/** * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under the BSD-style license found in the * LICENSE file in the root directory of this source tree. An additional grant * of patent rights can be found in the PATENTS file in the same directory. */ /*-************************************ * Compiler specific **************************************/ #ifdef _MSC_VER /* Visual Studio */ # define _CRT_SECURE_NO_WARNINGS /* fgets */ # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */ # pragma warning(disable : 4146) /* disable: C4146: minus unsigned expression */ #endif /*-************************************ * Includes **************************************/ #include <stdlib.h> /* free */ #include <stdio.h> /* fgets, sscanf */ #include <time.h> /* clock_t, clock() */ #include <string.h> /* strcmp */ #include "mem.h" #define ZSTD_STATIC_LINKING_ONLY /* ZSTD_maxCLevel */ #include "zstd.h" /* ZSTD_compressBound */ #define ZBUFF_STATIC_LINKING_ONLY /* ZBUFF_createCCtx_advanced */ #include "zbuff.h" /* ZBUFF_isError */ #include "datagen.h" /* RDG_genBuffer */ #define XXH_STATIC_LINKING_ONLY #include "xxhash.h" /* XXH64_* */ /*-************************************ * Constants **************************************/ #define KB *(1U<<10) #define MB *(1U<<20) #define GB *(1U<<30) static const U32 nbTestsDefault = 10000; #define COMPRESSIBLE_NOISE_LENGTH (10 MB) #define FUZ_COMPRESSIBILITY_DEFAULT 50 static const U32 prime1 = 2654435761U; static const U32 prime2 = 2246822519U; /*-************************************ * Display Macros **************************************/ #define DISPLAY(...) fprintf(stderr, __VA_ARGS__) #define DISPLAYLEVEL(l, ...) if (g_displayLevel>=l) { DISPLAY(__VA_ARGS__); } static U32 g_displayLevel = 2; #define DISPLAYUPDATE(l, ...) if (g_displayLevel>=l) { \ if ((FUZ_GetClockSpan(g_displayClock) > g_refreshRate) || (g_displayLevel>=4)) \ { g_displayClock = clock(); DISPLAY(__VA_ARGS__); \ if (g_displayLevel>=4) fflush(stderr); } } static const clock_t g_refreshRate = CLOCKS_PER_SEC * 15 / 100; static clock_t g_displayClock = 0; static clock_t g_clockTime = 0; /*-******************************************************* * Fuzzer functions *********************************************************/ #define MAX(a,b) ((a)>(b)?(a):(b)) static clock_t FUZ_GetClockSpan(clock_t clockStart) { return clock() - clockStart; /* works even when overflow. Max span ~ 30 mn */ } /*! FUZ_rand() : @return : a 27 bits random value, from a 32-bits `seed`. `seed` is also modified */ # define FUZ_rotl32(x,r) ((x << r) | (x >> (32 - r))) unsigned int FUZ_rand(unsigned int* seedPtr) { U32 rand32 = *seedPtr; rand32 *= prime1; rand32 += prime2; rand32 = FUZ_rotl32(rand32, 13); *seedPtr = rand32; return rand32 >> 5; } /* static unsigned FUZ_highbit32(U32 v32) { unsigned nbBits = 0; if (v32==0) return 0; for ( ; v32 ; v32>>=1) nbBits++; return nbBits; } */ static void* ZBUFF_allocFunction(void* opaque, size_t size) { void* address = malloc(size); (void)opaque; /* DISPLAYLEVEL(4, "alloc %p, %d opaque=%p \n", address, (int)size, opaque); */ return address; } static void ZBUFF_freeFunction(void* opaque, void* address) { (void)opaque; /* if (address) DISPLAYLEVEL(4, "free %p opaque=%p \n", address, opaque); */ free(address); } static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem customMem) { int testResult = 0; size_t CNBufferSize = COMPRESSIBLE_NOISE_LENGTH; void* CNBuffer = malloc(CNBufferSize); size_t const skippableFrameSize = 11; size_t const compressedBufferSize = (8 + skippableFrameSize) + ZSTD_compressBound(COMPRESSIBLE_NOISE_LENGTH); void* compressedBuffer = malloc(compressedBufferSize); size_t const decodedBufferSize = CNBufferSize; void* decodedBuffer = malloc(decodedBufferSize); size_t cSize, readSize, readSkipSize, genSize; U32 testNb=0; ZBUFF_CCtx* zc = ZBUFF_createCCtx_advanced(customMem); ZBUFF_DCtx* zd = ZBUFF_createDCtx_advanced(customMem); /* Create compressible test buffer */ if (!CNBuffer || !compressedBuffer || !decodedBuffer || !zc || !zd) { DISPLAY("Not enough memory, aborting\n"); goto _output_error; } RDG_genBuffer(CNBuffer, CNBufferSize, compressibility, 0., seed); /* generate skippable frame */ MEM_writeLE32(compressedBuffer, ZSTD_MAGIC_SKIPPABLE_START); MEM_writeLE32(((char*)compressedBuffer)+4, (U32)skippableFrameSize); cSize = skippableFrameSize + 8; /* Basic compression test */ DISPLAYLEVEL(4, "test%3i : compress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH); ZBUFF_compressInitDictionary(zc, CNBuffer, 128 KB, 1); readSize = CNBufferSize; genSize = compressedBufferSize; { size_t const r = ZBUFF_compressContinue(zc, ((char*)compressedBuffer)+cSize, &genSize, CNBuffer, &readSize); if (ZBUFF_isError(r)) goto _output_error; } if (readSize != CNBufferSize) goto _output_error; /* entire input should be consumed */ cSize += genSize; genSize = compressedBufferSize - cSize; { size_t const r = ZBUFF_compressEnd(zc, ((char*)compressedBuffer)+cSize, &genSize); if (r != 0) goto _output_error; } /* error, or some data not flushed */ cSize += genSize; DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/COMPRESSIBLE_NOISE_LENGTH*100); /* skippable frame test */ DISPLAYLEVEL(4, "test%3i : decompress skippable frame : ", testNb++); ZBUFF_decompressInitDictionary(zd, CNBuffer, 128 KB); readSkipSize = cSize; genSize = CNBufferSize; { size_t const r = ZBUFF_decompressContinue(zd, decodedBuffer, &genSize, compressedBuffer, &readSkipSize); if (r != 0) goto _output_error; } if (genSize != 0) goto _output_error; /* skippable frame len is 0 */ DISPLAYLEVEL(4, "OK \n"); /* Basic decompression test */ DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH); ZBUFF_decompressInitDictionary(zd, CNBuffer, 128 KB); readSize = cSize - readSkipSize; genSize = CNBufferSize; { size_t const r = ZBUFF_decompressContinue(zd, decodedBuffer, &genSize, ((char*)compressedBuffer)+readSkipSize, &readSize); if (r != 0) goto _output_error; } /* should reach end of frame == 0; otherwise, some data left, or an error */ if (genSize != CNBufferSize) goto _output_error; /* should regenerate the same amount */ if (readSize+readSkipSize != cSize) goto _output_error; /* should have read the entire frame */ DISPLAYLEVEL(4, "OK \n"); /* check regenerated data is byte exact */ DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++); { size_t i; for (i=0; i<CNBufferSize; i++) { if (((BYTE*)decodedBuffer)[i] != ((BYTE*)CNBuffer)[i]) goto _output_error;; } } DISPLAYLEVEL(4, "OK \n"); /* Byte-by-byte decompression test */ DISPLAYLEVEL(4, "test%3i : decompress byte-by-byte : ", testNb++); { size_t r, pIn=0, pOut=0; do { ZBUFF_decompressInitDictionary(zd, CNBuffer, 