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 "errorAndExit.h"
#include "inflate.h"

//The compressed and uncompressed buffer arrays
static const uint8_t* comprBuffer;
static uint8_t* uncomprBuffer;
//Position of the inflater in the buffer arrays
static const uint8_t* comprBufferNext;
static uint8_t* uncomprBufferNext;
//Buffer lengths
static unsigned long uncomprBufferSize;
static size_t remainingInput;
static size_t spaceInOutput;
//Internal variables used by miniz
static tinfl_decompressor decompressor;
static tinfl_status status;
static size_t in_bytes, out_bytes;

void inflateInit(uint8_t* comprBufferIn, uint8_t* uncomprBufferIn, unsigned long uncomprBufferSizeIn) {
  comprBuffer = comprBufferIn;
  uncomprBuffer = uncomprBufferIn;
  uncomprBufferSize = uncomprBufferSizeIn;
  tinfl_init(&decompressor);
}

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
    comprBufferNext = comprBuffer;
    remainingInput = numInputBytes;
  }

  //output buffer was previously fully filled and all output was processed. New uncompressed data can be written starting at offset 0
  if (spaceInOutput == 0) {
    uncomprBufferNext = (mz_uint8 *)uncomprBuffer;
    spaceInOutput = uncomprBufferSize;
  }

  struct InflateOutput out;
  out.hasReachedEnd = false;
  out.numBytesWrittenToOutput = 0UL;

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

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

    //Adjust buffer positions by the amount of bytes processed
    comprBufferNext = (const uint8_t *)(comprBufferNext + in_bytes);
    remainingInput -= in_bytes;
    uncomprBufferNext = (uint8_t *)(uncomprBufferNext + out_bytes);
    spaceInOutput -= out_bytes;
    out.numBytesWrittenToOutput += 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);
        errorAndExit();
      }
    }

    if (status == TINFL_STATUS_NEEDS_MORE_INPUT && remainingInput != 0) {
      fprintf(stderr, "Received status NEEDS_MORE_INPUT, with remaining input %lu and space in output %lu.\n", remainingInput, spaceInOutput);
    }
    if (status == TINFL_STATUS_HAS_MORE_OUTPUT && spaceInOutput != 0) {
      fprintf(stderr, "Received status HAS_MORE_OUTPUT, with remaining input %lu and space in output %lu.\n", remainingInput, spaceInOutput);
    }
  }

  //Return output
  if (remainingInput == 0) {
    out.needMoreInput = hasMoreBytes;
  } else {
    out.needMoreInput = false;
  }

  return out;
}