2.11BSD#431 - /usr/src/new/bm/Execute.c

   1: #include <stdio.h>
   2: #include "bm.h"
   3: #include "Extern.h"
   4: Execute(DescVec, NPats, TextFile, Buffer)
   5: struct PattDesc *DescVec[]; /* pointers to status vectors for the different
   6: 	* patterns, including skip tables, position in buffer, etc. */
   7: int NPats; /* number of patterns */
   8: char Buffer[]; /* holds text from file */
   9: int TextFile; /* file to search */
  10: {
  11:     long BuffPos; /* offset of first char in Buffer in TextFile */
  12:     int NRead, /* number of chars read from file */
  13:         NWanted, /* number of chars wanted */
  14:         NAvail, /* number of chars actually read */
  15:         BuffSize, /* number of chars in buffer */
  16:         BuffEx, /* flag to indicate that buffer has been searched */
  17:         ResSize,
  18:         /* number of characters in the last, incomplete line */
  19:         Found, /* flag indicates whether pattern found
  20: 		* completely and all matches printed */
  21:         Valid; /* was the match "valid", i.e. if -x used,
  22: 		* did the whole line match? */
  23:     char *BuffEnd; /* pointer to last char of last complete line */
  24: 
  25:     /*
  26: 	 * In order to optimize I/O for some machines which impose a severe
  27: 	 * penalty for I/O on an odd address, we play a nasty game.  First, we
  28: 	 * assume that the Buffer which is passed to us has an even address.
  29: 	 * Then whenever we move a buffer residual back to the beginning of
  30: 	 * the Buffer for the next read cycle, we actually move it to Buffer +
  31: 	 * Odd(Residual) where Odd() is 1 if Residual is odd, zero otherwise.
  32: 	 * This causes the the next read to go down on an even address.  We
  33: 	 * keep track of the beginning of data in the Buffer with BuffStart.
  34: 	 */
  35:     char *BuffStart;
  36: 
  37:     /* misc working variables */
  38: #ifdef notdef
  39:     int i;
  40: #else !notdef
  41:     register struct PattDesc    *Desc;
  42:     struct PattDesc         **Vec, **LastPatt = DescVec+NPats;
  43: #endif notdef
  44: 
  45:     /* initialize */
  46:     ResSize = 0;
  47:     Found = 0;
  48:     BuffPos = 0;
  49:     BuffStart = Buffer;
  50: #ifdef notdef
  51:     for (i=0; i < NPats; i++) {
  52:         DescVec[i] -> Success = 0;
  53:         DescVec[i] -> Start = Buffer;
  54:     } /* for */
  55: #else !notdef
  56:     for (Vec=DescVec; Vec < LastPatt; Vec++) {
  57:         Desc = *Vec;
  58:         Desc->Success = 0;
  59:         Desc->Start = Buffer;
  60:     }
  61: #endif notdef
  62:     /* now do the searching */
  63:     do {
  64:         /* first, read a bufferfull and set up the variables */
  65:         /*
  66: 		 * Some systems *even* get upset when you ask for an odd read
  67: 		 * length - ARGH!
  68: 		 */
  69:         NWanted = (int)((unsigned)(MAXBUFF - ResSize) & ~1);
  70:         NRead = 0;
  71:         do {
  72:             /*
  73: 			 * BuffStart+ResSize+BRead is even first time through
  74: 			 * this loop - afterwards, no guaranties, but for
  75: 			 * files this loop never goes more than once ...
  76: 			 * Can't do any better.
  77: 			 */
  78:             NAvail =
  79:                read(TextFile,BuffStart + ResSize + NRead, NWanted);
  80:             if (NAvail == -1) {
  81:                 fprintf(stderr,
  82:                   "bm: error reading from input file\n");
  83:                 exit(2);
  84:             } /* if */
  85:             NRead += NAvail; NWanted -= NAvail;
  86:         } while (NAvail && NWanted);
  87:         BuffEx = 0;
  88:         BuffSize = ResSize + NRead;
  89:         BuffEnd = BuffStart + BuffSize - 1;
  90:         /* locate the end of the last complete line */
  91:         while (*BuffEnd != '\n' && BuffEnd >= BuffStart)
  92:             --BuffEnd;
  93:         if (BuffEnd < BuffStart)
  94:             BuffEnd = BuffStart + BuffSize - 1;
  95:         while (!BuffEx) { /* work through one buffer full */
  96:             BuffEx = 1; /* set it provisionally, then clear
  97: 			* it if we find the buffer non-empty */
  98: #ifdef notdef
  99:             for (i=0; i< NPats; i++) {
 100:                 if (!DescVec[i]->Success)
 101:                 /* if the pattern  has not been found */
 102:                     DescVec[i]-> Success =
 103:                     Search(DescVec[i]->Pattern,
 104:                     DescVec[i]->PatLen, BuffStart, BuffEnd,
 105:                     DescVec[i]->Skip1, DescVec[i]->Skip2,
 106:                     DescVec[i]);
 107:                 if (DescVec[i]->Success){
 108:                 /* if a match occurred */
 109:                     BuffEx = 0;
 110:                     Valid = MatchFound(DescVec[i],BuffPos,
 111:                     BuffStart, BuffEnd);
 112:                     Found |= Valid;
 113:                     if ((sFlag || lFlag) && Found)
 114:                         return(0);
 115:                 } /* if */
 116:             } /* for */
 117: #else !notdef
 118:             for (Vec=DescVec; Vec < LastPatt; Vec++) {
 119:                 Desc = *Vec;
 120:                 if (!Desc->Success)
 121:                 /* if the pattern  has not been found */
 122:                     Desc-> Success =
 123:                     Search(Desc->Pattern,
 124:                     Desc->PatLen, BuffStart, BuffEnd,
 125:                     Desc->Skip1, Desc->Skip2,
 126:                     Desc);
 127:                 if (Desc->Success){
 128:                 /* if a match occurred */
 129:                     BuffEx = 0;
 130:                     Valid = MatchFound(Desc,BuffPos,
 131:                     BuffStart, BuffEnd);
 132:                     Found |= Valid;
 133:                     if ((sFlag || lFlag) && Found)
 134:                         return(0);
 135:                 } /* if */
 136:             } /* for */
 137: #endif notdef
 138:         } /* while */
 139:         if(NRead) {
 140:             ResSize = MoveResidue(DescVec,NPats,Buffer,&BuffStart,BuffEnd);
 141:             BuffPos += BuffSize - ResSize;
 142:         } /* if */
 143:     } while (NRead);
 144:     return(!Found);
 145: } /* Execute */

Defined functions