## CtplValue CtplValue — Generic values |

## Synopsis

    #include <ctpl/ctpl.h>

    enum                CtplValueType;
    struct              CtplValue;
    #define             CTPL_VALUE_HOLDS                    (value,
                                                             vtype)
    #define             CTPL_VALUE_HOLDS_INT                (value)
    #define             CTPL_VALUE_HOLDS_FLOAT              (value)
    #define             CTPL_VALUE_HOLDS_STRING             (value)
    #define             CTPL_VALUE_HOLDS_ARRAY              (value)
    void                ctpl_value_init                     (CtplValue *value);
    CtplValue *         ctpl_value_new                      (void);
    void                ctpl_value_copy                     (const CtplValue *src_value,
                                                             CtplValue *dst_value);
    CtplValue *         ctpl_value_dup                      (const CtplValue *value);
    void                ctpl_value_free_value               (CtplValue *value);
    void                ctpl_value_free                     (CtplValue *value);
    CtplValue *         ctpl_value_new_int                  (glong val);
    CtplValue *         ctpl_value_new_float                (gdouble val);
    CtplValue *         ctpl_value_new_string               (const gchar *val);
    CtplValue *         ctpl_value_new_arrayv               (CtplValueType type,
                                                             gsize count,
                                                             va_list ap);
    CtplValue *         ctpl_value_new_array                (CtplValueType type,
                                                             gsize count,
                                                             ...);
    void                ctpl_value_set_int                  (CtplValue *value,
                                                             glong val);
    void                ctpl_value_set_float                (CtplValue *value,
                                                             gdouble val);
    void                ctpl_value_set_string               (CtplValue *value,
                                                             const gchar *val);
    void                ctpl_value_set_arrayv               (CtplValue *value,
                                                             CtplValueType type,
                                                             gsize count,
                                                             va_list ap);
    void                ctpl_value_set_array                (CtplValue *value,
                                                             CtplValueType type,
                                                             gsize count,
                                                             ...);
    void                ctpl_value_set_array_intv           (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);
    void                ctpl_value_set_array_int            (CtplValue *value,
                                                             gsize count,
                                                             ...);
    void                ctpl_value_set_array_floatv         (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);
    void                ctpl_value_set_array_float          (CtplValue *value,
                                                             gsize count,
                                                             ...);
    void                ctpl_value_set_array_stringv        (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);
    void                ctpl_value_set_array_string         (CtplValue *value,
                                                             gsize count,
                                                             ...);
    void                ctpl_value_array_append             (CtplValue *value,
                                                             const CtplValue *val);
    void                ctpl_value_array_prepend            (CtplValue *value,
                                                             const CtplValue *val);
    void                ctpl_value_array_append_int         (CtplValue *value,
                                                             glong val);
    void                ctpl_value_array_prepend_int        (CtplValue *value,
                                                             glong val);
    void                ctpl_value_array_append_float       (CtplValue *value,
                                                             gdouble val);
    void                ctpl_value_array_prepend_float      (CtplValue *value,
                                                             gdouble val);
    void                ctpl_value_array_append_string      (CtplValue *value,
                                                             const gchar *val);
    void                ctpl_value_array_prepend_string     (CtplValue *value,
                                                             const gchar *val);
    gsize               ctpl_value_array_length             (const CtplValue *value);
    CtplValue *         ctpl_value_array_index              (const CtplValue *value,
                                                             gsize idx);
    CtplValueType       ctpl_value_get_held_type            (const CtplValue *value);
    glong               ctpl_value_get_int                  (const CtplValue *value);
    gdouble             ctpl_value_get_float                (const CtplValue *value);
    const gchar *       ctpl_value_get_string               (const CtplValue *value);
    const GSList *      ctpl_value_get_array                (const CtplValue *value);
    glong *             ctpl_value_get_array_int            (const CtplValue *value,
                                                             gsize *length);
    gdouble *           ctpl_value_get_array_float          (const CtplValue *value,
                                                             gsize *length);
    gchar **            ctpl_value_get_array_string         (const CtplValue *value,
                                                             gsize *length);
    gchar *             ctpl_value_to_string                (const CtplValue *value);
    gboolean            ctpl_value_convert                  (CtplValue *value,
                                                             CtplValueType vtype);
    const gchar *       ctpl_value_type_get_name            (CtplValueType type);
    #define             ctpl_value_get_held_type_name       (v)

## Description

A generic value manager.

