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//! Utilities to generate the low-level API. use lib::{self, slice}; use super::algorithm::distance; use super::num::Number; use super::result::*; // HELPERS /// Convert a pointer range to a slice safely. #[inline] pub(crate) unsafe fn slice_from_range<'a, T>(first: *const T, last: *const T) -> &'a [T] { assert!(first <= last && !first.is_null() && !last.is_null()); slice::from_raw_parts(first, distance(first, last)) } /// Convert a mutable pointer range to a mutable slice safely. #[inline] pub(crate) unsafe fn slice_from_range_mut<'a, T>(first: *mut T, last: *mut T) -> &'a mut [T] { assert!(first <= last && !first.is_null() && !last.is_null()); slice::from_raw_parts_mut(first, distance(first, last)) } /// Wrap the unsafe API into the safe, parse API trying to parse raw bytes. #[inline] pub(crate) fn try_from_bytes_wrapper<'a, T, Cb>(radix: u8, bytes: &'a [u8], cb: Cb) -> Result<T> where T: Number, Cb: FnOnce(u8, &'a [u8]) -> (T, usize, bool) { let (value, processed, overflow) = cb(radix, bytes); if bytes.is_empty() { empty_error(value) } else if overflow { overflow_error(value) } else if processed == bytes.len() { success(value) } else { invalid_digit_error(value, processed) } } // TO BYTES WRAPPER // Do not inline any of the API functions, both to preserve symbols, and // to flatten the internal API into these symbols. /// Macro to generate the low-level, FFI API using a pointer range. #[doc(hidden)] macro_rules! generate_from_range_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident) => ( /// Unchecked parser for a string-to-number conversion using pointer ranges. /// /// Returns the parsed value, ignoring any trailing invalid digits, /// and explicitly wrapping on arithmetic overflow. /// /// This parser is FFI-compatible, and therefore may be called externally /// from C code. /// /// * `first` - Pointer to the start of the input data. /// * `last` - Pointer to the one-past-the-end of the input data. /// /// # Panics /// /// Panics if either pointer is null. #[no_mangle] pub unsafe extern fn $decimal_name(first: *const u8, last: *const u8) -> $t { assert!(first <= last && !first.is_null() && !last.is_null()); let bytes = $crate::lib::slice::from_raw_parts(first, distance(first, last)); $cb(10, bytes).0 } /// Unchecked parser for a string-to-number conversion using pointer ranges. /// /// Returns the parsed value, ignoring any trailing invalid digits, /// and explicitly wrapping on arithmetic overflow. /// /// This parser is FFI-compatible, and therefore may be called externally /// from C code. /// /// * `radix` - Radix for the number parsing. /// * `first` - Pointer to the start of the input data. /// * `last` - Pointer to the one-past-the-end of the input data. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. Also panics /// if either pointer is null. #[cfg(feature = "radix")] #[no_mangle] pub unsafe extern fn $radix_name(radix: u8, first: *const u8, last: *const u8) -> $t { assert_radix!(radix); assert!(first <= last && !first.is_null() && !last.is_null()); let bytes = $crate::lib::slice::from_raw_parts(first, distance(first, last)); $cb(radix, bytes).0 } ) } /// Macro to generate the low-level, safe, parse API using a slice. #[doc(hidden)] macro_rules! generate_from_slice_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident) => ( /// Unchecked parser for a string-to-number conversion using Rust slices. /// /// Returns the parsed value, ignoring any trailing invalid digits, /// and explicitly wrapping on arithmetic overflow. /// /// * `bytes` - Slice containing a numeric string. #[inline] pub fn $decimal_name(bytes: &[u8]) -> $t { $cb(10, bytes).0 } /// Unchecked parser for a string-to-number conversion using Rust slices. /// /// Returns the parsed value, ignoring any trailing invalid digits, /// and explicitly wrapping on arithmetic overflow. /// /// * `radix` - Radix for the number parsing. /// * `bytes` - Slice containing a numeric string. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. #[cfg(feature = "radix")] #[inline] pub fn $radix_name(radix: u8, bytes: &[u8]) -> $t { assert_radix!