SPVM::StringBuffer - String Buffers

Name  Description  Usage  Details  Internal Data Structure  Interfaces  Fields  capacity  length  string  Class Methods  new  new_len  new_ref  Instance Methods  push  push_char  reserve  to_string  get_string  set_length  set  compare_string  equals_string  clone  cmp  eq  substr  index  contains  Copyright & License 

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Name

SPVM::StringBuffer − String Buffers

Description

The StringBuffer class in SPVM has methods to manipulate string buffers.

Usage

use StringBuffer;
# new
my $buffer = StringBuffer−>new;
my $buffer = StringBuffer−>new("abc");
# push string
$buffer−>push("def");
# Convert to the string
my $string = $buffer−>to_string;

Details

Internal Data Structure

The "string" stored in a StringBuffer object always starts at index 0.

The charactors in the range that is greater than or equal to "length" field and less than "capacity" field are filled with "\0".

Interfaces

	•		Cloneable
	•		Comparable
	•		EqualityCheckable

Fields

capacity

"has capacity : virtual ro int;"

The capacity. This is the length of the internally reserved characters to extend the length of the string buffer.

length

"has length : virtual ro int;"

The length of the string buffer.

string

"has string : mutable string;"

The internal string stored in the StringBuffer object.

Class Methods

new

"static method new : StringBuffer ($string : string = undef, $capacity : int = −1);"

Creates a new "StringBuffer" object using "new_len".

The passed $length to "new_len" is the length of $string. If the string is undef, it is 0.

$string is copied to the value of the the created string buffer.

new_len

"static method new_len : StringBuffer ($length : int, $capacity : int = −1);"

Creates a new "StringBuffer" object with $length and $capacity.

If $capacity is less than 0, $capacity is set to an appropriate value.

If $length is greater than $capacity, $capacity is set to $length.

Exceptions:

$length must be greater than or equal to 0. Otherwise an exception is thrown.

new_ref

"static method new_ref : StringBuffer ($string : mutable string);"

Creates a new StringBuffer object, and set "string" field to the string $string, and return the new object.

Exceptions:

The array $array must be defined. Otherwise an exception is thrown.

Instance Methods

push

"method push : void ($string : string, $offset : int = 0, $length : int = −1);"

Adds a $string from $offset to the position proceeded by $length after the end of the string in the string buffer.

Exceptions:

$string must be defined. Otherwise an exception is thrown.

$offset must be greater than or equal to 0. Otherwise an exception is thrown.

$offset + $length must be less than or equal to the length of $string. Otherwise an exception is thrown.

push_char

"method push_char : void ($char : int);"

Adds Ascii $char after the end of the string in the string buffer.

reserve

"method reserve : void ($new_capacity : int);"

Reserves the characters that size is $new_capacity.

If $new_capacity is greater than the capacity of the string buffer, the capacity of the string buffer is extended to $new_capacity.

Exceptions:

$new_capacity must be greater than or equal to 0. Otherwise an exception is thrown.

to_string

"method to_string : string ();"

Creates a new string with the length of the buffer and copies all characters in the buffer into the new string, and returns it.

get_string

"method get_string : string ();"

Returns the internal "string".

set_length

"method set_length : void ($length : int);"

Sets "length" fields.

If the length $length is greater than "length" field, the characters of the exceeding part are filled with "\0".

set

"method set : void ($string : string);"

Sets the string $string.

compare_string

"method compare_string : int ($string : string);"

The return value is the same as the return value of "cmp" operator given "$self−>to_string" and $string.

equals_string

"method equals_string : int ($string : string);"

If the string contained in the StringBuffer instance is equal to the string $string, returns 1, otherwise returns 0.

clone

"method clone ();"

Clones this string buffer and returns it.

This method is a method implementation for Cloneable interface.

cmp

"method cmp : int ($a : StringBuffer, $b : StringBuffer);"

Compares two StringBuffer and returns its result.

The return value is the same as the return value of "cmp" operator given "$a−>to_string" or undef(if $a is undef) and "$b−>to_string" or undef(if $b is undef).

This method is a method implementation for Comparable interface.

eq

"method eq : int ($a : StringBuffer, $b : StringBuffer);"

Checks if $a is equal to $b, and returns its result.

Implementation:

If $a and $b is defined, calls "cmp" method. If the return value is 0, returns 1, otherwise 0.

If only $a is not defined, returns 0.

If only $b is not defined, returns 0.

If both $a and $b is not defined, returns 1.

This method is a method implementation for EqualityCheckable interface.

substr

"method substr : string ($offset : int, $length : int = −1, $replacement : string = undef);"

Calls Fn#substr method given the value of "string" field, $offset, $length, and returns its return value.

If the replacement string $replacement is specified, also calls "replace" method.

Exceptions:

The offset $offset + the length $length must be less than or equal to the value of length field. Otherwise an exception is thrown.

Exceptions thrown by Fn#substr method could be thrown.

index

"method index : int ($substring : string, $begin : int = 0, $end : int = −1);"

Calls Fn#index method given "string" field, $substring, $bigen, $end, and retunrs its return value.

If $end is less than 0, it is set to the value of "length" field.

Exceptions:

The begin $begin must be between 0 and the length of string field. Otherwise an exception is thrown.

The end $end must be less than or equal to the length of string field. Otherwise an exception is thrown.

Exceptions thrown by Fn#index method could be thrown.

contains

"static method contains : int ($substring : string, $begin : int = 0, $end : int = −1);"

Checks if "string" field contains $substring.

Implementation:

The alias for the following code using "index" method.

my $ret = $self−>index($substring, $begin, $end) >= 0;

Exceptions:

Exceptions thrown by "index" method could be thrown.

Copyright & License

Copyright (c) 2023 Yuki Kimoto

MIT License

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