Dynamically allocated CtplValue are created with `ctpl_value_new()` and freed with `ctpl_value_free()`. Statically allocated ones are initialized with `ctpl_value_init()` and uninitialized with `ctpl_value_free_value()`.

You can set the data they holds with `ctpl_value_set_int()`, `ctpl_value_set_float()`, `ctpl_value_set_string()` and `ctpl_value_set_array()`; you can add elements to an array value with `ctpl_value_array_append()`, `ctpl_value_array_prepend()`, `ctpl_value_array_append_int()`, `ctpl_value_array_prepend_int()`, `ctpl_value_array_append_float()`, `ctpl_value_array_prepend_float()`, `ctpl_value_array_append_string()` and `ctpl_value_array_prepend_string()`.

To get the value held by a CtplValue, use `ctpl_value_get_int()`, `ctpl_value_get_float()`, `ctpl_value_get_string()`, `ctpl_value_get_array_int()`, `ctpl_value_get_array_float()` or `ctpl_value_get_array_string()` depending on the type of the value. For array value, yo can also use `ctpl_value_get_array()` to get the list of the different values in that array. You can get the type held by a value with `ctpl_value_get_held_type()`.

Value may be converted to other types with `ctpl_value_convert()`, and to a string representation using `ctpl_value_to_string()`.

Example 8. Simple usage of dynamically allocated generic values

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    CtplValue *val;

    val = ctpl_value_new ();
    ctpl_value_set_int (val, 42);

    /* Free all data allocated for the value and the held data */
    ctpl_value_free (val);

Example 9. Simple usage of statically allocated generic values

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    CtplValue val;

    ctpl_value_init (&val);
    ctpl_value_set_int (&val, 42);

    /* Free all memory that might have been allocated for the held
     * data */
    ctpl_value_free_value (&val);

## Details

### enum CtplValueType

    typedef enum _CtplValueType
    {
      CTPL_VTYPE_INT,
      CTPL_VTYPE_FLOAT,
      CTPL_VTYPE_STRING,
      CTPL_VTYPE_ARRAY
    } CtplValueType;

Represents the types that a CtplValue can hold.

`CTPL_VTYPE_INT` | Integer (C's long int)
`CTPL_VTYPE_FLOAT` | Floating point value (C's double)
`CTPL_VTYPE_STRING` | 0-terminated string (C string)
`CTPL_VTYPE_ARRAY` | Array of CtplValues

### struct CtplValue

    struct CtplValue {
    };

Represents a generic value.

### CTPL_VALUE_HOLDS()

    #define             CTPL_VALUE_HOLDS(value, vtype)

Checks whether a CtplValue holds a value of the given type.

`value` : | A CtplValue
`vtype` : | A CtplValueType
Returns : | `TRUE` if `value` holds a value of `vtype`, `FALSE` otherwise.

### CTPL_VALUE_HOLDS_INT()

    #define             CTPL_VALUE_HOLDS_INT(value)

Check whether a CtplValue holds an integer value.

`value` : | A CtplValue
Returns : | `TRUE` if `value` holds an integer, `FALSE` otherwise.

### CTPL_VALUE_HOLDS_FLOAT()

    #define             CTPL_VALUE_HOLDS_FLOAT(value)

Check whether a CtplValue holds a floating point value.

`value` : | A CtplValue
Returns : | `TRUE` if `value` holds a float, `FALSE` otherwise.

### CTPL_VALUE_HOLDS_STRING()

    #define             CTPL_VALUE_HOLDS_STRING(value)

Check whether a CtplValue holds a string.

