increase readability of encode.{c,h}

A new line is wrongfully added to empty input when using the line wrap
option.

Makefile

@@ -1,14 +1,15 @@
-CFLAGS = -g -Wall -Wextra -Werror
+CC ::= gcc
+CFLAGS ::= -Og -g -Wall -Wextra -Werror
 
-objects = main.o input.o output.o encode.o
+objects ::= $(patsubst %.c, %.o, $(wildcard *.c))
 
 b64 : $(objects)
-	cc -o b64 $(objects)
+	$(CC) -o b64 $(objects)
 
 main.o input.o : input.h
-main.o output.o : output.h
 main.o encode.o : encode.h
+main.o output.o : output.h
 
 .PHONY : clean
 clean :
-	rm -f b64 $(objects)
+	-rm -f b64 $(objects)

encode.c

@@ -2,99 +2,107 @@
 
 #define PADDING '='
 
-unsigned char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+static
-                      "abcdefghijklmnopqrstuvwxyz" \
+unsigned char b64toascii[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
-                      "0123456789" \
+                             "abcdefghijklmnopqrstuvwxyz" \
-                      "+/";
+                             "0123456789" \
+                             "+/";
+
+static
+unsigned char b64urltoascii[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+                                "abcdefghijklmnopqrstuvwxyz" \
+                                "0123456789" \
+                                "-_";
+
+static
+unsigned char asciitob64[] = {
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
+     0,  0,  0, 62,  0, 62,  0, 63, 52, 53,
+    54, 55, 56, 57, 58, 59, 60, 61,  0,  0,
+     0,  0,  0,  0,  0,  0,  1,  2,  3,  4,
+     5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+    15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+    25,  0,  0,  0,  0, 63,  0, 26, 27, 28,
+    29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
+    39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
+    49, 50, 51
+};
 
-unsigned char b64u[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
-                       "abcdefghijklmnopqrstuvwxyz" \
-                       "0123456789" \
-                       "-_";
 
 int
-encode(unsigned char *op, int olen, unsigned char *sp, int url)
+encode(unsigned char *octbuf, int octbufsize, unsigned char *sxtbuf, int urlencoded)
 {
-    int n;
+    unsigned char *table;
-    unsigned char *sb, *enc;
+    unsigned char *sxtbegin;
+    unsigned char *octleft;
+    int highorderbits;
 
-    sb = sp;
+    table = (!urlencoded) ? b64toascii : b64urltoascii;
-    enc = (!url) ? b64 : b64u;
+
-    switch (olen) {
+    sxtbegin = sxtbuf;
-        case 3:
+    octleft = octbuf + octbufsize - (octbufsize % 3);
-            *sp++ = enc[(*op & ~3) >> 2];
+    while (octbuf < octleft) {
-            n = (*op++ & 3) << 4;
+        *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-            *sp++ = enc[n + ((*op & ~15) >> 4)];
+        highorderbits = (*octbuf++ & 3) << 4;
-            n = (*op++ & 15) << 2;
+        *sxtbuf++ = table[highorderbits + ((*octbuf & ~15) >> 4)];
-            *sp++ = enc[n + ((*op & 192) >> 6)];
+        highorderbits = (*octbuf++ & 15) << 2;
-            *sp = enc[*op & ~192];
+        *sxtbuf++ = table[highorderbits + ((*octbuf & 192) >> 6)];
-            break;
+        *sxtbuf++ = table[*octbuf++ & ~192];
+    }
+    switch (octbufsize % 3) {
         case 2:
-            *sp++ = enc[(*op & ~3) >> 2];
+            *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-            n = (*op++ & 3) << 4;
+            highorderbits = (*octbuf++ & 3) << 4;
-            *sp++ = enc[n + ((*op & ~15) >> 4)];
+            *sxtbuf++ = table[highorderbits + ((*octbuf & ~15) >> 4)];
-            *sp++ = enc[(*op & 15) << 2];
+            *sxtbuf++ = table[(*octbuf & 15) << 2];
-            *sp = PADDING;
+            *sxtbuf++ = PADDING;
             break;
         case 1:
-            *sp++ = enc[(*op & ~3) >> 2];
+            *sxtbuf++ = table[(*octbuf & ~3) >> 2];
-            *sp++ = enc[(*op & 3) << 4];
+            *sxtbuf++ = table[(*octbuf & 3) << 4];
-            *sp++ = PADDING;
+            *sxtbuf++ = PADDING;
-            *sp = PADDING;
+            *sxtbuf++ = PADDING;
             break;
     }
 
-    return sp-sb+1;
+    return sxtbuf-sxtbegin;
 }
 
 int
-decode(unsigned char *sp, int slen, unsigned char *op, int url)
+decode(unsigned char *sxtbuf, int sxtbufsize, unsigned char *octbuf)
 {
-    int n, b, atob(int c, int url);
+    unsigned char *octbegin;
-    unsigned char *ob;
+    unsigned char *sxtleft;
+    int highorderbits;
+    int loworderbits;
 
