zlib (gzip) (二) winodws gzib使用

原创

jacklicto 2019-06-27 13:04:03 博主文章分类：C/C++ ©著作权

文章标签 gzlib #define #include #pragma 文章分类 JavaScript 前端开发

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压缩：

#include "stdafx.h"
#include "zlib/zlib.h"
#include <stdlib.h>
#include <windows.h>
#pragma comment (lib, "zlibstatic.lib")
static int  gzCompress(const unsigned char *src, int srcLen, unsigned char *dest, int destLen)
{
  z_stream c_stream;
  int err = 0;
  int windowBits = 15;
  int GZIP_ENCODING = 16;

  /* 压缩级别 */
//#define Z_NO_COMPRESSION         0  
//#define Z_BEST_SPEED             1  
//#define Z_BEST_COMPRESSION       9  
//#define Z_DEFAULT_COMPRESSION  (-1)  
  if (src && srcLen > 0)
  {
    c_stream.zalloc = (alloc_func)0;
    c_stream.zfree = (free_func)0;
    c_stream.opaque = (voidpf)0;
    if (deflateInit2(&c_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
      windowBits | GZIP_ENCODING, 8, Z_DEFAULT_STRATEGY) != Z_OK) return -1;
    c_stream.next_in = (Bytef *)src;
    c_stream.avail_in = srcLen;
    c_stream.next_out = (Bytef *)dest;
    c_stream.avail_out = destLen;
    while (c_stream.avail_in != 0 && c_stream.total_out < destLen)
    {
      if (deflate(&c_stream, Z_NO_FLUSH) != Z_OK) return -1;
    }
    if (c_stream.avail_in != 0) return c_stream.avail_in;
    for (;;) {
      if ((err = deflate(&c_stream, Z_FINISH)) == Z_STREAM_END) break;
      if (err != Z_OK) return -1;
    }
    if (deflateEnd(&c_stream) != Z_OK) return -1;
    return c_stream.total_out;
  }
  return -1;
}

解压：（有问题）

static int  gzDecompress(const char *src, int srcLen, const char *dst, int dstLen,
    int * outLen) {
    z_stream strm;
    strm.zalloc = NULL;
    strm.zfree = NULL;
    strm.opaque = NULL;

    strm.avail_in = srcLen;
    strm.avail_out = dstLen;
    strm.next_in = (Bytef *)src;
    strm.next_out = (Bytef *)dst;

    int err = -1, ret = -1;
    err = inflateInit2(&strm, MAX_WBITS + 16);
    if (err == Z_OK) {
        err = inflate(&strm, Z_FINISH);
        if (err == Z_STREAM_END) {
            ret = strm.total_out;
        }
        else {
            inflateEnd(&strm);
            return err;
        }
    }
    else {
        inflateEnd(&strm);
        return err;
    }
    inflateEnd(&strm);
    (*outLen) = ret;
    return err;
}

这个解压在 MD编译的情况下会有问题

更新一下

int utils_idcardverify::gzDecompress(const unsigned char *src, int srcLen, const unsigned char *dst,  
      int * outLen)
   
   {
      Byte *zdata = (Byte *)src;
      uLong nzdata = (uLong)srcLen;
      Byte *data = (Byte *)dst;
      uLong *ndata = (uLong*)outLen;
      int err = 0;
      z_stream d_stream = { 0 }; /* decompression stream */
      static char dummy_head[2] =
      {
         0x8 + 0x7 * 0x10,
         (((0x8 + 0x7 * 0x10) * 0x100 + 30) / 31 * 31) & 0xFF,
      };
      d_stream.zalloc = (alloc_func)0;
      d_stream.zfree = (free_func)0;
      d_stream.opaque = (voidpf)0;
      d_stream.next_in = zdata;
      d_stream.avail_in = 0;
      d_stream.next_out = data;
      //if (inflateInit2(&d_stream, -MAX_WBITS) != Z_OK) return -1;
      if (inflateInit2(&d_stream, 47) != Z_OK) return -1;
      while (d_stream.total_out < *ndata && d_stream.total_in < nzdata) {
         d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
         if ((err = inflate(&d_stream, Z_NO_FLUSH)) == Z_STREAM_END) break;
         if (err != Z_OK)
         {
            if (err == Z_DATA_ERROR)
            {
               d_stream.next_in = (Bytef*)dummy_head;
               d_stream.avail_in = sizeof(dummy_head);
               if ((err = inflate(&d_stream, Z_NO_FLUSH)) != Z_OK)
               {
                  return -1;
               }
            }
            else return -1;
         }
      }
      if (inflateEnd(&d_stream) != Z_OK) return -1;
      *ndata = d_stream.total_out;
      return 0;
   }