`value` : | A CtplValue
Returns : | `TRUE` if `value` holds a string, `FALSE` otherwise.

### CTPL_VALUE_HOLDS_ARRAY()

    #define             CTPL_VALUE_HOLDS_ARRAY(value)

Check whether a CtplValue holds an array of values.

`value` : | A CtplValue
Returns : | `TRUE` if `value` holds an array, `FALSE` otherwise.

### ctpl_value_init ()

    void                ctpl_value_init                     (CtplValue *value);

Initializes a CtplValue. This function is useful for statically allocated values, and is not required for dynamically allocated values created by `ctpl_value_new()`.

`value` : | An uninitialized CtplValue

### ctpl_value_new ()

    CtplValue *         ctpl_value_new                      (void);

Creates a new empty CtplValue.

Returns : | A newly allocated CtplValue that should be freed using `ctpl_value_free()`

### ctpl_value_copy ()

    void                ctpl_value_copy                     (const CtplValue *src_value,
                                                             CtplValue *dst_value);

Copies the value of a CtplValue into another. See `ctpl_value_dup()` if you want to duplicate the value and not only its content.

`src_value` : | A CtplValue to copy
`dst_value` : | A CtplValue into which copy `src_value`

### ctpl_value_dup ()

    CtplValue *         ctpl_value_dup                      (const CtplValue *value);

Duplicates a CtplValue. This function simply creates a new CtplValue with `ctpl_value_new()` then copies `value` into it using `ctpl_value_copy()`.

`value` : | A CtplValue to copy
Returns : | A newly allocated CtplValue

### ctpl_value_free_value ()

    void                ctpl_value_free_value               (CtplValue *value);

Frees the data held by a CtplValue. This function is only useful to the end user for statically allocated values since `ctpl_value_free()` does all the job needed to completely release an allocated CtplValue.

`value` : | A CtplValue

### ctpl_value_free ()

    void                ctpl_value_free                     (CtplValue *value);

Frees all resources used by a CtplValue. This function can't be used with statically allocated values since it also frees the value itself and not only its content. If you want to free a statically allocated value, use `ctpl_value_free_value()`.

`value` : | A CtplValue

### ctpl_value_new_int ()

    CtplValue *         ctpl_value_new_int                  (glong val);

Creates a new CtplValue and sets its value to `val`. See `ctpl_value_new()` and `ctpl_value_set_int()`.

`val` : | An integer
Returns : | A newly allocated CtplValue holding `val`.

### ctpl_value_new_float ()

    CtplValue *         ctpl_value_new_float                (gdouble val);

Creates a new CtplValue and sets its value to `val`. See `ctpl_value_new()` and `ctpl_value_set_float()`.

`val` : | A float
Returns : | A newly allocated CtplValue holding `val`.

### ctpl_value_new_string ()

    CtplValue *         ctpl_value_new_string               (const gchar *val);

Creates a new CtplValue and sets its value to `val`. See `ctpl_value_new()` and `ctpl_value_set_string()`.

`val` : | A string
Returns : | A newly allocated CtplValue holding `val`.

### ctpl_value_new_arrayv ()

    CtplValue *         ctpl_value_new_arrayv               (CtplValueType type,
                                                             gsize count,
                                                             va_list ap);

Creates a new CtplValue and sets its values to the given ones. See `ctpl_value_new()` and `ctpl_value_set_arrayv()`.

### Warning

As this function takes a variadic argument, there is no control on the values neither on their type nor on any other of their properties. Then, you have to take care to pass strictly right data to it if you won't see your program crash -- in the better case.

`type` : | The type of the array's elements
`count` : | The number of elements
`ap` : | A va_list containing the values of the type specified by `type`, ended by a `NULL` value
Returns : | A newly allocated CtplValue holding given values.

