ESP8266/others: Fix ArrayBuffers with 12 bit JsVars (previously they …

…overflowed)

ChangeLog

@@ -41,6 +41,7 @@
             Ensure we error if an unsupported byteOffset is supplied to types array constructor (fix #2439)
             I2C: Add I2C.readReg to combine I2C.writeTo+readFrom in an easy/fast way
             Microbit2: Set up SCK/LRCK to unused pins for neopixel to ensure neopixel will work ok
+            ESP8266/others: Fix ArrayBuffers with 12 bit JsVars (previously they overflowed)
 
      2v19 : Fix Object.values/entries for numeric keys after 2v18 regression (fix #2375)
             nRF52: for SD>5 use static buffers for advertising and scan response data (#2367)

src/jsnative.c

@@ -274,6 +274,16 @@ JsVar *jsnCallFunction(void *function, JsnArgumentType argumentSpecifier, JsVar
 
 // -----------------------------------------------------------------------------------------
 
+// compile time sanity tests
+
+char const sanity_test_arraybuffer_type_one_byte[sizeof(JsVarDataArrayBufferViewType) == 1 ? 1 : -1];
+char const sanity_test_arraybuffer_in_jsvar[sizeof(JsVarDataArrayBufferView) <= JSVAR_DATA_ARRAYBUFFER_LEN ? 1 : -1];
+char const sanity_test_native_in_jsvar[sizeof(JsVarDataNative) <= JSVAR_DATA_ARRAYBUFFER_LEN ? 1 : -1];
+char const sanity_test_nativestr_in_jsvar[sizeof(JsVarDataNativeStr) <= JSVAR_DATA_ARRAYBUFFER_LEN ? 1 : -1];
+
+
+// runtime sanity tests
+
 JsVarFloat sanity_pi() { return 3.141592; }
 int32_t sanity_int_pass(int32_t hello) { return (hello*10)+5; }
 int32_t sanity_int_flt_int(int32_t a, JsVarFloat b, int32_t c) {

src/jsutils.c

@@ -1017,6 +1017,17 @@ unsigned short int int_sqrt32(unsigned int x) {
   return res;
 }
 
+// Reverse the order of bytes in an array, in place
+void reverseBytes(char *data, int len) {
+  int halflen = len>>1;
+  int j = len-1;
+  for (int i=0;i<halflen;i++,j--) {
+    char t = data[i];
+    data[i] = data[j];
+    data[j] = t;
+  }
+}
+
 #ifdef ESPR_UNICODE_SUPPORT
 
 /// Returns true if this character denotes the start of a UTF8 sequence

src/jsutils.h

@@ -276,6 +276,8 @@ See comments after JsVar in jsvar.c for more info.
 
 /// Max length for a JSV_STRING, JsVar.varData.ref.refs (see comments under JsVar decl in jsvar.h)
 #define JSVAR_DATA_STRING_LEN (JSVAR_DATA_STRING_NAME_LEN + ((JSVARREF_BITS*3 + JSVARREFCOUNT_PACK_BITS)>>3))
+/// Max length for an arraybuffer since it uses firstChild
+#define JSVAR_DATA_ARRAYBUFFER_LEN (JSVAR_DATA_STRING_NAME_LEN + ((JSVARREF_BITS*2)>>3))
 /// Max length for a JSV_STRINGEXT, JsVar.varData.ref.lastChild (see comments under JsVar decl in jsvar.h)
 #define JSVAR_DATA_STRING_MAX_LEN (JSVAR_DATA_STRING_NAME_LEN + ((JSVARREF_BITS*3 + JSVARREFCOUNT_PACK_BITS + JSVARREFCOUNT_BITS)>>3))
 
@@ -619,6 +621,9 @@ bool calculateParity(uint8_t v);
 /// quick integer square root
 unsigned short int int_sqrt32(unsigned int x);
 
