From 93900930111901d1eadf07cace8fe5834dbf7a54 Mon Sep 17 00:00:00 2001
From: Jack <jmaxfiel@caltech.edu>
Date: Wed, 1 Apr 2020 21:50:49 -0400
Subject: [PATCH] Add huffman and example file
---
.gitignore | 2 +
Makefile | 7 +++-
example.bin | 1 +
huffman.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 123 insertions(+), 2 deletions(-)
create mode 100644 example.bin
create mode 100644 huffman.c
diff --git a/.gitignore b/.gitignore
index 822895d..5e7833a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
myzip0
myunzip0
+inflate
+huffman
\ No newline at end of file
diff --git a/Makefile b/Makefile
index f1e3ca9..026c9f2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,10 @@
-all : myzip0 myunzip0
+all : myzip0 myunzip0 huffman
myzip0 : myzip0.c
cc myzip0.c -o myzip0
myunzip0 : myunzip0.c
- cc myunzip0.c -o myunzip0
\ No newline at end of file
+ cc myunzip0.c -o myunzip0
+
+huffman : huffman.c
+ cc huffman.c -o huffman
\ No newline at end of file
diff --git a/example.bin b/example.bin
new file mode 100644
index 0000000..d90011e
--- /dev/null
+++ b/example.bin
@@ -0,0 +1 @@
+"3DUfwˆ™ª»ÌÝîÿ
\ No newline at end of file
diff --git a/huffman.c b/huffman.c
new file mode 100644
index 0000000..527f741
--- /dev/null
+++ b/huffman.c
@@ -0,0 +1,115 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+
+/* A struct for writing to files as
+ streams of individual bits */
+
+typedef struct __bit_writer
+{
+ FILE *file;
+ uint8_t byte;
+ int mod;
+} bit_writer;
+
+bit_writer *bit_writer_init(FILE *file)
+{
+ bit_writer *bw = malloc(sizeof(bit_writer));
+ assert(bw);
+ bw->file = file;
+ bw->byte = 0;
+ bw->mod = 0;
+ return bw;
+}
+
+void bit_writer_free(bit_writer *bw)
+{
+ free(bw);
+}
+
+void bit_writer_write_bit(bit_writer *bw, bool bit)
+{
+ bw->byte |= (bit > 0) << (bw->mod++);
+
+ if (bw->mod == 8)
+ {
+ fwrite(&bw->byte, 1, 1, bw->file);
+ bw->byte = 0;
+ bw->mod = 0;
+ }
+}
+
+void bit_writer_flush(bit_writer *bw)
+{
+ while (bw->mod != 0) bit_writer_write_bit(bw, 0);
+}
+
+void write_byte(bit_writer *bw, uint8_t byte)
+{
+
+ if (byte <= 143) /* 8 bit encoding */
+ {
+ uint32_t to_encode = 0x30 + (uint32_t) byte;
+ for (int b = 8 - 1; b >= 0; b--)
+ bit_writer_write_bit(bw, to_encode & (1 << b));
+ } else /* 9 bit encoding */
+ {
+ uint32_t to_encode = 0x100 + (uint32_t) byte;
+ for (int b = 9 - 1; b >= 0; b--)
+ {
+ // bool to_write = () != 0;
+ // printf("Writing %d\n", to_write);
+ bit_writer_write_bit(bw, to_encode & (1 << b));
+ }
+ }
+}
+
+int main(int argc, char *argv[])
+{
+ if (argc != 2)
+ {
+ printf("Usage: %s <input file>\n", argv[0]);
+ exit(1);
+ }
+
+ char *input_file_name = argv[1];
+ char *output_file_name = malloc(sizeof(char) *
+ (strlen(input_file_name) + strlen(".deflate") + 1));
+ sprintf(output_file_name, "%s.deflate", input_file_name);
+
+ FILE *input_file = fopen(input_file_name, "r");
+ FILE *output_file = fopen(output_file_name, "w");
+ free(output_file_name);
+ bit_writer *bw = bit_writer_init(output_file);
+
+
+
+ bit_writer_write_bit(bw, 1); /* BFINAL */
+
+ bit_writer_write_bit(bw, 1); /* BTYPE */
+ bit_writer_write_bit(bw, 0);
+
+ // write_byte(bw, 144);
+
+ char c;
+ while (fread(&c, 1, 1, input_file))
+ {
+ // printf("Writing %d\n", (int) c);
+ write_byte(bw, c);
+ }
+
+ for (int i = 0; i < 7; i++)
+ bit_writer_write_bit(bw, 0);
+
+ bit_writer_flush(bw);
+ bit_writer_free(bw);
+ fclose(output_file);
+ fclose(input_file);
+
+
+
+ return 0;
+}
\ No newline at end of file
--
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