### ctpl_value_new_array ()

    CtplValue *         ctpl_value_new_array                (CtplValueType type,
                                                             gsize count,
                                                             ...);

Creates a new CtplValue and sets its values to the given ones. See `ctpl_value_new_arrayv()`.

### Warning

As this function takes a variadic argument, there is no control on the values neither on their type nor on any other of their properties. Then, you have to take care to pass strictly right data to it if you won't see your program crash -- in the better case.

`type` : | The type of the array's elements
`count` : | The number of elements
`...` : | A `NULL`-ended list of elements of the type specified by `type`
Returns : | A newly allocated CtplValue holding given values.

### ctpl_value_set_int ()

    void                ctpl_value_set_int                  (CtplValue *value,
                                                             glong val);

Sets the value of a CtplValue to the given integer.

`value` : | A CtplValue
`val` : | An integer

### ctpl_value_set_float ()

    void                ctpl_value_set_float                (CtplValue *value,
                                                             gdouble val);

Sets the value of a CtplValue to the given float.

`value` : | A CtplValue
`val` : | A float

### ctpl_value_set_string ()

    void                ctpl_value_set_string               (CtplValue *value,
                                                             const gchar *val);

Sets the value of a CtplValue to the given string. The string is copied.

`value` : | A CtplValue
`val` : | A string

### ctpl_value_set_arrayv ()

    void                ctpl_value_set_arrayv               (CtplValue *value,
                                                             CtplValueType type,
                                                             gsize count,
                                                             va_list ap);

Sets the value of a CtplValue from the given list of elements. See `ctpl_value_array_append()`, `ctpl_value_array_append_int()`, `ctpl_value_array_append_float()` and `ctpl_value_array_append_string()`.

### Warning

As this function takes a variadic argument, there is no control on the values neither on their type nor on any other of their properties. Then, you have to take care to pass strictly right data to it if you won't see your program crash -- in the better case.

`value` : | A CtplValue
`type` : | The type of the given elements
`count` : | The number of elements
`ap` : | A `NULL`-ended va_list of the elements

### ctpl_value_set_array ()

    void                ctpl_value_set_array                (CtplValue *value,
                                                             CtplValueType type,
                                                             gsize count,
                                                             ...);

Sets the value of a CtplValue from the given elements. See `ctpl_value_set_arrayv()`.

### Warning

As this function takes a variadic argument, there is no control on the values neither on their type nor on any other of their properties. Then, you have to take care to pass strictly right data to it if you won't see your program crash -- in the better case.

`value` : | A CtplValue
`type` : | The type of the given elements
`count` : | The number of elements
`...` : | A `NULL`-ended list of elements

### ctpl_value_set_array_intv ()

    void                ctpl_value_set_array_intv           (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);

Sets the value of a CtplValue from the given integers. This is a convenience wrapper around `ctpl_value_set_arrayv()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`ap` : | A `NULL`-ended va_list of integers

### ctpl_value_set_array_int ()

    void                ctpl_value_set_array_int            (CtplValue *value,
                                                             gsize count,
                                                             ...);

Sets the value of a CtplValue from the given integers. This is a convenience wrapper around `ctpl_value_set_array()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`...` : | A `NULL`-ended list of integers

### ctpl_value_set_array_floatv ()

    void                ctpl_value_set_array_floatv         (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);

Sets the value of a CtplValue from the given floats. This is a convenience wrapper around `ctpl_value_set_arrayv()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`ap` : | A `NULL`-ended va_list of floats

### ctpl_value_set_array_float ()

    void                ctpl_value_set_array_float          (CtplValue *value,
                                                             gsize count,
                                                             ...);

Sets the value of a CtplValue from the given floats. This is a convenience wrapper around `ctpl_value_set_array()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`...` : | A `NULL`-ended list of floats

### ctpl_value_set_array_stringv ()

    void                ctpl_value_set_array_stringv        (CtplValue *value,
                                                             gsize count,
                                                             va_list ap);

Sets the value of a CtplValue from the given strings. This is a convenience wrapper around `ctpl_value_set_arrayv()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`ap` : | A `NULL`-ended va_list of strings (as const char*)

### ctpl_value_set_array_string ()

    void                ctpl_value_set_array_string         (CtplValue *value,
                                                             gsize count,
                                                             ...);

Sets the value of a CtplValue from the given strings. This is a convenience wrapper around `ctpl_value_set_array()`, and the same care have to been taken about.

