Perl_vnewSVpvf - use the pattern length to size the new PV buffer #23101
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This function currently creates a new SVt_PV with a minimum string
length buffer via:
sv = newSV(1);
Simple measurements from compiling perl show that this is often sufficient.
When it isn't, the final buffer length is often close to strlen(pat).
Common cases that require a realloc() now will not with this commit. In
other cases, realloc()s will still be required, but the number will
likely be smaller by one.
Although min length & alloc behaviour can vary across platforms and
compilers, the following numbers are likely indicative:
|strlen(pat)|Inital SvLEN before|Initial SvLEN now|Final SvLEN|
|-----------|-------------------|-----------------|-----------|
|004|16|016|016|
|058|16|060|060|
|071|16|073|120|
|104|16|106|106|
|104|16|106|200|
|122|16|124|124|
|123|16|125|125|
|123|16|125|168|
|377|16|379|379|
richardleach
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mauke
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Mar 13, 2025
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This function currently creates a new
SVt_PVwith a minimum string length buffer via:Simple measurements from compiling perl show that this is often sufficient.
When it isn't, the final buffer length is often close to
strlen(pat). Common cases that require arealloc()now will not with this commit. In other cases,realloc()s will still be required, but the number will likely be smaller by one.Although min length & alloc behaviour can vary across platforms and compilers, the following numbers are likely indicative: