adapted old code to use LZSSDecoder

Author: andreagilardoni

src/decompress/lzss.cpp

@@ -5,38 +5,16 @@
 #include "lzss.h"
 
 #include <stdlib.h>
-#include <stdint.h>
-
-/**************************************************************************************
-   DEFINE
- **************************************************************************************/
-
-#define EI 11             /* typically 10..13 */
-#define EJ  4             /* typically 4..5 */
-#define P   1             /* If match length <= P then output one character */
-#define N (1 << EI)       /* buffer size */
-#define F ((1 << EJ) + 1) /* lookahead buffer size */
-
-#define LZSS_EOF       (-1)
-
-#define FPUTC_BUF_SIZE (64)
-#define FGETC_BUF_SIZE (64)
 
 /**************************************************************************************
    GLOBAL VARIABLES
  **************************************************************************************/
 
-static uint32_t LZSS_FILE_SIZE = 0;
-static FILE * update_file = 0;
-static FILE * target_file = 0;
-
-int bit_buffer = 0, bit_mask = 128;
-unsigned char buffer[N * 2];
+static FILE * update_file = nullptr;
+static FILE * target_file = nullptr;
 
-static char write_buf[FPUTC_BUF_SIZE];
-static size_t write_buf_num_bytes = 0;
-static size_t bytes_written_fputc = 0;
-static ArduinoPortentaOtaWatchdogResetFuncPointer wdog_feed_func = 0;
+static ArduinoPortentaOtaWatchdogResetFuncPointer wdog_feed_func = nullptr;
+static LZSSDecoder* decoder = nullptr;
 
 /**************************************************************************************
    PUBLIC FUNCTIONS
@@ -57,122 +35,31 @@ void lzss_init(
     }
 
     decoder = new LZSSDecoder(
-        [](const uint8_t c) {
+        [target_file](const uint8_t c) {
             fwrite(&c, 1, 1, target_file);
         }
     );
 }
 
-void lzss_flush()
-{
-  bytes_written_fputc += write_buf_num_bytes;
-
-  if (wdog_feed_func)
-    wdog_feed_func();
-
-  fwrite(write_buf, 1, write_buf_num_bytes, target_file);
-
-  write_buf_num_bytes = 0;
-}
-
-/**************************************************************************************
-   PRIVATE FUNCTIONS
- **************************************************************************************/
-
-void lzss_fputc(int const c)
-{
-  /* Buffer the decompressed data into a buffer so
-   * we can perform block writes and don't need to
-   * write every byte singly on the flash (which 
-   * wouldn't be possible anyway).
-   */
-  write_buf[write_buf_num_bytes] = static_cast<char>(c);
-  write_buf_num_bytes++;
-
-  /* The write buffer is full of decompressed
-   * data, write it to the flash now.
-   */
-  if (write_buf_num_bytes == FPUTC_BUF_SIZE)
-    lzss_flush();
-}
-
-int lzss_fgetc()
-{
-  static uint8_t read_buf[FGETC_BUF_SIZE];
-  static size_t read_buf_pos = FGETC_BUF_SIZE;
-  static size_t bytes_read_fgetc = 0;
-  static size_t bytes_read_from_modem = 0;
-
-  /* lzss_file_size is set within SSUBoot:main 
-   * and contains the size of the LZSS file. Once
-   * all those bytes have been read its time to return
-   * LZSS_EOF in order to signal that the end of
-   * the file has been reached.
-   */
-  if (bytes_read_fgetc == LZSS_FILE_SIZE)
-    return LZSS_EOF;
-
-  /* If there is no data left to be read from the read buffer
-   * than read a new block and store it into the read buffer.
-   */
-  if (read_buf_pos == FGETC_BUF_SIZE)
-  {
-    /* Read the next block from the flash memory. */
-    bytes_read_from_modem += fread(read_buf, 1, FGETC_BUF_SIZE, update_file);
-    /* Reset the read buffer position. */
-    read_buf_pos = 0;
-  }
-
-  uint8_t const c = read_buf[read_buf_pos];
-  read_buf_pos++;
-  bytes_read_fgetc++;
-
-  return c;
+void lzss_flush() {
+    fflush(target_file);
 }
 
-/**************************************************************************************
-   LZSS FUNCTIONS
- **************************************************************************************/
-
-int getbit(int n) /* get n bits */
-{
-    int i, x;
-    static int buf, mask = 0;
-    
-    x = 0;
-    for (i = 0; i < n; i++) {
-        if (mask == 0) {
-            if ((buf = lzss_fgetc()) == LZSS_EOF) return LZSS_EOF;
-            mask = 128;
-        }
-        x <<= 1;
-        if (buf & mask) x++;
-        mask >>= 1;
+void lzss_decode() {
+    if(decoder == nullptr) {
+        return;
     }
-    return x;
-}
+    const size_t buf_size = 64;
+    uint8_t buffer[buf_size];
+    size_t res = 0;
 
-void lzss_decode(void)
-{
-    int i, j, k, r, c;
-    
-    for (i = 0; i < N - F; i++) buffer[i] = ' ';
-    r = N - F;
-    while ((c = getbit(1)) != LZSS_EOF) {
-        if (c) {
-            if ((c = getbit(8)) == LZSS_EOF) break;
-            lzss_fputc(c);
-            buffer[r++] = c;  r &= (N - 1);
-        } else {
-            if ((i = getbit(EI)) == LZSS_EOF) break;
-            if ((j = getbit(EJ)) == LZSS_EOF) break;
-            for (k = 0; k <= j + 1; k++) {
-                c = buffer[(i + k) & (N - 1)];
-                lzss_fputc(c);
-                buffer[r++] = c;  r &= (N - 1);
-            }
+    do {
+        if(wdog_feed_func) {
+            wdog_feed_func();
         }
-    }
+        res = fread(buffer, sizeof(uint8_t), buf_size, update_file);
+        decoder->decompress(buffer, res);
+    } while(res == buf_size);
 }