improve decode time

atob() has been replaced with a lookup table, removing previous
conditionals and function calls necessary to decode.

Makefile

@@ -1,12 +1,14 @@
-CFLAGS = -g -Wall -Wextra -Werror
+CC = gcc
+CFLAGS = -Og -g -Wall -Wextra -Werror
 
-objects = main.o input.o trans.o
+objects = main.o input.o output.o encode.o
 
 b64 : $(objects)
-	cc -o b64 $(objects)
+	$(CC) -o b64 $(objects)
 
-main.o trans.o input.o : input.h
-main.o trans.o : trans.h
+main.o input.o : input.h
+main.o encode.o : encode.h
+main.o output.o : output.h
 
 .PHONY : clean
 clean :

encode.c

@@ -0,0 +1,107 @@
+#include "encode.h"
+
+#define PADDING '='
+
+static
+unsigned char b64toascii[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+                             "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
+};
+
+
+int
+encode(unsigned char *op, int olen, unsigned char *sp, int url)
+{
+    int tmp;
+    unsigned char *table;
+    unsigned char *sbeg;
+    unsigned char *tend;
+
+    table = (!url) ? b64toascii : b64urltoascii;
+
+    sbeg = sp;
+    tend = op + olen - (olen % 3);
+    while (op < tend) {
+        *sp++ = table[(*op & ~3) >> 2];
+        tmp = (*op++ & 3) << 4;
+        *sp++ = table[tmp + ((*op & ~15) >> 4)];
+        tmp = (*op++ & 15) << 2;
+        *sp++ = table[tmp + ((*op & 192) >> 6)];
+        *sp++ = table[*op++ & ~192];
+    }
+    switch (olen % 3) {
+        case 2:
+            *sp++ = table[(*op & ~3) >> 2];
+            tmp = (*op++ & 3) << 4;
+            *sp++ = table[tmp + ((*op & ~15) >> 4)];
+            *sp++ = table[(*op & 15) << 2];
+            *sp++ = PADDING;
+            break;
+        case 1:
+            *sp++ = table[(*op & ~3) >> 2];
+            *sp++ = table[(*op & 3) << 4];
+            *sp++ = PADDING;
+            *sp++ = PADDING;
+            break;
+    }
+
+    return sp-sbeg;
+}
+
+int
+decode(unsigned char *sp, int slen, unsigned char *op)
+{
+    int tmp, b;
+    unsigned char *obeg;
+    unsigned char *qend;
+
+    obeg = op;
+    qend = sp + slen - (slen % 4);
+    while (sp < qend) {
+        tmp = asciitob64[*sp++] << 2;
+        b = asciitob64[*sp++];
+        *op++ = tmp + ((b & ~15) >> 4);
+        tmp = (b & 15) << 4;
+        b = asciitob64[*sp++];
+        *op++ = tmp + ((b & ~3) >> 2);
+        *op++ = ((b & 3) << 6) + asciitob64[*sp++];
+    }
+    switch (slen % 4) {
+        case 3:
+            tmp = asciitob64[*sp++] << 2;
+            b = asciitob64[*sp++];
+            *op++ = tmp + ((b & ~15) >> 4);
+            tmp = (b & 15) << 4;
+            *op++ = tmp + ((asciitob64[*sp++] & ~3) >> 2);
+            break;
+        case 2:
+            tmp = asciitob64[*sp++] << 2;
+            *op++ = tmp + ((asciitob64[*sp++] & ~15) >> 4);
+            break;
+    }
+
+    return op-obeg;
+}

encode.h

@@ -0,0 +1,10 @@
+#ifndef ENCODE_H
+#define ENCODE_H
+
+int
+encode(unsigned char *op, int olen, unsigned char *sp, int url);
+
+int
+decode(unsigned char *sp, int slen, unsigned char *op);
+
+#endif

input.c

@@ -1,37 +1,29 @@
 #include "input.h"
 
-#define OBUFSIZE  4
-#define SBUFSIZE  5
+#define PADDING  '='
 
-#define PADDING '='
-
-unsigned char o[OBUFSIZE];
-unsigned char s[SBUFSIZE];
-
-unsigned char *
-getocts(FILE *fp, int *np)
+int
+readb(FILE *fp, unsigned char *s, int slen)
 {
-    int n, c;
+    int read, tread;
+    unsigned char *send, *sbeg;
+    unsigned char *l, *r;
+    
+    read = tread = 0;
+    sbeg = l = r = s;
+    while (tread < slen && (read = fread(l, sizeof(*l), slen-tread, fp))) {
+        tread += read;
+        send = s + tread;
+        for (r = l; r < send; ++r)
+            if (*r != '\n')
+                *l++ = *r;
+        tread -= r - l;
+        if (l > sbeg) {
+            for (--l; *l == PADDING; --l)
+                ;
+            ++l;
+        }
+    }
 