`value` : | A CtplValue
`count` : | The number of given elements
`...` : | A `NULL`-ended list of strings (as const char*)

### ctpl_value_array_append ()

    void                ctpl_value_array_append             (CtplValue *value,
                                                             const CtplValue *val);

Appends a CtplValue to another CtplValue holding an array. The appended value is copied.

`value` : | A CtplValue holding an array
`val` : | A CtplValue to append

### ctpl_value_array_prepend ()

    void                ctpl_value_array_prepend            (CtplValue *value,
                                                             const CtplValue *val);

Prepends a CtplValue to another CtplValue holding an array. The prepended value is copied.

`value` : | A CtplValue holding an array
`val` : | A CtplValue to prepend

### ctpl_value_array_append_int ()

    void                ctpl_value_array_append_int         (CtplValue *value,
                                                             glong val);

Appends an integer to a CtplValue holding an array.

`value` : | A CtplValue holding an array
`val` : | An integer to append

### ctpl_value_array_prepend_int ()

    void                ctpl_value_array_prepend_int        (CtplValue *value,
                                                             glong val);

Prepends an integer to a CtplValue holding an array.

`value` : | A CtplValue holding an array
`val` : | An integer to prepend

### ctpl_value_array_append_float ()

    void                ctpl_value_array_append_float       (CtplValue *value,
                                                             gdouble val);

Appends a float to a CtplValue holding an array.

`value` : | A CtplValue holding an array
`val` : | A float to append

### ctpl_value_array_prepend_float ()

    void                ctpl_value_array_prepend_float      (CtplValue *value,
                                                             gdouble val);

Prepends a float to a CtplValue holding an array.

`value` : | A CtplValue holding an array
`val` : | A float to prepend

### ctpl_value_array_append_string ()

    void                ctpl_value_array_append_string      (CtplValue *value,
                                                             const gchar *val);

Appends a string to a CtplValue holding an array. The string is copied.

`value` : | A CtplValue holding an array
`val` : | A string to append

### ctpl_value_array_prepend_string ()

    void                ctpl_value_array_prepend_string     (CtplValue *value,
                                                             const gchar *val);

Prepends a string to a CtplValue holding an array. The string is copied.

`value` : | A CtplValue holding an array
`val` : | A string to prepend

### ctpl_value_array_length ()

    gsize               ctpl_value_array_length             (const CtplValue *value);

Gets the number of elements in a CtplValue that holds an array.

`value` : | A CtplValue holding an array
Returns : | The number of elements in `value`.

### ctpl_value_array_index ()

    CtplValue *         ctpl_value_array_index              (const CtplValue *value,
                                                             gsize idx);

Index an array, getting its `idx`-th element.

`value` : | A CtplValue holding an array
`idx` : | The array's index to get
Returns : | The `idx`-th element of `value`, or `NULL` if `idx` is out of bounds.

### ctpl_value_get_held_type ()

    CtplValueType       ctpl_value_get_held_type            (const CtplValue *value);

Gets the type held by the a CtplValue.

`value` : | A CtplValue
Returns : | The type held by the value.

### ctpl_value_get_int ()

    glong               ctpl_value_get_int                  (const CtplValue *value);

Gets the value of a CtplValue holding a integer.

`value` : | A CtplValue holding a int
Returns : | The integer value held by `value`.

### ctpl_value_get_float ()

    gdouble             ctpl_value_get_float                (const CtplValue *value);

Gets the value of a CtplValue holding a float.

`value` : | A CtplValue holding a float
Returns : | The float value held by `value`.

