app_voicemail: Refactor email generation functions

Refactors generic functions used for email generation
into utils.c so that they can be used by multiple
modules, including app_voicemail and app_minivm,
to avoid code duplication.

ASTERISK-29715 #close

Change-Id: I1de0ed3483623e9599711129edc817c45ad237ee

main/utils.c

@@ -570,6 +570,150 @@ static void base64_init(void)
 	b2a_url[(int)'_'] = 63;
 }
 
+#define BASELINELEN    72  /*!< Line length for Base 64 encoded messages */
+#define BASEMAXINLINE  256 /*!< Buffer size for Base 64 attachment encoding */
+
+/*! \brief Structure used for base64 encoding */
+struct baseio {
+	int iocp;
+	int iolen;
+	int linelength;
+	int ateof;
+	unsigned char iobuf[BASEMAXINLINE];
+};
+
+/*!
+ * \brief utility used by inchar(), for base_encode()
+ */
+static int inbuf(struct baseio *bio, FILE *fi)
+{
+	int l;
+
+	if (bio->ateof) {
+		return 0;
+	}
+
+	if ((l = fread(bio->iobuf, 1, BASEMAXINLINE, fi)) != BASEMAXINLINE) {
+		bio->ateof = 1;
+		if (l == 0) {
+			/* Assume EOF */
+			return 0;
+		}
+	}
+
+	bio->iolen = l;
+	bio->iocp = 0;
+
+	return 1;
+}
+
+/*!
+ * \brief utility used by base_encode()
+ */
+static int inchar(struct baseio *bio, FILE *fi)
+{
+	if (bio->iocp >= bio->iolen) {
+		if (!inbuf(bio, fi)) {
+			return EOF;
+		}
+	}
+
+	return bio->iobuf[bio->iocp++];
+}
+
+/*!
+ * \brief utility used by base_encode()
+ */
+static int ochar(struct baseio *bio, int c, FILE *so, const char *endl)
+{
+	if (bio->linelength >= BASELINELEN) {
+		if (fputs(endl, so) == EOF) {
+			return -1;
+		}
+
+		bio->linelength = 0;
+	}
+
+	if (putc(((unsigned char) c), so) == EOF) {
+		return -1;
+	}
+
+	bio->linelength++;
+
+	return 1;
+}
+
+int ast_base64_encode_file(FILE *inputfile, FILE *outputfile, const char *endl)
+{
+	static const unsigned char dtable[] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
+		'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+		'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0',
+		'1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};
+	int i, hiteof = 0;
+	struct baseio bio;
+
+	memset(&bio, 0, sizeof(bio));
+	bio.iocp = BASEMAXINLINE;
+
+	while (!hiteof){
+		unsigned char igroup[3], ogroup[4];
+		int c, n;
+
+		memset(igroup, 0, sizeof(igroup));
+
+		for (n = 0; n < 3; n++) {
+			if ((c = inchar(&bio, inputfile)) == EOF) {
+				hiteof = 1;
+				break;
+			}
+
+			igroup[n] = (unsigned char) c;
+		}
+
+		if (n > 0) {
+			ogroup[0]= dtable[igroup[0] >> 2];
+			ogroup[1]= dtable[((igroup[0] & 3) << 4) | (igroup[1] >> 4)];
+			ogroup[2]= dtable[((igroup[1] & 0xF) << 2) | (igroup[2] >> 6)];
+			ogroup[3]= dtable[igroup[2] & 0x3F];
+
+			if (n < 3) {
+				ogroup[3] = '=';
+
+				if (n < 2) {
+					ogroup[2] = '=';
+				}
+			}
+
+			for (i = 0; i < 4; i++) {
+				ochar(&bio, ogroup[i], outputfile, endl);
+			}
+		}
+	}
+
+	if (fputs(endl, outputfile) == EOF) {
+		return 0;
+	}
+
+	return 1;
+}
+
+int ast_base64_encode_file_path(const char *filename, FILE *outputfile, const char *endl)
+{
+	FILE *fi;
+	int res;
+
+	if (!(fi = fopen(filename, "rb"))) {
+		ast_log(AST_LOG_WARNING, "Failed to open file: %s: %s\n", filename, strerror(errno));
+		return -1;
+	}
+
+	res = ast_base64_encode_file(fi, outputfile, endl);
+
+	fclose(fi);
+
+	return res;
+}
+
 const struct ast_flags ast_uri_http = {AST_URI_UNRESERVED};
 const struct ast_flags ast_uri_http_legacy = {AST_URI_LEGACY_SPACE | AST_URI_UNRESERVED};
 const struct ast_flags ast_uri_sip_user = {AST_URI_UNRESERVED | AST_URI_SIP_USER_UNRESERVED};