-    ob = op;
+    octbegin = octbuf;
-    switch (slen) {
+    sxtleft = sxtbuf + sxtbufsize - (sxtbufsize % 4);
-        case 4:
+    while (sxtbuf < sxtleft) {
-            n = atob(*sp++, url) << 2;
+        highorderbits = asciitob64[*sxtbuf++] << 2;
-            b = atob(*sp++, url);
+        loworderbits = asciitob64[*sxtbuf++];
-            *op++ = n + ((b & ~15) >> 4);
+        *octbuf++ = highorderbits + ((loworderbits & ~15) >> 4);
-
+        highorderbits = (loworderbits & 15) << 4;
-            n = (b & 15) << 4;
+        loworderbits = asciitob64[*sxtbuf++];
-            b = atob(*sp++, url);
+        *octbuf++ = highorderbits + ((loworderbits & ~3) >> 2);
-            *op++ = n + ((b & ~3) >> 2);
+        *octbuf++ = ((loworderbits & 3) << 6) + asciitob64[*sxtbuf++];
-
+    }
-            *op = ((b & 3) << 6) + atob(*sp, url);
+    switch (sxtbufsize % 4) {
-            break;
         case 3:
-            n = atob(*sp++, url) << 2;
+            highorderbits = asciitob64[*sxtbuf++] << 2;
-            b = atob(*sp++, url);
+            loworderbits = asciitob64[*sxtbuf++];
-            *op++ = n + ((b & ~15) >> 4);
+            *octbuf++ = highorderbits + ((loworderbits & ~15) >> 4);
-
+            highorderbits = (loworderbits & 15) << 4;
-            n = (b & 15) << 4;
+            *octbuf++ = highorderbits + ((asciitob64[*sxtbuf++] & ~3) >> 2);
-            *op = n + ((atob(*sp, url) & ~3) >> 2);
             break;
         case 2:
-            n = atob(*sp++, url) << 2;
+            highorderbits = asciitob64[*sxtbuf++] << 2;
-            *op = n + ((atob(*sp, url) & ~15) >> 4);
+            *octbuf++ = highorderbits + ((asciitob64[*sxtbuf++] & ~15) >> 4);
             break;
     }
 
-    return op-ob+1;
+    return octbuf-octbegin;
-}
-
-int atob(int c, int url)
-{
-    if (c >= 'A' && c <= 'Z')
-        c -= 'A';
-    else if (c >= 'a' && c <= 'z')
-        c = c - 'a' + 26;
-    else if (c >= '0' && c <= '9')
-        c = c - '0' + 26 * 2;
-    else if (c == ((!url) ? '+' : '-'))
-        c = 62;
-    else
-        c = 63;
-
-    return c;
 }

encode.h

@@ -1,10 +1,10 @@
-#ifndef HEADER_ENCODE
+#ifndef ENCODE_H
-#define HEADER_ENCODE
+#define ENCODE_H
 
 int
-encode(unsigned char *op, int olen, unsigned char *sp, int url);
+encode(unsigned char *octbuf, int octbufsize, unsigned char *sxtbuf, int urlencoded);
 
 int
-decode(unsigned char *sp, int slen, unsigned char *op, int url);
+decode(unsigned char *sxtbuf, int sxtbufsize, unsigned char *octbuf);
 
 #endif

input.c

@@ -1,30 +1,32 @@
 #include "input.h"
 
-#define PADDING '='
+#define PADDING  '='
 
 int
-getocts(FILE *fp, unsigned char *o, int olen)
+readb(FILE *fptr, unsigned char *buf, int bufsize)
 {
-    int c, n;
+    int read;
+    int total;
+    unsigned char *begin;
+    unsigned char *end;
+    unsigned char *left;
+    unsigned char *right;
+    
+    read = total = 0;
+    begin = left = buf;
+    while (total < bufsize && (read = fread(left, sizeof(*left), bufsize-total, fptr))) {
+        total += read;
+        end = buf + total;
+        for (right = left; right < end; ++right)
+            if (*right != '\n')
+                *left++ = *right;
+        total -= right - left;
+    }
+    if (left > begin) {
+        for (--left; *left == PADDING; --left)
+            ;
+        ++left;
+    }
 
-    n = 0;
+    return left-begin;
-    while (n < olen-1 && (c = fgetc(fp)) != EOF)
-        o[n++] = c;
-
-    return n;
-}
-
-int
-getsxts(FILE *fp, unsigned char *s, int slen)
-{
-    int c, n, pad;
-
-    n = pad = 0;
-    while (n < slen-1 && (c = fgetc(fp)) != EOF && c != PADDING)
-        if (c != '\n')
-            s[n++] = c;
-    while (n+pad < slen-1)
-        s[n+pad++] = PADDING;
-
-    return n;
 }

input.h

@@ -1,12 +1,9 @@
-#ifndef HEADER_INPUT
+#ifndef INPUT_H
-#define HEADER_INPUT
+#define INPUT_H
 
 #include <stdio.h>
 
 int
-getocts(FILE *fp, unsigned char *o, int olen);
+readb(FILE *fptr, unsigned char *buf, int bufsize);
-
-int
-getsxts(FILE *fp, unsigned char *s, int slen);
 