-    n = 0;
-    while (n < OBUFSIZE-1 && (c = fgetc(fp)) != EOF)
-        o[n++] = c;
-    *np = n;
-
-    return (*np) ? o : NULL;
-}
-
-unsigned char *
-getsxts(FILE *fp, int *np)
-{
-    int n, p, c;
-
-    n = p = 0;
-    while (n < SBUFSIZE-1 && (c = fgetc(fp)) != EOF && c != PADDING)
-        s[n++] = c;
-    while (n+p < SBUFSIZE-1)
-        s[n+p++] = PADDING;
-    *np = n;
-
-    return (n) ? s : NULL;
+    return l-sbeg;
 }

input.h

@@ -1,15 +1,9 @@
-#ifndef HEADER_INPUT
-#define HEADER_INPUT
+#ifndef INPUT_H
+#define INPUT_H
 
 #include <stdio.h>
 
-extern unsigned char o[];
-extern unsigned char s[];
-
-unsigned char *
-getocts(FILE *fp, int *np);
-
-unsigned char *
-getsxts(FILE *fp, int *np);
+int
+readb(FILE *fp, unsigned char *s, int slen);
 
 #endif

main.c

@@ -1,58 +1,80 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "input.h"
-#include "trans.h"
+#include "output.h"
+#include "encode.h"
+
+#define OCTETBUF  1500
+#define SXTETBUF  2000
+
+unsigned char obuf[OCTETBUF];
+unsigned char sbuf[SXTETBUF];
 
 int
 main(int argc, char *argv[])
 {
-    int c, n, dec, hlp;
-    char *prog = *argv;
-    unsigned char *b;
-    FILE *fp;
+    int c, n, last;
+    int dec, url, hlp, wrp;
+    FILE *in, *out;
+    char *prog;
 
-    dec = hlp = 0;
+    prog = *argv;
+    dec = url = hlp = wrp = 0;
     while (--argc > 0 && (*++argv)[0] == '-')
         while ((c = *++argv[0]))
             switch (c) {
                 case 'd':
                     dec = 1;
                     break;
+                case 'u':
+                    url = 1;
+                    break;
                 case 'h':
                     hlp = 1;
                     break;
+                case 'w':
+                    wrp = 1;
+                    break;
                 default:
                     fprintf(stderr, "%s: illegal option %c\n", prog, c);
                     exit(EXIT_FAILURE);
                     break;
             }
     if (hlp) {
-        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);
-            }
-        } else {
-            while ((b = getocts(stdin, &n)))
-                    printf("%s", encode(b, n));
-        }
+        fprintf(stdout, "Usage: %s -duhw infile outfile\n", prog);
     } else {
-        if ((fp = fopen(*argv, "r")) == NULL) {
+        in = out = NULL;
+        if (argc >= 1 && (in = fopen(*argv, "r")) == NULL) {
             fprintf(stderr, "%s: can't open %s\n", prog, *argv);
             exit(EXIT_FAILURE);
         }
-        else if (dec) {
-            while ((b = getsxts(fp, &n))) {
-                    b = decode(b, &n);
-                    fwrite(b, sizeof(*b), n, stdout);
-            }
-        } else {
-            while ((b = getocts(fp, &n)))
-                    printf("%s", encode(b, n));
+        if (argc == 2 && (out = fopen(*(argv+1), "w")) == NULL) {
+            fprintf(stderr, "%s: can't open %s\n", prog, *(argv+1));
+            exit(EXIT_FAILURE);
         }
-        fclose(fp);
+        if (dec) {
+            while ((n = readb((in) ? in : stdin, sbuf, SXTETBUF))) {
+                n = decode(sbuf, n, obuf);
+                fwrite(obuf, sizeof(*obuf), n, (out) ? out : stdout);
+            }
+        } else if (wrp) {
+            last = 0;
+            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 = fread(obuf, sizeof(*obuf), OCTETBUF, (in) ? in : stdin))) {
+                n = encode(obuf, n, sbuf, url);
+                fwrite(sbuf, sizeof(*sbuf), n, (out) ? out : stdout);
+            }
+        }
+        if (in)
+            fclose(in);
+        if (out)
+            fclose(out);
     }
     exit(EXIT_SUCCESS);
 }

