Merge pull request #1478 from dhalbert/struct-compat

Improve struct compatibility with CPython

14 files changed, 477 insertions, 338 deletions

diff --git a/locale/ID.po b/locale/ID.po
index 8547493e9..cf317b42d 100644
--- a/locale/ID.po
+++ b/locale/ID.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -1363,9 +1363,9 @@ msgstr ""
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr ""
 
@@ -2649,10 +2649,20 @@ msgstr ""
 msgid "'S' and 'O' are not supported format types"
 msgstr ""
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Gagal untuk megalokasikan buffer RX dari %d byte"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr ""
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "buffers harus mempunyai panjang yang sama"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2739,24 +2749,24 @@ msgid ""
 "exit safe mode.\n"
 msgstr ""
 
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Panjang string UUID tidak valid"
+
 #~ msgid ""
-#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
+#~ "enough power for the whole circuit and press reset (after ejecting "
+#~ "CIRCUITPY).\n"
 #~ msgstr ""
-#~ "Silahkan taruh masalah disini dengan isi dari CIRCUITPY drive: anda \n"
-
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Parameter UUID tidak valid"
+#~ "tegangan cukup untuk semua sirkuit dan tekan reset (setelah mencabut "
+#~ "CIRCUITPY).\n"
 
 #~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
 #~ msgstr ""
 #~ "Sepertinya inti kode CircuitPython kita crash dengan sangat keras. Ups!\n"
 
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Parameter UUID tidak valid"
+
 #~ msgid ""
-#~ "enough power for the whole circuit and press reset (after ejecting "
-#~ "CIRCUITPY).\n"
+#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
 #~ msgstr ""
-#~ "tegangan cukup untuk semua sirkuit dan tekan reset (setelah mencabut "
-#~ "CIRCUITPY).\n"
-
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Panjang string UUID tidak valid"
+#~ "Silahkan taruh masalah disini dengan isi dari CIRCUITPY drive: anda \n"
diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 0a9e67685..4962a67ab 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -1330,9 +1330,9 @@ msgstr ""
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr ""
 
@@ -2612,10 +2612,19 @@ msgstr ""
 msgid "'S' and 'O' are not supported format types"
 msgstr ""
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr ""
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr ""
 
+#: shared-module/struct/__init__.c:179
+msgid "buffer size must match format"
+msgstr ""
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
diff --git a/locale/de_DE.po b/locale/de_DE.po
index 170104e9f..fe16a724b 100644
--- a/locale/de_DE.po
+++ b/locale/de_DE.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: Sebastian Plamauer\n"
 "Language-Team: \n"
@@ -1359,9 +1359,9 @@ msgstr ""
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr ""
 
@@ -2651,10 +2651,20 @@ msgstr "Kann '/' nicht remounten when USB aktiv ist"
 msgid "'S' and 'O' are not supported format types"
 msgstr ""
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Konnte keine RX Buffer mit %d allozieren"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr ""
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "Buffer müssen gleich lang sein"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2739,22 +2749,29 @@ msgid ""
 "exit safe mode.\n"
 msgstr ""
 
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Ungültige UUID-Stringlänge"
+#~ msgid "Can not add Characteristic."
+#~ msgstr "Kann das Merkmal nicht hinzufügen."
 
-#~ msgid "Can encode UUID into the advertisement packet."
-#~ msgstr "Kann UUID in das advertisement packet kodieren."
+#~ msgid "Can not add Service."
+#~ msgstr "Kann den Dienst nicht hinzufügen."
 
-#~ msgid ""
-#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
-#~ msgstr ""
-#~ "Bitte erstelle ein issue hier mit dem Inhalt deines CIRCUITPY-speichers:\n"
+#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
+#~ msgstr "CircuitPython ist abgestürzt. Ups!\n"
 
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Ungültiger UUID-Parameter"
+#~ msgid "Can not apply advertisement data. status: 0x%02x"
+#~ msgstr "Kann advertisement data nicht anwenden. Status: 0x%02x"
 
-#~ msgid "Invalid Service type"
-#~ msgstr "Ungültiger Diensttyp"
+#~ msgid "Cannot apply GAP parameters."
+#~ msgstr "Kann GAP Parameter nicht anwenden."
+
+#~ msgid "Can not encode UUID, to check length."
+#~ msgstr "Kann UUID nicht kodieren, um die Länge zu überprüfen."
+
+#~ msgid "Can not query for the device address."
+#~ msgstr "Kann nicht nach der Geräteadresse suchen."
+
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "Der Gerätename kann nicht im Stack verwendet werden."
 
 #~ msgid ""
 #~ "enough power for the whole circuit and press reset (after ejecting "
@@ -2763,26 +2780,19 @@ msgstr ""
 #~ "genug Strom für den ganzen Schaltkreis liefert und drücke reset (nach dem "
 #~ "sicheren Auswerfen von CIRCUITPY.)\n"
 
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "Der Gerätename kann nicht im Stack verwendet werden."
-
-#~ msgid "Can not query for the device address."
-#~ msgstr "Kann nicht nach der Geräteadresse suchen."
-
-#~ msgid "Can not encode UUID, to check length."
-#~ msgstr "Kann UUID nicht kodieren, um die Länge zu überprüfen."
-
-#~ msgid "Cannot apply GAP parameters."
-#~ msgstr "Kann GAP Parameter nicht anwenden."
+#~ msgid "Invalid Service type"
+#~ msgstr "Ungültiger Diensttyp"
 
-#~ msgid "Can not apply advertisement data. status: 0x%02x"
-#~ msgstr "Kann advertisement data nicht anwenden. Status: 0x%02x"
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Ungültiger UUID-Parameter"
 
-#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
-#~ msgstr "CircuitPython ist abgestürzt. Ups!\n"
+#~ msgid ""
+#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
+#~ msgstr ""
+#~ "Bitte erstelle ein issue hier mit dem Inhalt deines CIRCUITPY-speichers:\n"
 
-#~ msgid "Can not add Service."
-#~ msgstr "Kann den Dienst nicht hinzufügen."
+#~ msgid "Can encode UUID into the advertisement packet."
+#~ msgstr "Kann UUID in das advertisement packet kodieren."
 
