mirror of https://github.com/LeOS-GSI/LeOS-Genesis
305 lines
8.4 KiB
C
305 lines
8.4 KiB
C
/**
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* @file parse_number.h
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @section DESCRIPTION
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*
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* Numeric string parsing.
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*/
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#ifndef BADVPN_MISC_PARSE_NUMBER_H
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#define BADVPN_MISC_PARSE_NUMBER_H
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#include <stdint.h>
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#include <string.h>
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#include <stddef.h>
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#include <limits.h>
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#include <misc/debug.h>
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#include <misc/cstring.h>
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// public parsing functions
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static int decode_decimal_digit (char c);
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static int decode_hex_digit (char c);
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static int parse_unsigned_integer_bin (const char *str, size_t str_len, uintmax_t *out) WARN_UNUSED;
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static int parse_unsigned_integer (const char *str, uintmax_t *out) WARN_UNUSED;
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static int parse_unsigned_integer_cstr (b_cstring cstr, size_t offset, size_t length, uintmax_t *out) WARN_UNUSED;
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static int parse_unsigned_hex_integer_bin (const char *str, size_t str_len, uintmax_t *out) WARN_UNUSED;
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static int parse_unsigned_hex_integer (const char *str, uintmax_t *out) WARN_UNUSED;
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static int parse_signmag_integer_bin (const char *str, size_t str_len, int *out_sign, uintmax_t *out_mag) WARN_UNUSED;
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static int parse_signmag_integer (const char *str, int *out_sign, uintmax_t *out_mag) WARN_UNUSED;
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static int parse_signmag_integer_cstr (b_cstring cstr, size_t offset, size_t length, int *out_sign, uintmax_t *out_mag) WARN_UNUSED;
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// public generation functions
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static int compute_decimal_repr_size (uintmax_t x);
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static void generate_decimal_repr (uintmax_t x, char *out, int repr_size);
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static int generate_decimal_repr_string (uintmax_t x, char *out);
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// implementation follows
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// decimal representation of UINTMAX_MAX
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static const char parse_number__uintmax_max_str[] = "18446744073709551615";
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// make sure UINTMAX_MAX is what we think it is
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static const char parse_number__uintmax_max_str_assert[(UINTMAX_MAX == UINTMAX_C(18446744073709551615)) ? 1 : -1];
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static int decode_decimal_digit (char c)
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{
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switch (c) {
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case '0': return 0;
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case '1': return 1;
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case '2': return 2;
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case '3': return 3;
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case '4': return 4;
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case '5': return 5;
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case '6': return 6;
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case '7': return 7;
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case '8': return 8;
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case '9': return 9;
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}
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return -1;
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}
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static int decode_hex_digit (char c)
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{
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switch (c) {
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case '0': return 0;
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case '1': return 1;
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case '2': return 2;
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case '3': return 3;
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case '4': return 4;
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case '5': return 5;
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case '6': return 6;
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case '7': return 7;
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case '8': return 8;
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case '9': return 9;
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case 'A': case 'a': return 10;
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case 'B': case 'b': return 11;
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case 'C': case 'c': return 12;
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case 'D': case 'd': return 13;
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case 'E': case 'e': return 14;
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case 'F': case 'f': return 15;
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}
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return -1;
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}
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static int parse__no_overflow (const char *str, size_t str_len, uintmax_t *out)
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{
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uintmax_t n = 0;
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while (str_len > 0) {
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if (*str < '0' || *str > '9') {
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return 0;
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}
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n = 10 * n + (*str - '0');
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str++;
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str_len--;
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}
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*out = n;
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return 1;
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}
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int parse_unsigned_integer_bin (const char *str, size_t str_len, uintmax_t *out)
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{
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// we do not allow empty strings
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if (str_len == 0) {
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return 0;
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}
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// remove leading zeros
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while (str_len > 0 && *str == '0') {
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str++;
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str_len--;
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}
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// detect overflow
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if (str_len > sizeof(parse_number__uintmax_max_str) - 1 ||
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(str_len == sizeof(parse_number__uintmax_max_str) - 1 && memcmp(str, parse_number__uintmax_max_str, sizeof(parse_number__uintmax_max_str) - 1) > 0)) {
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return 0;
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}
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// will not overflow (but can still have invalid characters)
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return parse__no_overflow(str, str_len, out);
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}
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int parse_unsigned_integer (const char *str, uintmax_t *out)
