GUACAMOLE-637: Add convenience function for joining an array of strings using a given delimiter.

This commit is contained in:
Michael Jumper 2018-10-19 12:28:38 -07:00
parent a78f254611
commit 5bf6a1479c
2 changed files with 72 additions and 0 deletions

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@ -103,5 +103,53 @@ size_t guac_strlcpy(char* restrict dest, const char* restrict src, size_t n);
*/ */
size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n); size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n);
/**
* Concatenates each of the given strings, separated by the given delimiter,
* storing the result within a destination buffer. The number of bytes written
* will be no more than the given number of bytes, and the destination buffer
* is guaranteed to be null-terminated, even if doing so means that one or more
* of the intended strings are truncated or omitted from the end of the result,
* unless the destination buffer has no space available at all. As this
* function always returns the length of the string it tried to create (the
* length of all source strings and all delimiters added together), whether
* truncation has occurred can be detected by comparing the return value
* against the size of the destination buffer. If the value returned is greater
* than or equal to the size of the destination buffer, then the string has
* been truncated.
*
* The source strings, delimiter string, and destination buffer MAY NOT
* overlap.
*
* @param dest
* The buffer which should receive the result of joining the given strings.
* This buffer will always be null terminated unless zero bytes are
* available within the buffer.
*
* @param elements
* The elements to concatenate together, separated by the given delimiter.
* Each element MUST be null-terminated.
*
* @param nmemb
* The number of elements within the elements array.
*
* @param delim
* The delimiter to include between each pair of elements.
*
* @param n
* The number of bytes available within the destination buffer. If this
* value is not greater than zero, no bytes will be written to the
* destination buffer, and the destination buffer may not be null
* terminated. In all other cases, the destination buffer will always be
* null terminated, even if doing so means that the result will be
* truncated.
*
* @return
* The length of the string this function tried to create (the length of
* all source strings and all delimiters added together) in bytes,
* excluding the null terminator.
*/
size_t guac_strljoin(char* restrict dest, const char* restrict const* elements,
int nmemb, const char* restrict delim, size_t n);
#endif #endif

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@ -61,3 +61,27 @@ size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n) {
} }
size_t guac_strljoin(char* restrict dest, const char* restrict const* elements,
int nmemb, const char* restrict delim, size_t n) {
int length = 0;
const char* restrict const* current = elements;
/* If no elements are provided, nothing to do but ensure the destination
* buffer is null terminated */
if (nmemb <= 0)
return guac_strlcpy(dest, "", n);
/* Initialize destination buffer with first element */
length += guac_strlcpy(dest, *current, n);
/* Copy all remaining elements, separated by delimiter */
for (current++; nmemb > 1; current++, nmemb--) {
length += guac_strlcat(dest + length, delim, n - length);
length += guac_strlcat(dest + length, *current, n - length);
}
return length;
}