- refactor to a single .c file

- use longjmp() to handle errors
- add memory-optimization and disk-optimization modes

Makefile

@@ -1,36 +1,23 @@
 .PHONY: targets clean install test tag
 
 CC = cc
+CFLAGS = -D_XOPEN_SOURCE=700
 INSTALL = install
 prefix = /usr/local
 bindir = $(prefix)/bin
 datarootdir = $(prefix)/share
 mandir = $(datarootdir)/man
-src = $(wildcard *.c)
-deps = $(src:.c=.d)
-objs = $(src:.c=.o)
 targets = hardv hardv.1
 
 targets: $(targets)
 
--include $(deps)
-
-hardv: $(objs)
-	$(CC) $(LDFLAGS) -o $@ $^
-
-main.o: main.c version LICENSE
+hardv: hardv.c
 	$(CC) $(CFLAGS) \
 		-DVERSION="\"`cat version`\"" \
 		-DCOPYRT="\"`grep -i 'copyright (c)' LICENSE`\"" \
-		-o $@ -c $<
-
-%.o: %.c
-	$(CC) $(CFLAGS) -o $@ -c $<
-
-%.d: %.c
-	@$(CC) -MM $< | sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' >$@
+		-o $@ $^
 
-hardv.1: hardv.man1 version LICENSE
+hardv.1: hardv.1.s version LICENSE
 	@echo building manpage...
 	@set -e; \
 	cp $< $@; \
@@ -54,7 +41,7 @@ test: $(targets)
 	echo all tests passed;
 
 clean:
-	@rm -rf $(targets) $(deps) $(objs) *.tmp
+	@rm -rf $(targets) *.tmp
 	@for i in test/*; do \
 		cd $$i;	\
 		./clean; \

README.md

@@ -2,8 +2,8 @@ hardv
 =====
 (/*hɑ:rd'vi:*/)
 
-`hardv` is a CLI flashcard app for UNIX-compatible systems,
-conforming to the UNIX philosophy.
+`hardv` is a CLI flashcard app for Unix-compatible systems,
+conforming to the Unix philosophy.
 
 - Almost everything can be customized,
 with any programming language you prefer.
@@ -23,16 +23,25 @@ E.g.:
 	and more.
 
 - The format of input files are
-easy to be parsed by both human and other UNIX utilities
+easy to be parsed by both human and other Unix utilities
 like `grep`/`cut`/`sed`/`awk`/...
 
 - Metadata like scheduled time is written back to input files;
 Thus all your data is in files created and managed by yourself;
 Nothing would prevent you from migration or uninstall.
 
-- It is a UNIX filter, although an interactive one.
+- It is a Unix filter, although an interactive one.
 That makes `hardv` easy to be called by other programs.
 
+By default, `hardv` runs in the memory-optimization mode.
+Only one card is loaded in the memory at the same time.
+The process consumes about 512KB to 1MB memory
+for cards with typical size in common systems.
+However, `hardv` allows you to turn it into the disk-optimization mode.
+The disk-optimization mode consumes less disk I/O,
+at the cost of loading all cards of a file into the memory.
+See the `-d` option in the man page `hardv(1)`.
+
 Getting Started
 ---------------