strmlen: "Safe" String Manipulation Functions
In brodieG/cstringr: C String Manipulation Functions for R

Description Usage Arguments Details Value

Implements variants of strlcpy, strnlen, etc.

strmlen(str, maxlen = 10000L)

strmcpy(str, maxlen = 10000L)

smprintf2(format, a, b, maxlen = 10000L)

ucfirst(str, maxlen = 10000L)

lcfirst(str, maxlen = 10000L)

strbullet(str, bullet = "- ", ctd = "  ", maxlen = 10000L)

collapse(str, sep = "", maxlen = 10000L)

`str`	character string to measure or manipulate, should be scalar for `strmlen` and `strmcpy`
`maxlen`	integer(1L) size limit to truncate to, or to limit tokens to
`format`	character(1L) string to use as format template
`a`	character(1L) another string
`b`	character(1L) another string
`bullet`	character(1L) a string to use as the bullet symbol
`ctd`	character(1L) a string preferably the same number of characters as `bullet` to use after the first line wraps in a bullet
`sep`	character(1L) a separator to use when collapsing character vectors with `collapse`

These functions are intended to be used directly from C but are exposed here for testing purposes. They differ from similar existing versions in these respects:

Input strings are never modified; if changes are required to comply with length limits a copy that is R_alloced is returned
Only C99 code is used

Function specific details follow. Pay attention, the interfaces are not exactly the same as the C functions they intend to replace. For example smprintf does not have a str parameter like snprintf, and strmcpy returns a new character string instead of modifying one passed as an argument.).

strmlen: roughly equivalent to POSIX strnlen, but should be fully portable
strmcpy: if strmlen(str) is greater than maxlen, returns a copy of str with '\0' as the maxlen + 1th character (note return character array is not allocated beyond this NULL), otherwise returns a copy of str.
smprintf2: returns a newly R_alloced string that is just large enough to fit the combination of the format string and the tokens to sub in (note that tokens must be character so only " as a formatting element). To achieve this without overflow, ensures that format and each token is limited to maxlen - 1 characters. Fails if result string is longer than a size_t could index. Note that internally we define smprintf1 - smprintf6, but we are only exporting the one function directly to R for testing.
strbullet ads a bullet at front of string and padding after each new line
collapse is essentially the same as paste0(x, collapse=sep