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Fix mysql incompatiable caused by bit size greater than 64 and data filled with zeros.

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br0 2021-08-23 21:04:26 +08:00 committed by wangzelin.wzl
parent ed29cc159d
commit f4def44a03
2 changed files with 16 additions and 4 deletions
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10
src/share/object/ob_obj_cast.cpp
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@ -7829,13 +7829,19 @@ int get_bit_len(const ObString& str, int32_t& bit_len)
} else {
const char* ptr = str.ptr();
uint32_t uneven_value = reinterpret_cast<const unsigned char&>(ptr[0]);
int32_t len = str.length();
if (0 == uneven_value) {
bit_len = 1;
if (len > 8) {
// Compatible with MySQL, if the length of bit string greater than 8 Bytes,
// it would be considered too long. We set bit_len to OB_MAX_BIT_LENGTH + 1.
bit_len = OB_MAX_BIT_LENGTH + 1;
} else {
bit_len = 1;
}
} else {
// Built-in Function: int __builtin_clz (unsigned int x).
// Returns the number of leading 0-bits in x, starting at the most significant bit position.
// If x is 0, the result is undefined.
int32_t len = str.length();
int32_t uneven_len = static_cast<int32_t>(sizeof(unsigned int) * 8 - __builtin_clz(uneven_value));
bit_len = uneven_len + 8 * (len - 1);
}

10
src/sql/engine/expr/ob_datum_cast.cpp
View File

@ -916,13 +916,19 @@ static OB_INLINE int common_get_bit_len(const ObString& str, int32_t& bit_len)
} else {
const char* ptr = str.ptr();
uint32_t uneven_value = reinterpret_cast<const unsigned char&>(ptr[0]);
int32_t len = str.length();
if (0 == uneven_value) {
bit_len = 1;
if (len > 8) {
// Compatible with MySQL, if the length of bit string greater than 8 Bytes,
// it would be considered too long. We set bit_len to OB_MAX_BIT_LENGTH + 1.
bit_len = OB_MAX_BIT_LENGTH + 1;
} else {
bit_len = 1;
}
} else {
// Built-in Function: int __builtin_clz (unsigned int x).
// Returns the number of leading 0-bits in x, starting at the most significant bit position.
// If x is 0, the result is undefined.
int32_t len = str.length();
int32_t uneven_len = static_cast<int32_t>(sizeof(unsigned int) * 8 - __builtin_clz(uneven_value));
bit_len = uneven_len + 8 * (len - 1);
}