-#~ msgid "Can not add Characteristic."
-#~ msgstr "Kann das Merkmal nicht hinzufügen."
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Ungültige UUID-Stringlänge"
diff --git a/locale/en_US.po b/locale/en_US.po
index acd5f54cb..33b1e614b 100644
--- a/locale/en_US.po
+++ b/locale/en_US.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -1330,9 +1330,9 @@ msgstr ""
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr ""
 
@@ -2612,10 +2612,19 @@ msgstr ""
 msgid "'S' and 'O' are not supported format types"
 msgstr ""
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr ""
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr ""
 
+#: shared-module/struct/__init__.c:179
+msgid "buffer size must match format"
+msgstr ""
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
diff --git a/locale/es.po b/locale/es.po
index 799fc68bf..6daa4170b 100644
--- a/locale/es.po
+++ b/locale/es.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-08-24 22:56-0500\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -1366,9 +1366,9 @@ msgstr "división por cero"
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr "buffer demasiado pequeño"
 
@@ -2673,10 +2673,20 @@ msgstr "No se puede volver a montar '/' cuando el USB esta activo."
 msgid "'S' and 'O' are not supported format types"
 msgstr "'S' y 'O' no son compatibles con los tipos de formato"
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Falló la asignación del buffer RX de %d bytes"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr "demasiados argumentos provistos con el formato dado"
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "los buffers deben de tener la misma longitud"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2771,31 +2781,32 @@ msgstr ""
 "El botón reset fue presionado mientras arrancaba CircuitPython. Presiona "
 "otra vez para salir del modo seguro.\n"
 
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Longitud de string UUID inválida"
+#~ msgid "Baud rate too high for this SPI peripheral"
+#~ msgstr "Baud rate demasiado alto para este periférico SPI"
 
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Parámetro UUID inválido"
+#~ msgid "Invalid Service type"
+#~ msgstr "Tipo de Servicio inválido"
 
-#~ msgid "Can not query for the device address."
-#~ msgstr "No se puede consultar la dirección del dispositivo."
+#~ msgid "Can not apply advertisement data. status: 0x%02x"
+#~ msgstr "No se puede aplicar los datos de anuncio. status: 0x%02x"
 
-#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
-#~ msgstr ""
-#~ "Parece que nuestro código CircuitPython dejó de funcionar. Whoops!\n"
+#~ msgid "Can encode UUID into the advertisement packet."
+#~ msgstr "Se puede codificar el UUID en el paquete de anuncio."
 
-#~ msgid "Cannot set PPCP parameters."
-#~ msgstr "No se pueden establecer los parámetros PPCP."
+#~ msgid "Can not encode UUID, to check length."
+#~ msgstr "No se puede codificar el UUID, para revisar la longitud."
 
-#~ msgid ""
-#~ "enough power for the whole circuit and press reset (after ejecting "
-#~ "CIRCUITPY).\n"
-#~ msgstr ""
-#~ "suficiente poder para todo el circuito y presiona reset (después de "
-#~ "expulsar CIRCUITPY).\n"
+#~ msgid "Cannot apply GAP parameters."
+#~ msgstr "No se pueden aplicar los parámetros GAP."
 
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "No se puede aplicar el nombre del dispositivo en el stack."
+#~ msgid "Can not add Service."
+#~ msgstr "No se puede agregar el Servicio."
+
+#~ msgid "Wrong number of bytes provided"
+#~ msgstr "Numero erroneo de bytes dados"
+
+#~ msgid "Wrong address length"
+#~ msgstr "Longitud de address erronea"
 
 #, fuzzy
 #~ msgid ""
@@ -2804,29 +2815,28 @@ msgstr ""
 #~ "Por favor registra un issue en la siguiente URL con el contenidos de tu "
 #~ "unidad de almacenamiento CIRCUITPY:\n"
 
-#~ msgid "Wrong address length"
-#~ msgstr "Longitud de address erronea"
-
-#~ msgid "Wrong number of bytes provided"
-#~ msgstr "Numero erroneo de bytes dados"
-
-#~ msgid "Can not add Service."
-#~ msgstr "No se puede agregar el Servicio."
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "No se puede aplicar el nombre del dispositivo en el stack."
 
-#~ msgid "Cannot apply GAP parameters."
-#~ msgstr "No se pueden aplicar los parámetros GAP."
+#~ msgid ""
+#~ "enough power for the whole circuit and press reset (after ejecting "
+#~ "CIRCUITPY).\n"
+#~ msgstr ""
+#~ "suficiente poder para todo el circuito y presiona reset (después de "
+#~ "expulsar CIRCUITPY).\n"
 
-#~ msgid "Can not encode UUID, to check length."
-#~ msgstr "No se puede codificar el UUID, para revisar la longitud."
+#~ msgid "Cannot set PPCP parameters."
+#~ msgstr "No se pueden establecer los parámetros PPCP."
 
-#~ msgid "Can encode UUID into the advertisement packet."
-#~ msgstr "Se puede codificar el UUID en el paquete de anuncio."
+#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
+#~ msgstr ""
+#~ "Parece que nuestro código CircuitPython dejó de funcionar. Whoops!\n"
 
-#~ msgid "Can not apply advertisement data. status: 0x%02x"
-#~ msgstr "No se puede aplicar los datos de anuncio. status: 0x%02x"
+#~ msgid "Can not query for the device address."
+#~ msgstr "No se puede consultar la dirección del dispositivo."
 
