[jira] [Updated] (TEXT-87) StrBuilder Add Prefix Optimization

["BELUGA BEHR (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TEXT-87?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

BELUGA BEHR updated TEXT-87:
----------------------------
    Description: 
As a nice differentiation to Java's String Builder, please add an optimization for pre-appending.  Create the buffer a little larger and keep a pointer at the 0-index of the buffer so that pre-appending isn't necessarily a copy operations and instead is simply a pointer update and an array value update.

{code}

public StrBuilder(int initialCapacity, int preCapacity);

// So that on something like this, insert(0, 'A'), isn't a guaranteed array copy

    /**
     * Inserts the value into this builder.
     *
     * @param index  the index to add at, must be valid
     * @param value  the value to insert
     * @return this, to enable chaining
     * @throws IndexOutOfBoundsException if the index is invalid
     */
    public StrBuilder insert(final int index, final char value) {
        validateIndex(index);
        // if index == 0 and (bufIndex != 0)
        // buffer[--bufIndexindex] = value;
        // return this;
        ensureCapacity(size + 1);
        System.arraycopy(buffer, index, buffer, index + 1, size - index);
        buffer[index] = value;
        size++;
        return this;
    }
{code}

  was:
As a nice differentiation to Java's String Builder, please add an optimization for pre-appending.  Create the buffer a little larger and keep a pointer at the 0-index of the buffer so that pre-appending isn't necessarily a copy operations and instead is simply a pointer update and an array value update.

{code}

public StrBuilder(int initialCapacity, int preCapacity);

// So that on something like this, insert(0, 'A'), isn't a guaranteed array copy

    /**
     * Inserts the value into this builder.
     *
     * @param index  the index to add at, must be valid
     * @param value  the value to insert
     * @return this, to enable chaining
     * @throws IndexOutOfBoundsException if the index is invalid
     */
    public StrBuilder insert(final int index, final char value) {
        validateIndex(index);
        // if index == 0 and (bufIndex != 0)
        // buffer[bufIndexindex--] = value;
        // return this;
        ensureCapacity(size + 1);
        System.arraycopy(buffer, index, buffer, index + 1, size - index);
        buffer[index] = value;
        size++;
        return this;
    }
{code}


> StrBuilder Add Prefix Optimization
> ----------------------------------
>
>                 Key: TEXT-87
>                 URL: https://issues.apache.org/jira/browse/TEXT-87
>             Project: Commons Text
>          Issue Type: New Feature
>            Reporter: BELUGA BEHR
>            Priority: Trivial
>
> As a nice differentiation to Java's String Builder, please add an optimization for pre-appending.  Create the buffer a little larger and keep a pointer at the 0-index of the buffer so that pre-appending isn't necessarily a copy operations and instead is simply a pointer update and an array value update.
> {code}
> public StrBuilder(int initialCapacity, int preCapacity);
> // So that on something like this, insert(0, 'A'), isn't a guaranteed array copy
>     /**
>      * Inserts the value into this builder.
>      *
>      * @param index  the index to add at, must be valid
>      * @param value  the value to insert
>      * @return this, to enable chaining
>      * @throws IndexOutOfBoundsException if the index is invalid
>      */
>     public StrBuilder insert(final int index, final char value) {
>         validateIndex(index);
>         // if index == 0 and (bufIndex != 0)
>         // buffer[--bufIndexindex] = value;
>         // return this;
>         ensureCapacity(size + 1);
>         System.arraycopy(buffer, index, buffer, index + 1, size - index);
>         buffer[index] = value;
>         size++;
>         return this;
>     }
> {code}



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