[PATCH v8 06/18] efi_loader: add efi_create_indexed_name()

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

This function will be used from several places in UEFI subsystem
to generate some specific form of utf-16 variable name.
For example, L"Capsule0001"

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 include/efi_loader.h       |  3 +++
 lib/efi_loader/efi_setup.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 7eea5566fdc9..6865a4847d53 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -804,6 +804,9 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 /* runtime implementation of memcpy() */
 void efi_memcpy_runtime(void *dest, const void *src, size_t n);
 
+/* commonly used helper function */
+u16 *efi_create_indexed_name(u16 *buffer, const u16 *name, unsigned int index);
+
 #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
 
 /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
index 45226c5c1a53..6346eda771d0 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <charset.h>
 #include <bootm.h>
 #include <efi_loader.h>
 #include <efi_variable.h>
@@ -235,3 +236,32 @@ out:
 	efi_obj_list_initialized = ret;
 	return ret;
 }
+
+/**
+ * efi_create_indexed_name - create a string name with an index
+ * @buffer:	Buffer
+ * @name:	Name string
+ * @index:	Index
+ *
+ * Create a utf-16 string with @name, appending @index.
+ * For example, L"Capsule0001"
+ * This function is expected to be called only from several places
+ * in EFI subsystem. A caller should ensure that the buffer have
+ * enough space for a resulting string, including L"\0".
+ * No strict check against the length will be done here.
+ *
+ * Return: A pointer to the next position after the created string
+ *		in @buffer, or NULL otherwise
+ */
+u16 *efi_create_indexed_name(u16 *buffer, const u16 *name, unsigned int index)
+{
+	u16 *p;
+	char index_buf[5];
+
+	u16_strcpy(buffer, name);
+	p = buffer + utf16_strnlen(name, SIZE_MAX);
+	sprintf(index_buf, "%04X", index);
+	utf8_utf16_strcpy(&p, index_buf);
+
+	return p;
+}
-- 
2.28.0