1 files changed, 202 insertions, 0 deletions
diff --git a/usr/src/lib/libcustr/common/custr.c b/usr/src/lib/libcustr/common/custr.c
new file mode 100644
index 0000000000..5c5b0e370a
--- /dev/null
+++ b/usr/src/lib/libcustr/common/custr.c
@@ -0,0 +1,202 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * String utility functions with dynamic memory management.
+ */
+
+/*
+ * Copyright 2018 Joyent, Inc.
+ */
+
+#include <stdlib.h>
+#include <err.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <sys/debug.h>
+
+#include "libcustr.h"
+
+typedef enum {
+	CUSTR_FIXEDBUF	= 0x01
+} custr_flags_t;
+
+struct custr {
+	size_t cus_strlen;
+	size_t cus_datalen;
+	char *cus_data;
+	custr_flags_t cus_flags;
+};
+
+#define	STRING_CHUNK_SIZE	64
+
+void
+custr_reset(custr_t *cus)
+{
+	if (cus->cus_data == NULL)
+		return;
+
+	cus->cus_strlen = 0;
+	cus->cus_data[0] = '\0';
+}
+
+size_t
+custr_len(custr_t *cus)
+{
+	return (cus->cus_strlen);
+}
+
+const char *
+custr_cstr(custr_t *cus)
+{
+	if (cus->cus_data == NULL) {
+		VERIFY(cus->cus_strlen == 0);
+		VERIFY(cus->cus_datalen == 0);
+
+		/*
+		 * This function should never return NULL.  If no buffer has
+		 * been allocated, return a pointer to a zero-length string.
+		 */
+		return ("");
+	}
+	return (cus->cus_data);
+}
+
+int
+custr_append_vprintf(custr_t *cus, const char *fmt, va_list ap)
+{
+	int len = vsnprintf(NULL, 0, fmt, ap);
+	size_t chunksz = STRING_CHUNK_SIZE;
+
+	if (len == -1)
+		return (len);
+
+	while (chunksz < len) {
+		chunksz *= 2;
+	}
+
+	if (len + cus->cus_strlen + 1 >= cus->cus_datalen) {
+		char *new_data;
+		size_t new_datalen = cus->cus_datalen + chunksz;
+
+		if (cus->cus_flags & CUSTR_FIXEDBUF) {
+			errno = EOVERFLOW;
+			return (-1);
+		}
+
+		/*
+		 * Allocate replacement memory:
+		 */
+		if ((new_data = malloc(new_datalen)) == NULL) {
+			return (-1);
+		}
+
+		/*
+		 * Copy existing data into replacement memory and free
+		 * the old memory.
+		 */
+		if (cus->cus_data != NULL) {
+			(void) memcpy(new_data, cus->cus_data,
+			    cus->cus_strlen + 1);
+			free(cus->cus_data);
+		}
+
+		/*
+		 * Swap in the replacement buffer:
+		 */
+		cus->cus_data = new_data;
+		cus->cus_datalen = new_datalen;
+	}
+	/*
+	 * Append new string to existing string:
+	 */
+	len = vsnprintf(cus->cus_data + cus->cus_strlen,
+	    (uintptr_t)cus->cus_data - (uintptr_t)cus->cus_strlen, fmt, ap);
+	if (len == -1)
+		return (len);
+	cus->cus_strlen += len;
+
+	return (0);
+}
+
+int
+custr_appendc(custr_t *cus, char newc)
+{
+	return (custr_append_printf(cus, "%c", newc));
+}
+
+int
+custr_append_printf(custr_t *cus, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = custr_append_vprintf(cus, fmt, ap);
+	va_end(ap);
+
+	return (ret);
+}
+
+int
+custr_append(custr_t *cus, const char *name)
+{
+	return (custr_append_printf(cus, "%s", name));
+}
+
+int
+custr_alloc(custr_t **cus)
+{
+	custr_t *t;
+
+	if ((t = calloc(1, sizeof (*t))) == NULL) {
+		*cus = NULL;
+		return (-1);
+	}
+
+	*cus = t;
+	return (0);
+}
+
+int
+custr_alloc_buf(custr_t **cus, void *buf, size_t buflen)
+{
+	int ret;
+
+	if (buflen == 0 || buf == NULL) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	if ((ret = custr_alloc(cus)) != 0)
+		return (ret);
+
+	(*cus)->cus_data = buf;
+	(*cus)->cus_datalen = buflen;
+	(*cus)->cus_strlen = 0;
+	(*cus)->cus_flags = CUSTR_FIXEDBUF;
+	(*cus)->cus_data[0] = '\0';
+
+	return (0);
+}
+
+void
+custr_free(custr_t *cus)
+{
+	if (cus == NULL)
+		return;
+
+	if ((cus->cus_flags & CUSTR_FIXEDBUF) == 0)
+		free(cus->cus_data);
+	free(cus);
+}