Annotation of 43BSD/ucb/Mail/vars.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1980 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #ifndef lint
        !             8: static char *sccsid = "@(#)vars.c      5.2 (Berkeley) 6/21/85";
        !             9: #endif not lint
        !            10: 
        !            11: #include "rcv.h"
        !            12: 
        !            13: /*
        !            14:  * Mail -- a mail program
        !            15:  *
        !            16:  * Variable handling stuff.
        !            17:  */
        !            18: 
        !            19: /*
        !            20:  * Assign a value to a variable.
        !            21:  */
        !            22: 
        !            23: assign(name, value)
        !            24:        char name[], value[];
        !            25: {
        !            26:        register struct var *vp;
        !            27:        register int h;
        !            28: 
        !            29:        h = hash(name);
        !            30:        vp = lookup(name);
        !            31:        if (vp == NOVAR) {
        !            32:                vp = (struct var *) calloc(sizeof *vp, 1);
        !            33:                vp->v_name = vcopy(name);
        !            34:                vp->v_link = variables[h];
        !            35:                variables[h] = vp;
        !            36:        }
        !            37:        else
        !            38:                vfree(vp->v_value);
        !            39:        vp->v_value = vcopy(value);
        !            40: }
        !            41: 
        !            42: /*
        !            43:  * Free up a variable string.  We do not bother to allocate
        !            44:  * strings whose value is "" since they are expected to be frequent.
        !            45:  * Thus, we cannot free same!
        !            46:  */
        !            47: 
        !            48: vfree(cp)
        !            49:        register char *cp;
        !            50: {
        !            51:        if (!equal(cp, ""))
        !            52:                cfree(cp);
        !            53: }
        !            54: 
        !            55: /*
        !            56:  * Copy a variable value into permanent (ie, not collected after each
        !            57:  * command) space.  Do not bother to alloc space for ""
        !            58:  */
        !            59: 
        !            60: char *
        !            61: vcopy(str)
        !            62:        char str[];
        !            63: {
        !            64:        register char *top, *cp, *cp2;
        !            65: 
        !            66:        if (equal(str, ""))
        !            67:                return("");
        !            68:        if ((top = calloc(strlen(str)+1, 1)) == NULL)
        !            69:                panic ("Out of memory");
        !            70:        cp = top;
        !            71:        cp2 = str;
        !            72:        while (*cp++ = *cp2++)
        !            73:                ;
        !            74:        return(top);
        !            75: }
        !            76: 
        !            77: /*
        !            78:  * Get the value of a variable and return it.
        !            79:  * Look in the environment if its not available locally.
        !            80:  */
        !            81: 
        !            82: char *
        !            83: value(name)
        !            84:        char name[];
        !            85: {
        !            86:        register struct var *vp;
        !            87: 
        !            88:        if ((vp = lookup(name)) == NOVAR)
        !            89:                return(getenv(name));
        !            90:        return(vp->v_value);
        !            91: }
        !            92: 
        !            93: /*
        !            94:  * Locate a variable and return its variable
        !            95:  * node.
        !            96:  */
        !            97: 
        !            98: struct var *
        !            99: lookup(name)
        !           100:        char name[];
        !           101: {
        !           102:        register struct var *vp;
        !           103:        register int h;
        !           104: 
        !           105:        h = hash(name);
        !           106:        for (vp = variables[h]; vp != NOVAR; vp = vp->v_link)
        !           107:                if (equal(vp->v_name, name))
        !           108:                        return(vp);
        !           109:        return(NOVAR);
        !           110: }
        !           111: 
        !           112: /*
        !           113:  * Locate a group name and return it.
        !           114:  */
        !           115: 
        !           116: struct grouphead *
        !           117: findgroup(name)
        !           118:        char name[];
        !           119: {
        !           120:        register struct grouphead *gh;
        !           121:        register int h;
        !           122: 
        !           123:        h = hash(name);
        !           124:        for (gh = groups[h]; gh != NOGRP; gh = gh->g_link)
        !           125:                if (equal(gh->g_name, name))
        !           126:                        return(gh);
        !           127:        return(NOGRP);
        !           128: }
        !           129: 
        !           130: /*
        !           131:  * Print a group out on stdout
        !           132:  */
        !           133: 
        !           134: printgroup(name)
        !           135:        char name[];
        !           136: {
        !           137:        register struct grouphead *gh;
        !           138:        register struct group *gp;
        !           139: 
        !           140:        if ((gh = findgroup(name)) == NOGRP) {
        !           141:                printf("\"%s\": not a group\n", name);
        !           142:                return;
        !           143:        }
        !           144:        printf("%s\t", gh->g_name);
        !           145:        for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
        !           146:                printf(" %s", gp->ge_name);
        !           147:        printf("\n");
        !           148: }
        !           149: 
        !           150: /*
        !           151:  * Hash the passed string and return an index into
        !           152:  * the variable or group hash table.
        !           153:  */
        !           154: 
        !           155: hash(name)
        !           156:        char name[];
        !           157: {
        !           158:        register unsigned h;
        !           159:        register char *cp;
        !           160: 
        !           161:        for (cp = name, h = 0; *cp; h = (h << 2) + *cp++)
        !           162:                ;
        !           163:        if (h < 0)
        !           164:                h = -h;
        !           165:        if (h < 0)
        !           166:                h = 0;
        !           167:        return(h % HSHSIZE);
        !           168: }

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