[*] Initial commit

lonetix/numlib_atoi.c

@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+/**
+ * \file numlib_atoi.c
+ *
+ * Implements ASCII to integer conversion.
+ *
+ * \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
+ * \author    Lorenzo Cogotti
+ */
+
+#include "numlib.h"
+
+#include <assert.h>
+#include <limits.h>
+
+static int digitval(char ch)
+{
+	if (ch >= '0' && ch <= '9')
+		return ch - '0';
+	else if (ch >= 'A' && ch <= 'Z')
+		return ch - 'A' + 10;
+	else if (ch >= 'a' && ch <= 'z')
+		return ch - 'a' + 10;
+	else
+		return -1;
+}
+
+static unsigned long long ParseInt(const char *s,
+                                   char      **endptr,
+                                   unsigned    base,
+                                   int        *signp,
+                                   NumConvRet *outcome)
+{
+	int d;
+
+	// Single optional + or -
+	char c;
+	int sign;
+
+	const char *startptr = s;
+	unsigned long long u = 0;
+
+	sign = 1;
+	if (base > 36) {
+		*outcome = NCVEBADBASE;
+		goto done;
+	}
+
+	c    = *s;
+	if (c == '-' || c == '+') {
+		sign -= (c == '-') << 1;
+		s++;
+	}
+
+	// Determine base
+	if (base == 0) {
+		if (s[0] == '0') {
+			if (s[1] == 'x' || s[1] == 'X') {
+				s += 2;
+				base = 16;
+			} else if (s[1] == 'b' || s[1] == 'B') {
+				s += 2;
+				base = 2;
+			} else {
+				s++;
+				base = 8;
+			}
+		} else {
+			base = 10;
+		}
+	} else if (base == 16) {
+		if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
+			s += 2;
+	} else if (base == 2) {
+		if (s[0] == '0' && (s[1] == 'b' || s[1] == 'B'))
+			s += 2;
+	}
+
+	// Convert numeric value
+	*outcome = NCVENOERR;  // assume successful conversion
+
+	while ((d = digitval(*s)) >= 0 && d < (int) base) {
+		unsigned long long v = u * base + d;
+		if (u > v) {
+			// Overflow
+			v        = ULLONG_MAX;
+			*outcome = NCVEOVERFLOW;
+		}
+
+		u = v;
+		s++;
+	}
+
+	if (s == startptr)
+		*outcome = NCVENOTHING;
+
+done:
+	if (endptr)
+		*endptr = (char *) s;
+
+	*signp = sign;
+	return u;
+}
+
+unsigned long long Atoull(const char *s,
+                          char      **endp,
+                          unsigned    base,
+                          NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (sign < 0)
+		*outcome = NCVEUNDERFLOW;
+
+	return sign * mag;
+}
+
+unsigned long Atoul(const char *s,
+                    char      **endp,
+                    unsigned    base,
+                    NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (mag > ULONG_MAX)
+		*outcome = NCVEOVERFLOW;
+	if (sign < 0)
+		*outcome = NCVEUNDERFLOW;
+
+	return sign * mag;
+}
+
+unsigned Atou(const char *s, char **endp, unsigned base, NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (mag > UINT_MAX)
+		*outcome = NCVEOVERFLOW;
+	if (sign < 0)
+		*outcome = NCVEUNDERFLOW;
+
+	return sign * mag;
+}
+
+long long Atoll(const char *s, char **endp, unsigned base, NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (sign > 0 && mag > LLONG_MAX) {
+		*outcome = NCVEOVERFLOW;
+		return LLONG_MAX;
+	}
+	if (sign < 0 && mag > -((unsigned long long) LLONG_MIN)) {
+		*outcome = NCVEUNDERFLOW;
+		return LLONG_MIN;
+	}
+	return sign * mag;
+}
+
+long Atol(const char *s, char **endp, unsigned base, NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (sign > 0 && mag > LONG_MAX) {
+		*outcome = NCVEOVERFLOW;
+		return LONG_MAX;
+	}
+	if (sign < 0 && mag > -((unsigned long) LONG_MIN)) {
+		*outcome = NCVEUNDERFLOW;
+		return LONG_MIN;
+	}
+	return sign * mag;
+}
+
+int Atoi(const char *s, char **endp, unsigned base, NumConvRet *outcome)
+{
+	NumConvRet result;
+	if (!outcome)
+		outcome = &result;
+
+	int sign;
+	unsigned long long mag = ParseInt(s, endp, base, &sign, outcome);
+	if (sign > 0 && mag > INT_MAX) {
+		*outcome = NCVEOVERFLOW;
+		return INT_MAX;
+	}
+	if (sign < 0 && mag > -((unsigned) INT_MIN)) {
+		*outcome = NCVEUNDERFLOW;
+		return INT_MIN;
+	}
+	return sign * mag;
+}