libbb/human_readable.c: shrink; and reduce bss usage

also, move smart_ulltoaN there and comment usage locations

function                                             old     new   delta
static.unit_chars                                      7       9      +2
utoa_to_buf                                          110     108      -2
make_human_readable_str                              262     258      -4
fallbackSort                                        1723    1719      -4
static.fmt                                            97      92      -5
static.fmt_tenths                                     10       -     -10
static.str                                            21       4     -17
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/5 up/down: 2/-42)             Total: -40 bytes
   text    data     bss     dec     hex filename
 820981     453    6932  828366   ca3ce busybox_old
 820968     453    6916  828337   ca3b1 busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

6 files changed, 158 insertions, 146 deletions

diff --git a/coreutils/df.c b/coreutils/df.c
index c37b188..624ad94 100644
--- a/coreutils/df.c
+++ b/coreutils/df.c
@@ -92,7 +92,10 @@ int df_main(int argc, char **argv)
 	if (disp_units_hdr == NULL) {
 #if ENABLE_FEATURE_HUMAN_READABLE
 		disp_units_hdr = xasprintf("%s-blocks",
-			make_human_readable_str(df_disp_hr, 0, !!(opt & OPT_POSIX)));
+			/* print df_disp_hr, show no fractionals,
+			 * use suffixes if OPT_POSIX is set in opt */
+			make_human_readable_str(df_disp_hr, 0, !!(opt & OPT_POSIX))
+		);
 #else
 		disp_units_hdr = xasprintf("%lu-blocks", df_disp_hr);
 #endif
@@ -189,21 +192,27 @@ int df_main(int argc, char **argv)
 
 #if ENABLE_FEATURE_HUMAN_READABLE
 			printf(" %9s ",
+				/* f_blocks x f_bsize / df_disp_hr, show one fractional,
+				 * use suffixes if df_disp_hr == 0 */
 				make_human_readable_str(s.f_blocks, s.f_bsize, df_disp_hr));
 
 			printf(" %9s " + 1,
+				/* EXPR x f_bsize / df_disp_hr, show one fractional,
+				 * use suffixes if df_disp_hr == 0 */
 				make_human_readable_str((s.f_blocks - s.f_bfree),
 						s.f_bsize, df_disp_hr));
 
 			printf("%9s %3u%% %s\n",
-					make_human_readable_str(s.f_bavail, s.f_bsize, df_disp_hr),
-					blocks_percent_used, mount_point);
+				/* f_bavail x f_bsize / df_disp_hr, show one fractional,
+				 * use suffixes if df_disp_hr == 0 */
+				make_human_readable_str(s.f_bavail, s.f_bsize, df_disp_hr),
+				blocks_percent_used, mount_point);
 #else
 			printf(" %9lu %9lu %9lu %3u%% %s\n",
-					kscale(s.f_blocks, s.f_bsize),
-					kscale(s.f_blocks - s.f_bfree, s.f_bsize),
-					kscale(s.f_bavail, s.f_bsize),
-					blocks_percent_used, mount_point);
+				kscale(s.f_blocks, s.f_bsize),
+				kscale(s.f_blocks - s.f_bfree, s.f_bsize),
+				kscale(s.f_bavail, s.f_bsize),
+				blocks_percent_used, mount_point);
 #endif
 		}
 	}
diff --git a/coreutils/du.c b/coreutils/du.c
index ec283f8..730d6d1 100644
--- a/coreutils/du.c
+++ b/coreutils/du.c
@@ -58,14 +58,17 @@ static void print(unsigned long size, const char *filename)
 {
 	/* TODO - May not want to defer error checking here. */
 #if ENABLE_FEATURE_HUMAN_READABLE
-	printf("%s\t%s\n", make_human_readable_str(size, 512, G.disp_hr),
+	printf("%s\t%s\n",
+			/* size x 512 / G.disp_hr, show one fractional,
+			 * use suffixes if G.disp_hr == 0 */
+			make_human_readable_str(size, 512, G.disp_hr),
 			filename);
 #else
 	if (G.disp_k) {
 		size++;
 		size >>= 1;
 	}
-	printf("%ld\t%s\n", size, filename);
+	printf("%lu\t%s\n", size, filename);
 #endif
 }
 
