From 2084b2ae842e5ceeeba6950ffb6d8b6ac70b51fb Mon Sep 17 00:00:00 2001
From: Reina Harrington-Affine <reinakobayashi1217@gmail.com>
Date: Tue, 16 Sep 2025 18:54:10 +0000
Subject: [PATCH] WIP version of ex1-17-2.c that crashes during a memory safety
 check in store() for some reason. If I comment out the check, it spins and
 segfaults. Cause unknown.

---
 KNR C/ex1-17-2.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 KNR C/ex1-17-2.c

diff --git a/KNR C/ex1-17-2.c b/KNR C/ex1-17-2.c
new file mode 100644
index 0000000..25c56f8
--- /dev/null
+++ b/KNR C/ex1-17-2.c	
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+// Initialize array for bulk storage of incoming text. . .
+char buffer[32000] = {0};
+char output[64000] = {0};
+
+//Global information about the state of output[] to circumvent costly seeking
+//of double null by loop.
+int outputCrsr = 0;
+int* locOutCrsr = &outputCrsr;
+
+// Function for storing from the input buffer to array
+void store(char storage[]);
+// Function for sorting through data in buffer[]
+void enumerate(char data[]);
+// Function for recalling and printing data identified for recall by enumerate()
+void recall(char from[]);
+// Function to copy from one array to another
+void replicate(char from[], char to[]);
+
+int main(){
+	store(buffer); // Calls store() to write from stdin to storage
+	enumerate(buffer);// Calls enumerate() to seek and enumerate lines of 
+							// length 80 or greater.
+	recall (output); //calls recall() to print output[] to stdout
+	return 0;
+}
+
+// Important to note that store intentionally does not print EOF to the storage
+void store(char storage[]){
+	int cursor = 0;
+	int lim = 32000; //TODO Un-hardcode this. Using strlen resulted in a spin
+					 //due to interactions with a memory safety check in a
+					 //previous version.
+	for(int current = getchar(); current != EOF; ++cursor){
+		// Begin memory safety check. . .
+		if (cursor >= (lim - 1)){
+				printf("%s", "Error: Input exceeds size of storage (32kB).");
+				exit(EXIT_FAILURE);
+		}
+		storage[cursor] = current;
+	}
+}
+
+// Enumerate breaks on first encountered null character (i.e. end of used space
+//in data[]
+void enumerate(char data[]){
+	
+	int curLineLen = 0; // Current line length (characters since last newline)
+	int dataCursor = 0; // Currently accessed position in data[]
+	char workingStorage[32000]; // Local storage for enumerate while working
+	int wSCursor = 0; // Currently accessed position in workingStorage[]
+	
+	for(int current = data[dataCursor]; current != '\0'; ++dataCursor){
+		if(current != '\n'){
+			workingStorage[wSCursor] = current;
+			++curLineLen;
+		} else if (current == '\n' && curLineLen >= 80){
+			workingStorage[wSCursor] = current;
+			++wSCursor;
+			workingStorage[wSCursor] = '\0';
+			replicate(workingStorage, output);
+		} else if (current == '\n' && curLineLen < 80){
+			wSCursor = 0;
+		}
+	}
+}
+
+//TODO Shift internal cursor to first double null in output[], increment cursor,
+//and write new data to output[]. Break on first encountered input null. 
+void replicate(char from[], char to[]){
+
+//TODO Malloc a variable inside replicate() to replace outputCrsr and locOutCrsr
+//because the fact that replicate() depends on global variables like that is a
+//readability nightmare. This is the only fucntion that depends on them.
+
+	int toCrsr = 0;
+	int fromCrsr = 0;
+	int last = 0;
+
+	toCrsr = outputCrsr; //Shift toCrsr to the last written position in output.
+	++toCrsr; //Step forward 1 byte in to[] in order to preserve a null space
+
+	for(int current = from[fromCrsr]; current != '\0'; ++fromCrsr){
+		to[toCrsr] = from[fromCrsr];
+		++toCrsr;
+	}
+	*locOutCrsr = toCrsr; //Set global state of output.
+}
+
+void recall(char from[]){
+	printf("%s", from);
+}