ssn-installer/src/inflate.c

//Based on https://github.com/richgel999/miniz/blob/master/examples/example5.c (Public domain, April 11 2012, Rich Geldreich, richgel99@gmail.com)

#include <stdbool.h>
#include <stdio.h>

//Include miniz, disabling what we don't need
#define MINIZ_NO_STDIO
#define MINIZ_NO_ARCHIVE_APIS
#define MINIZ_NO_TIME
#define MINIZ_NO_ZLIB_APIS
#define MINIZ_NO_MALLOC
#include "../lib/miniz/miniz.h"

#include "inflate.h"

//The compressed and uncompressed buffer arrays
const char* comprBuffer;
char* uncomprBuffer;
//Position of the inflater in the buffer arrays
const char* comprBufferNext;
char* uncomprBufferNext;
//Buffer lengths
unsigned long uncomprBufferSize;
unsigned long remainingInput;
unsigned long spaceInOutput;
//Internal variables used by miniz
tinfl_decompressor inflator;
tdefl_status status;
size_t in_bytes, out_bytes;

void inflateInit(char* comprBufferIn, char* uncomprBufferIn, unsigned long uncomprBufferSizeIn) {
  comprBuffer = comprBufferIn;
  uncomprBuffer = uncomprBufferIn;
  uncomprBufferSize = uncomprBufferSizeIn;
  tinfl_init(&inflator);
}

struct InflateOutput inflateInflate(unsigned long numInputBytes, bool hasMoreBytes) {
  if (numInputBytes == 0) {
    //continue in input buffer where we were before
  } else {
    //go back to beginning of input buffer
    remainingInput = numInputBytes;
    comprBufferNext = (const mz_uint8 *)comprBuffer;
  }
  //output buffer has been emptied
  spaceInOutput = uncomprBufferSize;
  uncomprBufferNext = (mz_uint8 *)uncomprBuffer;

  struct InflateOutput out;
  out.hasReachedEnd = false;

  while (remainingInput > 0 && spaceInOutput > 0) {
    in_bytes = remainingInput;
    out_bytes = spaceInOutput;

    //Call decompression
    status = tinfl_decompress(
      &inflator,
      (const mz_uint8 *)comprBufferNext,
      &in_bytes,
      uncomprBuffer,
      (mz_uint8 *)uncomprBufferNext,
      &out_bytes,
      (hasMoreBytes ? TINFL_FLAG_HAS_MORE_INPUT : 0)
    );

    //Adjust buffer positions by the amount of bytes processed
    comprBufferNext = (const mz_uint8 *)comprBufferNext + in_bytes;
    remainingInput -= in_bytes;
    uncomprBufferNext = (mz_uint8 *)uncomprBufferNext + out_bytes;
    spaceInOutput -= out_bytes;

    //Check for errors
    if (status <= TINFL_STATUS_DONE) {
      if (status == TINFL_STATUS_DONE) {
        // Decompression completed successfully.
        out.hasReachedEnd = true;
        break;
      } else {
        // Decompression failed.
        fprintf(stderr, "tinfl_decompress() failed with status %i!\n", status);
        exit(1);
      }
    }

    //If output buffer is filled, we need to clear it before decompressing more data
    if (spaceInOutput == 0) {
      break;
    }
  }

  //Return output
  if (remainingInput == 0) {
    out.needMoreInput = hasMoreBytes;
  }
  out.numBytesWrittenToOutput = uncomprBufferSize - spaceInOutput;

  return out;
}