Diff: base64.cpp

Revision:

4:1354e56c7dd3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/base64.cpp	Wed Nov 20 08:06:46 2019 +0000
@@ -0,0 +1,180 @@
+#include "base64.h"
+
+const char *base64::szB64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+
+base64::base64() : lpszOutputString(NULL)
+{
+}
+
+base64::~base64()
+{
+    if(lpszOutputString)
+        delete[] lpszOutputString;
+}
+
+const char *base64::Encode(const char *szStr, int iLens)
+{
+    int i,j;
+
+    if(lpszOutputString)
+        delete[] lpszOutputString;
+
+    if(iLens == -1)
+        iLen = strlen(szStr);
+    else
+        iLen = iLens;
+
+    lpszOutputString =
+        new char[(int)((double)(iLen)*1.5)+10];
+    for(i = 0,j = 0; i < (iLen - (iLen % 3)); i+=3)
+    {
+        lpszOutputString[j] = szB64[(szStr[i] & 0xfc) >> 2];
+        lpszOutputString[j+1] = szB64[((szStr[i] &0x03) << 4) |
+                                    ((szStr[i+1] & 0xf0) >> 4)];
+        lpszOutputString[j+2] = szB64[((szStr[i+1] & 0x0f) <<2 ) |
+                                    ((szStr[i+2] & 0xc0) >> 6)];
+        lpszOutputString[j+3] = szB64[(szStr[i+2] & 0x3f)];
+        j += 4;
+    }
+    i = iLen-(iLen % 3);    // 残りのサイズを計算
+    switch(iLen % 3)
+    {
+    case 2: // 1文字分パディングが必要
+    {
+        lpszOutputString[j] = szB64[(szStr[i] & 0xfc) >> 2];
+        lpszOutputString[j+1] = szB64[((szStr[i] &0x03) << 4) |
+                                    ((szStr[i+1] & 0xf0) >> 4)];
+        lpszOutputString[j+2] = szB64[((szStr[i+1] & 0x0f) <<2 )];
+        lpszOutputString[j+3] = szB64[64];  // Pad
+        lpszOutputString[j+4] = '\0';
+    }
+    break;
+    case 1: // 2文字分パディングが必要
+    {
+        lpszOutputString[j] = szB64[(szStr[i] & 0xfc) >> 2];
+        lpszOutputString[j+1] = szB64[((szStr[i] &0x03) << 4)];
+        lpszOutputString[j+2] = szB64[64];  // Pad
+        lpszOutputString[j+3] = szB64[64];  // Pad
+        lpszOutputString[j+4] = '\0';
+    }
+    break;
+    }
+    lpszOutputString[j+4] = '\0';
+
+    return lpszOutputString;
+}
+
+void base64::Encode(istream& istr, ostream& ostr, int iRet)
+{
+    int i;
+    char c[3];
+
+    i = 0;
+    while(!istr.eof())
+    {
+        c[0] = c[1] = c[2] = '\0';
+        istr.read(c,3);
+
+        ostr << szB64[(c[0] & 0xfc) >> 2];
+        i++;    if(i >= iRet && iRet != -1){ ostr << endl; i = 0; }
+        ostr << szB64[((c[0] &0x03) << 4) | ((c[1] & 0xf0) >> 4)];
+        i++;    if(i >= iRet && iRet != -1){ ostr << endl; i = 0; }
+        if(istr.gcount() == 1)
+            ostr << szB64[64];
+        else
+            ostr << szB64[((c[1] & 0x0f) <<2 ) | ((c[2] & 0xc0) >> 6)];
+        i++;    if(i >= iRet && iRet != -1){ ostr << endl; i = 0; }
+        if(istr.gcount() == 3)
+            ostr << szB64[(c[2] & 0x3f)];
+        else
+            ostr << szB64[64];
+        i++;    if(i >= iRet && iRet != -1){ ostr << endl; i = 0; }
+    }
+    ostr.flush();
+}
+
+
+int base64::FindIndexInB64(char c)
+{
+    int index = 0;
+    while(szB64[index] != '\0' && szB64[index] != c)
+        index++;
+
+    if(szB64[index] == '\0')
+        return -1;  // 見つからず
+
+    return index;   // 見つかった。
+}
+
+const char *base64::Decode(const char *szStr)
+{
+    //lpszOutputString
+    int i, j, l,iWriteCount,len;
+    char c;
+    char buf[4];
+
+    len = iLen = strlen(szStr);
+    if(lpszOutputString)
+        delete[] lpszOutputString;
+
+    iLen = (int)(((double)(iLen)/4.0)*3.0) + 4;
+
+    lpszOutputString = new char[iLen];
+
+    for(i = 0, j = 0; i < len; i+=4)
+    {
+        iWriteCount = 3;
+        for(l = 0; l < 4 && i+l<len; l++)
+        {
+            c = szStr[i+l];
+            if(c == szB64[64])  // Pad
+                iWriteCount--;
+            else {
+                buf[l] = FindIndexInB64(c);
+                //if(buf[l] == -1) error!;
+            }
+        }
+        lpszOutputString[j] = ((buf[0] << 2) & 0xfc) | ((buf[1] >> 4) & 0x03);
+        if(iWriteCount >= 2)
+            lpszOutputString[j+1] = ((buf[1] << 4) & 0xf0) | ((buf[2] >> 2) & 0x0f);
+        if(iWriteCount == 3)
+            lpszOutputString[j+2] = ((buf[2] << 6) & 0xc0) | (buf[3] & 0x3f);
+        j+=iWriteCount;
+    }
+    iLen = j;
+    lpszOutputString[j] = '\0';
+
+    return lpszOutputString;
+}
+
+void base64::Decode(istream& istr, ostream& ostr)
+{
+    int i,iWriteCount;
+    char c;
+    char buf[4];
+    char out[3];
+
+    while(1)
+    {
+        iWriteCount = 3;
+        for(i = 0; i < 4; i++)
+        {
+            istr >> c;
+            if(istr.eof())
+            {
+                ostr.flush();
+                return;
+            }
+            if(c == szB64[64])  // Pad
+                iWriteCount--;
+            else {
+                buf[i] = FindIndexInB64(c);
+                //if(buf[i] == -1) error!;
+            }
+        }
+        out[0] = ((buf[0] << 2) & 0xfc) | ((buf[1] >> 4) & 0x03);
+        out[1] = ((buf[1] << 4) & 0xf0) | ((buf[2] >> 2) & 0x0f);
+        out[2] = ((buf[2] << 6) & 0xc0) | (buf[3] & 0x3f);
+        ostr.write(out, iWriteCount);
+    }
+}