c_cpp/etc/tiny/combine.c

   1 #include <stdlib.h> //EXIT_FAILURE
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <sys/mman.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9
  10 #define handle_error(msg) \
  11    do { perror(msg); exit(EXIT_FAILURE); } while (0)
  12
  13 #define EXTLEN 32
  14 // 8 should be enough
  15
  16 /*
  17 [HTTP/1.1 404 File Not Found
  18 Content-Type: text/octet
  19 User-ReturnCode: -29104
  20 Content-Length: 16
  21
  22 «Í˜vÿÿŽP]
  23
  24 Offset      0  1  2  3  4  5  6  7   8  9  A  B  C  D  E  F
  25
  26 00100000   48 54 54 50 2F 31 2E 31  20 34 30 34 20 46 69 6C   HTTP/1.1 404 Fil
  27 00100010   65 20 4E 6F 74 20 46 6F  75 6E 64 0D 0A 43 6F 6E   e Not Found  Con
  28 00100020   74 65 6E 74 2D 54 79 70  65 3A 20 74 65 78 74 2F   tent-Type: text/
  29 00100030   6F 63 74 65 74 0D 0A 55  73 65 72 2D 52 65 74 75   octet  User-Retu
  30 00100040   72 6E 43 6F 64 65 3A 20  2D 32 39 31 30 34 0D 0A   rnCode: -29104
  31 00100050   43 6F 6E 74 65 6E 74 2D  4C 65 6E 67 74 68 3A 20   Content-Length:
  32 00100060   31 36 0D 0A 0D 0A AB CD  98 76 FF FF 8E 50         16    «Í˜vÿÿŽP
  33 */
  34 char theStr[]="HTTP/1.1 404 File Not Found\r\nContent-Type: text/octet\r\nUser-ReturnCode: -29104\r\nContent-Length: 16\r\n\r\n\xAB\xCD\x98\x76\xFF\xFF\x8E\x50";
  35 int theStrLen = sizeof(theStr) - 1;
  36
  37 int main (int argc, char *argv[]) {
  38     printf("Searching for:\n[%s] %d %zd\n",theStr,theStrLen,strlen(theStr));
  39         if (argc!=4) {
  40                 fprintf(stderr,"Usage: %s <main file> <2nd file> <out file>\n",argv[0]);
  41                 exit(EXIT_FAILURE);
  42         }
  43     int in1, in2;
  44     FILE *outf;
  45     struct stat sb1, sb2;
  46     char *p1, *p2;
  47     in1 = open(argv[1], O_RDONLY);
  48     if (in1 == -1)
  49         handle_error("open1");
  50     in2 = open(argv[2], O_RDONLY);
  51     if (in2 == -1)
  52         handle_error("open2");
  53
  54     if (fstat(in1, &sb1) == -1)           /* To obtain file size */
  55         handle_error("fstat1");
  56     if (fstat(in2, &sb2) == -1)           /* To obtain file size */
  57         handle_error("fstat2");
  58     if (sb1.st_size != sb2.st_size) {
  59                 fprintf(stderr,"Input files with different size: %zd,%zd .\n",sb1.st_size,sb2.st_size);
  60                 exit(EXIT_FAILURE);
  61     }
  62     if ( !(sb1.st_size && sb2.st_size) ) {
  63                 fprintf(stderr,"Input files are empty.\n");
  64                 exit(EXIT_FAILURE);
  65     }
  66
  67     p1 = mmap(NULL, sb1.st_size, PROT_READ, MAP_PRIVATE, in1, 0);
  68     if (p1 == MAP_FAILED)
  69         handle_error("mmap1");
  70     p2 = mmap(NULL, sb2.st_size, PROT_READ, MAP_PRIVATE, in2, 0);
  71     if (p2 == MAP_FAILED)
  72         handle_error("mmap2");
  73
  74     outf = fopen(argv[3],"w+x");
  75     if (outf == NULL)
  76         handle_error("open3");
  77
  78     char *thisp, *lastp;
  79     thisp = p1;
  80     while ( thisp - p1 < sb1.st_size ) {
  81         if (*thisp == 'H') {
  82             if ( memcmp(thisp,theStr,theStrLen) == 0 ) {
  83                 printf("1 %zd\t(%zx)\t",thisp-p1,thisp-p1);
  84                 char *p2thisp = thisp - p1 + p2;
  85                 if ( memcmp(p2thisp,theStr,theStrLen) == 0 ) {
  86                     printf("Also 2 ");
  87                 }
  88                 if ( fwrite(p2thisp,theStrLen,1,outf) < 1 ) {
  89                     handle_error("write");
  90                 }
  91                 thisp += theStrLen;
  92                 p2thisp += theStrLen;
  93                 lastp = thisp-1;
  94                 char *extsp = thisp + EXTLEN;
  95                 while ( (*thisp != *p2thisp) || (thisp < extsp) ) {
  96                     fputc(*p2thisp,outf);
  97                     if (*thisp != *p2thisp)
  98                         printf("%zd:%02hhX-%02hhX ", thisp-lastp, *thisp, *p2thisp);
  99                     ++thisp;
 100                     ++p2thisp;
 101                 }
 102                 putchar('\n');
 103             } else { fputc(*thisp,outf);++thisp; }
 104         } else { fputc(*thisp,outf);++thisp; }
 105     }
 106
 107     fclose(outf);
 108     exit(EXIT_SUCCESS);
 109 }