128 KB); r = 1; while (r) { size_t inS = 1; size_t outS = 1; r = ZBUFF_decompressContinue(zd, ((BYTE*)decodedBuffer)+pOut, &outS, ((BYTE*)compressedBuffer)+pIn, &inS); pIn += inS; pOut += outS; } readSize = pIn; genSize = pOut; } while (genSize==0); } if (genSize != CNBufferSize) goto _output_error; /* should regenerate the same amount */ if (readSize != cSize) goto _output_error; /* should have read the entire frame */ DISPLAYLEVEL(4, "OK \n"); /* check regenerated data is byte exact */ DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++); { size_t i; for (i=0; i<CNBufferSize; i++) { if (((BYTE*)decodedBuffer)[i] != ((BYTE*)CNBuffer)[i]) goto _output_error;; } } DISPLAYLEVEL(4, "OK \n"); _end: ZBUFF_freeCCtx(zc); ZBUFF_freeDCtx(zd); free(CNBuffer); free(compressedBuffer); free(decodedBuffer); return testResult; _output_error: testResult = 1; DISPLAY("Error detected in Unit tests ! \n"); goto _end; } static size_t findDiff(const void* buf1, const void* buf2, size_t max) { const BYTE* b1 = (const BYTE*)buf1; const BYTE* b2 = (const BYTE*)buf2; size_t u; for (u=0; u<max; u++) { if (b1[u] != b2[u]) break; } return u; } static size_t FUZ_rLogLength(U32* seed, U32 logLength) { size_t const lengthMask = ((size_t)1 << logLength) - 1; return (lengthMask+1) + (FUZ_rand(seed) & lengthMask); } static size_t FUZ_randomLength(U32* seed, U32 maxLog) { U32 const logLength = FUZ_rand(seed) % maxLog; return FUZ_rLogLength(seed, logLength); } #define MIN(a,b) ( (a) < (b) ? (a) : (b) ) #define CHECK(cond, ...) if (cond) { DISPLAY("Error => "); DISPLAY(__VA_ARGS__); \ DISPLAY(" (seed %u, test nb %u) \n", seed, testNb); goto _output_error; } static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, double compressibility) { static const U32 maxSrcLog = 24; static const U32 maxSampleLog = 19; BYTE* cNoiseBuffer[5]; size_t const srcBufferSize = (size_t)1<<maxSrcLog; BYTE* copyBuffer; size_t const copyBufferSize= srcBufferSize + (1<<maxSampleLog); BYTE* cBuffer; size_t const cBufferSize = ZSTD_compressBound(srcBufferSize); BYTE* dstBuffer; size_t dstBufferSize = srcBufferSize; U32 result = 0; U32 testNb = 0; U32 coreSeed = seed; ZBUFF_CCtx* zc; ZBUFF_DCtx* zd; clock_t startClock = clock(); /* allocations */ zc = ZBUFF_createCCtx(); zd = ZBUFF_createDCtx(); cNoiseBuffer[0] = (BYTE*)malloc (srcBufferSize); cNoiseBuffer[1] = (BYTE*)malloc (srcBufferSize); cNoiseBuffer[2] = (BYTE*)malloc (srcBufferSize); cNoiseBuffer[3] = (BYTE*)malloc (srcBufferSize); cNoiseBuffer[4] = (BYTE*)malloc (srcBufferSize); copyBuffer= (BYTE*)malloc (copyBufferSize); dstBuffer = (BYTE*)malloc (dstBufferSize); cBuffer = (BYTE*)malloc (cBufferSize); CHECK (!cNoiseBuffer[0] || !cNoiseBuffer[1] || !cNoiseBuffer[2] || !cNoiseBuffer[3] || !cNoiseBuffer[4] || !copyBuffer || !dstBuffer || !cBuffer || !zc || !zd, "Not enough memory, fuzzer tests cancelled"); /* Create initial samples */ RDG_genBuffer(cNoiseBuffer[0], srcBufferSize, 0.00, 0., coreSeed); /* pure noise */ RDG_genBuffer(cNoiseBuffer[1], srcBufferSize, 0.05, 0., coreSeed); /* barely compressible */ RDG_genBuffer(cNoiseBuffer[2], srcBufferSize, compressibility, 0., coreSeed); RDG_genBuffer(cNoiseBuffer[3], srcBufferSize, 0.95, 0., coreSeed); /* highly compressible */ RDG_genBuffer(cNoiseBuffer[4], srcBufferSize, 1.00, 0., coreSeed); /* sparse