Initial commit, write base64 encoder

set1/Makefile

@@ -0,0 +1,14 @@
+
+CC = gcc
+CFLAGS = -Wall -Wpedantic -Wextra -std=c99 -g
+RM = rm
+
+all: base64
+
+base64: base64.c
+	$(CC) -o $@ $^
+
+clean:
+	$(RM) base64
+	$(RM) *.o
+

set1/base64.c

@@ -0,0 +1,68 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * base64.c: reads in raw bytes and converts to/outputs in base64 format
+ * x1phosura 2022
+ */
+
+#define BUF_LEN 4096
+
+#define b64_output putchar
+//#define b64_output b64_out_debug
+
+size_t out_index = 0;
+char out_buf[BUF_LEN];
+
+void b64_out_debug(char c)
+{
+	printf("Using '%c' from base64 alphabet\n", c);
+	out_buf[out_index] = c; // TODO: check out_index
+	++out_index;
+}
+
+char *b64_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+
+void main(int argc, char *argv[])
+{
+	char c, spoke = 0;
+	int tmp, alph_index = 0;
+	
+	while ((c = getchar()) != EOF) {
+		switch (spoke) {
+		case 0:
+			alph_index = c >> 2;                  // get last 6 bits
+			tmp = (c & 0x03) << 4;                // extract last 2 bits
+			break;
+		case 1:
+			alph_index = c >> 4;                  // get last 4 bits
+			alph_index += tmp;
+			tmp = (c & 0x0f) << 2;
+			break;
+		case 2:
+			alph_index = tmp;
+			alph_index += c >> 6;
+			b64_output(b64_alphabet[alph_index]);
+			alph_index = c & 0x3f;
+			break;
+		}
+		b64_output(b64_alphabet[alph_index]);
+		spoke = (spoke + 1) % 3;
+	}
+
+	if (spoke == 1) {
+		alph_index = tmp;
+		b64_output(b64_alphabet[alph_index]);
+		b64_output('=');
+		b64_output('=');
+	} else if (spoke == 2) {
+		alph_index = tmp;
+		b64_output(b64_alphabet[alph_index]);
+		b64_output('=');
+	}
+
+	putchar('\n');
+}
+