©2004 by Marc J. Rochkind. All rights reserved. Portions marked "Open Source" may be copied under license.

 

                 

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c6/search0.c

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/*
    editor front-end (unidirectional pipes)
    AUP2, Sec. 6.05

    Copyright 2003 by Marc J. Rochkind. All rights reserved.
    May be copied only for purposes and under conditions described
    on the Web page www.basepath.com/aup/copyright.htm.

    The Example Files are provided "as is," without any warranty;
    without even the implied warranty of merchantability or fitness
    for a particular purpose. The author and his publisher are not
    responsible for any damages, direct or incidental, resulting
    from the use or non-use of these Example Files.

    The Example Files may contain defects, and some contain deliberate
    coding mistakes that were included for educational reasons.
    You are responsible for determining if and how the Example Files
    are to be used.

*/
/*
    Sec.
*/
#include "defs.h"

/*[edinvoke]*/
static FILE *sndfp, *rcvfp;

static bool edinvoke(void)
{
    int pfdout[2], pfdin[2];
    pid_t pid;

    ec_neg1( pipe(pfdout) )
    ec_neg1( pipe(pfdin) )
    switch (pid = fork()) {
    case -1:
        EC_FAIL
    case 0:
        ec_neg1( dup2(pfdout[0], STDIN_FILENO) )
        ec_neg1( dup2(pfdin[1], STDOUT_FILENO) )
        ec_neg1( close(pfdout[0]) )
        ec_neg1( close(pfdout[1]) )
        ec_neg1( close(pfdin[0]) )
        ec_neg1( close(pfdin[1]) )
        execlp("ed", "ed", "-", NULL);
        EC_FAIL
    }
    ec_neg1( close(pfdout[0]) )
    ec_neg1( close(pfdin[1]) )
    ec_null( sndfp = fdopen(pfdout[1], "w") )
    ec_null( rcvfp = fdopen(pfdin[0], "r") )
    return true;

EC_CLEANUP_BGN
    if (pid == 0) {
        EC_FLUSH("edinvoke");
        _exit(EXIT_FAILURE);
    }
    return false;
EC_CLEANUP_END
}
/*[edsnd]*/
static bool edsnd(const char *s)
{
    ec_eof( fputs(s, sndfp) )
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}

static bool edrcv(char *s, size_t smax)
{
    ec_null( fgets(s, smax, rcvfp) )
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}

static bool turnaround(void)
{
    ec_false( edsnd("r end-of-file\n") )
    ec_eof( fflush(sndfp) )
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}
/*[rcvall]*/
static bool rcvall(void)
{
    char s[200];

    ec_false( turnaround() )
    while (true) {
        ec_false( edrcv(s, sizeof(s)) )
        if (strcmp(s, "?end-of-file\n") == 0)
            break;
        printf("%s", s);
    }
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}
/*[prompt]*/
static bool prompt(const char *msg, char *result, size_t resultmax,
  bool *eofp)
{
    char *p;

    printf("\n%s? ", msg);
    if (fgets(result, resultmax, stdin) == NULL) {
        if (ferror(stdin))
            EC_FAIL
        *eofp = true;
    }
    else {
        if ((p = strrchr(result, '\n')) != NULL)
            *p = '\0';
        *eofp = false;
    }
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}
/*[main]*/
int main(void)
{
    char s[100], line[200];
    bool eof;

    ec_false( prompt("File", s, sizeof(s), &eof) )
    if (eof)
        exit(EXIT_SUCCESS);
    ec_false( edinvoke() )
    snprintf(line, sizeof(line), "e %s\n", s);
    ec_false( edsnd(line) )
    ec_false( rcvall() );
    while (true) {
        ec_false( prompt("Search pattern", s, sizeof(s), &eof) )
        if (eof)
            break;
        snprintf(line, sizeof(line), "g/%s/p\n", s);
        ec_false( edsnd(line) )
        ec_false( rcvall() );
    }
    ec_false( edsnd("q\n") )
    exit(EXIT_SUCCESS);

EC_CLEANUP_BGN
    exit(EXIT_FAILURE);
EC_CLEANUP_END
}
/*[]*/

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