1/* 2 * Reads an unsigned LEB128 value, updating the given pointer to point
3 * just past the end of the read value. This function tolerates
4 * non-zero high-order bits in the fifth encoded byte.
5*/ 6 DEX_INLINE int readUnsignedLeb128(const u1** pStream) {
7const u1* ptr = *pStream;
8int result = *(ptr++);
910if (result > 0x7f) {
11int cur = *(ptr++);
12 result = (result & 0x7f) | ((cur & 0x7f) << 7);
13if (cur > 0x7f) {
14 cur = *(ptr++);
15 result |= (cur & 0x7f) << 14;
16if (cur > 0x7f) {
17 cur = *(ptr++);
18 result |= (cur & 0x7f) << 21;
19if (cur > 0x7f) {
20/*21 * Note: We don't check to see if cur is out of
22 * range here, meaning we tolerate garbage in the
23 * high four-order bits.
24*/25 cur = *(ptr++);
26 result |= cur << 28;
27 }
28 }
29 }
30 }
3132 *pStream = ptr;
33return result;
34}
3536/*37 * Reads a signed LEB128 value, updating the given pointer to point
38 * just past the end of the read value. This function tolerates
39 * non-zero high-order bits in the fifth encoded byte.
40*/41 DEX_INLINE int readSignedLeb128(const u1** pStream) {
42const u1* ptr = *pStream;
43int result = *(ptr++);
4445if (result <= 0x7f) {
46 result = (result << 25) >> 25;
47 } else {
48int cur = *(ptr++);
49 result = (result & 0x7f) | ((cur & 0x7f) << 7);
50if (cur <= 0x7f) {
51 result = (result << 18) >> 18;
52 } else {
53 cur = *(ptr++);
54 result |= (cur & 0x7f) << 14;
55if (cur <= 0x7f) {
56 result = (result << 11) >> 11;
57 } else {
58 cur = *(ptr++);
59 result |= (cur & 0x7f) << 21;
60if (cur <= 0x7f) {
61 result = (result << 4) >> 4;
62 } else {
63/*64 * Note: We don't check to see if cur is out of
65 * range here, meaning we tolerate garbage in the
66 * high four-order bits.
67*/68 cur = *(ptr++);
69 result |= cur << 28;
70 }
71 }
72 }
73 }
7475 *pStream = ptr;
76return result;
77 }
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posted on 2013-07-30 00:42 chx4 閱讀(...) 評論(...) ?編輯 收藏
