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Overview
Comment: | Add the decode-email.c utility program source code. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
17b4d3e49a3797f1434ec3261a61fda7 |
User & Date: | drh 2018-06-23 15:49:57.750 |
Context
2018-06-23
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16:44 | Improved documentation. No substantive code changes. ... (check-in: 9cf915d4 user: drh tags: trunk) | |
15:49 | Add the decode-email.c utility program source code. ... (check-in: 17b4d3e4 user: drh tags: trunk) | |
15:48 | Add an initial draft of design notes for the email notification system. ... (check-in: aeb98be8 user: drh tags: trunk) | |
Changes
Added tools/decode-email.c.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | /* ** This program reads a raw email file and attempts to decode it into ** a more human-readable format. The following decodings are done: ** ** (1) Header values are prefixed by "| " at the left margin. ** ** (2) Content-Transfer-Encoding is recognized and the content is ** decoded for display. */ #define _GNU_SOURCE #include <stdio.h> #include <string.h> #include <ctype.h> #define BINARY 0 #define BASE64 1 #define QUOTED 2 static int decode_hex(char c){ if( c>='0' && c<='9' ) return c - '0'; if( c>='A' && c<='F' ) return c - 'A' + 10; if( c>='a' && c<='f' ) return c - 'a' + 10; return -1; } static void convert_file(const char *zFilename, FILE *in){ int inHdr = 1; int n; int nBoundary; int decodeType = 0; int textMimetype = 1; char *zB; char zBoundary[200]; char zLine[5000]; char zOut[5000]; while( fgets(zLine, sizeof(zLine), in) ){ if( !inHdr && zLine[0]=='-' && zLine[1]=='-' && strncmp(zLine+2,zBoundary,nBoundary)==0 ){ printf("|----------------- end of body section ---------|\n"); inHdr = 1; } if( !inHdr ){ if( textMimetype && decodeType==BASE64 ){ int ii, jj, c, x, y; int bits = 0; for(ii=jj=0; (c = zLine[ii])!=0; ii++){ if( c>='A' && c<='Z' ){ x = c - 'A'; }else if( c>='a' && c<='z' ){ x = c - 'a' + 26; }else if( c>='0' && c<='9' ){ x = c - '0' + 52; }else if( c=='+' ){ x = 62; }else if( c=='/' ){ x = 63; }else if( c=='=' ){ x = 0; }else{ continue; } if( bits==0 ){ y = x; bits = 6; }else if( bits==6 ){ zOut[jj++] = ((y<<2) & 0xfc) | ((x>>4) & 0x03); y = x & 0xf; bits = 4; }else if( bits==4 ){ zOut[jj++] = ((y<<4) & 0xf0) | ((x>>2) & 0x0f); y = x & 0x3; bits = 2; }else if( bits==2 ){ zOut[jj++] = ((y<<6) & 0xc0) | (x & 0x3f); bits = 0; } } zOut[jj] = 0; printf("%s", zOut); }else if( textMimetype && decodeType==QUOTED ){ int ii, jj, c; for(ii=jj=0; (c = zLine[ii])!=0; ii++){ if( c=='=' ){ int x1 = decode_hex(zLine[ii+1]); int x2 = decode_hex(zLine[ii+2]); if( x1>=0 && x2>=0 ){ zOut[jj++] = (x1<<4) | x2; ii += 2; }else if( zLine[ii+1]=='\r' && zLine[ii+2]=='\n' ){ ii += 2; } }else{ zOut[jj++] = c; } } zOut[jj] = 0; printf("%s", zOut); }else{ printf("%s", zLine); } continue; } n = (int)strlen(zLine); while( n>0 && isspace(zLine[n-1]) ){ n--; } zLine[n] = 0; if( n==0 ){ inHdr = 0; printf("|----------------- end of header ---------------|\n"); continue; } printf("| %s\n", zLine); if( strncasecmp(zLine,"Content-Type:", 13)==0 ){ textMimetype = strstr(zLine, "text/")!=0; printf("|** %s content type **|\n", textMimetype ? "Text" : "Non-text"); } if( strncasecmp(zLine,"Content-Transfer-Encoding:", 26)==0 ){ if( strcasestr(zLine, "base64") ){ decodeType = BASE64; }else if( strcasestr(zLine, "quoted-printable") ){ decodeType = QUOTED; }else{ decodeType = BINARY; } printf("|** Content encoding %s **|\n", decodeType==BASE64 ? "BASE64" : decodeType==QUOTED ? "QUOTED" : "BINARY"); } zB = strstr(zLine, "boundary=\""); if( zB ){ int kk; zB += 10; for(kk=0; zB[kk] && zB[kk]!='"' && kk<sizeof(zBoundary)-1; kk++){ zBoundary[kk] = zB[kk]; } zBoundary[kk] = 0; nBoundary = kk; printf("|** boundary [%s] **|\n", zBoundary); } } } int main(int argc, char **argv){ if( argc==1 ){ convert_file("<stdin>", stdin); return 0; }else{ int i; for(i=1; i<argc; i++){ FILE *in = fopen(argv[i], "rb"); if( in==0 ){ fprintf(stderr, "cannot open \"%s\"", argv[i]); }else{ convert_file(argv[i], in); fclose(in); } } } return 0; } |