implement -d (dump data) option.

1 files changed, 97 insertions, 22 deletions

diff --git a/uxd.c b/uxd.c
index 183c422..1651a2f 100644
--- a/uxd.c
+++ b/uxd.c
@@ -115,7 +115,7 @@ char * const special_symbols[] = {
 
 /* options */
 int alternate_colors = 1; /* -1 */
-int print_info = 0;   /* -i */
+int print_info_opt = 0;   /* -i */
 int bold = 0;         /* -b */
 int hilite_multi = 0; /* -r */
 int mono = 0;         /* -m */
@@ -125,6 +125,8 @@ int seek_offset_zero = 0; /* -S */
 long limit;           /* -l */
 const char *hex_byte_fmt = "%02x";   /* -u */
 const char *hex_word_fmt = "%04x: "; /* "  */
+char *dump_data_arg = NULL; /* -d */
+long dump_data_idx  = 0;    /* -d */
 
 /* stats for -i option */
 long byte_count = 0;
@@ -221,12 +223,18 @@ void parse_args(int argc, char **argv) {
 			version();
 	}
 
-	while((opt = my_getopt(argc, argv, "1ic:nbl:rmo:S:s:uhv")) != -1) {
+	while((opt = my_getopt(argc, argv, "d:1ic:nbl:rmo:S:s:uhv")) != -1) {
 		switch(opt) {
+			case 'd':
+				if(dump_data_arg) {
+					fprintf(stderr, "%s: multiple -d options not supported.\n", self);
+					exit(1);
+				}
+				dump_data_arg = optarg; break;
 			case '1':
 				alternate_colors = 0; break;
 			case 'i':
-				print_info = 1; break;
+				print_info_opt = 1; break;
 			case 'c':
 				mono = 0; parse_colors(optarg); break;
 			case 'n':
@@ -263,11 +271,18 @@ void parse_args(int argc, char **argv) {
 		}
 	}
 
-	/* filename (if present) must come after all -options, and
-	   there can only be one filename. */
-	if(optind < (argc - 1)) usage();
+	if(dump_data_arg) {
+		if(optind != argc) {
+			fprintf(stderr, "%s: cannot give a filename when -d is used.\n", self);
+			exit(1);
+		}
+	} else {
+		/* filename (if present) must come after all -options, and
+		   there can only be one filename. */
+		if(optind < (argc - 1)) usage();
 
-	open_input(argv[optind]);
+		open_input(argv[optind]);
+	}
 }
 
 /* read options from the environment and the command line, create a
@@ -487,6 +502,29 @@ int is_out_of_range(int count, unsigned char *b) {
 	return 1;
 }
 
+int get_next_byte(void) {
+	int c;
+
+	if(dump_data_arg) {
+		/* have to cast this to unsigned char and back to int,
+		   to emulate fgetc() */
+		c = (unsigned char)dump_data_arg[dump_data_idx++];
+		if(!c) c = EOF;
+	} else {
+		c = fgetc(input);
+	}
+
+	return c;
+}
+
+void push_back_byte(int c) {
+	if(dump_data_arg) {
+		if(dump_data_idx) dump_data_idx--;
+	} else {
+		ungetc(c, input);
+	}
+}
+
 /* This is the 'workhorse', called for each character in the file.
    Return value: false = EOF, true = more data to read */
 int dump_utf8_char(void) {
@@ -497,7 +535,7 @@ int dump_utf8_char(void) {
 	int c, cont_count, i;
 	static int byte0;
 
-	c = fgetc(input);
+	c = get_next_byte();
 	if(c == EOF)
 		return 0;
 
@@ -532,7 +570,7 @@ int dump_utf8_char(void) {
 	/* read and validate the continuation bytes, if any */
 	for(i = 0; i < cont_count; i++) {
 		int cb;
-		c = fgetc(input);
+		c = get_next_byte();
 
 		if(c == EOF) {
 			/* EOF in mid-sequence. Don't return 0 here, since we still
@@ -550,7 +588,7 @@ int dump_utf8_char(void) {
 			/* Expected 10xxxxxx, got something else */
 			cont_count = i;
 			bad = 1;
-			ungetc(cb, input);
+			push_back_byte(cb);
 			break;
 		}
 	}
@@ -646,15 +684,21 @@ void seek_input(void) {
 		fake_seek();
 		filepos = seekpos;
 	} else {
+		fprintf(stderr, "%s: are you trying to seek backwards in stdin?\n", self);
 		perror(self);
 		exit(1);
 	}
 }
 
-void dump_file(void) {
-	if(seekpos) seek_input();
-	if(seek_offset_zero) filepos = 0;
+void print_info(void) {
+	printf("Bytes: %ld\n", byte_count);
+	printf("Characters: %ld\n", char_count);
+	printf("  ASCII: %ld\n", ascii_count);
+	printf("  Multibyte: %ld\n", multi_count);
+	printf("Bad sequences: %ld\n", bad_count);
+}
 
+void dump_loop(void) {
 	while(dump_utf8_char())
 		if(limit && (filepos >= limit)) break;
 
@@ -662,19 +706,50 @@ void dump_file(void) {
 	if(dump_column)
 		print_line();
 
-	if(print_info) {
-		printf("Bytes: %ld\n", byte_count);
-		printf("Characters: %ld\n", char_count);
-		printf("  ASCII: %ld\n", ascii_count);
-		printf("  Multibyte: %ld\n", multi_count);
-		printf("Bad sequences: %ld\n", bad_count);
-	}
+}
+
+void dump_file(void) {
+	if(seekpos) seek_input();
+	if(seek_offset_zero) filepos = 0;
+
+	dump_loop();
+
+	fclose(input);
+}
+
+void dump_data(void) {
+	int datalen;
+
+	datalen = strlen(dump_data_arg);
+
+	if(seekpos >= datalen)
+		return;
+
+	if(seekpos < 0)
+		dump_data_idx = datalen + seekpos;
+	else if(seekpos)
+		dump_data_idx = seekpos;
+
+	if(seek_offset_zero)
+		filepos = 0;
+	else
+		filepos = dump_data_idx;
+
+	dump_loop();
 }
 
 int main(int argc, char **argv) {
 	set_self(argv[0]);
+
 	parse_options(argc, argv);
-	dump_file();
-	fclose(input);
+
+	if(dump_data_arg)
+		dump_data();
+	else
+		dump_file();
+
+	if(print_info_opt)
+		print_info();
+
 	return 0;
 }