-#~ msgid "Invalid Service type"
-#~ msgstr "Tipo de Servicio inválido"
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Parámetro UUID inválido"
 
-#~ msgid "Baud rate too high for this SPI peripheral"
-#~ msgstr "Baud rate demasiado alto para este periférico SPI"
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Longitud de string UUID inválida"
diff --git a/locale/fil.po b/locale/fil.po
index 6b3e408c7..8d112726e 100644
--- a/locale/fil.po
+++ b/locale/fil.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-12-20 22:15-0800\n"
 "Last-Translator: Timothy <me@timothygarcia.ca>\n"
 "Language-Team: fil\n"
@@ -1367,9 +1367,9 @@ msgstr "dibisyon ng zero"
 msgid "schedule stack full"
 msgstr "puno na ang schedule stack"
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr "masyadong maliit ang buffer"
 
@@ -2679,10 +2679,20 @@ msgstr "Hindi ma-remount '/' kapag aktibo ang USB."
 msgid "'S' and 'O' are not supported format types"
 msgstr "Ang 'S' at 'O' ay hindi suportadong uri ng format"
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Nabigong ilaan ang RX buffer ng %d bytes"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr "masyadong maraming mga argumento na ibinigay sa ibinigay na format"
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "aarehas na haba dapat ang buffer slices"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2777,31 +2787,33 @@ msgstr ""
 "Ang reset button ay pinindot habang nag boot ang CircuitPython. Pindutin "
 "ulit para lumabas sa safe mode.\n"
 
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Mali ang UUID string length"
+#, fuzzy
+#~ msgid "palette must be displayio.Palette"
+#~ msgstr "ang palette ay dapat 32 bytes ang haba"
 
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Mali ang UUID parameter"
+#~ msgid "Invalid Service type"
+#~ msgstr "Mali ang tipo ng serbisyo"
 
-#~ msgid "Can not query for the device address."
-#~ msgstr "Hindi maaaring mag-query para sa address ng device."
+#~ msgid "Can not apply advertisement data. status: 0x%02x"
+#~ msgstr "Hindi ma i-apply ang advertisement data. status: 0x%02x"
 
-#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
-#~ msgstr ""
-#~ "Mukhang ang core CircuitPython code ay nag-crash ng malakas. Aray!\n"
+#~ msgid "Can encode UUID into the advertisement packet."
+#~ msgstr "Maaring i-encode ang UUID sa advertisement packet."
 
-#~ msgid "Cannot set PPCP parameters."
-#~ msgstr "Hindi ma-set ang PPCP parameters."
+#~ msgid "Can not encode UUID, to check length."
+#~ msgstr "Hindi ma-encode UUID, para suriin ang haba."
 
-#~ msgid ""
-#~ "enough power for the whole circuit and press reset (after ejecting "
-#~ "CIRCUITPY).\n"
-#~ msgstr ""
-#~ "ay nagbibigay ng sapat na power para sa buong circuit at i-press ang "
-#~ "reset (pagkatapos i-eject ang CIRCUITPY).\n"
+#~ msgid "Cannot apply GAP parameters."
+#~ msgstr "Hindi ma-apply ang GAP parameters."
 
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "Hindi maaaring ma-aplay ang device name sa stack."
+#~ msgid "Can not add Service."
+#~ msgstr "Hindi maidaragdag ang serbisyo."
+
+#~ msgid "Wrong number of bytes provided"
+#~ msgstr "Mali ang bilang ng bytes"
+
+#~ msgid "Wrong address length"
+#~ msgstr "Mali ang address length"
 
 #~ msgid ""
 #~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
@@ -2809,30 +2821,28 @@ msgstr ""
 #~ "Mag-file ng isang isyu dito gamit ang mga nilalaman ng iyong CIRCUITPY "
 #~ "drive:\n"
 
-#~ msgid "Wrong address length"
-#~ msgstr "Mali ang address length"
-
-#~ msgid "Wrong number of bytes provided"
-#~ msgstr "Mali ang bilang ng bytes"
-
-#~ msgid "Can not add Service."
-#~ msgstr "Hindi maidaragdag ang serbisyo."
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "Hindi maaaring ma-aplay ang device name sa stack."
 
-#~ msgid "Cannot apply GAP parameters."
-#~ msgstr "Hindi ma-apply ang GAP parameters."
+#~ msgid ""
+#~ "enough power for the whole circuit and press reset (after ejecting "
+#~ "CIRCUITPY).\n"
+#~ msgstr ""
+#~ "ay nagbibigay ng sapat na power para sa buong circuit at i-press ang "
+#~ "reset (pagkatapos i-eject ang CIRCUITPY).\n"
 
-#~ msgid "Can not encode UUID, to check length."
-#~ msgstr "Hindi ma-encode UUID, para suriin ang haba."
+#~ msgid "Cannot set PPCP parameters."
+#~ msgstr "Hindi ma-set ang PPCP parameters."
 
-#~ msgid "Can encode UUID into the advertisement packet."
-#~ msgstr "Maaring i-encode ang UUID sa advertisement packet."
+#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
+#~ msgstr ""
+#~ "Mukhang ang core CircuitPython code ay nag-crash ng malakas. Aray!\n"
 
-#~ msgid "Can not apply advertisement data. status: 0x%02x"
-#~ msgstr "Hindi ma i-apply ang advertisement data. status: 0x%02x"
+#~ msgid "Can not query for the device address."
+#~ msgstr "Hindi maaaring mag-query para sa address ng device."
 
