new.c: Order two return statements to match comment.

[nmh] / sbr / base64.c

diff --git a/sbr/base64.c b/sbr/base64.c
index 7ceb27b95759651d6bd36732d60904bb3150674d..cbd225dee062c60fa42ebb8415350bc17cb4f835 100644 (file)
--- a/sbr/base64.c
+++ b/sbr/base64.c
@@ -1,5 +1,4 @@
-/*
- * base64.c -- routines for converting to base64
+/* base64.c -- routines for converting to base64

  *
  * This code is Copyright (c) 2012, by the authors of nmh.  See the
  * COPYRIGHT file in the root directory of the nmh distribution for
  *
  * This code is Copyright (c) 2012, by the authors of nmh.  See the
  * COPYRIGHT file in the root directory of the nmh distribution for


@@ -8,10 +7,23 @@
 
 #include <h/mh.h>
 #include <h/mime.h>
 
 #include <h/mh.h>
 #include <h/mime.h>

+#include <h/md5.h>
+#include <inttypes.h>

 
 

-static char nib2b64[0x40+1] =
+static const char nib2b64[0x40+1] =

        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 

+/*
+ * Copy data from one file to another, converting to base64-encoding.
+ *
+ * Arguments include:
+ *
+ * in          - Input filehandle (unencoded data)
+ * out         - Output filename (base64-encoded data)
+ * crlf                - If set, output encoded CRLF for every LF on input.
+ *
+ * Returns OK on success, NOTOK otherwise.
+ */

 int
 writeBase64aux (FILE *in, FILE *out, int crlf)
 {
 int
 writeBase64aux (FILE *in, FILE *out, int crlf)
 {


@@ -48,7 +60,15 @@ writeBase64aux (FILE *in, FILE *out, int crlf)
                     * everything down and push the last character back.
                     */
                    if (i == cc - 1) {
                     * everything down and push the last character back.
                     */
                    if (i == cc - 1) {

-                       ungetc('\n', in);
+                       /*
+                        * If we're at the end of the input, there might be
+                        * more room in inbuf; if so, add it there.  Otherwise
+                        * push it back to the input.
+                        */
+                       if (cc < sizeof(inbuf))
+                           inbuf[cc++] = '\n';
+                       else
+                           ungetc('\n', in);

                        skipnl = 1;
                    } else {
                        /* This only works as long as sizeof(inbuf) == 3 */
                        skipnl = 1;
                    } else {
                        /* This only works as long as sizeof(inbuf) == 3 */


@@ -75,7 +95,10 @@ writeBase64aux (FILE *in, FILE *out, int crlf)
                outbuf[2] = '=';
        }
 
                outbuf[2] = '=';
        }
 

-       fwrite (outbuf, sizeof(*outbuf), sizeof(outbuf), out);
+       if (fwrite (outbuf, sizeof(*outbuf), sizeof(outbuf), out) <
+            sizeof outbuf) {
+           advise ("writeBase64aux", "fwrite");
+       }

 
        if (cc < sizeof(inbuf)) {
            putc ('\n', out);
 
        if (cc < sizeof(inbuf)) {
            putc ('\n', out);


@@ -100,7 +123,7 @@ writeBase64aux (FILE *in, FILE *out, int crlf)
      4 * [length/3]  +  length/57  +  2
    But double the length will certainly be sufficient. */
 int
      4 * [length/3]  +  length/57  +  2
    But double the length will certainly be sufficient. */
 int

-writeBase64 (unsigned char *in, size_t length, unsigned char *out)
+writeBase64 (const unsigned char *in, size_t length, unsigned char *out)

 {
     unsigned int n = BPERLIN;
 
 {
     unsigned int n = BPERLIN;
 


@@ -108,20 +131,19 @@ writeBase64 (unsigned char *in, size_t length, unsigned char *out)
        unsigned long bits;
        unsigned char *bp;
        unsigned int cc;
        unsigned long bits;
        unsigned char *bp;
        unsigned int cc;