(radix); $cb(radix, bytes).0 } ) } /// Macro to generate the low-level, FFI, try_parse API using a pointer range. #[doc(hidden)] macro_rules! generate_try_from_range_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident) => ( /// Checked parser for a string-to-number conversion using Rust pointer ranges. /// /// Returns a C-compatible result containing the parsed value, /// and an error container any errors that occurred during parser. /// /// Numeric overflow takes precedence over the presence of an invalid /// digit, and therefore may mask an invalid digit error. /// /// * `first` - Pointer to the start of the input data. /// * `last` - Pointer to the one-past-the-end of the input data. /// /// # Panics /// /// Panics if either pointer is null. #[no_mangle] pub unsafe extern fn $decimal_name(first: *const u8, last: *const u8) -> Result<$t> { let bytes = $crate::util::api::slice_from_range(first, last); $crate::util::api::try_from_bytes_wrapper::<$t, _>(10, bytes, $cb) } /// Checked parser for a string-to-number conversion using Rust pointer ranges. /// /// Returns a C-compatible result containing the parsed value, /// and an error container any errors that occurred during parser. /// /// Numeric overflow takes precedence over the presence of an invalid /// digit, and therefore may mask an invalid digit error. /// /// * `radix` - Radix for the number parsing. /// * `first` - Pointer to the start of the input data. /// * `last` - Pointer to the one-past-the-end of the input data. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. Also panics /// if either pointer is null. #[cfg(feature = "radix")] #[no_mangle] pub unsafe extern fn $radix_name(radix: u8, first: *const u8, last: *const u8) -> Result<$t> { assert_radix!(radix); let bytes = $crate::util::api::slice_from_range(first, last); $crate::util::api::try_from_bytes_wrapper::<$t, _>(radix, bytes, $cb) } ) } /// Macro to generate the low-level, safe, try_parse API using a slice. #[doc(hidden)] macro_rules! generate_try_from_slice_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident) => ( /// Checked parser for a string-to-number conversion using Rust slices. /// /// Returns a C-compatible result containing the parsed value, /// and an error container any errors that occurred during parser. /// /// Numeric overflow takes precedence over the presence of an invalid /// digit, and therefore may mask an invalid digit error. /// /// * `bytes` - Slice containing a numeric string. #[inline] pub fn $decimal_name(bytes: &[u8]) -> Result<$t> { $crate::util::api::try_from_bytes_wrapper::<$t, _>(10, bytes, $cb) } /// Checked parser for a string-to-number conversion using Rust slices. /// /// Returns a C-compatible result containing the parsed value, /// and an error container any errors that occurred during parser. /// /// Numeric overflow takes precedence over the presence of an invalid /// digit, and therefore may mask an invalid digit error. /// /// * `radix` - Radix for the number parsing. /// * `bytes` - Slice containing a numeric string. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. #[cfg(feature = "radix")] #[inline] pub fn $radix_name(radix: u8, bytes: &[u8]) -> Result<$t> { assert_radix!(radix); $crate::util::api::try_from_bytes_wrapper::<$t, _>(radix, bytes, $cb) } ) } // TO BYTES WRAPPER /// Macro to generate the low-level, FFI, to_string API using a range. #[doc(hidden)] macro_rules! generate_to_range_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident, $size:ident) => ( /// Serializer for a number-to-string conversion using pointer ranges. /// /// Returns a pointer to the 1-past-the-last-byte-written, so that /// the range `[first, last)` contains the written bytes. No /// null-terminator is written. /// /// The data in the range may be uninitialized, these values are /// never read, only written to. /// /// * `value` - Number to serialize. /// * `first` - Pointer to the start of the buffer to write to. /// * `last` - Pointer to the one-past-the-end of the buffer to write to. /// /// # Panics /// /// Panics if the buffer is not of sufficient size, The caller /// must provide a range of sufficient size, and neither pointer /// may be null. In order to ensure the function will not panic, /// ensure the buffer has at least `MAX_*_SIZE` elements, using /// the proper constant for the serialized type from the /// lexical_core crate root. #[no_mangle] pub unsafe extern fn $decimal_name(value: $t, first: *mut u8, last: *mut u8) -> *mut u8 { let bytes = $crate::util::api::slice_from_range_mut(first, last); assert_buffer!