git » fp-git.git » commit eae2c47

diff --git a/stuff/contest/lzg/uncompress.c b/stuff/contest/lzg/uncompress.c
new file mode 100644
index 0000000..56112f9
--- /dev/null
+++ b/stuff/contest/lzg/uncompress.c
@@ -0,0 +1,131 @@
+/*
+ * This sample code is to test the LZG algorithm
+ *
+ * Compile with:
+ *  gcc -o uncompress uncompress.c
+ *
+ * Usage:
+ *  ./uncompress (input file) (output file)
+ *
+ * note that input file must be a valid LZG compressed file with
+ * permission to be read and output file should be a nonexistent file
+ * or it will be overwritten.
+ *
+ * This document is GPL
+ */
+
+#include <stdio.h>
+
+/* BEGIN of page pasted part */
+
+/* A big number */
+#define MAX_MOD_SIZE_IN_LZG    32001
+
+/* modulus to be used in the 10 bits of the algorithm */
+#define MAX_MXD_SIZE_IN_LZG    0x400 /* 1024 */
+
+/* LZG expansion algorithm sub function */
+unsigned char popBit(unsigned char *byte) {
+	unsigned char bit=(unsigned char)((*byte)&1);
+	(*byte)>>=1;
+	return bit;
+}
+
+/* Expands LZ Groody algorithm. This is the core of PR */
+void expandLzg(const unsigned char* array, int arraySize, 
+								unsigned char* img, int *imageSize) {
+	char k;
+	int location,h,cursor=0,pos=0;
+	unsigned char maskbyte,rep;
+
+	/* img is an unsigned char[] sized 0x400 */
+	/* clean output garbage */
+	for(location=0;location<MAX_MOD_SIZE_IN_LZG;img[location]=0,location++);
+
+	/* main loop */
+	while (pos<arraySize) {
+		maskbyte=array[pos++];
+		for (k=8;k&&(pos<arraySize);k--) {
+			if (popBit(&maskbyte)) {
+				img[cursor++]=array[pos++];
+			} else {
+				/*
+				 * location:
+				 *  10 bits for the slide position (S). Add 66 to this number.
+				 * rep:
+				 *  6 bits for the repetition number (R). Add 3 to this number.
+				 */
+				rep=      3  + ((array[pos] & 0xfc /*11111100*/) >>2);
+				location= 66 + ((array[pos] & 0x03 /*00000011*/) <<8) + array[pos+1];
+				
+				pos+=2;
+				
+				/* Here is the difference between big and small images */
+				while (rep--) {
+					h=cursor/MAX_MXD_SIZE_IN_LZG-
+						((location%MAX_MXD_SIZE_IN_LZG)>(cursor%MAX_MXD_SIZE_IN_LZG));
+					/*
+					 * if the image is stored in an array of 1024 x n bytes
+					 * "h" is the height and "location" is the width
+					 */
+					img[cursor++]=img[
+						((h<0)?0:h)*MAX_MXD_SIZE_IN_LZG+
+						(location++)%MAX_MXD_SIZE_IN_LZG
+					];
+				}
+			}
+		}
+	}
+
+	*imageSize=cursor;
+}
+
+/* END of page pasted part */
+
+int main(int argc, char** argv) {
+	/* declare variables */
+	unsigned char uncompressed[MAX_MOD_SIZE_IN_LZG];
+	unsigned char compressed[MAX_MOD_SIZE_IN_LZG];
+	int uncompressedSize;
+	int compressedSize;
+	FILE* fp;
+				
+	/* validate input */
+	if (argc!=3) {
+		fprintf(stderr,"Syntax: %s [cmp file] [target raw file]\n",*argv);
+		return 1;
+	}
+
+	/* open file */
+	fp=fopen(argv[1],"rb");
+	if (!fp) {
+		fprintf(stderr,"Error opening '%s'. Does it exist?\n",argv[1]);
+		return 2;
+	}
+
+	/* read file to array */
+	uncompressedSize=fread(uncompressed,1,sizeof(uncompressed),fp);
+	
+	/* close file */
+	fclose(fp);
+
+	/* compress file */
+	expandLzg(uncompressed,uncompressedSize,compressed,&compressedSize);
+
+	/* save results */
+	fp=fopen(argv[2],"wb");	
+	if (!fp) {
+		fprintf(stderr,"Error opening '%s' for writting. Do you have permissions?\n",argv[2]);
+		return 4;
+	}
+	fwrite(compressed,compressedSize,1,fp);
+	fclose(fp);
+
+	/* show results on screen */
+	printf ("Results:\n Input file: %s (%d)\n Output file: %s (%d)\n",
+		argv[1],uncompressedSize,argv[2],compressedSize);
+
+	/* end */
+	return 0;
+}
+