Annotation of 42BSD/ucb/Mail/vars.c, revision 1.1

1.1     ! root        1: #ifndef lint
        !             2: static char sccsid[] = "@(#)vars.c     2.5 (Berkeley) 8/11/83";
        !             3: #endif
        !             4: 
        !             5: #include "rcv.h"
        !             6: 
        !             7: /*
        !             8:  * Mail -- a mail program
        !             9:  *
        !            10:  * Variable handling stuff.
        !            11:  */
        !            12: 
        !            13: /*
        !            14:  * Assign a value to a variable.
        !            15:  */
        !            16: 
        !            17: assign(name, value)
        !            18:        char name[], value[];
        !            19: {
        !            20:        register struct var *vp;
        !            21:        register int h;
        !            22: 
        !            23:        h = hash(name);
        !            24:        vp = lookup(name);
        !            25:        if (vp == NOVAR) {
        !            26:                vp = (struct var *) calloc(sizeof *vp, 1);
        !            27:                vp->v_name = vcopy(name);
        !            28:                vp->v_link = variables[h];
        !            29:                variables[h] = vp;
        !            30:        }
        !            31:        else
        !            32:                vfree(vp->v_value);
        !            33:        vp->v_value = vcopy(value);
        !            34: }
        !            35: 
        !            36: /*
        !            37:  * Free up a variable string.  We do not bother to allocate
        !            38:  * strings whose value is "" since they are expected to be frequent.
        !            39:  * Thus, we cannot free same!
        !            40:  */
        !            41: 
        !            42: vfree(cp)
        !            43:        register char *cp;
        !            44: {
        !            45:        if (!equal(cp, ""))
        !            46:                cfree(cp);
        !            47: }
        !            48: 
        !            49: /*
        !            50:  * Copy a variable value into permanent (ie, not collected after each
        !            51:  * command) space.  Do not bother to alloc space for ""
        !            52:  */
        !            53: 
        !            54: char *
        !            55: vcopy(str)
        !            56:        char str[];
        !            57: {
        !            58:        register char *top, *cp, *cp2;
        !            59: 
        !            60:        if (equal(str, ""))
        !            61:                return("");
        !            62:        if ((top = calloc(strlen(str)+1, 1)) == NULL)
        !            63:                panic ("Out of memory");
        !            64:        cp = top;
        !            65:        cp2 = str;
        !            66:        while (*cp++ = *cp2++)
        !            67:                ;
        !            68:        return(top);
        !            69: }
        !            70: 
        !            71: /*
        !            72:  * Get the value of a variable and return it.
        !            73:  * Look in the environment if its not available locally.
        !            74:  */
        !            75: 
        !            76: char *
        !            77: value(name)
        !            78:        char name[];
        !            79: {
        !            80:        register struct var *vp;
        !            81: 
        !            82:        if ((vp = lookup(name)) == NOVAR)
        !            83:                return(getenv(name));
        !            84:        return(vp->v_value);
        !            85: }
        !            86: 
        !            87: /*
        !            88:  * Locate a variable and return its variable
        !            89:  * node.
        !            90:  */
        !            91: 
        !            92: struct var *
        !            93: lookup(name)
        !            94:        char name[];
        !            95: {
        !            96:        register struct var *vp;
        !            97:        register int h;
        !            98: 
        !            99:        h = hash(name);
        !           100:        for (vp = variables[h]; vp != NOVAR; vp = vp->v_link)
        !           101:                if (equal(vp->v_name, name))
        !           102:                        return(vp);
        !           103:        return(NOVAR);
        !           104: }
        !           105: 
        !           106: /*
        !           107:  * Locate a group name and return it.
        !           108:  */
        !           109: 
        !           110: struct grouphead *
        !           111: findgroup(name)
        !           112:        char name[];
        !           113: {
        !           114:        register struct grouphead *gh;
        !           115:        register int h;
        !           116: 
        !           117:        h = hash(name);
        !           118:        for (gh = groups[h]; gh != NOGRP; gh = gh->g_link)
        !           119:                if (equal(gh->g_name, name))
        !           120:                        return(gh);
        !           121:        return(NOGRP);
        !           122: }
        !           123: 
        !           124: /*
        !           125:  * Print a group out on stdout
        !           126:  */
        !           127: 
        !           128: printgroup(name)
        !           129:        char name[];
        !           130: {
        !           131:        register struct grouphead *gh;
        !           132:        register struct group *gp;
        !           133: 
        !           134:        if ((gh = findgroup(name)) == NOGRP) {
        !           135:                printf("\"%s\": not a group\n", name);
        !           136:                return;
        !           137:        }
        !           138:        printf("%s\t", gh->g_name);
        !           139:        for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
        !           140:                printf(" %s", gp->ge_name);
        !           141:        printf("\n");
        !           142: }
        !           143: 
        !           144: /*
        !           145:  * Hash the passed string and return an index into
        !           146:  * the variable or group hash table.
        !           147:  */
        !           148: 
        !           149: hash(name)
        !           150:        char name[];
        !           151: {
        !           152:        register unsigned h;
        !           153:        register char *cp;
        !           154: 
        !           155:        for (cp = name, h = 0; *cp; h = (h << 2) + *cp++)
        !           156:                ;
        !           157:        if (h < 0)
        !           158:                h = -h;
        !           159:        if (h < 0)
        !           160:                h = 0;
        !           161:        return(h % HSHSIZE);
        !           162: }

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