-#~ msgid "Invalid Service type"
-#~ msgstr "Mali ang tipo ng serbisyo"
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Mali ang UUID parameter"
 
-#, fuzzy
-#~ msgid "palette must be displayio.Palette"
-#~ msgstr "ang palette ay dapat 32 bytes ang haba"
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Mali ang UUID string length"
diff --git a/locale/fr.po b/locale/fr.po
index 236ce4345..2110a4c6e 100644
--- a/locale/fr.po
+++ b/locale/fr.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: 0.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-12-23 20:05+0100\n"
 "Last-Translator: Pierrick Couturier <arofarn@arofarn.info>\n"
 "Language-Team: fr\n"
@@ -1366,9 +1366,9 @@ msgstr "division par zéro"
 msgid "schedule stack full"
 msgstr "pile de plannification pleine"
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr "tampon trop petit"
 
@@ -2703,10 +2703,20 @@ msgstr "'/' ne peut être remonté quand l'USB est actif."
 msgid "'S' and 'O' are not supported format types"
 msgstr "'S' et 'O' ne sont pas des types de format supportés"
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Echec de l'allocation de %d octets du tampon RX"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr "trop d'arguments fournis avec ce format"
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "les slices de tampon doivent être de longueurs égales"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2806,63 +2816,63 @@ msgstr ""
 "Le bouton 'reset' a été appuyé pendant le démarrage de CircuitPython. "
 "Appuyer denouveau pour quitter de le mode sans-échec.\n"
 
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Longeur de chaîne UUID invalide"
-
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Paramètre UUID invalide"
-
-#, fuzzy
-#~ msgid "palette must be displayio.Palette"
-#~ msgstr "la palette doit être une displayio.Palette"
+#~ msgid "Cannot set PPCP parameters."
+#~ msgstr "Impossible d'appliquer les paramètres PPCP"
 
-#, fuzzy
-#~ msgid "value_size must be power of two"
-#~ msgstr "value_size doit être une puissance de 2"
+#~ msgid "Can not add Characteristic."
+#~ msgstr "Impossible d'ajouter la Characteristic."
 
-#~ msgid "Cannot apply GAP parameters."
-#~ msgstr "Impossible d'appliquer les paramètres GAP"
+#~ msgid "Can not query for the device address."
+#~ msgstr "Impossible d'obtenir l'adresse du périphérique"
 
-#~ msgid "Invalid Service type"
-#~ msgstr "Type de service invalide"
+#~ msgid "Can not add Service."
+#~ msgstr "Impossible d'ajouter le Service"
 
 #~ msgid ""
-#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
+#~ "enough power for the whole circuit and press reset (after ejecting "
+#~ "CIRCUITPY).\n"
 #~ msgstr ""
-#~ "SVP, remontez le problème là avec le contenu du lecteur CIRCUITPY:\n"
+#~ "assez de puissance pour l'ensemble du circuit et appuyez sur "
+#~ "'reset' (après avoir éjecter CIRCUITPY).\n"
 
-#~ msgid "Can not encode UUID, to check length."
-#~ msgstr "Impossible d'encoder l'UUID pour vérifier la longueur."
+#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
+#~ msgstr ""
+#~ "Il semblerait que votre code CircuitPython a durement planté. Oups!\n"
 
-#~ msgid "Wrong address length"
-#~ msgstr "Mauvaise longueur d'adresse"
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "Impossible d'appliquer le nom de périphérique dans la pile"
 
 #, fuzzy
 #~ msgid "Wrong number of bytes provided"
 #~ msgstr "mauvais nombre d'octets fourni'"
 
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "Impossible d'appliquer le nom de périphérique dans la pile"
+#~ msgid "Wrong address length"
+#~ msgstr "Mauvaise longueur d'adresse"
 
-#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
-#~ msgstr ""
-#~ "Il semblerait que votre code CircuitPython a durement planté. Oups!\n"
+#~ msgid "Can not encode UUID, to check length."
+#~ msgstr "Impossible d'encoder l'UUID pour vérifier la longueur."
 
 #~ msgid ""
-#~ "enough power for the whole circuit and press reset (after ejecting "
-#~ "CIRCUITPY).\n"
+#~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
 #~ msgstr ""
-#~ "assez de puissance pour l'ensemble du circuit et appuyez sur "
-#~ "'reset' (après avoir éjecter CIRCUITPY).\n"
+#~ "SVP, remontez le problème là avec le contenu du lecteur CIRCUITPY:\n"
 
-#~ msgid "Can not add Service."
-#~ msgstr "Impossible d'ajouter le Service"
+#~ msgid "Invalid Service type"
+#~ msgstr "Type de service invalide"
 
-#~ msgid "Can not query for the device address."
-#~ msgstr "Impossible d'obtenir l'adresse du périphérique"
+#~ msgid "Cannot apply GAP parameters."
+#~ msgstr "Impossible d'appliquer les paramètres GAP"
 
-#~ msgid "Can not add Characteristic."
-#~ msgstr "Impossible d'ajouter la Characteristic."
+#, fuzzy
+#~ msgid "value_size must be power of two"
+#~ msgstr "value_size doit être une puissance de 2"
 
-#~ msgid "Cannot set PPCP parameters."
-#~ msgstr "Impossible d'appliquer les paramètres PPCP"
+#, fuzzy
+#~ msgid "palette must be displayio.Palette"
+#~ msgstr "la palette doit être une displayio.Palette"
+
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Paramètre UUID invalide"
+
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Longeur de chaîne UUID invalide"
diff --git a/locale/it_IT.po b/locale/it_IT.po
index 225e51cf5..cb413f073 100644
--- a/locale/it_IT.po
+++ b/locale/it_IT.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-10-02 16:27+0200\n"
 "Last-Translator: Enrico Paganin <enrico.paganin@mail.com>\n"
 "Language-Team: \n"
@@ -1366,9 +1366,9 @@ msgstr "divisione per zero"
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr "buffer troppo piccolo"
 
@@ -2685,10 +2685,20 @@ msgstr "Non è possibile rimontare '/' mentre l'USB è attiva."
 msgid "'S' and 'O' are not supported format types"
 msgstr "'S' e 'O' non sono formati supportati"
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Fallita allocazione del buffer RX di %d byte"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr "troppi argomenti forniti con il formato specificato"
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "slice del buffer devono essere della stessa lunghezza"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2775,27 +2785,35 @@ msgid ""
 "exit safe mode.\n"
 msgstr ""
 
-#~ msgid "Invalid UUID string length"
-#~ msgstr "Lunghezza della stringa UUID non valida"
+#~ msgid "Cannot apply GAP parameters."
+#~ msgstr "Impossibile applicare i parametri GAP."
 
