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Annotation of researchv10no/cmd/sort/tables.c, revision 1.1.1.1

1.1       root        1: /* Copyright 1990, AT&T Bell Labs */
                      2: #include <stdlib.h>
                      3: #include <string.h>
                      4: #include <ctype.h>
                      5: #include "fsort.h"
                      6: 
                      7: /* STACK=1000 makes lots of room under normal conditions.
                      8:    But it can be broken.  40 cycles like this will do it:
                      9:        a,b,...z,za,zb,...zz,zza,zzb,...,zzz,zzza,...
                     10:    Minor changes to rsort() would allow the stack to be
                     11:    extended discontiguously.  Pity we don't have alloca any more.
                     12: */
                     13: 
                     14: #define BUFFER 6000000
                     15: #define MINBUF 10000   /* not worth trying */
                     16: #define STACK 1000
                     17: 
                     18: uchar *bufmax;
                     19: struct rec *buffer;
                     20: unsigned long bufsiz = BUFFER;
                     21: struct rec endfile;
                     22: struct list *stack;
                     23: struct list *stackmax;
                     24: 
                     25: uchar ident[256];      /* identity transform */
                     26: uchar fold[256];       /* fold upper case to lower */
                     27: 
                     28: uchar all[256];                /* all chars significant */
                     29: uchar dict[256];       /* sig chars for dictionary order */
                     30: uchar ascii[256];      /* ascii graphics significant */
                     31: 
                     32: void
                     33: tabinit(void)
                     34: {
                     35:        int i;
                     36:        memset((char*)all,1,256);
                     37: 
                     38:        memset((char*)(dict+'0'),1,10);
                     39:        memset((char*)(dict+'A'),1,26);
                     40:        memset((char*)(dict+'a'),1,26);
                     41:        dict[' '] = dict['\t'] = 1;
                     42: 
                     43:        memset((char*)(ascii+040),1,0137); /* 040-0176 */
                     44: 
                     45:        for(i=0; i<256; i++)
                     46:                fold[i] = ident[i] = i;
                     47:        for(i='a'; i<='z'; i++)
                     48:                fold[i] += 'A' - 'a';
                     49: 
                     50:        stack = (struct list*)malloc(STACK*sizeof(*stack));
                     51:        do {
                     52:                if((buffer=(struct rec*)malloc(bufsiz)) != 0)
                     53:                        break;
                     54:        } while((bufsiz/=2) > MINBUF);
                     55:        if(buffer==0 || stack==0)
                     56:                fatal("can't get working space", "", 0);
                     57:        bufmax = (uchar*)buffer + bufsiz - 2*sizeof(*buffer);
                     58:        stack->head = stack->tail = 0;
                     59:        stackmax = stack + STACK;
                     60: }
                     61: 
                     62: void
                     63: tabfree(void)
                     64: {
                     65:        free(stack);
                     66:        free(buffer);
                     67: }
                     68: 
                     69: void
                     70: optiony(char *s)
                     71: {
                     72:        long size = atol(s);
                     73:        if(!isdigit(s[0]))
                     74:                fatal("no size for -y","",0);
                     75:        if(size >= MINBUF/10)   /* tiny helps debugging */
                     76:                bufsiz = size;
                     77:        else if(size == 0)
                     78:                bufsiz = 10L*BUFFER;
                     79:        else fatal("-y too small", "", 0);
                     80: }

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