From e5a87eb26c73f78f3ba60afac0821b35299c7552 Mon Sep 17 00:00:00 2001
From: avdgrinten <alexander.vandergrinten@gmail.com>
Date: Sun, 14 May 2017 15:37:10 +0200
Subject: [PATCH] ansi: Implement strtoimax()

---
 libc/generic/ansi/src/inttypes-stubs.cpp | 58 ++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 3 deletions(-)

diff --git a/libc/generic/ansi/src/inttypes-stubs.cpp b/libc/generic/ansi/src/inttypes-stubs.cpp
index 866410e5..bc2ddd0a 100644
--- a/libc/generic/ansi/src/inttypes-stubs.cpp
+++ b/libc/generic/ansi/src/inttypes-stubs.cpp
@@ -1,7 +1,12 @@
 
+#include <ctype.h>
 #include <inttypes.h>
+#include <string.h>
+
 #include <mlibc/ensure.h>
 
+static const char *__mlibc_digits = "0123456789abcdefghijklmnopqrstuvwxyz";
+
 intmax_t imaxabs(intmax_t) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
@@ -10,9 +15,56 @@ imaxdiv_t imaxdiv(intmax_t, intmax_t) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
 }
-intmax_t strtoimax(const char *__restrict, char **__restrict, int) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+intmax_t strtoimax(const char *__restrict it, char **__restrict out, int base) {
+	// TODO: This function has to check for overflow!
+	intmax_t v = 0;
+	bool negate = false;
+
+	// TODO: In this case we have to detect the base based on the prefix.
+	__ensure(base);
+
+	if(*it == '+') {
+		it++;
+	}else if(*it == '-') {
+		negate = true;
+		it++;
+	}
+
+	if(base == 8) {
+		if(*it != 0)
+			goto parse_digits;
+		it++;
+	}else if(base == 16) {
+		if(*it != 0)
+			goto parse_digits;
+		it++;
+		if(*it != 'x' && *it != 'X')
+			goto parse_digits;
+		it++;
+	}
+
+parse_digits:
+	while(*it) {
+		if(isspace(*it)) {
+			it++;
+			continue;
+		}
+
+		__ensure(base <= 10); // TODO: For base > 10 we need to implement tolower().
+		//auto c = strchr(__mlibc_digits, tolower(*it));
+		auto c = strchr(__mlibc_digits, *it);
+		if(!c || (__mlibc_digits - c) >= base)
+			break;
+		v = v * base + (__mlibc_digits - c);
+		it++;
+	}
+
+	if(negate)
+		v = -v;
+
+	if(out)
+		*out = const_cast<char *>(it);
+	return v;
 }
 uintmax_t strtoumax(const char *__restrict, char **__restrict, int) {
 	__ensure(!"Not implemented");