An embedded-friendly library for decompressing files from zip archives

Hi,

I'm still not able to read the unzipped data chunk by chunk. If I would read it at once, It would not fit into RAM. My unzipped data size is 393 KB If I comment out Block 2, it is working, but I would like to read 512 bytes one after another:

...
#define BUFF_SIZE 512
static uint8_t l_Buff[BUFF_SIZE];
...
    // Block 1
    zip.openCurrentFile();
    mySeek(&myfile, 0, SEEK_SET);
    int readSize = zip.readCurrentFile(l_Buff, BUFF_SIZE);
    Serial.print("Bytes read in buffer: "); Serial.println(readSize);
    binFile.write(l_Buff, BUFF_SIZE);

    // Block 2
    mySeek(&myfile, 512, SEEK_SET);
    readSize = zip.readCurrentFile(l_Buff, BUFF_SIZE);
    Serial.print("Bytes read in buffer: "); Serial.println(readSize);
    binFile.write(l_Buff, BUFF_SIZE);

Hi,

I could create a simple program to test your library with SdFat library, instead of standard Arduino SD. But I realized, that I still have a problem. I would like to implement FOTA, so I will download the application.zip file. Then I want to unzip it (application.bin). The .bin file is quite large (393216 byte). I don't have this much memory. (I have 56+4 KB of SRAM on STM32F429ZI).

So my question, how can I use your library, so that I can write this larga application.bin to the SD card in chunkwise manner?

Here is my code:

#include <Arduino.h>
#include <unzipLIB.h>
#include "SdFat.h"
#include "sdios.h"

SPIClass SPI_4(PE6, PE5, PE2); // MOSI, MISO. SCLK
const uint8_t SD_CS_PIN = PE4;
#define SD_CONFIG SdSpiConfig(SD_CS_PIN, DEDICATED_SPI, SD_SCK_MHZ(4), &SPI_4)

UNZIP zip; // statically allocate the UNZIP structure (41K)
SdFat sd;
File root;
static File myfile;
static File myfileAnother;

void * myOpen(const char *filename, int32_t *size) {
  root.open("/");
  myfileAnother.open(filename);
  *size = (uint32_t)myfileAnother.fileSize();
  return (void *)&myfileAnother;
}

void myClose(void *p) {
  ZIPFILE *pzf = (ZIPFILE *)p;
  File *f = (File *)pzf->fHandle;
  if (f) f->close();
}

int32_t myRead(void *p, uint8_t *buffer, int32_t length) {
  ZIPFILE *pzf = (ZIPFILE *)p;
  File *f = (File *)pzf->fHandle;
  return f->read(buffer, length);
}

int32_t mySeek(void *p, int32_t position, int iType) {
  ZIPFILE *pzf = (ZIPFILE *)p;
  File *f = (File *)pzf->fHandle;
  if (iType == SEEK_SET)
    return f->seek(position);
  else if (iType == SEEK_END) {
    return f->seek(position + pzf->iSize); 
  } else { // SEEK_CUR
    long l = f->position();
    return f->seek(l + position);
  }
}

void setup() {
  Serial.begin(115200);

  while (!Serial && millis() < 3000);
  Serial.println("Search for ZIP files on the SD card");
  
  if (!sd.begin(SD_CONFIG))
  {
    sd.initErrorHalt(&Serial);
    Serial.println("Unable to access SD Card");
  }

  if (!root.open("/"))
  {
    Serial.println("Open root failed");
  }
  //////////////////////////////////////////////////////////////////////////////
  int rc;
  char szComment[256], szName[256];
  unz_file_info fi;

  const char *name = "application.zip";
  if (!myfile.open(name, O_RDONLY))
  {
    Serial.println("Opening application.zip failed");
  }
  Serial.println("Openend application.zip");
  rc = rc = zip.openZIP(name, myOpen, myClose, myRead, mySeek);
  if (rc == UNZ_OK) {
    Serial.print("ZIP file found");

    // Display the global comment and all of the filenames within
    rc = zip.getGlobalComment(szComment, sizeof(szComment));
    Serial.print("Files in this archive: ");
    zip.gotoFirstFile();
    rc = UNZ_OK;
    rc = zip.getFileInfo(&fi, szName, sizeof(szName), NULL, 0, szComment, sizeof(szComment));

    if (rc == UNZ_OK) {
      Serial.println(szName);
      Serial.print("Compressed size: "); Serial.println(fi.compressed_size, DEC);
      Serial.print("Uncompressed size: "); Serial.println(fi.uncompressed_size, DEC);
      
    }
    zip.closeZIP();
  }
}

void loop() {}

Hello, I would have a question. Do you have some example code for SdFat library (https://github.com/greiman/SdFat)? I would like to use your library, but on STM32, I can't use the standard SD library.