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allwpilib/wpiutil/src/main/native/include/wpi/util/string.h
2025-11-07 23:09:21 -08:00

131 lines
3.4 KiB
C++

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#pragma once
#ifdef __cplusplus
#include <cstring>
#include <string_view>
#endif
/**
* A const UTF8 string.
*/
struct WPI_String {
/** Contents. */
const char* str;
/** Length */
size_t len;
};
#ifdef __cplusplus
namespace wpi {
/** Converts a WPI_String to a string_view */
constexpr std::string_view to_string_view(const struct WPI_String* str) {
if (str) {
return {str->str, str->len};
} else {
return "";
}
}
/** Converts a string_view to a WPI_String */
constexpr WPI_String make_string(std::string_view view) {
return WPI_String{view.data(), view.size()};
}
} // namespace wpi
#endif // __cplusplus
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
/**
* Initializes a WPI_String from a null terminated UTF-8 string.
* If input string is null, initializes output to 0 length.
* The output length does not include the null terminator.
*
* The lifetime of the output string is the lifetime of the input string.
* Do not call WPI_FreeString() with the output of this call.
*
* @param wpiString output string
* @param utf8String input string (null terminated)
*/
void WPI_InitString(struct WPI_String* wpiString, const char* utf8String);
/**
* Initializes a WPI_String from a UTF-8 string and length.
* If input string is null or 0 length, initializes output to 0 length.
* The input string does not need to be null terminated.
*
* The lifetime of the output string is the lifetime of the input string.
* Do not call WPI_FreeString() with the output of this call.
*
* @param wpiString output string
* @param utf8String input string
* @param length input string length in chars
*/
void WPI_InitStringWithLength(struct WPI_String* wpiString,
const char* utf8String, size_t length);
/**
* Allocates a WPI_String for the specified length.
* The resultant string must be freed with WPI_FreeString().
*
* @param wpiString output string
* @param length string length in chars to allocate
* @return mutable pointer to allocated buffer
*
*/
char* WPI_AllocateString(struct WPI_String* wpiString, size_t length);
/**
* Frees a WPI_String that was allocated with WPI_AllocateString()
*
* @param wpiString string to free
*/
void WPI_FreeString(const struct WPI_String* wpiString);
/**
* Allocates an array of WPI_Strings.
*
* @param length array length
* @return string array
*/
struct WPI_String* WPI_AllocateStringArray(size_t length);
/**
* Frees a WPI_String array returned by WPI_AllocateStringArray().
*
* @param wpiStringArray string array to free
* @param length length of array
*/
void WPI_FreeStringArray(const struct WPI_String* wpiStringArray,
size_t length);
#ifdef __cplusplus
} // extern "C"
#endif // __cplusplus
#ifdef __cplusplus
namespace wpi {
/** Allocates a copy of a string_view and stores the result into a WPI_String */
inline WPI_String alloc_wpi_string(std::string_view view) {
WPI_String out;
size_t len = view.size();
std::memcpy(WPI_AllocateString(&out, len), view.data(), len);
return out;
}
/** Allocates a copy of a WPI_String */
inline WPI_String copy_wpi_string(const WPI_String& str) {
if (str.str == nullptr || str.len == 0) {
return WPI_String{nullptr, 0};
}
return alloc_wpi_string(to_string_view(&str));
}
} // namespace wpi
#endif