std/stringbuilder

A growable string buffer.

#include "std/string_builder"

StringBuilder

struct StringBuilder
    data CStr
    len int
    cap int
end

Field	Type	Description
data	CStr	Buffer pointer
len	int	Current length in bytes
cap	int	Allocated capacity in bytes

Creating

sb_new

pub func *StringBuilder sb_new[]

Allocates a new StringBuilder with default capacity (SB_DEFAULT_CAP, 1024 bytes) and returns a pointer to it.

var sb *StringBuilder
&sb call sb_new !<

No free

There is no free for a StringBuilder yet. Allocations live until the program exits.

No growth

sb_append does not grow the buffer. Appending more than cap bytes overflows. Check len + sv.len <= cap before appending.

Appending

sb_append

pub func void sb_append[*StringBuilder sb, *string sv]

Appends a string to the builder. Copies sv.len bytes from sv.data into sb.data at offset sb.len, then advances sb.len.

var sb *StringBuilder
&sb call sb_new !<
sb "hello" call sb_append

Converting

sb_to_string

pub func void sb_to_string[*StringBuilder sb, *string sv]

Points sv.data at the builder's buffer and sets sv.len to the builder's length.

var sb *StringBuilder
var sv string
&sb call sb_new !<
sb &sv call sb_to_string
sv call println

No ownership transfer

The resulting string points into the builder's buffer. If the builder is modified afterwards, the string changes too. There is no copy.

Example

var sb *StringBuilder
&sb call sb_new !<

sb "Hello, " call sb_append
sb "World!"  call sb_append

var sv string
sb &sv call sb_to_string
sv call println    // Hello, World!