Changeset b84e114 in mainline

Timestamp:

2011-02-23T21:55:24Z (14 years ago)

Author:

Vojtech Horky <vojtechhorky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

d0dcfa80

Parents:

7eebe2a

Message:

Retrieval of USB string

Location:

uspace/lib/usb

Files:

• include/usb/request.h (modified) (1 diff)
• src/request.c (modified) (1 diff)

uspace/lib/usb/include/usb/request.h

@@ -109 +109 @@
 int usb_request_get_supported_languages(usb_endpoint_pipe_t *,
     l18_win_locales_t **, size_t *);
+int usb_request_get_string(usb_endpoint_pipe_t *, size_t, l18_win_locales_t,
+    char **);
 
 #endif

uspace/lib/usb/src/request.c

@@ -496 +496 @@
 }
 
+/** Get string (descriptor) from USB device.
+ *
+ * The string is returned in native encoding of the operating system.
+ * For HelenOS, that is UTF-8.
+ *
+ * @param[in] pipe Control endpoint pipe (session must be already started).
+ * @param[in] index String index (in native endianess).
+ * @param[in] lang String language (in native endianess).
+ * @param[out] string_ptr Where to store allocated string in native encoding.
+ * @return Error code.
+ */
+int usb_request_get_string(usb_endpoint_pipe_t *pipe,
+    size_t index, l18_win_locales_t lang, char **string_ptr)
+{
+        if (string_ptr == NULL) {
+                return EBADMEM;
+        }
+        /* Index is actually one byte value. */
+        if (index > 0xFF) {
+                return ERANGE;
+        }
+        /* Language is actually two byte value. */
+        if (lang > 0xFFFF) {
+                return ERANGE;
+        }
+
+        int rc;
+
+        /* Prepare dynamically allocated variables. */
+        uint8_t *string = NULL;
+        wchar_t *string_chars = NULL;
+
+        /* Get the actual descriptor. */
+        size_t string_size;
+        rc = usb_request_get_descriptor_alloc(pipe,
+            USB_REQUEST_TYPE_STANDARD, USB_DESCTYPE_STRING,
+            index, uint16_host2usb(lang),
+            (void **) &string, &string_size);
+        if (rc != EOK) {
+                goto leave;
+        }
+
+        if (string_size <= 2) {
+                rc =  EEMPTY;
+                goto leave;
+        }
+        /* Substract first 2 bytes (length and descriptor type). */
+        string_size -= 2;
+
+        /* Odd number of bytes - descriptor is broken? */
+        if ((string_size % 2) != 0) {
+                /* FIXME: shall we return with error or silently ignore? */
+                rc = ESTALL;
+                goto leave;
+        }
+
+        size_t string_char_count = string_size / 2;
+        string_chars = malloc(sizeof(wchar_t) * (string_char_count + 1));
+        if (string_chars == NULL) {
+                rc = ENOMEM;
+                goto leave;
+        }
+
+        /*
+         * Build a wide string.
+         * And do not forget to set NULL terminator (string descriptors
+         * do not have them).
+         */
+        size_t i;
+        for (i = 0; i < string_char_count; i++) {
+                uint16_t uni_char = (string[2 + 2 * i + 1] << 8)
+                    + string[2 + 2 * i];
+                string_chars[i] = uni_char;
+        }
+        string_chars[string_char_count] = 0;
+
+
+        /* Convert to normal string. */
+        char *str = wstr_to_astr(string_chars);
+        if (str == NULL) {
+                rc = ENOMEM;
+                goto leave;
+        }
+
+        *string_ptr = str;
+        rc = EOK;
+
+leave:
+        if (string != NULL) {
+                free(string);
+        }
+        if (string_chars != NULL) {
+                free(string_chars);
+        }
+
+        return rc;
+}
+
 /**
  * @}