| // Copyright 2011 Google Inc. All Rights Reserved. |
| |
| #ifndef ART_SRC_LEB128_H_ |
| #define ART_SRC_LEB128_H_ |
| |
| #include "globals.h" |
| |
| namespace art { |
| |
| // Reads an unsigned LEB128 value, updating the given pointer to point |
| // just past the end of the read value. This function tolerates |
| // non-zero high-order bits in the fifth encoded byte. |
| static inline uint32_t DecodeUnsignedLeb128(const byte** data) { |
| const byte* ptr = *data; |
| int result = *(ptr++); |
| if (result > 0x7f) { |
| int cur = *(ptr++); |
| result = (result & 0x7f) | ((cur & 0x7f) << 7); |
| if (cur > 0x7f) { |
| cur = *(ptr++); |
| result |= (cur & 0x7f) << 14; |
| if (cur > 0x7f) { |
| cur = *(ptr++); |
| result |= (cur & 0x7f) << 21; |
| if (cur > 0x7f) { |
| // Note: We don't check to see if cur is out of range here, |
| // meaning we tolerate garbage in the four high-order bits. |
| cur = *(ptr++); |
| result |= cur << 28; |
| } |
| } |
| } |
| } |
| *data = ptr; |
| return (uint32_t)result; |
| } |
| |
| // Reads a signed LEB128 value, updating the given pointer to point |
| // just past the end of the read value. This function tolerates |
| // non-zero high-order bits in the fifth encoded byte. |
| static inline int32_t DecodeSignedLeb128(const byte** data) { |
| const byte* ptr = *data; |
| int32_t result = *(ptr++); |
| if (result <= 0x7f) { |
| result = (result << 25) >> 25; |
| } else { |
| int cur = *(ptr++); |
| result = (result & 0x7f) | ((cur & 0x7f) << 7); |
| if (cur <= 0x7f) { |
| result = (result << 18) >> 18; |
| } else { |
| cur = *(ptr++); |
| result |= (cur & 0x7f) << 14; |
| if (cur <= 0x7f) { |
| result = (result << 11) >> 11; |
| } else { |
| cur = *(ptr++); |
| result |= (cur & 0x7f) << 21; |
| if (cur <= 0x7f) { |
| result = (result << 4) >> 4; |
| } else { |
| // Note: We don't check to see if cur is out of range here, |
| // meaning we tolerate garbage in the four high-order bits. |
| cur = *(ptr++); |
| result |= cur << 28; |
| } |
| } |
| } |
| } |
| *data = ptr; |
| return result; |
| } |
| |
| } // namespace art |
| |
| #endif // ART_SRC_LEB128_H_ |