diff options
| -rw-r--r-- | ext/ffi/ffi.c | 114 |
1 files changed, 80 insertions, 34 deletions
diff --git a/ext/ffi/ffi.c b/ext/ffi/ffi.c index 20a215a42a..c058cb9721 100644 --- a/ext/ffi/ffi.c +++ b/ext/ffi/ffi.c @@ -531,32 +531,60 @@ again: } /* }}} */ -static void zend_ffi_bit_field_to_zval(void *ptr, zend_ffi_field *field, zval *rv) /* {{{ */ +static uint64_t zend_ffi_bit_field_read(void *ptr, zend_ffi_field *field) /* {{{ */ { - uint64_t *p1 = (uint64_t *)((char*)ptr + (field->first_bit / 64) * 8); - uint64_t *p2 = (uint64_t *)((char*)ptr + ((field->first_bit + field->bits - 1) / 64) * 8); - uint64_t pos = field->first_bit % 64; - uint64_t shift = 64 - (field->bits % 64); - uint64_t val; + size_t bit = field->first_bit; + size_t last_bit = bit + field->bits - 1; + uint8_t *p = (uint8_t *) ptr + bit / 8; + uint8_t *last_p = (uint8_t *) ptr + last_bit / 8; + size_t pos = bit % 8; + size_t insert_pos = 0; + uint8_t mask; + uint64_t val = 0; - if (p1 == p2) { - if (field->bits == 64) { - val = *p1; - shift = 0; - } else { - val = *p1 << (shift - pos); - } - } else { - val = (*p1 >> pos) | (*p2 << (64 - pos)); + /* Bitfield fits into a single byte */ + if (p == last_p) { + mask = (1U << field->bits) - 1U; + return (*p >> pos) & mask; + } + + /* Read partial prefix byte */ + if (pos != 0) { + size_t num_bits = 8 - pos; + mask = ((1U << num_bits) - 1U) << pos; + val = (*p++ >> pos) & mask; + insert_pos += num_bits; + } + + /* Read full bytes */ + while (p < last_p) { + val |= *p++ << insert_pos; + insert_pos += 8; + } + + /* Read partial suffix byte */ + if (p == last_p) { + size_t num_bits = last_bit % 8 + 1; + mask = (1U << num_bits) - 1U; + val |= (*p & mask) << insert_pos; } + + return val; +} + +static void zend_ffi_bit_field_to_zval(void *ptr, zend_ffi_field *field, zval *rv) /* {{{ */ +{ + uint64_t val = zend_ffi_bit_field_read(ptr, field); if (ZEND_FFI_TYPE(field->type)->kind == ZEND_FFI_TYPE_CHAR || ZEND_FFI_TYPE(field->type)->kind == ZEND_FFI_TYPE_SINT8 || ZEND_FFI_TYPE(field->type)->kind == ZEND_FFI_TYPE_SINT16 || ZEND_FFI_TYPE(field->type)->kind == ZEND_FFI_TYPE_SINT32 || ZEND_FFI_TYPE(field->type)->kind == ZEND_FFI_TYPE_SINT64) { - val = (int64_t)val >> shift; - } else { - val = val >> shift; + /* Sign extend */ + uint64_t shift = 64 - (field->bits % 64); + if (shift != 0) { + val = (int64_t)(val << shift) >> shift; + } } ZVAL_LONG(rv, val); } @@ -564,25 +592,43 @@ static void zend_ffi_bit_field_to_zval(void *ptr, zend_ffi_field *field, zval *r static int zend_ffi_zval_to_bit_field(void *ptr, zend_ffi_field *field, zval *value) /* {{{ */ { - uint64_t *p1 = (uint64_t *)((char*)ptr + (field->first_bit / 64) * 8); - uint64_t *p2 = (uint64_t *)((char*)ptr + ((field->first_bit + field->bits - 1) / (8 * 8)) * 8); - uint64_t pos = field->first_bit % 64; - uint64_t mask; uint64_t val = zval_get_long(value); + size_t bit = field->first_bit; + size_t last_bit = bit + field->bits - 1; + uint8_t *p = (uint8_t *) ptr + bit / 8; + uint8_t *last_p = (uint8_t *) ptr + last_bit / 8; + size_t pos = bit % 8; + uint8_t mask; + + /* Bitfield fits into a single byte */ + if (p == last_p) { + mask = ((1U << field->bits) - 1U) << pos; + *p = (*p & ~mask) | ((val << pos) & mask); + return SUCCESS; + } - if (p1 == p2) { - if (field->bits == 64) { - *p1 = val; - } else { - mask = ((1ULL << field->bits) - 1ULL) << pos; - *p1 = (*p1 & ~mask) | ((val << pos) & mask); - } - } else { - mask = ((1ULL << (64 - pos)) - 1ULL) << pos; - *p1 = (*p1 & ~mask) | ((val << pos) & mask); - mask = (1ULL << pos) - 1ULL; - *p2 = (*p2 & ~mask) | ((val >> (64 - pos)) & mask); + /* Write partial prefix byte */ + if (pos != 0) { + size_t num_bits = 8 - pos; + mask = ((1U << num_bits) - 1U) << pos; + *p = (*p & ~mask) | ((val << pos) & mask); + p++; + val >>= num_bits; + } + + /* Write full bytes */ + while (p < last_p) { + *p++ = val; + val >>= 8; } + + /* Write partial suffix byte */ + if (p == last_p) { + size_t num_bits = last_bit % 8 + 1; + mask = (1U << num_bits) - 1U; + *p = (*p & ~mask) | (val & mask); + } + return SUCCESS; } /* }}} */ |