. |
| Text | A string stored in an object’s memory. | |
| Pointer | A holder of the memory address of an object. | |
| Boolean | A truth value (true or false; 1 or 0), stored in an object’s memory. |
- TCM sites are the arithmetic, bitwise shift, concatenation, pointer arithmetics, pointer scal- ing, relational, and boolean operators.
- Application examples are provided here.