gzip解压和压缩
我发现网上很少有这样完整例子,加上英文有不好,走了好多弯路.我现在把从网上找到例子帖出来,可以解压HTTP gzip的
#include <stdlib.h> #include <string.h> #include <errno.h> #include <zlib.h> /* Compress data */ int zcompress(Bytef *data, uLong ndata, Bytef *zdata, uLong *nzdata) { z_stream c_stream; int err = 0; if(data && ndata > 0) { c_stream.zalloc = (alloc_func)0; c_stream.zfree = (free_func)0; c_stream.opaque = (voidpf)0; if(deflateInit(&c_stream, Z_DEFAULT_COMPRESSION) != Z_OK) return -1; c_stream.next_in = data; c_stream.avail_in = ndata; c_stream.next_out = zdata; c_stream.avail_out = *nzdata; while (c_stream.avail_in != 0 && c_stream.total_out < *nzdata) { 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; *nzdata = c_stream.total_out; return 0; } return -1; } /* Compress gzip data */ int gzcompress(Bytef *data, uLong ndata, Bytef *zdata, uLong *nzdata) { z_stream c_stream; int err = 0; if(data && ndata > 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, -MAX_WBITS, 8, Z_DEFAULT_STRATEGY) != Z_OK) return -1; c_stream.next_in = data; c_stream.avail_in = ndata; c_stream.next_out = zdata; c_stream.avail_out = *nzdata; while (c_stream.avail_in != 0 && c_stream.total_out < *nzdata) { 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; *nzdata = c_stream.total_out; return 0; } return -1; } /* Uncompress data */ int zdecompress(Byte *zdata, uLong nzdata, Byte *data, uLong *ndata) { int err = 0; z_stream d_stream; /* decompression stream */ 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(inflateInit(&d_stream) != 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) return -1; } if(inflateEnd(&d_stream) != Z_OK) return -1; *ndata = d_stream.total_out; return 0; } /* HTTP gzip decompress */ int httpgzdecompress(Byte *zdata, uLong nzdata, Byte *data, uLong *ndata) { 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, 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; } /* Uncompress gzip data */ int gzdecompress(Byte *zdata, uLong nzdata, Byte *data, uLong *ndata) { 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; } #ifdef _DEBUG_ZSTREAM #define BUF_SIZE 65535 int main() { char *data = "kjdalkfjdflkjdlkfjdklfjdlkfjlkdjflkdjflddajfkdjfkdfaskf;ldsfk;ldakf;ldskfl;dskf;ld"; uLong ndata = strlen(data); Bytef zdata[BUF_SIZE]; uLong nzdata = BUF_SIZE; Bytef odata[BUF_SIZE]; uLong nodata = BUF_SIZE; memset(zdata, 0, BUF_SIZE); //if(zcompress((Bytef *)data, ndata, zdata, &nzdata) == 0) if(gzcompress((Bytef *)data, ndata, zdata, &nzdata) == 0) { fprintf(stdout, "nzdata:%d %s/n", nzdata, zdata); memset(odata, 0, BUF_SIZE); //if(zdecompress(zdata, ndata, odata, &nodata) == 0) if(gzdecompress(zdata, ndata, odata, &nodata) == 0) { fprintf(stdout, "%d %s/n", nodata, odata); } } } #endif