(bytes, $size); let len = $cb(value, 10, bytes); bytes.as_mut_ptr().add(len) } /// Serializer for a number-to-string conversion using pointer ranges. /// /// Returns a pointer to the 1-past-the-last-byte-written, so that /// the range `[first, last)` contains the written bytes. No /// null-terminator is written. /// /// The data in the range may be uninitialized, these values are /// never read, only written to. /// /// * `value` - Number to serialize. /// * `radix` - Radix for number encoding. /// * `first` - Pointer to the start of the buffer to write to. /// * `last` - Pointer to the one-past-the-end of the buffer to write to. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. /// /// Also panics if the buffer is not of sufficient size, The caller /// must provide a range of sufficient size, and neither pointer /// may be null. In order to ensure the function will not panic, /// ensure the buffer has at least `MAX_*_SIZE` elements, using /// the proper constant for the serialized type from the /// lexical_core crate root. #[cfg(feature = "radix")] #[no_mangle] pub unsafe extern fn $radix_name(value: $t, radix: u8, first: *mut u8, last: *mut u8) -> *mut u8 { assert_radix!(radix); let bytes = $crate::util::api::slice_from_range_mut(first, last); assert_buffer!(bytes, $size); let len = $cb(value, radix, bytes); bytes.as_mut_ptr().add(len) } ) } /// Macro to generate the low-level, safe, to_string API using a slice. #[doc(hidden)] macro_rules! generate_to_slice_api { ($decimal_name:ident, $radix_name:ident, $t:ty, $cb:ident, $size:ident) => ( /// Serializer for a number-to-string conversion using Rust slices. /// /// Returns a subslice of the input buffer containing the written bytes, /// starting from the same address in memory as the input slice. /// /// If the buffer is not of sufficient size (see the constants /// named `MAX_*_SIZE` in the lexical_core crate), this function /// will panic (and call abort). You must provide a slice /// of sufficient length. The data in the slice may be /// uninitialized, these values are never read, only written to. /// /// * `value` - Number to serialize. /// * `bytes` - Slice containing a numeric string. /// /// # Panics /// /// Panics if the buffer is not of sufficient size, The caller /// must provide a slice of sufficient size. In order to ensure /// the function will not panic, ensure the buffer has at least /// `MAX_*_SIZE` elements, using the proper constant for the /// serialized type from the lexical_core crate root. #[inline] pub fn $decimal_name<'a>(value: $t, bytes: &'a mut [u8]) -> &'a mut [u8] { assert_buffer!(bytes, $size); let len = $cb(value, 10, bytes); &mut index_mut!(bytes[..len]) } /// Serializer for a number-to-string conversion using Rust slices. /// /// Returns a subslice of the input buffer containing the written bytes, /// starting from the same address in memory as the input slice. /// /// If the buffer is not of sufficient size (see the constants /// named `MAX_*_SIZE` in the lexical_core crate), this function /// will panic (and call abort). You must provide a slice /// of sufficient length. The data in the slice may be /// uninitialized, these values are never read, only written to. /// /// * `value` - Number to serialize. /// * `radix` - Radix for number encoding. /// * `bytes` - Slice containing a numeric string. /// /// # Panics /// /// Panics if the radix is not in the range `[2, 36]`. /// /// Also panics if the buffer is not of sufficient size, The caller /// must provide a slice of sufficient size. In order to ensure /// the function will not panic, ensure the buffer has at least /// `MAX_*_SIZE` elements, using the proper constant for the /// serialized type from the lexical_core crate root. #[cfg(feature = "radix")] #[inline] pub fn $radix_name<'a>(value: $t, radix: u8, bytes: &'a mut [u8]) -> &'a mut [u8] { assert_radix!(radix); assert_buffer!(bytes, $size); // This is always safe, since len is returned as // `distance(bytes.as_ptr(), slc.as_ptr())`, where `slc` is // a subslice from writes. let len = $cb(value, radix, bytes); &mut index_mut!(bytes[..len]) } ) }