+// Reverse the order of bytes in an array, in place
+void reverseBytes(char *data, int len);
+
 /** get the amount of free stack we have, in bytes */
 size_t jsuGetFreeStack();
 

src/jsvar.c

@@ -2389,7 +2389,7 @@ JsVar *jsvGetArrayBufferBackingString(JsVar *arrayBuffer, uint32_t *offset) {
 JsVar *jsvArrayBufferGet(JsVar *arrayBuffer, size_t idx) {
   JsvArrayBufferIterator it;
   jsvArrayBufferIteratorNew(&it, arrayBuffer, idx);
-  JsVar *v = jsvArrayBufferIteratorGetValue(&it);
+  JsVar *v = jsvArrayBufferIteratorGetValue(&it, false/*little endian*/);
   jsvArrayBufferIteratorFree(&it);
   return v;
 }
@@ -2398,7 +2398,7 @@ JsVar *jsvArrayBufferGet(JsVar *arrayBuffer, size_t idx) {
 void jsvArrayBufferSet(JsVar *arrayBuffer, size_t idx, JsVar *value) {
   JsvArrayBufferIterator it;
   jsvArrayBufferIteratorNew(&it, arrayBuffer, idx);
-  jsvArrayBufferIteratorSetValue(&it, value);
+  jsvArrayBufferIteratorSetValue(&it, value, false/*little endian*/);
   jsvArrayBufferIteratorFree(&it);
 }
 

src/jsvar.h

@@ -115,7 +115,6 @@ typedef enum {
   ARRAYBUFFERVIEW_FLOAT = 32,
   ARRAYBUFFERVIEW_CLAMPED = 64, // As in Uint8ClampedArray - clamp to the acceptable bounds
   ARRAYBUFFERVIEW_ARRAYBUFFER = 1 | 128, ///< Basic ArrayBuffer type
-  ARRAYBUFFERVIEW_BIG_ENDIAN = 256, ///< access as big endian (normally little)
   ARRAYBUFFERVIEW_UINT8   = 1,
   ARRAYBUFFERVIEW_INT8    = 1 | ARRAYBUFFERVIEW_SIGNED,
   ARRAYBUFFERVIEW_UINT16  = 2,
@@ -247,7 +246,7 @@ typedef struct JsVarStruct {
 
 
  | Offset | Size | Name    | STRING | STR_EXT  | NAME_STR | NAME_INT | INT  | DOUBLE  | OBJ/FUNC/ARRAY | ARRAYBUFFER | NATIVE_STR | FLAT_STR |
- |        |      |         |        |          |          |          |      |         |                |             | FLASH_STR  |          |
+ | 16b    |      |         |        |          |          |          |      |         |                |             | FLASH_STR  |          |
  |--------|------|---------|--------|----------|----------|----------|------|---------|----------------|-------------|------------|----------|
  | 0 - 3  | 4    | varData | data   | data     |  data    | data     | data | data    | nativePtr      | size        | ptr        | charLen  |
  | 4 - 5  | ?    | next    | data   | data     |  next    | next     |  -   | data    | argTypes       | format      | len        | -        |

src/jsvariterator.c

@@ -558,16 +558,9 @@ static void jsvArrayBufferIteratorGetValueData(JsvArrayBufferIterator *it, char
   if (it->type == ARRAYBUFFERVIEW_UNDEFINED) return;
   assert(!it->hasAccessedElement); // we just haven't implemented this case yet
   int i,dataLen = (int)JSV_ARRAYBUFFER_GET_SIZE(it->type);
-  if (it->type & ARRAYBUFFERVIEW_BIG_ENDIAN) {
-    for (i=dataLen-1;i>=0;i--) {
-       data[i] = jsvStringIteratorGetChar(&it->it);
-       if (dataLen!=1) jsvStringIteratorNext(&it->it);
-     }
-  } else {
-    for (i=0;i<dataLen;i++) {
-      data[i] = jsvStringIteratorGetChar(&it->it);
-      if (dataLen!=1) jsvStringIteratorNext(&it->it);
-    }
+  for (i=0;i<dataLen;i++) {
+    data[i] = jsvStringIteratorGetChar(&it->it);
+    if (dataLen!=1) jsvStringIteratorNext(&it->it);
   }
   if (dataLen!=1) it->hasAccessedElement = true;
 }
@@ -592,15 +585,17 @@ static JsVarFloat jsvArrayBufferIteratorDataToFloat(JsvArrayBufferIterator *it,
   return v;
 }
 
