Annotation of 3BSD/cmd/ucbmail/vars.c, revision 1.1

1.1     ! root        1: #
        !             2: 
        !             3: #include "rcv.h"
        !             4: 
        !             5: /*
        !             6:  * Mail -- a mail program
        !             7:  *
        !             8:  * Variable handling stuff.
        !             9:  */
        !            10: 
        !            11: /*
        !            12:  * Assign a value to a variable.
        !            13:  */
        !            14: 
        !            15: assign(name, value)
        !            16:        char name[], value[];
        !            17: {
        !            18:        register struct var *vp;
        !            19:        register int h;
        !            20: 
        !            21:        h = hash(name);
        !            22:        vp = lookup(name);
        !            23:        if (vp == NOVAR) {
        !            24:                vp = (struct var *) calloc(sizeof *vp, 1);
        !            25:                vp->v_name = vcopy(name);
        !            26:                vp->v_link = variables[h];
        !            27:                variables[h] = vp;
        !            28:        }
        !            29:        else
        !            30:                vfree(vp->v_value);
        !            31:        vp->v_value = vcopy(value);
        !            32: }
        !            33: 
        !            34: /*
        !            35:  * Free up a variable string.  We do not bother to allocate
        !            36:  * strings whose value is "" since they are expected to be frequent.
        !            37:  * Thus, we cannot free same!
        !            38:  */
        !            39: 
        !            40: vfree(cp)
        !            41:        register char *cp;
        !            42: {
        !            43:        if (!equal(cp, ""))
        !            44:                cfree(cp);
        !            45: }
        !            46: 
        !            47: /*
        !            48:  * Copy a variable value into permanent (ie, not collected after each
        !            49:  * command) space.  Do not bother to alloc space for ""
        !            50:  */
        !            51: 
        !            52: char *
        !            53: vcopy(str)
        !            54:        char str[];
        !            55: {
        !            56:        register char *top, *cp, *cp2;
        !            57: 
        !            58:        if (equal(str, ""))
        !            59:                return("");
        !            60:        top = calloc(strlen(str)+1, 1);
        !            61:        cp = top;
        !            62:        cp2 = str;
        !            63:        while (*cp++ = *cp2++)
        !            64:                ;
        !            65:        return(top);
        !            66: }
        !            67: 
        !            68: /*
        !            69:  * Get the value of a variable and return it.
        !            70:  * Look in the environment if its not available locally.
        !            71:  */
        !            72: 
        !            73: char *
        !            74: value(name)
        !            75:        char name[];
        !            76: {
        !            77:        register struct var *vp;
        !            78: 
        !            79:        if ((vp = lookup(name)) == NOVAR)
        !            80:                return(getenv(name));
        !            81:        return(vp->v_value);
        !            82: }
        !            83: 
        !            84: /*
        !            85:  * Locate a variable and return its variable
        !            86:  * node.
        !            87:  */
        !            88: 
        !            89: struct var *
        !            90: lookup(name)
        !            91:        char name[];
        !            92: {
        !            93:        register struct var *vp;
        !            94:        register int h;
        !            95: 
        !            96:        h = hash(name);
        !            97:        for (vp = variables[h]; vp != NOVAR; vp = vp->v_link)
        !            98:                if (equal(vp->v_name, name))
        !            99:                        return(vp);
        !           100:        return(NOVAR);
        !           101: }
        !           102: 
        !           103: /*
        !           104:  * Locate a group name and return it.
        !           105:  */
        !           106: 
        !           107: struct grouphead *
        !           108: findgroup(name)
        !           109:        char name[];
        !           110: {
        !           111:        register struct grouphead *gh;
        !           112:        register int h;
        !           113: 
        !           114:        h = hash(name);
        !           115:        for (gh = groups[h]; gh != NOGRP; gh = gh->g_link)
        !           116:                if (equal(gh->g_name, name))
        !           117:                        return(gh);
        !           118:        return(NOGRP);
        !           119: }
        !           120: 
        !           121: /*
        !           122:  * Print a group out on stdout
        !           123:  */
        !           124: 
        !           125: printgroup(name)
        !           126:        char name[];
        !           127: {
        !           128:        register struct grouphead *gh;
        !           129:        register struct group *gp;
        !           130: 
        !           131:        if ((gh = findgroup(name)) == NOGRP) {
        !           132:                printf("\"%s\": not a group\n", name);
        !           133:                return;
        !           134:        }
        !           135:        printf("%s\t", gh->g_name);
        !           136:        for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
        !           137:                printf(" %s", gp->ge_name);
        !           138:        printf("\n");
        !           139: }
        !           140: 
        !           141: /*
        !           142:  * Hash the passed string and return an index into
        !           143:  * the variable or group hash table.
        !           144:  */
        !           145: 
        !           146: hash(name)
        !           147:        char name[];
        !           148: {
        !           149:        register int h;
        !           150:        register char *cp;
        !           151: 
        !           152:        for (cp = name, h = 0; *cp; h = (h << 2) + *cp++)
        !           153:                ;
        !           154:        h &= ~0100000;
        !           155:        return(h % HSHSIZE);
        !           156: }

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