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Parametro UUID non valido"
+#~ msgid ""
+#~ "enough power for the whole circuit and press reset (after ejecting "
+#~ "CIRCUITPY).\n"
+#~ msgstr ""
+#~ "abbastanza potenza per l'intero circuito e premere reset (dopo aver "
+#~ "espulso CIRCUITPY).\n"
 
-#~ msgid "Invalid Service type"
-#~ msgstr "Tipo di servizio non valido"
+#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
+#~ msgstr ""
+#~ "Sembra che il codice del core di CircuitPython sia crashato malamente. "
+#~ "Whoops!\n"
 
-#, fuzzy
-#~ msgid "Wrong number of bytes provided"
-#~ msgstr "numero di argomenti errato"
+#~ msgid "Can not query for the device address."
+#~ msgstr "Non è possibile trovare l'indirizzo del dispositivo."
 
-#~ msgid "Cannot set PPCP parameters."
-#~ msgstr "Impossibile impostare i parametri PPCP."
+#~ msgid "Can not apply advertisement data. status: 0x%02x"
+#~ msgstr "Impossible inserire dati advertisement. status: 0x%02x"
 
-#~ msgid "Can not add Characteristic."
-#~ msgstr "Non è possibile aggiungere Characteristic."
+#~ msgid "Can not add Service."
+#~ msgstr "Non è possibile aggiungere Service."
 
-#~ msgid "Can not encode UUID, to check length."
-#~ msgstr "Non è possibile codificare l'UUID, lunghezza da controllare."
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "Non è possibile inserire il nome del dipositivo nella lista."
+
+#~ msgid "Can encode UUID into the advertisement packet."
+#~ msgstr "È possibile codificare l'UUID nel pacchetto di advertisement."
 
 #~ msgid ""
 #~ "Please file an issue here with the contents of your CIRCUITPY drive:\n"
@@ -2803,32 +2821,24 @@ msgstr ""
 #~ "Ti preghiamo di compilare una issue con il contenuto del tuo drie "
 #~ "CIRCUITPY:\n"
 
-#~ msgid "Can encode UUID into the advertisement packet."
-#~ msgstr "È possibile codificare l'UUID nel pacchetto di advertisement."
-
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "Non è possibile inserire il nome del dipositivo nella lista."
+#~ msgid "Can not encode UUID, to check length."
+#~ msgstr "Non è possibile codificare l'UUID, lunghezza da controllare."
 
-#~ msgid "Can not add Service."
-#~ msgstr "Non è possibile aggiungere Service."
+#~ msgid "Can not add Characteristic."
+#~ msgstr "Non è possibile aggiungere Characteristic."
 
-#~ msgid "Can not apply advertisement data. status: 0x%02x"
-#~ msgstr "Impossible inserire dati advertisement. status: 0x%02x"
+#~ msgid "Cannot set PPCP parameters."
+#~ msgstr "Impossibile impostare i parametri PPCP."
 
-#~ msgid "Can not query for the device address."
-#~ msgstr "Non è possibile trovare l'indirizzo del dispositivo."
+#, fuzzy
+#~ msgid "Wrong number of bytes provided"
+#~ msgstr "numero di argomenti errato"
 
-#~ msgid "Looks like our core CircuitPython code crashed hard. Whoops!\n"
-#~ msgstr ""
-#~ "Sembra che il codice del core di CircuitPython sia crashato malamente. "
-#~ "Whoops!\n"
+#~ msgid "Invalid Service type"
+#~ msgstr "Tipo di servizio non valido"
 
-#~ msgid ""
-#~ "enough power for the whole circuit and press reset (after ejecting "
-#~ "CIRCUITPY).\n"
-#~ msgstr ""
-#~ "abbastanza potenza per l'intero circuito e premere reset (dopo aver "
-#~ "espulso CIRCUITPY).\n"
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Parametro UUID non valido"
 
-#~ msgid "Cannot apply GAP parameters."
-#~ msgstr "Impossibile applicare i parametri GAP."
+#~ msgid "Invalid UUID string length"
+#~ msgstr "Lunghezza della stringa UUID non valida"
diff --git a/locale/pt_BR.po b/locale/pt_BR.po
index a0d81d182..457850a55 100644
--- a/locale/pt_BR.po
+++ b/locale/pt_BR.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-01-20 17:33-0800\n"
+"POT-Creation-Date: 2019-01-20 22:46-0500\n"
 "PO-Revision-Date: 2018-10-02 21:14-0000\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -1348,9 +1348,9 @@ msgstr "divisão por zero"
 msgid "schedule stack full"
 msgstr ""
 
-#: py/modstruct.c:145 py/modstruct.c:153 py/modstruct.c:234 py/modstruct.c:244
-#: shared-bindings/struct/__init__.c:103 shared-bindings/struct/__init__.c:145
-#: shared-module/struct/__init__.c:91 shared-module/struct/__init__.c:175
+#: py/modstruct.c:148 py/modstruct.c:156 py/modstruct.c:244 py/modstruct.c:254
+#: shared-bindings/struct/__init__.c:102 shared-bindings/struct/__init__.c:161
+#: shared-module/struct/__init__.c:183
 msgid "buffer too small"
 msgstr ""
 
@@ -2642,10 +2642,20 @@ msgstr "Não é possível remontar '/' enquanto o USB estiver ativo."
 msgid "'S' and 'O' are not supported format types"
 msgstr "'S' e 'O' não são tipos de formato suportados"
 
-#: shared-module/struct/__init__.c:83
+#: shared-module/struct/__init__.c:128
+#, fuzzy, c-format
+msgid "unpack requires a buffer of %d bytes"
+msgstr "Falha ao alocar buffer RX de %d bytes"
+
+#: shared-module/struct/__init__.c:136
 msgid "too many arguments provided with the given format"
 msgstr "Muitos argumentos fornecidos com o formato dado"
 
+#: shared-module/struct/__init__.c:179
+#, fuzzy
+msgid "buffer size must match format"
+msgstr "buffers devem ser o mesmo tamanho"
+
 #: shared-module/usb_hid/Device.c:45
 #, c-format
 msgid "Buffer incorrect size. Should be %d bytes."
@@ -2726,32 +2736,32 @@ msgid ""
 "exit safe mode.\n"
 msgstr ""
 
-#~ msgid "Can not query for the device address."
-#~ msgstr "Não é possível consultar o endereço do dispositivo."
-
-#~ msgid "Invalid Service type"
-#~ msgstr "Tipo de serviço inválido"
+#~ msgid "Cannot set PPCP parameters."
+#~ msgstr "Não é possível definir parâmetros PPCP."
 
