On Tue, 12 Mar 2024 10:34:33 GMT, Shaojin Wen <d...@openjdk.org> wrote:
>> The current BigDecimal(String) constructor calls String#toCharArray, which >> has a memory allocation. >> >> >> public BigDecimal(String val) { >> this(val.toCharArray(), 0, val.length()); // allocate char[] >> } >> >> >> When the length is greater than 18, create a char[] >> >> >> boolean isCompact = (len <= MAX_COMPACT_DIGITS); // 18 >> if (!isCompact) { >> // ... >> } else { >> char[] coeff = new char[len]; // allocate char[] >> // ... >> } >> >> >> This PR eliminates the two memory allocations mentioned above, resulting in >> an approximate 60% increase in performance.. > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > refactor CharArraySequence src/java.base/share/classes/java/math/BigInteger.java line 608: > 606: * Constructs a new BigInteger using a char array with radix=10. > 607: * Sign is precalculated outside and not allowed in the val. The > {@code val} > 608: * array is assumed to be unchanged for the duration of the > constructor This removed comment about the array being assumed to be unchanged is still applicable to the `CharSequence` (since it'll be backed by the passed in `char[]`). ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18177#discussion_r1521309524