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/**
* @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 "prism/util/pm_buffer.h"
#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
/**
* A structure represents an arbitrary-sized integer.
*/
typedef struct {
/**
* Embedded value for small integer. This value is set to 0 if the value
* does not fit into uint32_t.
*/
uint32_t value;
/**
* The number of allocated values. length is set to 0 if the integer fits
* into uint32_t.
*/
size_t length;
/**
* List of 32-bit integers. Set to NULL if the integer fits into uint32_t.
*/
uint32_t *values;
/**
* 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 default decimal base, with no prefix. Leading 0s will be ignored. */
PM_INTEGER_BASE_DEFAULT,
/** 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 hexadecimal 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);
/**
* Compare two integers. This function returns -1 if the left integer is less
* than the right integer, 0 if they are equal, and 1 if the left integer is
* greater than the right integer.
*
* @param left The left integer to compare.
* @param right The right integer to compare.
* @return The result of the comparison.
*/
int pm_integer_compare(const pm_integer_t *left, const pm_integer_t *right);
/**
* Reduce a ratio of integers to its simplest form.
*
* If either the numerator or denominator do not fit into a 32-bit integer, then
* this function is a no-op. In the future, we may consider reducing even the
* larger numbers, but for now we're going to keep it simple.
*
* @param numerator The numerator of the ratio.
* @param denominator The denominator of the ratio.
*/
void pm_integers_reduce(pm_integer_t *numerator, pm_integer_t *denominator);
/**
* Convert an integer to a decimal string.
*
* @param buffer The buffer to append the string to.
* @param integer The integer to convert to a string.
*/
PRISM_EXPORTED_FUNCTION void pm_integer_string(pm_buffer_t *buffer, 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
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