 #endif

main.c

@@ -4,20 +4,21 @@
 #include "output.h"
 #include "encode.h"
 
-#define OBUFSIZE 4
+#define OCTETBUF  1500
-#define SBUFSIZE 5
+#define SXTETBUF  2000
 
-unsigned char obuf[OBUFSIZE];
+unsigned char obuf[OCTETBUF];
-unsigned char sbuf[SBUFSIZE];
+unsigned char sbuf[SXTETBUF];
 
 int
 main(int argc, char *argv[])
 {
-    int c, n, l;
+    int c, n, last;
     int dec, url, hlp, wrp;
-    char *prog = *argv;
     FILE *in, *out;
+    char *prog;
 
+    prog = *argv;
     dec = url = hlp = wrp = 0;
     while (--argc > 0 && (*++argv)[0] == '-')
         while ((c = *++argv[0]))
@@ -42,6 +43,7 @@ main(int argc, char *argv[])
     if (hlp) {
         fprintf(stdout, "Usage: %s -duhw infile outfile\n", prog);
     } else {
+        in = out = NULL;
         if (argc >= 1 && (in = fopen(*argv, "r")) == NULL) {
             fprintf(stderr, "%s: can't open %s\n", prog, *argv);
             exit(EXIT_FAILURE);
@@ -51,22 +53,23 @@ main(int argc, char *argv[])
             exit(EXIT_FAILURE);
         }
         if (dec) {
-            while ((n = getsxts((argc >= 1) ? in : stdin, sbuf, SBUFSIZE))) {
+            while ((n = readb((in) ? in : stdin, sbuf, SXTETBUF))) {
-                n = decode(sbuf, n, obuf, url);
+                n = decode(sbuf, n, obuf);
-                fwrite(obuf, sizeof(*obuf), n, (argc == 2) ? out : stdout);
+                fwrite(obuf, sizeof(*obuf), n, (out) ? out : stdout);
             }
+        } else if (wrp) {
+            last = '\n';
+            while ((n = fread(obuf, sizeof(*obuf), OCTETBUF, (in) ? in : stdin))) {
+                n = encode(obuf, n, sbuf, url);
+                last = printw((out) ? out : stdout, sbuf, n);
+            }
+            if (last != '\n')
+                fprintf((out) ? out : stdout, "\n");
         } else {
-            while ((n = getocts((argc >= 1) ? in : stdin, obuf, OBUFSIZE))) {
+            while ((n = fread(obuf, sizeof(*obuf), OCTETBUF, (in) ? in : stdin))) {
-                if (wrp) {
+                n = encode(obuf, n, sbuf, url);
-                    n = encode(obuf, n, sbuf, url);
+                fwrite(sbuf, sizeof(*sbuf), n, (out) ? out : stdout);
-                    l = printw((argc == 2) ? out : stdout, sbuf, n);
-                } else {
-                    encode(obuf, n, sbuf, url);
-                    fprintf((argc == 2) ? out : stdout, "%s", sbuf);
-                }
             }
-            if (wrp && l != '\n')
-                fprintf((argc == 2) ? out : stdout, "\n");
         }
         if (in)
             fclose(in);

output.c

@@ -3,16 +3,35 @@
 #define WRAPCOL 76
 
 char
-printw(FILE *fp, unsigned char *s, int slen)
+printw(FILE *fptr, unsigned char *buf, int bufsize)
 {
-    static int col;
+    static int column;
     int c;
 
-    while (slen--) {
+    c = '\n';
-        fputc((c = *s++), fp);
+    if (column > 0) {
-        ++col;
+        if (bufsize >= WRAPCOL-column) {
-        if (!(col %= WRAPCOL))
+            fwrite(buf, sizeof(*buf), WRAPCOL-column, fptr);
-            fputc((c = '\n'), fp);
+            buf += WRAPCOL-column;
+            bufsize -= WRAPCOL-column;
+            column = 0;
+            fputc('\n', fptr);
+        } else {
+            fwrite(buf, sizeof(*buf), bufsize, fptr);
+            column += bufsize;
+            buf += bufsize;
+            bufsize -= bufsize;
+            c = *(buf+bufsize-1);
+        }
+    }
+    for (; bufsize >= WRAPCOL; bufsize -= WRAPCOL, buf += WRAPCOL) {
+        fwrite(buf, sizeof(*buf), WRAPCOL, fptr);
+        fputc('\n', fptr);
+    }
+    if (bufsize > 0) {
+        fwrite(buf, sizeof(*buf), bufsize, fptr);
+        column += bufsize;
+        c = *(buf+bufsize-1);
     }
 
     return c;

output.h

@@ -1,9 +1,9 @@
-#ifndef HEADER_OUTPUT
+#ifndef OUTPUT_H
-#define HEADER_OUTPUT
+#define OUTPUT_H
 
 #include <stdio.h>
 
 char
-printw(FILE *fp, unsigned char *s, int slen);
+printw(FILE *fptr, unsigned char *buf, int bufsize);
 
 #endif