-#~ msgid "Can not apply device name in the stack."
-#~ msgstr "Não é possível aplicar o nome do dispositivo na pilha."
+#~ msgid "Can encode UUID into the advertisement packet."
+#~ msgstr "Pode codificar o UUID no pacote de anúncios."
 
-#~ msgid "Baud rate too high for this SPI peripheral"
-#~ msgstr "Taxa de transmissão muito alta para esse periférico SPI"
+#~ msgid "Can not apply advertisement data. status: 0x%02x"
+#~ msgstr "Não é possível aplicar dados de anúncio. status: 0x%02x"
 
-#~ msgid "Can not add Characteristic."
-#~ msgstr "Não é possível adicionar Característica."
+#~ msgid "Invalid UUID parameter"
+#~ msgstr "Parâmetro UUID inválido"
 
 #~ msgid "Cannot apply GAP parameters."
 #~ msgstr "Não é possível aplicar parâmetros GAP."
 
-#~ msgid "Invalid UUID parameter"
-#~ msgstr "Parâmetro UUID inválido"
+#~ msgid "Can not add Characteristic."
+#~ msgstr "Não é possível adicionar Característica."
 
-#~ msgid "Can not apply advertisement data. status: 0x%02x"
-#~ msgstr "Não é possível aplicar dados de anúncio. status: 0x%02x"
+#~ msgid "Baud rate too high for this SPI peripheral"
+#~ msgstr "Taxa de transmissão muito alta para esse periférico SPI"
 
-#~ msgid "Can encode UUID into the advertisement packet."
-#~ msgstr "Pode codificar o UUID no pacote de anúncios."
+#~ msgid "Can not apply device name in the stack."
+#~ msgstr "Não é possível aplicar o nome do dispositivo na pilha."
 
-#~ msgid "Cannot set PPCP parameters."
-#~ msgstr "Não é possível definir parâmetros PPCP."
+#~ msgid "Invalid Service type"
+#~ msgstr "Tipo de serviço inválido"
+
+#~ msgid "Can not query for the device address."
+#~ msgstr "Não é possível consultar o endereço do dispositivo."
diff --git a/py/binary.c b/py/binary.c
index ca851c936..9c3a49e8f 100644
--- a/py/binary.c
+++ b/py/binary.c
@@ -49,7 +49,7 @@ size_t mp_binary_get_size(char struct_type, char val_type, mp_uint_t *palign) {
     switch (struct_type) {
         case '<': case '>':
             switch (val_type) {
-                case 'b': case 'B':
+                case 'b': case 'B': case 'x':
                     size = 1; break;
                 case 'h': case 'H':
                     size = 2; break;
@@ -79,7 +79,7 @@ size_t mp_binary_get_size(char struct_type, char val_type, mp_uint_t *palign) {
             // particular (or any) ABI.
             switch (val_type) {
                 case BYTEARRAY_TYPECODE:
-                case 'b': case 'B':
+                case 'b': case 'B': case 'x':
                     align = size = 1; break;
                 case 'h': case 'H':
                     align = alignof(short);
@@ -126,6 +126,7 @@ mp_obj_t mp_binary_get_val_array(char typecode, void *p, mp_uint_t index) {
             break;
         case BYTEARRAY_TYPECODE:
         case 'B':
+        case 'x':   // value will be discarded
             val = ((unsigned char*)p)[index];
             break;
         case 'h':
@@ -364,6 +365,8 @@ void mp_binary_set_val_array_from_int(char typecode, void *p, mp_uint_t index, m
         case 'B':
             ((unsigned char*)p)[index] = val;
             break;
+        case 'x':
+            ((unsigned char*)p)[index] = 0;
         case 'h':
             ((short*)p)[index] = val;
             break;
diff --git a/py/modstruct.c b/py/modstruct.c
index 3f1b2f8b8..a238d3935 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -97,7 +97,10 @@ STATIC size_t calc_size_items(const char *fmt, size_t *total_sz) {
             total_cnt += 1;
             size += cnt;
         } else {
-            total_cnt += cnt;
+            // Pad bytes are skipped and don't get included in the item count.
+            if (*fmt != 'x') {
+                total_cnt += cnt;
+            }
             mp_uint_t align;
             size_t sz = mp_binary_get_size(fmt_type, *fmt, &align);
             while (cnt--) {
@@ -166,7 +169,10 @@ STATIC mp_obj_t struct_unpack_from(size_t n_args, const mp_obj_t *args) {
         } else {
             while (cnt--) {
                 item = mp_binary_get_val(fmt_type, *fmt, &p);
-                res->items[i++] = item;
+                // Pad bytes ('x') are just skipped.
+                if (*fmt != 'x') {
+                    res->items[i++] = item;
+                }
             }
         }
         fmt++;
@@ -204,7 +210,11 @@ STATIC void struct_pack_into_internal(mp_obj_t fmt_in, byte *p, size_t n_args, c
         } else {
             // If we run out of args then we just finish; CPython would raise struct.error
             while (cnt-- && i < n_args) {
-                mp_binary_set_val(fmt_type, *fmt, args[i++], &p);
+                mp_binary_set_val(fmt_type, *fmt, args[i], &p);
+                // Pad bytes don't have a corresponding argument.
+                if (*fmt != 'x') {
+                    i++;
+                }
             }
         }
         fmt++;
diff --git a/shared-bindings/struct/__init__.c b/shared-bindings/struct/__init__.c
index 093597785..9240a15bb 100644
--- a/shared-bindings/struct/__init__.c
+++ b/shared-bindings/struct/__init__.c
@@ -51,7 +51,7 @@
 //|
 //| Supported size/byte order prefixes: *@*, *<*, *>*, *!*.
 //|
-//| Supported format codes: *b*, *B*, *h*, *H*, *i*, *I*, *l*, *L*, *q*, *Q*,
+//| Supported format codes: *b*, *B*, *x*, *h*, *H*, *i*, *I*, *l*, *L*, *q*, *Q*,
 //| *s*, *P*, *f*, *d* (the latter 2 depending on the floating-point support).
 //|
 