content */ memset(copyBuffer, 0x65, copyBufferSize); /* make copyBuffer considered initialized */ /* catch up testNb */ for (testNb=1; testNb < startTest; testNb++) FUZ_rand(&coreSeed); /* test loop */ for ( ; (testNb <= nbTests) || (FUZ_GetClockSpan(startClock) < g_clockTime) ; testNb++ ) { U32 lseed; const BYTE* srcBuffer; const BYTE* dict; size_t maxTestSize, dictSize; size_t cSize, totalTestSize, totalCSize, totalGenSize; size_t errorCode; U32 n, nbChunks; XXH64_state_t xxhState; U64 crcOrig; /* init */ DISPLAYUPDATE(2, "\r%6u", testNb); if (nbTests >= testNb) DISPLAYUPDATE(2, "/%6u ", nbTests); FUZ_rand(&coreSeed); lseed = coreSeed ^ prime1; /* states full reset (unsynchronized) */ /* some issues only happen when reusing states in a specific sequence of parameters */ if ((FUZ_rand(&lseed) & 0xFF) == 131) { ZBUFF_freeCCtx(zc); zc = ZBUFF_createCCtx(); } if ((FUZ_rand(&lseed) & 0xFF) == 132) { ZBUFF_freeDCtx(zd); zd = ZBUFF_createDCtx(); } /* srcBuffer selection [0-4] */ { U32 buffNb = FUZ_rand(&lseed) & 0x7F; if (buffNb & 7) buffNb=2; /* most common : compressible (P) */ else { buffNb >>= 3; if (buffNb & 7) { const U32 tnb[2] = { 1, 3 }; /* barely/highly compressible */ buffNb = tnb[buffNb >> 3]; } else { const U32 tnb[2] = { 0, 4 }; /* not compressible / sparse */ buffNb = tnb[buffNb >> 3]; } } srcBuffer = cNoiseBuffer[buffNb]; } /* compression init */ { U32 const testLog = FUZ_rand(&lseed) % maxSrcLog; U32 const cLevel = (FUZ_rand(&lseed) % (ZSTD_maxCLevel() - (testLog/3))) + 1; maxTestSize = FUZ_rLogLength(&lseed, testLog); dictSize = (FUZ_rand(&lseed)==1) ? FUZ_randomLength(&lseed, maxSampleLog) : 0; /* random dictionary selection */ { size_t const dictStart = FUZ_rand(&lseed) % (srcBufferSize - dictSize); dict = srcBuffer + dictStart; } { ZSTD_parameters params = ZSTD_getParams(cLevel, 0, dictSize); params.fParams.checksumFlag = FUZ_rand(&lseed) & 1; params.fParams.noDictIDFlag = FUZ_rand(&lseed) & 1; { size_t const initError = ZBUFF_compressInit_advanced(zc, dict, dictSize, params, 0); CHECK (ZBUFF_isError(initError),"init error : %s", ZBUFF_getErrorName(initError)); } } } /* multi-segments compression test */ XXH64_reset(&xxhState, 0); nbChunks = (FUZ_rand(&lseed) & 127) + 2; for (n=0, cSize=0, totalTestSize=0 ; (n<nbChunks) && (totalTestSize < maxTestSize) ; n++) { /* compress random chunk into random size dst buffer */ { size_t readChunkSize = FUZ_randomLength(&lseed, maxSampleLog); size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog); size_t dstBuffSize = MIN(cBufferSize - cSize, randomDstSize); size_t const srcStart = FUZ_rand(&lseed) % (srcBufferSize - readChunkSize); size_t const compressionError = ZBUFF_compressContinue(zc, cBuffer+cSize, &dstBuffSize, srcBuffer+srcStart, &readChunkSize); CHECK (ZBUFF_isError(compressionError), "compression error : %s", ZBUFF_getErrorName(compressionError)); XXH64_update(&xxhState, srcBuffer+srcStart, readChunkSize); memcpy(copyBuffer+totalTestSize, srcBuffer+srcStart, readChunkSize); cSize += dstBuffSize; totalTestSize += readChunkSize; } /* random flush operation, to mess around */ if ((FUZ_rand(&lseed) & 15) == 0) { size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog); size_t dstBuffSize = MIN(cBufferSize - cSize, randomDstSize); size_t const flushError = ZBUFF_compressFlush(zc, cBuffer+cSize, &dstBuffSize); CHECK (ZBUFF_isError(flushError), "flush error : %s", ZBUFF_getErrorName(flushError)); cSize += dstBuffSize; } } /* final frame epilogue */ { size_t remainingToFlush = (size_t)(-1); while (remainingToFlush) { size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog); size_t dstBuffSize = MIN(cBufferSize - cSize, randomDstSize); U32 const enoughDstSize = dstBuffSize >= remainingToFlush; remainingToFlush = ZBUFF_compressEnd(zc, cBuffer+cSize, &dstBuffSize); CHECK (ZBUFF_isError(remainingToFlush), "flush error : %s", ZBUFF_getErrorName(remainingToFlush)); CHECK (enoughDstSize && remainingToFlush, "ZBUFF_compressEnd() not fully flushed (%u remaining), but enough space available", (U32)remainingToFlush); cSize += dstBuffSize; } } crcOrig = XXH64_digest(&xxhState); /* multi - fragments decompression test */ ZBUFF_decompressInitDictionary(zd, dict, dictSize); errorCode = 1; for (totalCSize = 0, totalGenSize = 0 ; errorCode ; ) { size_t readCSrcSize = FUZ_randomLength(&lseed, maxSampleLog); size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog); size_t dstBuffSize = MIN(dstBufferSize - totalGenSize, randomDstSize); errorCode = ZBUFF_decompressContinue(zd, dstBuffer+totalGenSize, &dstBuffSize, cBuffer+totalCSize, &readCSrcSize); CHECK (ZBUFF_isError(errorCode), "decompression error : %s", ZBUFF_getErrorName(errorCode)); totalGenSize += dstBuffSize; totalCSize += readCSrcSize; } CHECK (errorCode != 0, "frame not fully decoded"); CHECK (totalGenSize != totalTestSize, "decompressed data : wrong size") CHECK (totalCSize != cSize, "compressed data should be fully read") { U64 const crcDest = XXH64(dstBuffer, totalTestSize, 0); if (crcDest!=crcOrig) findDiff(copyBuffer, dstBuffer, totalTestSize); CHECK (crcDest!=crcOrig, "decompressed data corrupted"); } /*===== noisy/erroneous src decompression test =====*/ /* add some noise */ { U32 const nbNoiseChunks = (FUZ_rand(&lseed) & 7) + 2; U32 nn; for (nn=0; nn<nbNoiseChunks; nn++) { size_t const randomNoiseSize = FUZ_randomLength(&lseed, maxSampleLog); size_t const noiseSize = MIN((cSize/3) , randomNoiseSize); size_t const noiseStart = FUZ_rand(&lseed) % (srcBufferSize - noiseSize); size_t const cStart = FUZ_rand(&lseed) % (cSize - noiseSize); memcpy(cBuffer+cStart, srcBuffer+noiseStart, noiseSize); } } /* try decompression on noisy data */ ZBUFF_decompressInit(zd); totalCSize = 0; totalGenSize = 0; while ( (totalCSize < cSize) && (totalGenSize < dstBufferSize) ) { size_t readCSrcSize = FUZ_randomLength(&lseed, maxSampleLog); size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog); size_t dstBuffSize = MIN(dstBufferSize - totalGenSize, randomDstSize); size_t const decompressError = ZBUFF_decompressContinue(zd, dstBuffer+totalGenSize, &dstBuffSize, cBuffer+totalCSize, &readCSrcSize); if (ZBUFF_isError(decompressError)) break; /* error correctly detected */ totalGenSize += dstBuffSize; totalCSize += readCSrcSize; } } DISPLAY("\r%u fuzzer tests completed \n", testNb); _cleanup: ZBUFF_freeCCtx(zc); ZBUFF_freeDCtx(zd); free(cNoiseBuffer[0]); free(cNoiseBuffer[1]); free(cNoiseBuffer[2]); free(cNoiseBuffer[3]); free(cNoiseBuffer[4]); free(copyBuffer); free(cBuffer); free(dstBuffer); return result; _output_error: result = 1; goto _cleanup; } /*-******************************************************* * Command line *********************************************************/ int FUZ_usage(const char* programName) { DISPLAY( "Usage :\n"); DISPLAY( " %s [args]\n", programName); DISPLAY( "\n"); DISPLAY( "Arguments :\n"); DISPLAY( " -i# : Nb of tests (default:%u) \n", nbTestsDefault); DISPLAY( " -s# : Select seed (default:prompt user)\n"); DISPLAY( " -t# : Select starting test number (default:0)\n"); DISPLAY( " -P# : Select compressibility in %% (default:%i%%)\n", FUZ_COMPRESSIBILITY_DEFAULT); DISPLAY( " -v : verbose\n"); DISPLAY( " -p : pause at the end\n"); DISPLAY( " -h : display help and exit\n"); return 0; } int main(int argc, const char** argv) { U32 seed=0; int seedset=0; int argNb; int nbTests = nbTestsDefault; int testNb = 0; int proba = FUZ_COMPRESSIBILITY_DEFAULT; int result=0; U32 mainPause = 0; const char* programName = argv[0]; ZSTD_customMem customMem = { ZBUFF_allocFunction, ZBUFF_freeFunction, NULL }; ZSTD_customMem customNULL = { NULL, NULL, NULL }; /* Check command line */ for(argNb=1; argNb<argc; argNb++) { const char* argument = argv[argNb]; if(!argument) continue; /* Protection if argument empty */ /* Parsing commands. Aggregated commands are allowed */ if (argument[0]=='-') { argument++; while (*argument!=0) { switch(*argument) { case 'h': return FUZ_usage(programName); case 'v': argument++; g_displayLevel=4; break; case 'q': argument++; g_displayLevel--; break; case 'p': /* pause at the end */ argument++; mainPause = 1; break; case 'i': argument++; nbTests=0; g_clockTime=0; while ((*argument>='0') && (*argument<='9')) { nbTests *= 10; nbTests += *argument - '0'; argument++; } break; case 'T': argument++; nbTests=0; g_clockTime=0; while ((*argument>='0') && (*argument<='9')) { g_clockTime *= 10; g_clockTime += *argument - '0'; argument++; } if (*argument=='m') g_clockTime *=60, argument++; if (*argument=='n') argument++; g_clockTime *= CLOCKS_PER_SEC; break; case 's': argument++; seed=0; seedset=1; while ((*argument>='0') && (*argument<='9')) { seed *= 10; seed += *argument - '0'; argument++; } break; case 't': argument++; testNb=0; while ((*argument>='0') && (*argument<='9')) { testNb *= 10; testNb += *argument - '0'; argument++; } break; case 'P': /* compressibility % */ argument++; proba=0; while ((*argument>='0') && (*argument<='9')) { proba *= 10; proba += *argument - '0'; argument++; } if (proba<0) proba=0; if (proba>100) proba=100; break; default: return FUZ_usage(programName); } } } } /* for(argNb=1; argNb<argc; argNb++) */ /* Get Seed */ DISPLAY("Starting zstd_buffered tester (%i-bits, %s)\n", (int)(sizeof(size_t)*8), ZSTD_VERSION_STRING); if (!seedset) { time_t const t = time(NULL); U32 const h = XXH32(&t, sizeof(t), 1); seed = h % 10000; } DISPLAY("Seed = %u\n", seed); if (proba!=FUZ_COMPRESSIBILITY_DEFAULT) DISPLAY("Compressibility : %i%%\n", proba); if (nbTests<=0) nbTests=1; if (testNb==0) { result = basicUnitTests(0, ((double)proba) / 100, customNULL); /* constant seed for predictability */ if (!result) { DISPLAYLEVEL(4, "Unit tests using customMem :\n") result = basicUnitTests(0, ((double)proba) / 100, customMem); /* use custom memory allocation functions */ } } if (!result) result = fuzzerTests(seed, nbTests, testNb, ((double)proba) / 100); if (mainPause) { int unused; DISPLAY("Press Enter \n"); unused = getchar(); (void)unused; } return result; }