| 48 | } |
| 49 | |
| 50 | string StringValue::LargestSmallerString() const { |
| 51 | uint32_t len = Len(); |
| 52 | if (len == 0) return ""; |
| 53 | const char* ptr = Ptr(); |
| 54 | if (len == 1 && ptr[0] == 0x00) return ""; |
| 55 | |
| 56 | int i = len - 1; |
| 57 | while (i >= 0 && ptr[i] == 0x00) i--; |
| 58 | if (UNLIKELY(i == -1)) { |
| 59 | // All characters are 0x00. Return a string with len-1 0x00 chars. |
| 60 | return string(len - 1, 0x00); |
| 61 | } |
| 62 | |
| 63 | // i is pointing at a character != 0x00. |
| 64 | if (i < len - 1) { |
| 65 | // return 'this' without the last trailing 0x00 |
| 66 | return string(ptr, len - 1); |
| 67 | } |
| 68 | DCHECK_EQ(i, len - 1); |
| 69 | |
| 70 | // Copy characters of this in [0, i] to 'result' and perform a '-1' operation on the |
| 71 | // ith char. |
| 72 | string result; |
| 73 | result.reserve(i + 1); |
| 74 | // copy all i characters in [0, i-1] to 'result' |
| 75 | result.append(ptr, i); |
| 76 | // append a char which is ptr[i]-1 |
| 77 | result.append(1, (uint8_t)(ptr[i]) - 1); |
| 78 | return result; |
| 79 | } |
| 80 | |
| 81 | string StringValue::LeastLargerString() const { |
| 82 | uint32_t len = Len(); |