Chilkat HOME .NET Core C# Android™ AutoIt C C# C++ Chilkat2-Python CkPython Classic ASP DataFlex Delphi ActiveX Delphi DLL Go Java Lianja Mono C# Node.js Objective-C PHP ActiveX PHP Extension Perl PowerBuilder PowerShell PureBasic Ruby SQL Server Swift 2 Swift 3,4,5... Tcl Unicode C Unicode C++ VB.NET VBScript Visual Basic 6.0 Visual FoxPro Xojo Plugin
(Unicode C) How to Tell if a File is .p7m or .p7sThis example explains how to detect if a file is a .p7m or .p7s. It provides as solution to the following problem:
Sometimes people submit P7S/P7M with wrong extensions. Can I check if file is P7S or P7M with Chilkat? Also see What is a P7M or P7S File?
#include <C_CkBinDataW.h> #include <C_CkStringBuilderW.h> void ChilkatSample(void) { HCkBinDataW bd; BOOL success; HCkStringBuilderW sb; BOOL caseSensitive; // A .p7m or .p7s file is binary and contains PKCS7. // PKCS7 is ASN.1, and always begins with a SEQUENCE tag (a byte equal to 0x30) // followed by an encoded length. // If the file is larger than 128 bytes (and it SHOULD be), the encoded length will begin with either 0x80, 0x81, 0x82, or 0x83. // It can also begin with 0x84, but only for very large files (where the length is too large for 3 bytes). // See How ASN.1 Encodes Lengths // Therefore, if we have a file that might be .p7m or .p7s, we can check by // examining the 1st 2 bytes of the file. bd = CkBinDataW_Create(); success = CkBinDataW_LoadFile(bd,L"qa_data/p7m/a.p7m"); if (success == FALSE) { wprintf(L"Failed to load the file.\n"); CkBinDataW_Dispose(bd); return; } sb = CkStringBuilderW_Create(); CkStringBuilderW_Append(sb,CkBinDataW_getEncodedChunk(bd,0,2,L"hex")); caseSensitive = TRUE; if (CkStringBuilderW_ContentsEqual(sb,L"3080",caseSensitive) || CkStringBuilderW_ContentsEqual(sb,L"3081",caseSensitive) || CkStringBuilderW_ContentsEqual(sb,L"3082",caseSensitive) || CkStringBuilderW_ContentsEqual(sb,L"3083",caseSensitive)) { wprintf(L"This is a .p7m or .p7s file.\n"); } else { wprintf(L"This is not a .p7m or .p7s file.\n"); } CkBinDataW_Dispose(bd); CkStringBuilderW_Dispose(sb); } |
© 2000-2024 Chilkat Software, Inc. All Rights Reserved.