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#### 6.6.6.3 Interpreting Bytevector Contents as Integers

The contents of a bytevector can be interpreted as a sequence of integers of any given size, sign, and endianness.

(let ((bv (make-bytevector 4))) (bytevector-u8-set! bv 0 #x12) (bytevector-u8-set! bv 1 #x34) (bytevector-u8-set! bv 2 #x56) (bytevector-u8-set! bv 3 #x78) (map (lambda (number) (number->string number 16)) (list (bytevector-u8-ref bv 0) (bytevector-u16-ref bv 0 (endianness big)) (bytevector-u32-ref bv 0 (endianness little))))) ⇒ ("12" "1234" "78563412")

The most generic procedures to interpret bytevector contents as integers are described below.

- Scheme Procedure:
**bytevector-uint-ref***bv index endianness size* - C Function:
**scm_bytevector_uint_ref***(bv, index, endianness, size)* Return the

`size`-byte long unsigned integer at index`index`in`bv`, decoded according to`endianness`.

- Scheme Procedure:
**bytevector-sint-ref***bv index endianness size* - C Function:
**scm_bytevector_sint_ref***(bv, index, endianness, size)* Return the

`size`-byte long signed integer at index`index`in`bv`, decoded according to`endianness`.

- Scheme Procedure:
**bytevector-uint-set!***bv index value endianness size* - C Function:
**scm_bytevector_uint_set_x***(bv, index, value, endianness, size)* Set the

`size`-byte long unsigned integer at`index`to`value`, encoded according to`endianness`.

- Scheme Procedure:
**bytevector-sint-set!***bv index value endianness size* - C Function:
**scm_bytevector_sint_set_x***(bv, index, value, endianness, size)* Set the

`size`-byte long signed integer at`index`to`value`, encoded according to`endianness`.

The following procedures are similar to the ones above, but specialized to a given integer size:

- Scheme Procedure:
**bytevector-u8-ref***bv index* - Scheme Procedure:
**bytevector-s8-ref***bv index* - Scheme Procedure:
**bytevector-u16-ref***bv index endianness* - Scheme Procedure:
**bytevector-s16-ref***bv index endianness* - Scheme Procedure:
**bytevector-u32-ref***bv index endianness* - Scheme Procedure:
**bytevector-s32-ref***bv index endianness* - Scheme Procedure:
**bytevector-u64-ref***bv index endianness* - Scheme Procedure:
**bytevector-s64-ref***bv index endianness* - C Function:
**scm_bytevector_u8_ref***(bv, index)* - C Function:
**scm_bytevector_s8_ref***(bv, index)* - C Function:
**scm_bytevector_u16_ref***(bv, index, endianness)* - C Function:
**scm_bytevector_s16_ref***(bv, index, endianness)* - C Function:
**scm_bytevector_u32_ref***(bv, index, endianness)* - C Function:
**scm_bytevector_s32_ref***(bv, index, endianness)* - C Function:
**scm_bytevector_u64_ref***(bv, index, endianness)* - C Function:
**scm_bytevector_s64_ref***(bv, index, endianness)* Return the unsigned

`n`-bit (signed) integer (where`n`is 8, 16, 32 or 64) from`bv`at`index`, decoded according to`endianness`.

- Scheme Procedure:
**bytevector-u8-set!***bv index value* - Scheme Procedure:
**bytevector-s8-set!***bv index value* - Scheme Procedure:
**bytevector-u16-set!***bv index value endianness* - Scheme Procedure:
**bytevector-s16-set!***bv index value endianness* - Scheme Procedure:
**bytevector-u32-set!***bv index value endianness* - Scheme Procedure:
**bytevector-s32-set!***bv index value endianness* - Scheme Procedure:
**bytevector-u64-set!***bv index value endianness* - Scheme Procedure:
**bytevector-s64-set!***bv index value endianness* - C Function:
**scm_bytevector_u8_set_x***(bv, index, value)* - C Function:
**scm_bytevector_s8_set_x***(bv, index, value)* - C Function:
**scm_bytevector_u16_set_x***(bv, index, value, endianness)* - C Function:
**scm_bytevector_s16_set_x***(bv, index, value, endianness)* - C Function:
**scm_bytevector_u32_set_x***(bv, index, value, endianness)* - C Function:
**scm_bytevector_s32_set_x***(bv, index, value, endianness)* - C Function:
**scm_bytevector_u64_set_x***(bv, index, value, endianness)* - C Function:
**scm_bytevector_s64_set_x***(bv, index, value, endianness)* Store

`value`as an`n`-bit (signed) integer (where`n`is 8, 16, 32 or 64) in`bv`at`index`, encoded according to`endianness`.

Finally, a variant specialized for the host’s endianness is available
for each of these functions (with the exception of the `u8`

accessors, for obvious reasons):

- Scheme Procedure:
**bytevector-u16-native-ref***bv index* - Scheme Procedure:
**bytevector-s16-native-ref***bv index* - Scheme Procedure:
**bytevector-u32-native-ref***bv index* - Scheme Procedure:
**bytevector-s32-native-ref***bv index* - Scheme Procedure:
**bytevector-u64-native-ref***bv index* - Scheme Procedure:
**bytevector-s64-native-ref***bv index* - C Function:
**scm_bytevector_u16_native_ref***(bv, index)* - C Function:
**scm_bytevector_s16_native_ref***(bv, index)* - C Function:
**scm_bytevector_u32_native_ref***(bv, index)* - C Function:
**scm_bytevector_s32_native_ref***(bv, index)* - C Function:
**scm_bytevector_u64_native_ref***(bv, index)* - C Function:
**scm_bytevector_s64_native_ref***(bv, index)* Return the unsigned

`n`-bit (signed) integer (where`n`is 8, 16, 32 or 64) from`bv`at`index`, decoded according to the host’s native endianness.

- Scheme Procedure:
**bytevector-u16-native-set!***bv index value* - Scheme Procedure:
**bytevector-s16-native-set!***bv index value* - Scheme Procedure:
**bytevector-u32-native-set!***bv index value* - Scheme Procedure:
**bytevector-s32-native-set!***bv index value* - Scheme Procedure:
**bytevector-u64-native-set!***bv index value* - Scheme Procedure:
**bytevector-s64-native-set!***bv index value* - C Function:
**scm_bytevector_u16_native_set_x***(bv, index, value)* - C Function:
**scm_bytevector_s16_native_set_x***(bv, index, value)* - C Function:
**scm_bytevector_u32_native_set_x***(bv, index, value)* - C Function:
**scm_bytevector_s32_native_set_x***(bv, index, value)* - C Function:
**scm_bytevector_u64_native_set_x***(bv, index, value)* - C Function:
**scm_bytevector_s64_native_set_x***(bv, index, value)* Store

`value`as an`n`-bit (signed) integer (where`n`is 8, 16, 32 or 64) in`bv`at`index`, encoded according to the host’s native endianness.

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