Function parsePGArray

src/fe_utils/string_utils.c:839–909

* Deconstruct the text representation of a 1-dimensional Postgres array * into individual items. * * On success, returns true and sets *itemarray and *nitems to describe * an array of individual strings. On parse failure, returns false; * *itemarray may exist or be NULL. * * NOTE: free'ing itemarray is sufficient to deallocate the working storage. */

 * NOTE: free'ing itemarray is sufficient to deallocate the working storage.
 */
bool
parsePGArray(const char *atext, char ***itemarray, int *nitems)
{
	int			inputlen;
	char	  **items;
	char	   *strings;
	int			curitem;

	/*
	 * We expect input in the form of "{item,item,item}" where any item is
	 * either raw data, or surrounded by double quotes (in which case embedded
	 * characters including backslashes and quotes are backslashed).
	 *
	 * We build the result as an array of pointers followed by the actual
	 * string data, all in one malloc block for convenience of deallocation.
	 * The worst-case storage need is not more than one pointer and one
	 * character for each input character (consider "{,,,,,,,,,,}").
	 */
	*itemarray = NULL;
	*nitems = 0;
	inputlen = strlen(atext);
	if (inputlen < 2 || atext[0] != '{' || atext[inputlen - 1] != '}')
		return false;			/* bad input */
	items = (char **) malloc(inputlen * (sizeof(char *) + sizeof(char)));
	if (items == NULL)
		return false;			/* out of memory */
	*itemarray = items;
	strings = (char *) (items + inputlen);

	atext++;					/* advance over initial '{' */
	curitem = 0;
	while (*atext != '}')
	{
		if (*atext == '\0')
			return false;		/* premature end of string */
		items[curitem] = strings;
		while (*atext != '}' && *atext != ',')
		{
			if (*atext == '\0')
				return false;	/* premature end of string */
			if (*atext != '"')
				*strings++ = *atext++;	/* copy unquoted data */
			else
			{
				/* process quoted substring */
				atext++;
				while (*atext != '"')
				{
					if (*atext == '\0')
						return false;	/* premature end of string */
					if (*atext == '\\')
					{
						atext++;
						if (*atext == '\0')
							return false;	/* premature end of string */
					}
					*strings++ = *atext++;	/* copy quoted data */
				}