@@ -74,7 +74,6 @@ MP_DEFINE_CONST_FUN_OBJ_1(struct_calcsize_obj, struct_calcsize);
 //|
 
 STATIC mp_obj_t struct_pack(size_t n_args, const mp_obj_t *args) {
-    // TODO: "The arguments must match the values required by the format exactly."
     mp_int_t size = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
     vstr_t vstr;
     vstr_init_len(&vstr, size);
@@ -115,49 +114,67 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_pack_into_obj, 3, MP_OBJ_FUN_ARGS_MAX
 //| .. function:: unpack(fmt, data)
 //|
 //|   Unpack from the data according to the format string fmt. The return value
-//|   is a tuple of the unpacked values.
+//|   is a tuple of the unpacked values. The buffer size must match the size
+//|   required by the format.
 //|
 
-//| .. function:: unpack_from(fmt, data, offset)
+STATIC mp_obj_t struct_unpack(size_t n_args, const mp_obj_t *args) {
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
+    byte *p = bufinfo.buf;
+    byte *end_p = &p[bufinfo.len];
+
+    // true means check the size must be exactly right.
+    return MP_OBJ_FROM_PTR(shared_modules_struct_unpack_from(args[0] , p, end_p, true));
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_unpack_obj, 2, 3, struct_unpack);
+
+//| .. function:: unpack_from(fmt, data, offset=0)
 //|
 //|   Unpack from the data starting at offset according to the format string fmt.
 //|   offset may be negative to count from the end of buffer. The return value is
-//|   a tuple of the unpacked values.
+//|   a tuple of the unpacked values. The buffer size must be at least as big
+//|   as the size required by the form.
 //|
 
-STATIC mp_obj_t struct_unpack_from(size_t n_args, const mp_obj_t *args) {
-    // unpack requires that the buffer be exactly the right size.
-    // unpack_from requires that the buffer be "big enough".
-    // Since we implement unpack and unpack_from using the same function
-    // we relax the "exact" requirement, and only implement "big enough".
+STATIC mp_obj_t struct_unpack_from(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_format, ARG_buffer, ARG_offset };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_format, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_offset, MP_ARG_INT, {.u_int = 0} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
     mp_buffer_info_t bufinfo;
-    mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
+    mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_READ);
     byte *p = bufinfo.buf;
     byte *end_p = &p[bufinfo.len];
 
-    if (n_args > 2) {
-        mp_int_t offset = mp_obj_get_int(args[2]);
-        // offset arg provided
+    mp_int_t offset = args[ARG_offset].u_int;
+    if (offset < 0) {
+        // negative offsets are relative to the end of the buffer
+        offset = bufinfo.len + offset;
         if (offset < 0) {
-            // negative offsets are relative to the end of the buffer
-            offset = bufinfo.len + offset;
-            if (offset < 0) {
-                mp_raise_RuntimeError(translate("buffer too small"));
-            }
+            mp_raise_RuntimeError(translate("buffer too small"));
         }
-        p += offset;
     }
+    p += offset;
 
-    return MP_OBJ_FROM_PTR(shared_modules_struct_unpack_from(args[0] , p, end_p));
+    // false means the size doesn't have to be exact. struct.unpack_from() only requires
+    // that be buffer be big enough.
+    return MP_OBJ_FROM_PTR(shared_modules_struct_unpack_from(args[ARG_format].u_obj, p, end_p, false));
 }
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_unpack_from_obj, 2, 3, struct_unpack_from);
+MP_DEFINE_CONST_FUN_OBJ_KW(struct_unpack_from_obj, 0, struct_unpack_from);
 
 STATIC const mp_rom_map_elem_t mp_module_struct_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_struct) },
     { MP_ROM_QSTR(MP_QSTR_calcsize), MP_ROM_PTR(&struct_calcsize_obj) },
     { MP_ROM_QSTR(MP_QSTR_pack), MP_ROM_PTR(&struct_pack_obj) },
     { MP_ROM_QSTR(MP_QSTR_pack_into), MP_ROM_PTR(&struct_pack_into_obj) },
-    { MP_ROM_QSTR(MP_QSTR_unpack), MP_ROM_PTR(&struct_unpack_from_obj) },
+    { MP_ROM_QSTR(MP_QSTR_unpack), MP_ROM_PTR(&struct_unpack_obj) },
     { MP_ROM_QSTR(MP_QSTR_unpack_from), MP_ROM_PTR(&struct_unpack_from_obj) },
 };
 
diff --git a/shared-bindings/struct/__init__.h b/shared-bindings/struct/__init__.h
index c4e867aaa..a7e72b11c 100644
--- a/shared-bindings/struct/__init__.h
+++ b/shared-bindings/struct/__init__.h
@@ -29,6 +29,6 @@
 
 void shared_modules_struct_pack_into(mp_obj_t fmt_in, byte *p, byte* end_p, size_t n_args, const mp_obj_t *args);
 mp_uint_t shared_modules_struct_calcsize(mp_obj_t fmt_in);
-mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byte *end_p);
+mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byte *end_p, bool exact_size);
 
 #endif  // MICROPY_INCLUDED_SHARED_BINDINGS_RANDOM___INIT___H
diff --git a/shared-module/struct/__init__.c b/shared-module/struct/__init__.c
index 78c04f07b..28e7c0c3f 100644
--- a/shared-module/struct/__init__.c
+++ b/shared-module/struct/__init__.c
@@ -71,45 +71,6 @@ mp_uint_t get_fmt_num(const char **p) {
     return val;
 }
 