-JsVar *jsvArrayBufferIteratorGetValue(JsvArrayBufferIterator *it) {
+JsVar *jsvArrayBufferIteratorGetValue(JsvArrayBufferIterator *it, bool bigEndian) {
   if (it->type == ARRAYBUFFERVIEW_UNDEFINED) return 0;
   char data[8];
   jsvArrayBufferIteratorGetValueData(it, data);
+  if (bigEndian)
+      reverseBytes(data, JSV_ARRAYBUFFER_GET_SIZE(it->type));
   if (JSV_ARRAYBUFFER_IS_FLOAT(it->type)) {
     return jsvNewFromFloat(jsvArrayBufferIteratorDataToFloat(it, data));
   } else {
     JsVarInt i = jsvArrayBufferIteratorDataToInt(it, data);
-    if ((it->type & ~ARRAYBUFFERVIEW_BIG_ENDIAN) == ARRAYBUFFERVIEW_UINT32)
+    if (it->type == ARRAYBUFFERVIEW_UINT32)
       return jsvNewFromLongInteger((long long)(uint32_t)i);
     return jsvNewFromInteger(i);
   }
@@ -609,7 +604,7 @@ JsVar *jsvArrayBufferIteratorGetValue(JsvArrayBufferIterator *it) {
 JsVar *jsvArrayBufferIteratorGetValueAndRewind(JsvArrayBufferIterator *it) {
   JsvStringIterator oldIt;
   jsvStringIteratorClone(&oldIt, &it->it);
-  JsVar *v = jsvArrayBufferIteratorGetValue(it);
+  JsVar *v = jsvArrayBufferIteratorGetValue(it, false/*little endian*/);
   jsvStringIteratorFree(&it->it);
   it->it = oldIt;
   it->hasAccessedElement = false;
@@ -675,7 +670,7 @@ void jsvArrayBufferIteratorSetIntegerValue(JsvArrayBufferIterator *it, JsVarInt
   if (dataLen!=1) it->hasAccessedElement = true;
 }
 
-void jsvArrayBufferIteratorSetValue(JsvArrayBufferIterator *it, JsVar *value) {
+void jsvArrayBufferIteratorSetValue(JsvArrayBufferIterator *it, JsVar *value, bool bigEndian) {
   if (it->type == ARRAYBUFFERVIEW_UNDEFINED) return;
   assert(!it->hasAccessedElement); // we just haven't implemented this case yet
   char data[8];
@@ -687,16 +682,12 @@ void jsvArrayBufferIteratorSetValue(JsvArrayBufferIterator *it, JsVar *value) {
     jsvArrayBufferIteratorIntToData(data, (unsigned)dataLen, it->type, jsvGetInteger(value));
   }
 
