From 0a599caf862f459e179f3d3841f9764a608381bc Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Wed, 16 Oct 2019 22:43:18 +0200
Subject: Added simple hashing function like the one in lecture

---
 sem1/osc/mm10/Makefile | 12 ++++++++---
 sem1/osc/mm10/opg4.l   | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 3 deletions(-)
 create mode 100644 sem1/osc/mm10/opg4.l

diff --git a/sem1/osc/mm10/Makefile b/sem1/osc/mm10/Makefile
index 3d4089e..99bd635 100644
--- a/sem1/osc/mm10/Makefile
+++ b/sem1/osc/mm10/Makefile
@@ -1,4 +1,4 @@
-opgaver=opg1 opg3
+opgaver=opg1 opg3 opg4
 
 LEX=flex
 CC=gcc
@@ -8,12 +8,18 @@ DEFAULT_TARGET=all
 %: %.yy.c
 	$(CC) -o $@ $^ $(LINKFLAG)
 
+%.o: %.c
+	$(CC) -c -o $@ $^
+
 %.yy.c: %.l
 	$(LEX) -o $@ $^
 
 all: $(opgaver)
 
-phony: all clean
+phony: all clean run
+
+run: $(BIN)
+	./$(BIN)
 
 clean:
-	rm $(opgaver)
+	rm -f $(opgaver)
diff --git a/sem1/osc/mm10/opg4.l b/sem1/osc/mm10/opg4.l
new file mode 100644
index 0000000..9d18634
--- /dev/null
+++ b/sem1/osc/mm10/opg4.l
@@ -0,0 +1,58 @@
+%{
+
+#include <stdio.h>
+#include <stdint.h>
+
+#define BEGIN_T 1
+#define END_T 2
+#define NUM_T 3
+#define VAR_T 4
+#define HASHSIZE 100
+
+%}
+
+VAR			[a-zA-Z][a-zA-Z\_\-0-9]*
+TAL			[0-9]+
+
+%%
+
+begin		{printf("Found a BEGIN\n"); return BEGIN_T;}
+end			{printf("Found a END\n"); return END_T;}
+{VAR}		{printf("Found a variable %s\n", yytext); return VAR_T;}
+{TAL}		{printf("Found a number %d\n", strtol(yytext, NULL, 10)); return NUM_T;}
+
+%%
+
+unsigned int hash(char *s) {
+	uint32_t hv = 0;
+	for( int i = 0; s[i] != '\0'; i++ ) {
+		// take MSB 6 bits of hv and xors with LSB of s[i]
+		uint32_t v = ( hv >> 26 ) ^ (s[i] & 0x3f);
+
+		// Push those back on hv
+		hv = (hv << 4) | v;
+	}
+	// Return appropriate size
+	return hv % HASHSIZE;
+}
+
+int main(void) {
+
+	char str[100];
+	while( fgets(str, 100, stdin) ) {
+		printf("%s: %d\n", str, hash(str));
+	}
+
+	return 0;
+
+	for(;;) {
+		int t = yylex();
+		printf("yylex: %d\n", t);
+		if( t == END_T ) {
+			break;
+		}
+	}
+
+	return 0;
+	
+}
-- 
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