Wren testing

wren/vm/wren_utils.c

@@ -0,0 +1,207 @@
+#include <string.h>
+
+#include "wren_utils.h"
+#include "wren_vm.h"
+
+DEFINE_BUFFER(Byte, uint8_t);
+DEFINE_BUFFER(Int, int);
+DEFINE_BUFFER(String, ObjString*);
+
+void wrenSymbolTableInit(SymbolTable* symbols)
+{
+  wrenStringBufferInit(symbols);
+}
+
+void wrenSymbolTableClear(WrenVM* vm, SymbolTable* symbols)
+{
+  wrenStringBufferClear(vm, symbols);
+}
+
+int wrenSymbolTableAdd(WrenVM* vm, SymbolTable* symbols,
+                       const char* name, size_t length)
+{
+  ObjString* symbol = AS_STRING(wrenNewStringLength(vm, name, length));
+  
+  wrenPushRoot(vm, &symbol->obj);
+  wrenStringBufferWrite(vm, symbols, symbol);
+  wrenPopRoot(vm);
+  
+  return symbols->count - 1;
+}
+
+int wrenSymbolTableEnsure(WrenVM* vm, SymbolTable* symbols,
+                          const char* name, size_t length)
+{
+  // See if the symbol is already defined.
+  int existing = wrenSymbolTableFind(symbols, name, length);
+  if (existing != -1) return existing;
+
+  // New symbol, so add it.
+  return wrenSymbolTableAdd(vm, symbols, name, length);
+}
+
+int wrenSymbolTableFind(const SymbolTable* symbols,
+                        const char* name, size_t length)
+{
+  // See if the symbol is already defined.
+  // TODO: O(n). Do something better.
+  for (int i = 0; i < symbols->count; i++)
+  {
+    if (wrenStringEqualsCString(symbols->data[i], name, length)) return i;
+  }
+
+  return -1;
+}
+
+void wrenBlackenSymbolTable(WrenVM* vm, SymbolTable* symbolTable)
+{
+  for (int i = 0; i < symbolTable->count; i++)
+  {
+    wrenGrayObj(vm, &symbolTable->data[i]->obj);
+  }
+  
+  // Keep track of how much memory is still in use.
+  vm->bytesAllocated += symbolTable->capacity * sizeof(*symbolTable->data);
+}
+
+int wrenUtf8EncodeNumBytes(int value)
+{
+  ASSERT(value >= 0, "Cannot encode a negative value.");
+  
+  if (value <= 0x7f) return 1;
+  if (value <= 0x7ff) return 2;
+  if (value <= 0xffff) return 3;
+  if (value <= 0x10ffff) return 4;
+  return 0;
+}
+
+int wrenUtf8Encode(int value, uint8_t* bytes)
+{
+  if (value <= 0x7f)
+  {
+    // Single byte (i.e. fits in ASCII).
+    *bytes = value & 0x7f;
+    return 1;
+  }
+  else if (value <= 0x7ff)
+  {
+    // Two byte sequence: 110xxxxx 10xxxxxx.
+    *bytes = 0xc0 | ((value & 0x7c0) >> 6);
+    bytes++;
+    *bytes = 0x80 | (value & 0x3f);
+    return 2;
+  }
+  else if (value <= 0xffff)
+  {
+    // Three byte sequence: 1110xxxx 10xxxxxx 10xxxxxx.
+    *bytes = 0xe0 | ((value & 0xf000) >> 12);
+    bytes++;
+    *bytes = 0x80 | ((value & 0xfc0) >> 6);
+    bytes++;
+    *bytes = 0x80 | (value & 0x3f);
+    return 3;
+  }
+  else if (value <= 0x10ffff)
+  {
+    // Four byte sequence: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx.
+    *bytes = 0xf0 | ((value & 0x1c0000) >> 18);
+    bytes++;
+    *bytes = 0x80 | ((value & 0x3f000) >> 12);
+    bytes++;
+    *bytes = 0x80 | ((value & 0xfc0) >> 6);
+    bytes++;
+    *bytes = 0x80 | (value & 0x3f);
+    return 4;
+  }
+
+  // Invalid Unicode value. See: http://tools.ietf.org/html/rfc3629
+  UNREACHABLE();
+  return 0;
+}
+
+int wrenUtf8Decode(const uint8_t* bytes, uint32_t length)
+{
+  // Single byte (i.e. fits in ASCII).
+  if (*bytes <= 0x7f) return *bytes;
+
+  int value;
+  uint32_t remainingBytes;
+  if ((*bytes & 0xe0) == 0xc0)
+  {
+    // Two byte sequence: 110xxxxx 10xxxxxx.
+    value = *bytes & 0x1f;
+    remainingBytes = 1;
+  }
+  else if ((*bytes & 0xf0) == 0xe0)
+  {
+    // Three byte sequence: 1110xxxx	 10xxxxxx 10xxxxxx.
+    value = *bytes & 0x0f;
+    remainingBytes = 2;
+  }
+  else if ((*bytes & 0xf8) == 0xf0)
+  {
+    // Four byte sequence: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx.
+    value = *bytes & 0x07;
+    remainingBytes = 3;
+  }
+  else
+  {
+    // Invalid UTF-8 sequence.
+    return -1;
+  }
+
+  // Don't read past the end of the buffer on truncated UTF-8.
+  if (remainingBytes > length - 1) return -1;
+
+  while (remainingBytes > 0)
+  {
+    bytes++;
+    remainingBytes--;
+
+    // Remaining bytes must be of form 10xxxxxx.
+    if ((*bytes & 0xc0) != 0x80) return -1;
+
+    value = value << 6 | (*bytes & 0x3f);
+  }
+
+  return value;
+}
+
+int wrenUtf8DecodeNumBytes(uint8_t byte)
+{
+  // If the byte starts with 10xxxxx, it's the middle of a UTF-8 sequence, so
+  // don't count it at all.
+  if ((byte & 0xc0) == 0x80) return 0;
+  
+  // The first byte's high bits tell us how many bytes are in the UTF-8
+  // sequence.
+  if ((byte & 0xf8) == 0xf0) return 4;
+  if ((byte & 0xf0) == 0xe0) return 3;
+  if ((byte & 0xe0) == 0xc0) return 2;
+  return 1;
+}
+
+// From: http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2Float
+int wrenPowerOf2Ceil(int n)
+{
+  n--;
+  n |= n >> 1;
+  n |= n >> 2;
+  n |= n >> 4;
+  n |= n >> 8;
+  n |= n >> 16;
+  n++;
+  
+  return n;
+}
+
+uint32_t wrenValidateIndex(uint32_t count, int64_t value)
+{
+  // Negative indices count from the end.
+  if (value < 0) value = count + value;
+
+  // Check bounds.
+  if (value >= 0 && value < count) return (uint32_t)value;
+
+  return UINT32_MAX;
+}