ruby/prism/util/pm_integer.h

104 lines
3 KiB
C

/**
* @file pm_integer.h
*
* This module provides functions for working with arbitrary-sized integers.
*/
#ifndef PRISM_NUMBER_H
#define PRISM_NUMBER_H
#include "prism/defines.h"
#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
/**
* A node in the linked list of a pm_integer_t.
*/
typedef struct pm_integer_word {
/** A pointer to the next node in the list. */
struct pm_integer_word *next;
/** The value of the node. */
uint32_t value;
} pm_integer_word_t;
/**
* This structure represents an arbitrary-sized integer. It is implemented as a
* linked list of 32-bit integers, with the least significant digit at the head
* of the list.
*/
typedef struct {
/** The number of nodes in the linked list that have been allocated. */
size_t length;
/**
* The head of the linked list, embedded directly so that allocations do not
* need to be performed for small integers.
*/
pm_integer_word_t head;
/**
* Whether or not the integer is negative. It is stored this way so that a
* zeroed pm_integer_t is always positive zero.
*/
bool negative;
} pm_integer_t;
/**
* An enum controlling the base of an integer. It is expected that the base is
* already known before parsing the integer, even though it could be derived
* from the string itself.
*/
typedef enum {
/** The binary base, indicated by a 0b or 0B prefix. */
PM_INTEGER_BASE_BINARY,
/** The octal base, indicated by a 0, 0o, or 0O prefix. */
PM_INTEGER_BASE_OCTAL,
/** The decimal base, indicated by a 0d, 0D, or empty prefix. */
PM_INTEGER_BASE_DECIMAL,
/** The hexidecimal base, indicated by a 0x or 0X prefix. */
PM_INTEGER_BASE_HEXADECIMAL,
/**
* An unknown base, in which case pm_integer_parse will derive it based on
* the content of the string. This is less efficient and does more
* comparisons, so if callers know the base ahead of time, they should use
* that instead.
*/
PM_INTEGER_BASE_UNKNOWN
} pm_integer_base_t;
/**
* Parse an integer from a string. This assumes that the format of the integer
* has already been validated, as internal validation checks are not performed
* here.
*
* @param integer The integer to parse into.
* @param base The base of the integer.
* @param start The start of the string.
* @param end The end of the string.
*/
PRISM_EXPORTED_FUNCTION void pm_integer_parse(pm_integer_t *integer, pm_integer_base_t base, const uint8_t *start, const uint8_t *end);
/**
* Return the memory size of the integer.
*
* @param integer The integer to get the memory size of.
* @return The size of the memory associated with the integer.
*/
size_t pm_integer_memsize(const pm_integer_t *integer);
/**
* Free the internal memory of an integer. This memory will only be allocated if
* the integer exceeds the size of a single node in the linked list.
*
* @param integer The integer to free.
*/
PRISM_EXPORTED_FUNCTION void pm_integer_free(pm_integer_t *integer);
#endif