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Refactoring rz_buf_uleb128 & rz_buf_sleb128

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wargio 2022-04-11 15:16:46 +02:00 committed by Giovanni
parent 5fa722efab
commit 90dea96fbc
2 changed files with 51 additions and 51 deletions
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4
librz/include/rz_util/rz_buf.h
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@ -130,8 +130,8 @@ RZ_API void rz_buf_free(RzBuffer *b);
RZ_API void rz_buf_set_overflow_byte(RZ_NONNULL RzBuffer *b, ut8 Oxff);
RZ_DEPRECATE RZ_API RZ_BORROW const ut8 *rz_buf_data(RZ_NONNULL RzBuffer *b, ut64 *size);
RZ_API st64 rz_buf_uleb128(RzBuffer *b, ut64 *v);
RZ_API st64 rz_buf_sleb128(RzBuffer *b, st64 *v);
RZ_API st64 rz_buf_uleb128(RZ_NONNULL RzBuffer *buffer, RZ_NONNULL ut64 *value);
RZ_API st64 rz_buf_sleb128(RZ_NONNULL RzBuffer *buffer, RZ_NONNULL st64 *value);
static inline st64 rz_buf_uleb128_at(RzBuffer *b, ut64 addr, ut64 *v) {
rz_buf_seek(b, addr, RZ_BUF_SET);

98
librz/util/buf.c
View file

@ -1293,70 +1293,70 @@ RZ_DEPRECATE RZ_API RZ_BORROW const ut8 *rz_buf_data(RZ_NONNULL RzBuffer *b, ut6
}
/**
* \brief ...
* \param b ...
* \param v ...
* \return ...
* \brief Decodes ULEB128 from RzBuffer
*
* ...
* \param buffer Buffer used to decode the ULEB128.
* \param value Decoded value.
* \return The number of bytes used.
*/
RZ_API st64 rz_buf_uleb128(RzBuffer *b, ut64 *v) {
ut8 c = 0xff;
ut64 s = 0, sum = 0, l = 0;
RZ_API st64 rz_buf_uleb128(RZ_NONNULL RzBuffer *buffer, RZ_NONNULL ut64 *value) {
rz_return_val_if_fail(buffer && value, -1);
ut64 sum = 0, used = 0, slice;
ut32 shift = 0;
ut8 byte = 0;
do {
ut8 data;
st64 r = rz_buf_read(b, &data, sizeof(data));
if (r <= 0) {
if (rz_buf_read(buffer, &byte, sizeof(byte)) < 1) {
// malformed uleb128 due end of buffer
return -1;
}
c = data & 0xff;
if (s < 64) {
sum |= ((ut64)(c & 0x7f) << s);
s += 7;
} else {
sum = 0;
used++;
slice = byte & 0x7f;
if ((shift >= 64 && slice != 0) || ((slice << shift) >> shift) != slice) {
// uleb128 too big for ut64
return -1;
}
l++;
} while (c & 0x80);
if (v) {
*v = sum;
}
return l;
sum += slice << shift;
shift += 7;
} while (byte >= 128);
*value = sum;
return used;
}
/**
* \brief ...
* \param b ...
* \param v ...
* \return ...
* \brief Decodes SLEB128 from RzBuffer
*
* ...
* \param buffer Buffer used to decode the SLEB128.
* \param value Decoded value.
* \return The number of bytes used.
*/
RZ_API st64 rz_buf_sleb128(RzBuffer *b, st64 *v) {
st64 result = 0, offset = 0;
ut8 value;
RZ_API st64 rz_buf_sleb128(RZ_NONNULL RzBuffer *buffer, RZ_NONNULL st64 *value) {
rz_return_val_if_fail(buffer && value, -1);
ut64 used = 0, slice;
st64 sum = 0;
ut32 shift = 0;
ut8 byte = 0;
do {
st64 chunk;
st64 r = rz_buf_read(b, &value, sizeof(value));
if (r != sizeof(value)) {
if (rz_buf_read(buffer, &byte, sizeof(byte)) < 1) {
// malformed sleb128 due end of buffer
return -1;
}
chunk = value & 0x7f;
if (offset < 64) {
result |= (chunk << offset);
offset += 7;
} else {
result = 0;
used++;
slice = byte & 0x7f;
if ((shift >= 64 && slice != (sum < 0 ? 0x7f : 0x00)) ||
(shift == 63 && slice != 0 && slice != 0x7f)) {
// sleb128 too big for st64
return -1;
}
} while (value & 0x80);
sum |= slice << shift;
shift += 7;
} while (byte >= 128);
if ((value & 0x40) != 0) {
if (offset < 64) {
result |= ~0ULL << offset;
}
if (shift < 64 && (byte & 0x40)) {
// extends negative sign
sum |= (-1ull) << shift;
}
if (v) {
*v = result;
}
return offset / 7;
*value = sum;
return used;
}