-       for (cc = 0, bp = in; length > 0 && cc < 3; ++cc, ++bp, --length)
+       for (cc = 0; length > 0 && cc < 3; ++cc, --length)

           /* empty */ ;
 
           /* empty */ ;
 

-       if (cc == 0) {
+       if (cc == 0)

            break;
            break;

-       } else {
-           bits = (in[0] & 0xff) << 16;
-           if (cc > 1) {
-               bits |= (in[1] & 0xff) << 8;
-               if (cc > 2) {
-                   bits |= in[2] & 0xff;
-               }
-           }
-       }
+
+        bits = (in[0] & 0xff) << 16;
+        if (cc > 1) {
+            bits |= (in[1] & 0xff) << 8;
+            if (cc > 2) {
+                bits |= in[2] & 0xff;
+            }
+        }

 
        for (bp = out + 4; bp > out; bits >>= 6)
            *--bp = nib2b64[bits & 0x3f];
 
        for (bp = out + 4; bp > out; bits >>= 6)
            *--bp = nib2b64[bits & 0x3f];


@@ -149,32 +171,31 @@ writeBase64 (unsigned char *in, size_t length, unsigned char *out)
     return OK;
 }
 
     return OK;
 }
 

-/* 
+/*

  * Essentially a duplicate of writeBase64, but without line wrapping or
  * newline termination (note: string IS NUL terminated)
  */
 
 int
  * Essentially a duplicate of writeBase64, but without line wrapping or
  * newline termination (note: string IS NUL terminated)
  */
 
 int

-writeBase64raw (unsigned char *in, size_t length, unsigned char *out)
+writeBase64raw (const unsigned char *in, size_t length, unsigned char *out)

 {
     while (1) {
        unsigned long bits;
        unsigned char *bp;
        unsigned int cc;
 {
     while (1) {
        unsigned long bits;
        unsigned char *bp;
        unsigned int cc;

-       for (cc = 0, bp = in; length > 0 && cc < 3; ++cc, ++bp, --length)
+       for (cc = 0; length > 0 && cc < 3; ++cc, --length)

           /* empty */ ;
 
           /* empty */ ;
 

-       if (cc == 0) {
+       if (cc == 0)

            break;
            break;

-       } else {
-           bits = (in[0] & 0xff) << 16;
-           if (cc > 1) {
-               bits |= (in[1] & 0xff) << 8;
-               if (cc > 2) {
-                   bits |= in[2] & 0xff;
-               }
-           }
-       }
+
+        bits = (in[0] & 0xff) << 16;
+        if (cc > 1) {
+            bits |= (in[1] & 0xff) << 8;
+            if (cc > 2) {
+                bits |= in[2] & 0xff;
+            }
+        }

 
        for (bp = out + 4; bp > out; bits >>= 6)
            *--bp = nib2b64[bits & 0x3f];
 
        for (bp = out + 4; bp > out; bits >>= 6)
            *--bp = nib2b64[bits & 0x3f];


@@ -194,3 +215,163 @@ writeBase64raw (unsigned char *in, size_t length, unsigned char *out)
 