-void shared_modules_struct_pack_into(mp_obj_t fmt_in, byte *p, byte* end_p, size_t n_args, const mp_obj_t *args) {
-    const char *fmt = mp_obj_str_get_str(fmt_in);
-    char fmt_type = get_fmt_type(&fmt);
-
-    size_t i;
-    for (i = 0; i < n_args;) {
-        mp_uint_t sz = 1;
-        if (*fmt == '\0') {
-            // more arguments given than used by format string; CPython raises struct.error here
-            mp_raise_RuntimeError(translate("too many arguments provided with the given format"));
-        }
-        struct_validate_format(*fmt);
-
-        if (unichar_isdigit(*fmt)) {
-            sz = get_fmt_num(&fmt);
-        }
-        if (p + sz > end_p) {
-            mp_raise_RuntimeError(translate("buffer too small"));
-        }
-
-        if (*fmt == 's') {
-            mp_buffer_info_t bufinfo;
-            mp_get_buffer_raise(args[i++], &bufinfo, MP_BUFFER_READ);
-            mp_uint_t to_copy = sz;
-            if (bufinfo.len < to_copy) {
-                to_copy = bufinfo.len;
-            }
-            memcpy(p, bufinfo.buf, to_copy);
-            memset(p + to_copy, 0, sz - to_copy);
-            p += sz;
-        } else {
-            while (sz--) {
-                mp_binary_set_val(fmt_type, *fmt, args[i++], &p);
-            }
-        }
-        fmt++;
-    }
-}
-
 mp_uint_t calcsize_items(const char *fmt) {
     mp_uint_t cnt = 0;
     while (*fmt) {
@@ -120,7 +81,10 @@ mp_uint_t calcsize_items(const char *fmt) {
                 num = 1;
             }
         }
-        cnt += num;
+        // Pad bytes are skipped and don't get included in the item count.
+        if (*fmt != 'x') {
+            cnt += num;
+        }
         fmt++;
     }
     return cnt;
@@ -155,14 +119,71 @@ mp_uint_t shared_modules_struct_calcsize(mp_obj_t fmt_in) {
     return size;
 }
 
+void shared_modules_struct_pack_into(mp_obj_t fmt_in, byte *p, byte* end_p, size_t n_args, const mp_obj_t *args) {
+    const char *fmt = mp_obj_str_get_str(fmt_in);
+    char fmt_type = get_fmt_type(&fmt);
+    const mp_uint_t total_sz = shared_modules_struct_calcsize(fmt_in);
+
+    if (p + total_sz != end_p) {
+        mp_raise_msg_varg(&mp_type_RuntimeError, translate("unpack requires a buffer of %d bytes"), total_sz);
+    }
+
+    size_t i;
+    for (i = 0; i < n_args;) {
+        mp_uint_t sz = 1;
+        if (*fmt == '\0') {
+            // more arguments given than used by format string; CPython raises struct.error here
+            mp_raise_RuntimeError(translate("too many arguments provided with the given format"));
+        }
+        struct_validate_format(*fmt);
+
+        if (unichar_isdigit(*fmt)) {
+            sz = get_fmt_num(&fmt);
+        }
+
+        if (*fmt == 's') {
+            mp_buffer_info_t bufinfo;
+            mp_get_buffer_raise(args[i++], &bufinfo, MP_BUFFER_READ);
+            mp_uint_t to_copy = sz;
+            if (bufinfo.len < to_copy) {
+                to_copy = bufinfo.len;
+            }
+            memcpy(p, bufinfo.buf, to_copy);
+            memset(p + to_copy, 0, sz - to_copy);
+            p += sz;
+        } else {
+            while (sz--) {
+                mp_binary_set_val(fmt_type, *fmt, args[i], &p);
+                // Pad bytes don't have a corresponding argument.
+                if (*fmt != 'x') {
+                    i++;
+                }
+            }
+        }
+        fmt++;
+    }
+}
 
-mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byte *end_p) {
+mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byte *end_p, bool exact_size) {
 
   const char *fmt = mp_obj_str_get_str(fmt_in);
   char fmt_type = get_fmt_type(&fmt);
-  mp_uint_t num_items = calcsize_items(fmt);
+  const mp_uint_t num_items = calcsize_items(fmt);
+  const mp_uint_t total_sz = shared_modules_struct_calcsize(fmt_in);
   mp_obj_tuple_t *res = MP_OBJ_TO_PTR(mp_obj_new_tuple(num_items, NULL));
 
+  // If exact_size, make sure the buffer is exactly the right size.
+  // Otherwise just make sure it's big enough.
+  if (exact_size) {
+      if (p + total_sz != end_p) {
+          mp_raise_RuntimeError(translate("buffer size must match format"));
+      }
+  } else {
+      if (p + total_sz > end_p) {
+          mp_raise_RuntimeError(translate("buffer too small"));
+      }
+  }
+
   for (uint i = 0; i < num_items;) {
       mp_uint_t sz = 1;
 
@@ -171,9 +192,6 @@ mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byt
       if (unichar_isdigit(*fmt)) {
           sz = get_fmt_num(&fmt);
       }
-      if (p + sz > end_p) {
-          mp_raise_RuntimeError(translate("buffer too small"));
-      }
       mp_obj_t item;
       if (*fmt == 's') {
           item = mp_obj_new_bytes(p, sz);
@@ -182,7 +200,10 @@ mp_obj_tuple_t * shared_modules_struct_unpack_from(mp_obj_t fmt_in, byte *p, byt
       } else {
           while (sz--) {
               item = mp_binary_get_val(fmt_type, *fmt, &p);
-              res->items[i++] = item;
+              // Pad bytes are not stored.
+              if (*fmt != 'x') {
+                  res->items[i++] = item;
+              }
           }
       }
       fmt++;