From 9ffa7dde857c29c1f74e1738284e4b3abfa72f10 Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Mon, 21 Mar 2022 21:54:58 +0100
Subject: [PATCH] Add strcmp and readline

---
 utils.c | 61 +++++++++++++++++++++++++++++++++++++++++----------------
 utils.h |  2 ++
 2 files changed, 46 insertions(+), 17 deletions(-)

diff --git a/utils.c b/utils.c
index cd173fb..221a9ff 100644
--- a/utils.c
+++ b/utils.c
@@ -1,25 +1,25 @@
-#include <stdint.h>
-#include "uart.h"
 #include "clock.h"
+#include "uart.h"
+#include <stdint.h>
 
 // K&R inspirated
 
 void printhex(unsigned int d)
 {
 	char n;
-	for(int c=28;c>=0;c-=4) {
+	for (int c = 28; c >= 0; c -= 4) {
 		// get highest tetrad
-		n=(d>>c)&0xF;
+		n = (d >> c) & 0xF;
 		// 0-9 => '0'-'9', 10-15 => 'A'-'F'
-		n+=n>9?0x37:0x30;
+		n += n > 9 ? 0x37 : 0x30;
 		putc(n);
 	}
 }
 
 int strlen(char s[])
 {
-	int i=0;
-	while(s[i]!= '\0') {
+	int i = 0;
+	while (s[i] != '\0') {
 		++i;
 	}
 	return i;
@@ -28,20 +28,20 @@ int strlen(char s[])
 void reverse(char s[])
 {
 	int c, i, j;
-	for(i=0, j=strlen(s)-1; i<j; i++, j--) {
-		c=s[i];
-		s[i]=s[j];
-		s[j]=c;
+	for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
+		c    = s[i];
+		s[i] = s[j];
+		s[j] = c;
 	}
 }
 
 void itoa(unsigned int n, char s[])
 {
-	int i=0;
+	int i = 0;
 	do {
-		s[i++]=n%10+'0';
-	} while((n/=10)>0);
-	s[i]='\0';
+		s[i++] = n % 10 + '0';
+	} while ((n /= 10) > 0);
+	s[i] = '\0';
 	reverse(s);
 }
 
@@ -49,7 +49,7 @@ void printdec(unsigned int d)
 {
 	char s[16];
 	itoa(d, s);
-	for(int i=0; i<strlen(s); i++) {
+	for (int i = 0; i < strlen(s); i++) {
 		putc(s[i]);
 	}
 }
@@ -61,7 +61,7 @@ void printclock()
 					  "PWM",      "HEVC", "EMMC2", "M2MC",  "PIXEL_BVB"};
 
 	puts("Clocks:\n");
-	for(int i =1; i <= CLK_PIXEL_BVB; i++ ){
+	for (int i = 1; i <= CLK_PIXEL_BVB; i++) {
 		puts(" ");
 		puts(clocktxts[i]);
 		puts(": ");
@@ -71,3 +71,30 @@ void printclock()
 		puts(" Hz\n");
 	}
 }
+
+int readline(char *buf, int maxlen)
+{
+	int num = 0;
+	while (num < maxlen - 1) {
+		char c = uart_recv();
+		// It seems like screen sends \r when I press enter
+		if (c == '\n' || c == '\0' || c == '\r') {
+			break;
+		}
+		buf[num] = c;
+		num++;
+	}
+	buf[num] = '\0';
+	return num;
+}
+
+// Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2
+int strcmp(const char s1[], const char s2[])
+{
+    int i;
+    for (i = 0; s1[i] == s2[i]; i++) {
+        if (s1[i] == '\0')
+            return 0;
+    }
+    return s1[i] - s2[i];
+}
diff --git a/utils.h b/utils.h
index 4dfed5d..c3abbaa 100644
--- a/utils.h
+++ b/utils.h
@@ -6,3 +6,5 @@ void reverse(char s[]);
 void itoa(unsigned int n, char s[]);
 void printdec(unsigned int d);
 void printclock();
+int strcmp(const char s1[], const char s2[]);
+int readline(char *buf, int maxlen);