     return OK;
 }
 
     return OK;
 }

+
+
+static const unsigned char b642nib[0x80] = {
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
+    0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
+    0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
+    0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
+    0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
+    0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
+    0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
+    0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
+    0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff
+};
+
+/*
+ * Decode a base64 string.  The result, decoded, must be freed by the caller.
+ *
+ * encoded      - the string to be decoded
+ * decoded      - the decoded bytes
+ * len          - number of decoded bytes
+ * skip-crs     - non-zero for text content, and for which CR's should be
+ *                skipped
+ * digest       - for an MD5 digest, it can be null
+ */
+int
+decodeBase64 (const char *encoded, unsigned char **decoded, size_t *len,
+             int skip_crs, unsigned char *digest) {
+    const char *cp = encoded;
+    int self_delimiting = 0;
+    int bitno, skip;
+    uint32_t bits;
+    /* Size the decoded string very conservatively. */
+    charstring_t decoded_c = charstring_create (strlen (encoded));
+    MD5_CTX mdContext;
+
+    if (digest)
+        MD5Init (&mdContext);
+
+    bitno = 18;
+    bits = 0L;
+    skip = 0;
+
+    for (; *cp; ++cp) {
+        switch (*cp) {
+            unsigned char value;
+
+            default:
+                if (isspace ((unsigned char) *cp)) {
+                    break;
+                }
+                if (skip  ||  (((unsigned char) *cp) & 0x80)  ||
+                    (value = b642nib[((unsigned char) *cp) & 0x7f]) > 0x3f) {
+                    inform("invalid base64 byte %#x: %.42s",
+                        *(unsigned char *)cp, cp);
+                    charstring_free (decoded_c);
+                    *decoded = NULL;
+
+                    return NOTOK;
+                }
+
+                bits |= value << bitno;
+test_end:
+                if ((bitno -= 6) < 0) {
+                    char b = (char) ((bits >> 16) & 0xff);
+
+                    if (! skip_crs  ||  b != '\r') {
+                        charstring_push_back (decoded_c, b);
+                    }
+                    if (digest)
+                        MD5Update (&mdContext, (unsigned char *) &b, 1);
+                    if (skip < 2) {
+                        b = (bits >> 8) & 0xff;
+                        if (! skip_crs  ||  b != '\r') {
+                            charstring_push_back (decoded_c, b);
+                        }
+                        if (digest)
+                            MD5Update (&mdContext, (unsigned char *) &b, 1);
+                        if (skip < 1) {
+                            b = bits & 0xff;
+                            if (! skip_crs  ||  b != '\r') {
+                                charstring_push_back (decoded_c, b);
+                            }
+                            if (digest)
+                                MD5Update (&mdContext, (unsigned char *) &b, 1);
+                        }
+                    }
+
+                    bitno = 18;
+                    bits = 0L;
+                    skip = 0;
+                }
+                break;
+
+            case '=':
+                if (++skip <= 3)
+                    goto test_end;
+                self_delimiting = 1;
+                break;
+        }
+    }
+
+    if (! self_delimiting  &&  bitno != 18) {
+        /* Show some context for the error. */
+        cp -= min(cp - encoded, 20);
+        inform("premature ending (bitno %d) near %s", bitno, cp);
+        charstring_free (decoded_c);
+        *decoded = NULL;
+
+        return NOTOK;
+    }
+
+    *decoded = (unsigned char *) charstring_buffer_copy (decoded_c);
+    *len = charstring_bytes (decoded_c);
+    charstring_free (decoded_c);
+
+    if (digest) {
+        MD5Final (digest, &mdContext);
+    }
+
+    return OK;
+}
+
+
+/*
+ * Prepare an unsigned char array for display by replacing non-printable
+ * ASCII bytes with their hex representation.  Assumes ASCII input.  output
+ * is allocated by the function and must be freed by the caller.
+ */
+void
+hexify (const unsigned char *input, size_t len, char **output) {
+    /* Start with a charstring capacity that's arbitrarily larger than len. */
+    const charstring_t tmp = charstring_create (2 * len);
+    const unsigned char *cp = input;
+    size_t i;
+
+    for (i = 0; i < len; ++i, ++cp) {
+        if (isascii(*cp) && isprint(*cp)) {
+            charstring_push_back (tmp, (const char) *cp);
+        } else {
+            char s[16];
+            const int num = snprintf(s, sizeof s, "[0x%02x]", *cp);
+
+            if (num <= 0  ||  (unsigned int) num >= sizeof s) {
+                inform("hexify failed to write nonprintable character, needed %d bytes", num + 1);
+            } else {
+                charstring_append_cstring (tmp, s);
+            }
+        }
+    }
+
+    *output = charstring_buffer_copy (tmp);
+    charstring_free (tmp);
+}