本文整理汇总了C++中APInt::zextOrSelf方法的典型用法代码示例。如果您正苦于以下问题：C++ APInt::zextOrSelf方法的具体用法？C++ APInt::zextOrSelf怎么用？C++ APInt::zextOrSelf使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类APInt的用法示例。
在下文中一共展示了APInt::zextOrSelf方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: APInt
APInt
swift::Compress::EncodeStringAsNumber(StringRef In, EncodingKind Kind) {
// Allocate enough space for the first character plus one bit which is the
// stop bit for variable length encoding.
unsigned BW = (1 + Huffman::LongestEncodingLength);
APInt num = APInt(BW, 0);
// We set the high bit to zero in order to support encoding
// of chars that start with zero (for variable length encoding).
if (Kind == EncodingKind::Variable) {
num = ++num;
}
// Encode variable-length strings.
if (Kind == EncodingKind::Variable) {
size_t num_bits = 0;
size_t bits = 0;
// Append the characters in the string in reverse. This will allow
// us to decode by appending to a string and not prepending.
for (int i = In.size() - 1; i >= 0; i--) {
char ch = In[i];
// The local variables 'bits' and 'num_bits' are used as a small
// bitstream. Keep accumulating bits into them until they overflow.
// At that point move them into the APInt.
uint64_t local_bits;
uint64_t local_num_bits;
// Find the huffman encoding of the character.
Huffman::variable_encode(local_bits, local_num_bits, ch);
// Add the encoded character into our bitstream.
num_bits += local_num_bits;
bits = (bits << local_num_bits) + local_bits;
// Check if there is enough room for another word. If not, flush
// the local bitstream into the APInt.
if (num_bits >= (64 - Huffman::LongestEncodingLength)) {
// Make room for the new bits and add the bits.
num = num.zext(num.getBitWidth() + num_bits);
num = num.shl(num_bits); num = num + bits;
num_bits = 0; bits = 0;
}
}
// Flush the local bitstream into the APInt number.
if (num_bits) {
num = num.zext(num.getBitWidth() + num_bits);
num = num.shl(num_bits); num = num + bits;
num_bits = 0; bits = 0;
}
// Make sure that we have a minimal word size to be able to perform
// calculations on our alphabet.
return num.zextOrSelf(std::max(64u, num.getBitWidth()));
}
// Encode fixed width strings.
for (int i = In.size() - 1; i >= 0; i--) {
char ch = In[i];
// Extend the number and create room for encoding another character.
unsigned MinBits = num.getActiveBits() + Huffman::LongestEncodingLength;
num = num.zextOrTrunc(std::max(64u, MinBits));
EncodeFixedWidth(num, ch);
}
return num;
}