-  if (it->type & ARRAYBUFFERVIEW_BIG_ENDIAN) {
-    for (i=dataLen-1;i>=0;i--) {
-      jsvStringIteratorSetChar(&it->it, data[i]);
-      if (dataLen!=1) jsvStringIteratorNext(&it->it);
-    }
-  } else {
-    for (i=0;i<dataLen;i++) {
-      jsvStringIteratorSetChar(&it->it, data[i]);
-      if (dataLen!=1) jsvStringIteratorNext(&it->it);
-    }
+  if (bigEndian)
+    reverseBytes(data, dataLen);
+
+  for (i=0;i<dataLen;i++) {
+    jsvStringIteratorSetChar(&it->it, data[i]);
+    if (dataLen!=1) jsvStringIteratorNext(&it->it);
   }
   if (dataLen!=1) it->hasAccessedElement = true;
 }
@@ -712,7 +703,7 @@ void jsvArrayBufferIteratorSetByteValue(JsvArrayBufferIterator *it, char c) {
 void jsvArrayBufferIteratorSetValueAndRewind(JsvArrayBufferIterator *it, JsVar *value) {
   JsvStringIterator oldIt;
   jsvStringIteratorClone(&oldIt, &it->it);
-  jsvArrayBufferIteratorSetValue(it, value);
+  jsvArrayBufferIteratorSetValue(it, value, false/*little endian*/);
   jsvStringIteratorFree(&it->it);
   jsvStringIteratorClone(&it->it, &oldIt);
   jsvStringIteratorFree(&oldIt);

src/jsvariterator.h

@@ -260,11 +260,11 @@ void jsvArrayBufferIteratorClone(JsvArrayBufferIterator *dstit, JsvArrayBufferIt
 /** ArrayBuffers have the slightly odd side-effect that you can't write an element
  * once you have read it. That's why we have jsvArrayBufferIteratorGetValueAndRewind
  * which allows this, but is slower. */
-JsVar *jsvArrayBufferIteratorGetValue(JsvArrayBufferIterator *it);
+JsVar *jsvArrayBufferIteratorGetValue(JsvArrayBufferIterator *it, bool bigEndian);
 JsVar *jsvArrayBufferIteratorGetValueAndRewind(JsvArrayBufferIterator *it);
 JsVarInt jsvArrayBufferIteratorGetIntegerValue(JsvArrayBufferIterator *it);
 JsVarFloat jsvArrayBufferIteratorGetFloatValue(JsvArrayBufferIterator *it);
-void   jsvArrayBufferIteratorSetValue(JsvArrayBufferIterator *it, JsVar *value);
+void   jsvArrayBufferIteratorSetValue(JsvArrayBufferIterator *it, JsVar *value, bool bigEndian);
 void   jsvArrayBufferIteratorSetValueAndRewind(JsvArrayBufferIterator *it, JsVar *value);
 void   jsvArrayBufferIteratorSetIntegerValue(JsvArrayBufferIterator *it, JsVarInt value);
 void   jsvArrayBufferIteratorSetByteValue(JsvArrayBufferIterator *it, char c); ///< special case for when we know we're writing to a byte array

src/jswrap_arraybuffer.c

@@ -655,7 +655,7 @@ void jswrap_arraybufferview_set(JsVar *parent, JsVar *arr, int offset) {
       jsvArrayBufferIteratorSetIntegerValue(&itdst, jsvIteratorGetIntegerValue(&itsrc));
     } else {
       JsVar *value = jsvIteratorGetValue(&itsrc);
-      jsvArrayBufferIteratorSetValue(&itdst, value);
+      jsvArrayBufferIteratorSetValue(&itdst, value, false/*little endian*/);
       jsvUnLock(value);
     }
     jsvArrayBufferIteratorNext(&itdst);
@@ -723,7 +723,7 @@ JsVar *jswrap_arraybufferview_map(JsVar *parent, JsVar *funcVar, JsVar *thisVar)
       mapped = jspeFunctionCall(funcVar, 0, thisVar, false, 3, args);
       jsvUnLockMany(2,args);
       if (mapped) {
-        jsvArrayBufferIteratorSetValue(&itdst, mapped);
+        jsvArrayBufferIteratorSetValue(&itdst, mapped, false/*little endian*/);
         jsvUnLock(mapped);
       }
     }

src/jswrap_dataview.c

@@ -70,7 +70,6 @@ JsVar *jswrap_dataview_constructor(JsVar *buffer, int byteOffset, int byteLength
   return dataview;
 }
 