### ctpl_value_get_string ()

    const gchar *       ctpl_value_get_string               (const CtplValue *value);

Gets the value of a CtplValue holding a string.

`value` : | A CtplValue holding a string
Returns : | A string owned by the value that should not be modified or freed, or `NULL` if an error occurs.

### ctpl_value_get_array ()

    const GSList *      ctpl_value_get_array                (const CtplValue *value);

Gets the values of a CtplValue holding an array as a GSList in which each element holds a CtplValue holding the element value.

`value` : | A CtplValue holding an array
Returns : | A GSList owned by the value that must not be freed, neither the list itself nor its values, or `NULL` on error. [element-type Ctpl.Value][transfer none]

### ctpl_value_get_array_int ()

    glong *             ctpl_value_get_array_int            (const CtplValue *value,
                                                             gsize *length);

Gets the values of a CtplValue as an array of int. The value must hold an array and all array's elements must be integers.

`value` : | A CtplValue holding an array of integers
`length` : | Return location for the array length, or `NULL`. [out][allow-none]
Returns : | A newly allocated array of integers that should be freed with `g_free()` or `NULL` on error. [array length=length][transfer full]

### ctpl_value_get_array_float ()

    gdouble *           ctpl_value_get_array_float          (const CtplValue *value,
                                                             gsize *length);

Gets the values of a CtplValue as an array of floats. `value` must hold an array and all array's elements must be floats.

`value` : | A CtplValue holding an array of floats
`length` : | Return location for the array length, or `NULL`. [out][allow-none]
Returns : | A newly allocated array of floats that should be freed with `g_free()` or `NULL` on error. [array length=length][transfer full]

### ctpl_value_get_array_string ()

    gchar **            ctpl_value_get_array_string         (const CtplValue *value,
                                                             gsize *length);

Gets the values held by a CtplValue as an array of strings. `value` must hold an array containing only strings.

`value` : | A CtplValue holding an array of strings
`length` : | Return location for the length of the returned array, or `NULL`. [out][allow-none]
Returns : | A newly allocated `NULL`-terminated array of strings, or `NULL` on error. Free with `g_strfreev()` when no longer needed. [array length=length][transfer full]

### ctpl_value_to_string ()

    gchar *             ctpl_value_to_string                (const CtplValue *value);

Converts a CtplValue to a string.

### Note

Arrays are flattened to the form [val1, val2, val3]. It may not be what you want, but flattening an array is not the primary goal of this function and you should consider doing it yourself if it is what you want - flattening an array.

`value` : | A CtplValue
Returns : | A newly allocated string representing the value. You should free this value with `g_free()` when no longer needed.

### ctpl_value_convert ()

    gboolean            ctpl_value_convert                  (CtplValue *value,
                                                             CtplValueType vtype);

Tries to convert a CtplValue to another type.

The performed conversion might be called "non-destructive": the value will not loose precision, but the conversion will rather fail if it would lead to a loss. An good example is converting a floating-point value to an integer one: the conversion will only happen if it would not truncate the floating part.

### Warning

The current implementation of floating-point value comparison might be lossy, and then the above example might be somewhat wrong in practice.

### Note

Converting to a string uses `ctpl_value_to_string()`. Even if it will never fail, the result might not be the one you expect when converting an array.

`value` : | A CtplValue to convert
`vtype` : | The type to which convert `value`
Returns : | `TRUE` if the conversion succeeded, `FALSE` otherwise.

### ctpl_value_type_get_name ()

    const gchar *       ctpl_value_type_get_name            (CtplValueType type);

Gets a human-readable name for a value type.

`type` : | A CtplValueType
Returns : | A static string of a displayable name for `type`. This string must not be modified or freed.

### ctpl_value_get_held_type_name()

    #define             ctpl_value_get_held_type_name(v)

Gets a human-readable name for the type held by a value. See also `ctpl_value_type_get_name()`.

`v` : | A CtplValue pointer
Returns : | A static string of a displayable name of the type held by `v`. This string must not be modified or freed.