output.c

@@ -0,0 +1,38 @@
+#include "output.h"
+
+#define WRAPCOL 76
+
+char
+printw(FILE *fp, unsigned char *s, int slen)
+{
+    static int col;
+    int c;
+
+    c = '\n';
+    if (col) {
+        if (slen >= WRAPCOL-col) {
+            fwrite(s, sizeof(*s), WRAPCOL-col, fp);
+            s += WRAPCOL-col;
+            slen -= WRAPCOL-col;
+            col = 0;
+            fputc('\n', fp);
+        } else {
+            fwrite(s, sizeof(*s), slen, fp);
+            s += slen;
+            col += slen;
+            slen -= slen;
+            c = *(s+slen-1);
+        }
+    }
+    for (; slen >= WRAPCOL; slen -= WRAPCOL, s += WRAPCOL) {
+        fwrite(s, sizeof(*s), WRAPCOL, fp);
+        fputc('\n', fp);
+    }
+    if (slen > 0) {
+        fwrite(s, sizeof(*s), slen, fp);
+        col += slen;
+        c = *(s+slen-1);
+    }
+
+    return c;
+}

output.h

@@ -0,0 +1,9 @@
+#ifndef OUTPUT_H
+#define OUTPUT_H
+
+#include <stdio.h>
+
+char
+printw(FILE *fp, unsigned char *s, int slen);
+
+#endif

trans.c

@@ -1,97 +0,0 @@
-#include "trans.h"
-
-#define PADDING '='
-
-unsigned char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
-                      "abcdefghijklmnopqrstuvwxyz" \
-                      "0123456789" \
-                      "+/";
-
-unsigned char *
-encode(unsigned char *op, int np)
-{
-    extern unsigned char s[];
-    unsigned char *sp;
-    int n;
-
-    sp = s;
-    switch (np) {
-        case 3:
-            *sp++ = b64[(*op & ~3) >> 2];
-            n = (*op++ & 3) << 4;
-            *sp++ = b64[n + ((*op & ~15) >> 4)];
-            n = (*op++ & 15) << 2;
-            *sp++ = b64[n + ((*op & 192) >> 6)];
-            *sp = b64[*op & ~192];
-            break;
-        case 2:
-            *sp++ = b64[(*op & ~3) >> 2];
-            n = (*op++ & 3) << 4;
-            *sp++ = b64[n + ((*op & ~15) >> 4)];
-            *sp++ = b64[(*op & 15) << 2];
-            *sp = PADDING;
-            break;
-        case 1:
-            *sp++ = b64[(*op & ~3) >> 2];
-            *sp++ = b64[(*op & 3) << 4];
-            *sp++ = PADDING;
-            *sp = PADDING;
-            break;
-    }
-
-    return s;
-}
-
-unsigned char *
-decode(unsigned char *sp, int *np)
-{
-    extern unsigned char o[];
-    unsigned char *op;
-    int n, b, atob(int c);
-
-    op = o;
-    switch (*np) {
-        case 4:
-            n = atob(*sp++) << 2;
-            b = atob(*sp++);
-            *op++ = n + ((b & ~15) >> 4);
-
-            n = (b & 15) << 4;
-            b = atob(*sp++);
-            *op++ = n + ((b & ~3) >> 2);
-
-            *op = ((b & 3) << 6) + atob(*sp);
-            break;
-        case 3:
-            n = atob(*sp++) << 2;
-            b = atob(*sp++);
-            *op++ = n + ((b & ~15) >> 4);
-
-            n = (b & 15) << 4;
-            *op = n + ((atob(*sp) & ~3) >> 2);
-            break;
-        case 2:
-            n = atob(*sp++) << 2;
-            *op = n + ((atob(*sp) & ~15) >> 4);
-            break;
-    }
-    *np = op-o+1;
-
-    return o;
-}
-
-int atob(int c)
-{
-    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 == '+')
-        c = 62;
-    else
-        c = 63;
-
-    return c;
-}

trans.h

@@ -1,12 +0,0 @@
-#ifndef HEADER_TRANS
-#define HEADER_TRANS
-
-#include "input.h"
-
-unsigned char *
-encode(unsigned char *op, int np);
-
-unsigned char *
-decode(unsigned char *sp, int *np);
-
-#endif