1 files changed, 162 insertions, 0 deletions
diff --git a/icecompr/iceuncompr.c b/icecompr/iceuncompr.c
new file mode 100644
index 0000000..04e7dc8
--- /dev/null
+++ b/icecompr/iceuncompr.c
@@ -0,0 +1,162 @@
+// This is free and unencumbered software released into the public domain.
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+FILE *input_file;
+FILE *output_file;
+
+int read_bitcounter;
+int read_buffer;
+
+int write_bitcounter;
+int write_buffer;
+
+static int read_bit()
+{
+	if (read_bitcounter == 0) {
+		read_bitcounter = 8;
+		read_buffer = fgetc(input_file);
+	}
+
+	read_bitcounter--;
+	return (read_buffer >> read_bitcounter) & 1;
+}
+
+static void write_bit(int value)
+{
+	write_bitcounter--;
+
+	if (value)
+		write_buffer |= 1 << write_bitcounter;
+	
+	if (write_bitcounter == 0) {
+		fputc(write_buffer, output_file);
+		write_bitcounter = 8;
+		write_buffer = 0;
+	}
+}
+
+static int read_int(int bits)
+{
+	int ret = 0;
+	while (bits-- > 0)
+		if (read_bit())
+			ret |= 1 << bits;
+	return ret;
+}
+
+static void write_zeros(int bits)
+{
+	while (bits-- > 0)
+		write_bit(0);
+}
+
+int ice_uncompress()
+{
+	read_bitcounter = 0;
+	read_buffer = 0;
+
+	write_bitcounter = 8;
+	write_buffer = 0;
+
+	int magic1_ok = read_int(32) == 0x49434543;
+	int magic2_ok = read_int(32) == 0x4f4d5052;
+
+	if (!magic1_ok || !magic2_ok) {
+		fprintf(stderr, "Missing ICECOMPR magic. Abort!\n");
+		return 1;
+	}
+
+	while (1)
+	{
+		if (read_bit()) {
+			write_zeros(read_int(2));
+			write_bit(1);
+		} else
+		if (read_bit()) {
+			write_zeros(read_int(5));
+			write_bit(1);
+		} else
+		if (read_bit()) {
+			write_zeros(read_int(8));
+			write_bit(1);
+		} else
+		if (read_bit()) {
+			int n = read_int(6);
+			while (n--)
+				write_bit(read_bit());
+			write_bit(1);
+		} else
+		if (read_bit()) {
+			write_zeros(read_int(23));
+			write_bit(1);
+		} else {
+			write_zeros(read_int(23));
+			break;
+		}
+	}
+
+	return 0;
+}
+
+void help()
+{
+	printf("\n");
+	printf("Usage: iceuncompr [input-file [output-file]]\n");
+	printf("\n");
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	input_file = stdin;
+	output_file = stdout;
+
+	int opt;
+	while ((opt = getopt(argc, argv, "v")) != -1)
+	{
+		switch (opt)
+		{
+		case 'v':
+			break;
+		default:
+			help();
+		}
+	}
+
+	if (optind < argc) {
+		input_file = fopen(argv[optind], "rb");
+		if (input_file == NULL) {
+			fprintf(stderr, "Failed to open input file `%s': %s\n", argv[optind], strerror(errno));
+			return 1;
+		}
+		optind++;
+	}
+
+	if (optind < argc) {
+		output_file = fopen(argv[optind], "wb");
+		if (output_file == NULL) {
+			fprintf(stderr, "Failed to open output file `%s': %s\n", argv[optind], strerror(errno));
+			return 1;
+		}
+		optind++;
+	}
+
+	if (optind != argc)
+		help();
+
+	if (optind != argc)
+		help();
+
+	return ice_uncompress();
+}
+