pm_string.h File Reference

A generic string type that can have various ownership semantics. More...

#include "prism/defines.h"
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

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Data Structures
struct	pm_string_t
	A generic string type that can have various ownership semantics. More...

Macros
#define	PM_STRING_EMPTY   ((pm_string_t) { .type = PM_STRING_CONSTANT, .source = NULL, .length = 0 })
	Defines an empty string.

Enumerations
enum	pm_string_init_result_t { PM_STRING_INIT_SUCCESS = 0 , PM_STRING_INIT_ERROR_GENERIC = 1 , PM_STRING_INIT_ERROR_DIRECTORY = 2 }
	Represents the result of calling pm_string_mapped_init or pm_string_file_init. More...

Functions
PRISM_EXPORTED_FUNCTION size_t	pm_string_sizeof (void)
	Returns the size of the pm_string_t struct.
void	pm_string_shared_init (pm_string_t *string, const uint8_t *start, const uint8_t *end)
	Initialize a shared string that is based on initial input.
void	pm_string_owned_init (pm_string_t *string, uint8_t *source, size_t length)
	Initialize an owned string that is responsible for freeing allocated memory.
void	pm_string_constant_init (pm_string_t *string, const char *source, size_t length)
	Initialize a constant string that doesn't own its memory source.
PRISM_EXPORTED_FUNCTION pm_string_init_result_t	pm_string_mapped_init (pm_string_t *string, const char *filepath)
	Read the file indicated by the filepath parameter into source and load its contents and size into the given pm_string_t.
PRISM_EXPORTED_FUNCTION pm_string_init_result_t	pm_string_file_init (pm_string_t *string, const char *filepath)
	Read the file indicated by the filepath parameter into source and load its contents and size into the given pm_string_t.
void	pm_string_ensure_owned (pm_string_t *string)
	Ensure the string is owned.
int	pm_string_compare (const pm_string_t *left, const pm_string_t *right)
	Compare the underlying lengths and bytes of two strings.
PRISM_EXPORTED_FUNCTION size_t	pm_string_length (const pm_string_t *string)
	Returns the length associated with the string.
PRISM_EXPORTED_FUNCTION const uint8_t *	pm_string_source (const pm_string_t *string)
	Returns the start pointer associated with the string.
PRISM_EXPORTED_FUNCTION void	pm_string_free (pm_string_t *string)
	Free the associated memory of the given string.

Detailed Description

A generic string type that can have various ownership semantics.

Macro Definition Documentation

PM_STRING_EMPTY

#define PM_STRING_EMPTY   ((pm_string_t) { .type = PM_STRING_CONSTANT, .source = NULL, .length = 0 })

Defines an empty string.

This is useful for initializing a string that will be filled in later.

Enumeration Type Documentation

pm_string_init_result_t

enum pm_string_init_result_t

Represents the result of calling pm_string_mapped_init or pm_string_file_init.

We need this additional information because there is not a platform-agnostic way to indicate that the file that was attempted to be opened was a directory.

Enumerator
PM_STRING_INIT_SUCCESS	Indicates that the string was successfully initialized.
PM_STRING_INIT_ERROR_GENERIC	Indicates a generic error from a string_*_init function, where the type of error should be read from errno or GetLastError().
PM_STRING_INIT_ERROR_DIRECTORY	Indicates that the file that was attempted to be opened was a directory.

Function Documentation

pm_string_sizeof()

PRISM_EXPORTED_FUNCTION size_t pm_string_sizeof

(

void

)

Returns the size of the pm_string_t struct.

This is necessary to allocate the correct amount of memory in the FFI backend.

Returns

The size of the pm_string_t struct.

This is necessary to allocate the correct amount of memory in the FFI backend.

pm_string_shared_init()

void pm_string_shared_init	(	pm_string_t *	string,
		const uint8_t *	start,
		const uint8_t *	end
	)

Initialize a shared string that is based on initial input.

Parameters

string	The string to initialize.
start	The start of the string.
end	The end of the string.

pm_string_owned_init()

void pm_string_owned_init	(	pm_string_t *	string,
		uint8_t *	source,
		size_t	length
	)

Initialize an owned string that is responsible for freeing allocated memory.

Parameters

string	The string to initialize.
source	The source of the string.
length	The length of the string.

pm_string_constant_init()

void pm_string_constant_init	(	pm_string_t *	string,
		const char *	source,
		size_t	length
	)

Initialize a constant string that doesn't own its memory source.

Parameters

string	The string to initialize.
source	The source of the string.
length	The length of the string.

pm_string_mapped_init()

PRISM_EXPORTED_FUNCTION pm_string_init_result_t pm_string_mapped_init	(	pm_string_t *	string,
		const char *	filepath
	)

Read the file indicated by the filepath parameter into source and load its contents and size into the given pm_string_t.

The given pm_string_t should be freed using pm_string_free when it is no longer used.

We want to use demand paging as much as possible in order to avoid having to read the entire file into memory (which could be detrimental to performance for large files). This means that if we're on windows we'll use MapViewOfFile, on POSIX systems that have access to mmap we'll use mmap, and on other POSIX systems we'll use read.

Parameters

string	The string to initialize.
filepath	The filepath to read.

Returns

The success of the read, indicated by the value of the enum.

The given pm_string_t should be freed using pm_string_free when it is no longer used.

We want to use demand paging as much as possible in order to avoid having to read the entire file into memory (which could be detrimental to performance for large files). This means that if we're on windows we'll use MapViewOfFile, on POSIX systems that have access to mmap we'll use mmap, and on other POSIX systems we'll use read.

pm_string_file_init()

PRISM_EXPORTED_FUNCTION pm_string_init_result_t pm_string_file_init	(	pm_string_t *	string,
		const char *	filepath
	)

Read the file indicated by the filepath parameter into source and load its contents and size into the given pm_string_t.

The given pm_string_t should be freed using pm_string_free when it is no longer used.

Parameters

string	The string to initialize.
filepath	The filepath to read.

Returns

The success of the read, indicated by the value of the enum.

The given pm_string_t should be freed using pm_string_free when it is no longer used.

pm_string_ensure_owned()

void pm_string_ensure_owned

(

pm_string_t *

string

)

Ensure the string is owned.

If it is not, then reinitialize it as owned and copy over the previous source.

Parameters

string

The string to ensure is owned.

If it is not, then reinitialize it as owned and copy over the previous source.

pm_string_compare()

int pm_string_compare	(	const pm_string_t *	left,
		const pm_string_t *	right
	)

Compare the underlying lengths and bytes of two strings.

Returns 0 if the strings are equal, a negative number if the left string is less than the right string, and a positive number if the left string is greater than the right string.

Parameters

left	The left string to compare.
right	The right string to compare.

Returns

The comparison result.

Returns 0 if the strings are equal, a negative number if the left string is less than the right string, and a positive number if the left string is greater than the right string.

pm_string_length()

PRISM_EXPORTED_FUNCTION size_t pm_string_length

(

const pm_string_t *

string

)

Returns the length associated with the string.

Parameters

string

The string to get the length of.

Returns

The length of the string.

pm_string_source()

PRISM_EXPORTED_FUNCTION const uint8_t * pm_string_source

(

const pm_string_t *

string

)

Returns the start pointer associated with the string.

Parameters

string

The string to get the start pointer of.

Returns

The start pointer of the string.

pm_string_free()

PRISM_EXPORTED_FUNCTION void pm_string_free

(

pm_string_t *

string

)

Free the associated memory of the given string.

Parameters

string

The string to free.