Added example for LZPacker::compress()

examples/ESP32/Deflate_lz77/Deflate_lz77.ino

@@ -0,0 +1,107 @@
+#ifndef ESP32
+  #error "this sketch is only available on ESP32 architecture"
+#endif
+
+// Set **destination** filesystem by uncommenting one of these:
+//#define DEST_FS_USES_SPIFFS
+#define DEST_FS_USES_LITTLEFS
+//#define DEST_FS_USES_SD
+//#define DEST_FS_USES_FFAT   // ESP32 only
+//#define DEST_FS_USES_SD_MMC // ESP32 only
+#include <ESP32-targz.h>
+
+
+void setup()
+{
+  Serial.begin(115200);
+  delay(1000);
+  Serial.println("Hello world");
+
+  if(!LittleFS.begin())
+  {
+      Serial.println("LittleFS Failed, halting");
+      while(1);
+  }
+  Serial.println("LittleFS started");
+
+
+  {
+    const char *txtFileName = "/jargon.txt";
+    const char *fzFileName = "/out.fz";
+
+    unsigned int srcBufLen;
+    unsigned char *srcBuf;
+
+
+    {
+      // load the uncompressed text file into memory
+      File fin = LittleFS.open(txtFileName);
+      if(!fin)
+      {
+        Serial.println("Unable to read input file, halting");
+        while(1);
+      }
+      srcBufLen = fin.size();
+      srcBuf = (unsigned char *)malloc(srcBufLen+1);
+      if( srcBuf == NULL )
+      {
+        Serial.printf("Failed to malloc() %d bytes, halting.\nHint: use a smaller file.\n", srcBufLen);
+        while(1);
+      }
+      size_t bytesRead = fin.readBytes( (char*)srcBuf, srcBufLen);
+      printf("Loaded %d bytes from file into ram\n", bytesRead);
+      fin.close();
+    }
+
+
+    {
+      if( LittleFS.exists(fzFileName))
+        LittleFS.remove(fzFileName); // delete artifacts from previous test
+
+      // open the fz file for writing
+      File fout = LittleFS.open(fzFileName, "w");
+      if(!fout)
+      {
+        Serial.println("Unable to create output file, halting");
+        while(1);
+      }
+
+      // deflate!
+      size_t outputSize = LZPacker::compress( srcBuf, srcBufLen, &fout );
+      Serial.printf("Compressed %d input bytes to %u raw bytes, file size is %d bytes\n", srcBufLen, outputSize, fout.position() );
+      free(srcBuf); // free the buffer
+      fout.close();
+    }
+
+
+    {
+      // now open the fz file for reading
+      File flz = LittleFS.open(fzFileName);
+      if(!flz)
+      {
+        Serial.println("Unable to open lz file, halting");
+        while(1);
+      }
+
+      // create GzUnpacker instance
+      GzUnpacker *GZUnpacker = new GzUnpacker();
+      // attach callback to write the uncompressed data
+      GZUnpacker->setStreamWriter(
+        [](unsigned char* buff, size_t buffsize)->bool
+        {
+          Serial.write(buff, buffsize); return true;
+        }
+      );
+      // inflate!
+      GZUnpacker->gzStreamExpander(&flz, flz.size());
+    }
+
+  }
+
+
+}
+
+void loop()
+{
+
+}