encoding.c: Implement a peekc API.

src/libespeak-ng/encoding.c

 	return decoder->get(decoder);
 }
 
+uint32_t
+text_decoder_peekc(espeak_ng_TEXT_DECODER *decoder)
+{
+	const uint8_t *current = decoder->current;
+	uint32_t c = decoder->get(decoder);
+	decoder->current = current;
+	return c;
+}
+
 const void *
 text_decoder_get_buffer(espeak_ng_TEXT_DECODER *decoder)
 {

src/libespeak-ng/encoding.h

 uint32_t
 text_decoder_getc(espeak_ng_TEXT_DECODER *decoder);
 
+uint32_t
+text_decoder_peekc(espeak_ng_TEXT_DECODER *decoder);
+
 const void *
 text_decoder_get_buffer(espeak_ng_TEXT_DECODER *decoder);
 

tests/encoding.c

 	destroy_text_decoder(decoder);
 }
 
+void
+test_peekc()
+{
+	printf("testing peekc\n");
+
+	espeak_ng_TEXT_DECODER *decoder = create_text_decoder();
+
+	assert(text_decoder_decode_string(decoder, "aGd", 3, ESPEAKNG_ENCODING_US_ASCII) == ENS_OK);
+	assert(text_decoder_eof(decoder) == 0);
+	assert(text_decoder_getc(decoder) == 'a');
+	assert(text_decoder_eof(decoder) == 0);
+	assert(text_decoder_peekc(decoder) == 'G');
+	assert(text_decoder_eof(decoder) == 0);
+	assert(text_decoder_getc(decoder) == 'G');
+	assert(text_decoder_eof(decoder) == 0);
+	assert(text_decoder_peekc(decoder) == 'd');
+	assert(text_decoder_eof(decoder) == 0);
+	assert(text_decoder_getc(decoder) == 'd');
+	assert(text_decoder_eof(decoder) == 1);
+
+	destroy_text_decoder(decoder);
+}
+
 int
 main(int argc, char **argv)
 {
 	test_wchar_decoder();
 	test_auto_decoder();
 
+	test_peekc();
+
 	printf("done\n");
 
 	return EXIT_SUCCESS;