-
 JsVar *jswrap_dataview_get(JsVar *dataview, JsVarDataArrayBufferViewType type, int byteOffset, bool littleEndian) {
   JsVar *buffer = jsvObjectGetChildIfExists(dataview, "buffer");
   if (!jsvIsArrayBuffer(buffer)) {
@@ -80,13 +79,13 @@ JsVar *jswrap_dataview_get(JsVar *dataview, JsVarDataArrayBufferViewType type, i
   byteOffset += jsvGetIntegerAndUnLock(jsvObjectGetChildIfExists(dataview, "byteOffset"));
   JsVarInt length = JSV_ARRAYBUFFER_GET_SIZE(type);
   // TODO: range error based on byteLength?
-  if (!littleEndian) type |= ARRAYBUFFERVIEW_BIG_ENDIAN;
+
   JsVar *arr = jswrap_typedarray_constructor(type, buffer, byteOffset, length);
   jsvUnLock(buffer);
   if (!arr) return 0;
   JsvArrayBufferIterator it;
   jsvArrayBufferIteratorNew(&it, arr, 0);
-  JsVar *value = jsvArrayBufferIteratorGetValue(&it);
+  JsVar *value = jsvArrayBufferIteratorGetValue(&it, !littleEndian);
   jsvArrayBufferIteratorFree(&it);
   jsvUnLock(arr);
   return value;
@@ -100,13 +99,12 @@ void jswrap_dataview_set(JsVar *dataview, JsVarDataArrayBufferViewType type, int
   byteOffset += jsvGetIntegerAndUnLock(jsvObjectGetChildIfExists(dataview, "byteOffset"));
   JsVarInt length = JSV_ARRAYBUFFER_GET_SIZE(type);
   // TODO: range error based on byteLength?
-  if (!littleEndian) type |= ARRAYBUFFERVIEW_BIG_ENDIAN;
   JsVar *arr = jswrap_typedarray_constructor(type, buffer, byteOffset, length);
   jsvUnLock(buffer);
   if (!arr) return;
   JsvArrayBufferIterator it;
   jsvArrayBufferIteratorNew(&it, arr, 0);
-  jsvArrayBufferIteratorSetValue(&it, value);
+  jsvArrayBufferIteratorSetValue(&it, value, !littleEndian);
   jsvArrayBufferIteratorFree(&it);
   jsvUnLock(arr);
 }

src/jswrap_espruino.c

@@ -1751,7 +1751,7 @@ void jswrap_espruino_mapInPlace(JsVar *from, JsVar *to, JsVar *map, JsVarInt bit
         assert(jsvIsArrayBuffer(map));
         v2 = jsvArrayBufferGet(map, (size_t)v);
       }
-      jsvArrayBufferIteratorSetValue(&itTo, v2);
+      jsvArrayBufferIteratorSetValue(&itTo, v2, false/*little endian*/);
       jsvUnLock(v2);
     } else { // no map - push right through
       jsvArrayBufferIteratorSetIntegerValue(&itTo, v);

src/jswrap_json.c

@@ -417,7 +417,7 @@ void jsfGetJSONWithCallback(JsVar *var, JsVar *varName, JSONFlags flags, const c
           if (it.index>0) cbprintf(user_callback, user_data, (flags&JSON_PRETTY)?", ":",");
           if (flags&JSON_ALL_NEWLINES) jsonNewLine(nflags, whitespace, user_callback, user_data);
           if (limited && it.index==length-JSON_LIMITED_AMOUNT) cbprintf(user_callback, user_data, JSON_LIMIT_TEXT);
-          JsVar *item = jsvArrayBufferIteratorGetValue(&it);
+          JsVar *item = jsvArrayBufferIteratorGetValue(&it, false/*little endian*/);
           jsfGetJSONWithCallback(item, NULL, nflags, whitespace, user_callback, user_data);
           jsvUnLock(item);
         }