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{
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return parse_unsigned_integer_bin(str, strlen(str), out);
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}
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int parse_unsigned_integer_cstr (b_cstring cstr, size_t offset, size_t length, uintmax_t *out)
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{
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b_cstring_assert_range(cstr, offset, length);
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if (length == 0) {
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return 0;
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}
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uintmax_t n = 0;
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B_CSTRING_LOOP_RANGE(cstr, offset, length, pos, chunk_data, chunk_length, {
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for (size_t i = 0; i < chunk_length; i++) {
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int digit = decode_decimal_digit(chunk_data[i]);
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if (digit < 0) {
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return 0;
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}
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if (n > UINTMAX_MAX / 10) {
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return 0;
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}
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n *= 10;
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if (digit > UINTMAX_MAX - n) {
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return 0;
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}
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n += digit;
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}
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})
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*out = n;
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return 1;
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}
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int parse_unsigned_hex_integer_bin (const char *str, size_t str_len, uintmax_t *out)
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{
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uintmax_t n = 0;
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if (str_len == 0) {
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return 0;
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}
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while (str_len > 0) {
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int digit = decode_hex_digit(*str);
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if (digit < 0) {
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return 0;
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}
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if (n > UINTMAX_MAX / 16) {
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return 0;
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}
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n *= 16;
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if (digit > UINTMAX_MAX - n) {
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return 0;
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}
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n += digit;
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str++;
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str_len--;
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}
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*out = n;
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return 1;
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}
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int parse_unsigned_hex_integer (const char *str, uintmax_t *out)
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{
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return parse_unsigned_hex_integer_bin(str, strlen(str), out);
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}
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int parse_signmag_integer_bin (const char *str, size_t str_len, int *out_sign, uintmax_t *out_mag)
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{
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int sign = 1;
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if (str_len > 0 && (str[0] == '+' || str[0] == '-')) {
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sign = 1 - 2 * (str[0] == '-');
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str++;
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str_len--;
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}
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if (!parse_unsigned_integer_bin(str, str_len, out_mag)) {
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return 0;
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}
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*out_sign = sign;
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return 1;
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}
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int parse_signmag_integer (const char *str, int *out_sign, uintmax_t *out_mag)
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{
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return parse_signmag_integer_bin(str, strlen(str), out_sign, out_mag);
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}
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int parse_signmag_integer_cstr (b_cstring cstr, size_t offset, size_t length, int *out_sign, uintmax_t *out_mag)
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{
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b_cstring_assert_range(cstr, offset, length);
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int sign = 1;
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if (length > 0 && (b_cstring_at(cstr, offset) == '+' || b_cstring_at(cstr, offset) == '-')) {
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sign = 1 - 2 * (b_cstring_at(cstr, offset) == '-');
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offset++;
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length--;
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}
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if (!parse_unsigned_integer_cstr(cstr, offset, length, out_mag)) {
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return 0;
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}
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*out_sign = sign;
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return 1;
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}
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int compute_decimal_repr_size (uintmax_t x)
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{
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int size = 0;
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do {
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size++;
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x /= 10;
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} while (x > 0);
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return size;
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}
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void generate_decimal_repr (uintmax_t x, char *out, int repr_size)
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{
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ASSERT(out)
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ASSERT(repr_size == compute_decimal_repr_size(x))
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out += repr_size;
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do {
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*(--out) = '0' + (x % 10);
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x /= 10;
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} while (x > 0);
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}
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int generate_decimal_repr_string (uintmax_t x, char *out)
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{
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ASSERT(out)
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int repr_size = compute_decimal_repr_size(x);
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generate_decimal_repr(x, out, repr_size);
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out[repr_size] = '\0';
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return repr_size;
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}
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#endif
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