utils/strscan

This module provides functions for converting strings to numbers.

Interface

#include <utils/strscan.h>

Enumerations

StrScanFmt

/* Describes conversion status and format of the output. */
typedef enum {
    STRSCAN_ERROR, /* Error during conversion. All other values denote successful conversion. */
    STRSCAN_NUM,   /* Output is double. */
    STRSCAN_IMAG,  /* Output is double, but the input was warked with I/i suffix. */
    STRSCAN_INT,   /* Output is int32_t, stored in lower 4 bytes of the output buffer. */
    STRSCAN_U32,   /* Output is uint32_t, stored in lower 4 bytes of the output buffer. */
    STRSCAN_I64,   /* Output is int64_t. */
    STRSCAN_U64,   /* Output is uint64_t. */
} StrScanFmt;

Functions

StrScanFmt strscan_tonumber(const uint8_t *p, double *d, uint32_t opt)

Converts a string pointed to by p to a number and stores the result in a buffer pointed to by d. Uses flags in opt to control the conversion. Supported flags are:

Flag	Description
STRSCAN_OPT_TONUM	Convert to double.
STRSCAN_OPT_IMAG	Convert to double. If the input is marked with the I suffix, STRSCAN_IMAG will be returned.
STRSCAN_OPT_LL	Convert to long long (both signed and unsigned), allowing following suffixes for the input: LL, ULL, LLU. CAVEAT. As the result of conversion is stored in the buffer pointed to by a double * pointer, it’s caller’s responsibility to interpret the output properly. Return value should be checked for this purpose.
STRSCAN_OPT_C	Convert to int or long (both signed and unsigned) , allowing following suffixes for the input: U, UL, LU. CAVEAT. As the result of conversion is stored in the buffer pointed to by a double * pointer, it’s caller’s responsibility to interpret the output properly. Return value should be checked for this purpose. If the input was converted to int (signed or unsigned), the result is stored in the lower 4 bytes of the output buffer.

Returns conversion status of StrScanFmt.

Literals are parsed according to following EBNF definition (NB! This is a draft version):

literal                    = spaces , [ sign ] , literal-payload , spaces
literal-payload            = special-literal | numeric-literal
special-literal            = ( "I" | "i" ) , ( "N" | "n" ) , ( "F" | "f" ) | ( "I" | "i") , ( "N" | "n" ) , ( "F" | "f" ), ( "I" | "i") , ( "N" | "n" ) , ( "I" | "i") , ( "T" | "t" ), ( "Y" | "y" ) | ( "N" | "n" ) , ( "A" | "a" ) , ( "N" | "n" )
numeric-literal            = integer-literal | floating-point-literal
integer-literal            = integer-literal-digits [ integer-literal-suffix ]
integer-literal-digits     = integer-literal-oct | integer-literal-dec | integer-literal-hex
integer-literal-suffix     = ( "U" | "u" ) | ( "L" | "l" ) | ( "U" | "u" ) , ( "L" | "l" ) | ( "L" | "l" ) , ( "U" | "u" )  | ( "L" | "l" ) , ( "L" | "l" ) | ( "U" | "u" ) , ( "L" | "l" ) , ( "L" | "l" ) | ( "L" | "l" ) , ( "L" | "l" ) , ( "U" | "u" )
integer-literal-oct        = "0" , { octal-digit }
integer-literal-dec        = { decimal-digit } , [ exponent-dec ]
integer-literal-hex        = "0" , "x" , { hexadecimal-digit } , [ exponent-hex ]
floating-point-literal     = floating-point-literal-dec | floating-point-literal-hex
floating-point-literal-dec = { decimal-digit } , "." , [ { decimal-digit } ] , [ exponent-dec ]
floating-point-literal-hex = "0" , "x" , { hexadecimal-digit } , "." , [ { hexadecimal-digit } ] , [ exponent-hex ]
exponent-dec               = "E" , [sign] , { decimal-digit }
exponent-hex               = "P" , [sign] , { decimal-digit }
octal-digit                = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7"
decimal-digit              = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
hexadecimal-digit          = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" | ( "A" | "a" ) | ( "B" | "b" ) | ( "C" | "c" ) | ( "D" | "d" ) | ( "E" | "e" ) | ( "F" | "f" )
spaces                     = "" | { " " | "\t" }
sign                       = "+" | "-"