lib/util: add spdk_strsepq()

Parsing function for delimited strings with embedded quotes.

Originally based on code imported from istgt.

Change-Id: I448feb53ea232048ed8c68738e12bc3660eb4235
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>

include/spdk/string.h

@@ -54,6 +54,19 @@ char *spdk_sprintf_alloc(const char *format, ...) __attribute__((format(printf,
  */
 char *spdk_strlwr(char *s);
 
+/**
+ * Parse a delimited string with quote handling.
+ *
+ * \param stringp Pointer to starting location in string. *stringp will be updated to point to the
+ * start of the next field, or NULL if the end of the string has been reached.
+ * \param delim Null-terminated string containing the list of accepted delimiters.
+ *
+ * \return Pointer to beginning of the current field.
+ *
+ * Note that the string will be modified in place to add the string terminator to each field.
+ */
+char *spdk_strsepq(char **stringp, const char *delim);
+
 #ifdef __cplusplus
 }
 #endif

lib/util/string.c

@@ -35,6 +35,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <ctype.h>
 
 #include "spdk/string.h"
@@ -100,3 +101,68 @@ spdk_strlwr(char *s)
 
 	return s;
 }
+
+char *
+spdk_strsepq(char **stringp, const char *delim)
+{
+	char *p, *q, *r;
+	int quoted = 0, bslash = 0;
+
+	p = *stringp;
+	if (p == NULL) {
+		return NULL;
+	}
+
+	r = q = p;
+	while (*q != '\0' && *q != '\n') {
+		/* eat quoted characters */
+		if (bslash) {
+			bslash = 0;
+			*r++ = *q++;
+			continue;
+		} else if (quoted) {
+			if (quoted == '"' && *q == '\\') {
+				bslash = 1;
+				q++;
+				continue;
+			} else if (*q == quoted) {
+				quoted = 0;
+				q++;
+				continue;
+			}
+			*r++ = *q++;
+			continue;
+		} else if (*q == '\\') {
+			bslash = 1;
+			q++;
+			continue;
+		} else if (*q == '"' || *q == '\'') {
+			quoted = *q;
+			q++;
+			continue;
+		}
+
+		/* separator? */
+		if (strchr(delim, *q) == NULL) {
+			*r++ = *q++;
+			continue;
+		}
+
+		/* new string */
+		q++;
+		break;
+	}
+	*r = '\0';
+
+	/* skip tailer */
+	while (*q != '\0' && strchr(delim, *q) != NULL) {
+		q++;
+	}
+	if (*q != '\0') {
+		*stringp = q;
+	} else {
+		*stringp = NULL;
+	}
+
+	return p;
+}