change function definitions

Buffers are no longer wired into any input or translation functions.
They are supplied as arguments through main.

input.c

@@ -1,37 +1,29 @@
 #include "input.h"
 
-#define OBUFSIZE  4
-#define SBUFSIZE  5
-
 #define PADDING '='
 
-unsigned char o[OBUFSIZE];
-unsigned char s[SBUFSIZE];
-
-unsigned char *
-getocts(FILE *fp, int *np)
+int
+getocts(FILE *fp, unsigned char *o, int olen)
 {
-    int n, c;
+    int c, n;
 
     n = 0;
-    while (n < OBUFSIZE-1 && (c = fgetc(fp)) != EOF)
+    while (n < olen-1 && (c = fgetc(fp)) != EOF)
         o[n++] = c;
-    *np = n;
 
-    return (*np) ? o : NULL;
+    return n;
 }
 
-unsigned char *
-getsxts(FILE *fp, int *np)
+int
+getsxts(FILE *fp, unsigned char *s, int slen)
 {
-    int n, p, c;
+    int c, n, pad;
 
-    n = p = 0;
-    while (n < SBUFSIZE-1 && (c = fgetc(fp)) != EOF && c != PADDING)
+    n = pad = 0;
+    while (n < slen-1 && (c = fgetc(fp)) != EOF && c != PADDING)
         s[n++] = c;
-    while (n+p < SBUFSIZE-1)
-        s[n+p++] = PADDING;
-    *np = n;
+    while (n+pad < slen-1)
+        s[n+pad++] = PADDING;
 
-    return (n) ? s : NULL;
+    return n;
 }

input.h

@@ -3,13 +3,10 @@
 
 #include <stdio.h>
 
-extern unsigned char o[];
-extern unsigned char s[];
+int
+getocts(FILE *fp, unsigned char *o, int olen);
 
-unsigned char *
-getocts(FILE *fp, int *np);
-
-unsigned char *
-getsxts(FILE *fp, int *np);
+int
+getsxts(FILE *fp, unsigned char *s, int slen);
 
 #endif

main.c

@@ -3,12 +3,17 @@
 #include "input.h"
 #include "trans.h"
 
+#define OBUFSIZE 4
+#define SBUFSIZE 5
+
+unsigned char obuf[OBUFSIZE];
+unsigned char sbuf[SBUFSIZE];
+
 int
 main(int argc, char *argv[])
 {
     int c, n, dec, hlp;
     char *prog = *argv;
-    unsigned char *b;
     FILE *fp;
 
     dec = hlp = 0;
@@ -30,13 +35,15 @@ main(int argc, char *argv[])
         fprintf(stdout, "Usage: %s -d -h file\n", prog);
     } else if (argc != 1) {
         if (dec) {
-            while ((b = getsxts(stdin, &n))) {
-                    b = decode(b, &n);
-                    fwrite(b, sizeof(*b), n, stdout);
+            while ((n = getsxts(stdin, sbuf, SBUFSIZE))) {
+                n = decode(sbuf, n, obuf);
+                fwrite(obuf, sizeof(*obuf), n, stdout);
             }
         } else {
-            while ((b = getocts(stdin, &n)))
-                    printf("%s", encode(b, n));
+            while ((n = getocts(stdin, obuf, OBUFSIZE))) {
+                encode(obuf, n, sbuf);
+                printf("%s", sbuf);
+            }
         }
     } else {
         if ((fp = fopen(*argv, "r")) == NULL) {
@@ -44,13 +51,15 @@ main(int argc, char *argv[])
             exit(EXIT_FAILURE);
         }
         else if (dec) {
-            while ((b = getsxts(fp, &n))) {
-                    b = decode(b, &n);
-                    fwrite(b, sizeof(*b), n, stdout);
+            while ((n = getsxts(fp, sbuf, SBUFSIZE))) {
+                n = decode(sbuf, n, obuf);
+                fwrite(obuf, sizeof(*obuf), n, stdout);
             }
         } else {
-            while ((b = getocts(fp, &n)))
-                    printf("%s", encode(b, n));
+            while ((n = getocts(fp, obuf, OBUFSIZE))) {
+                encode(obuf, n, sbuf);
+                printf("%s", sbuf);
+            }
         }
         fclose(fp);
     }

trans.c

@@ -7,15 +7,14 @@ unsigned char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
                       "0123456789" \
                       "+/";
 
-unsigned char *
-encode(unsigned char *op, int np)
+int
+encode(unsigned char *op, int olen, unsigned char *sp)
 {
-    extern unsigned char s[];
-    unsigned char *sp;
     int n;
+    unsigned char *sb;
 
-    sp = s;
-    switch (np) {
+    sb = sp;
+    switch (olen) {
         case 3:
             *sp++ = b64[(*op & ~3) >> 2];
             n = (*op++ & 3) << 4;
@@ -39,18 +38,17 @@ encode(unsigned char *op, int np)
             break;
     }
 
-    return s;
+    return sp-sb+1;
 }
 
-unsigned char *
-decode(unsigned char *sp, int *np)
+int
+decode(unsigned char *sp, int slen, unsigned char *op)
 {
-    extern unsigned char o[];
-    unsigned char *op;
     int n, b, atob(int c);
+    unsigned char *ob;
 
-    op = o;
-    switch (*np) {
+    ob = op;
+    switch (slen) {
         case 4:
             n = atob(*sp++) << 2;
             b = atob(*sp++);
@@ -75,9 +73,8 @@ decode(unsigned char *sp, int *np)
             *op = n + ((atob(*sp) & ~15) >> 4);
             break;
     }
-    *np = op-o+1;
 
-    return o;
+    return op-ob+1;
 }
 
 int atob(int c)

trans.h

@@ -1,12 +1,10 @@
 #ifndef HEADER_TRANS
 #define HEADER_TRANS
 
-#include "input.h"
+int
+encode(unsigned char *op, int olen, unsigned char *sp);
 
-unsigned char *
-encode(unsigned char *op, int np);
-
-unsigned char *
-decode(unsigned char *sp, int *np);
+int
+decode(unsigned char *sp, int slen, unsigned char *op);
 
 #endif