diff --git a/coreutils/ls.c b/coreutils/ls.c
index a067aa3..38cabca 100644
--- a/coreutils/ls.c
+++ b/coreutils/ls.c
@@ -829,7 +829,9 @@ static NOINLINE unsigned list_single(const struct dnode *dn)
 		} else {
 			if (all_fmt & LS_DISP_HR) {
 				column += printf("%9s ",
-					make_human_readable_str(dn->dstat.st_size, 1, 0));
+					/* print st_size, show one fractional, use suffixes */
+					make_human_readable_str(dn->dstat.st_size, 1, 0)
+				);
 			} else {
 				column += printf("%9"OFF_FMT"u ", (off_t) dn->dstat.st_size);
 			}
diff --git a/include/libbb.h b/include/libbb.h
index dca14b4..be175d7 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -691,6 +691,10 @@ char *itoa_to_buf(int n, char *buf, unsigned buflen) FAST_FUNC;
 /* Intelligent formatters of bignums */
 void smart_ulltoa4(unsigned long long ul, char buf[5], const char *scale) FAST_FUNC;
 void smart_ulltoa5(unsigned long long ul, char buf[5], const char *scale) FAST_FUNC;
+/* If block_size == 0, display size without fractional part,
+ * else display (size * block_size) with one decimal digit.
+ * If display_unit == 0, add suffix (K,M,G...),
+ * else divide by display_unit and do not use suffix. */
 //TODO: provide pointer to buf (avoid statics)?
 const char *make_human_readable_str(unsigned long long size,
 		unsigned long block_size, unsigned long display_unit) FAST_FUNC;
diff --git a/libbb/human_readable.c b/libbb/human_readable.c
index 05e7d86..3050d7d 100644
--- a/libbb/human_readable.c
+++ b/libbb/human_readable.c
@@ -30,70 +30,168 @@
 
 #include "libbb.h"
 
-const char* FAST_FUNC make_human_readable_str(unsigned long long size,
+const char* FAST_FUNC make_human_readable_str(unsigned long long val,
 	unsigned long block_size, unsigned long display_unit)
 {
-	/* The code will adjust for additional (appended) units */
 	static const char unit_chars[] ALIGN1 = {
-		'\0', 'K', 'M', 'G', 'T', 'P', 'E'
+		'\0', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'
 	};
-	static const char fmt[] ALIGN1 = "%llu";
-	static const char fmt_tenths[] ALIGN1 = "%llu.%d%c";
 
-	static char str[21] ALIGN1;  /* Sufficient for 64 bit unsigned integers */
+	static char *str;
 
-	unsigned long long val;
-	int frac;
+	unsigned frac; /* 0..9 - the fractional digit */
 	const char *u;
-	const char *f;
-	smallint no_tenths;
+	const char *fmt;
 
-	if (size == 0)
+	if (val == 0)
 		return "0";
 
-	/* If block_size is 0 then do not print tenths */
-	no_tenths = 0;
-	if (block_size == 0) {
-		no_tenths = 1;
-		block_size = 1;
-	}
-
-	u = unit_chars;
-	val = size * block_size;
-	f = fmt;
+	fmt = "%llu";
+	if (block_size > 1)
+		val *= block_size;
 	frac = 0;
+	u = unit_chars;
 
 	if (display_unit) {
 		val += display_unit/2;	/* Deal with rounding */
-		val /= display_unit;	/* Don't combine with the line above!!! */
+		val /= display_unit;	/* Don't combine with the line above! */
 		/* will just print it as ulonglong (below) */
 	} else {
 		while ((val >= 1024)
-		 && (u < unit_chars + sizeof(unit_chars) - 1)
+		 /* && (u < unit_chars + sizeof(unit_chars) - 1) - never happens */
 		) {
-			f = fmt_tenths;
+			fmt = "%llu.%u%c";
 			u++;
-			frac = (((int)(val % 1024)) * 10 + 1024/2) / 1024;
+			frac = (((unsigned)val % 1024) * 10 + 1024/2) / 1024;
 			val /= 1024;
 		}
-		if (frac >= 10) {		/* We need to round up here. */
+		if (frac >= 10) { /* we need to round up here */
 			++val;
 			frac = 0;
 		}
 #if 1
-		/* Sample code to omit decimal point and tenths digit. */
-		if (no_tenths) {
+		/* If block_size is 0, dont print fractional part */
+		if (block_size == 0) {
 			if (frac >= 5) {
 				++val;
 			}
-			f = "%llu%*c" /* fmt_no_tenths */;
+			fmt = "%llu%*c";
 			frac = 1;
 		}
 #endif
 	}
 
-	/* If f==fmt then 'frac' and 'u' are ignored. */
-	snprintf(str, sizeof(str), f, val, frac, *u);
-
+	if (!str) {
+		/* sufficient for any width of val */
+		str = xmalloc(sizeof(val)*3 + 2 + 3);
+	}
+	sprintf(str, fmt, val, frac, *u);
 	return str;
 }
+
+
+/* vda's implementations of the similar idea */
+
+/* Convert unsigned long long value into compact 5-char representation.
+ * String is not terminated (buf[5] is untouched) */
+void FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[6], const char *scale)
+{
+	const char *fmt;
+	char c;
+	unsigned v, u, idx = 0;
+
+	if (ul > 99999) { // do not scale if 99999 or less
+		ul *= 10;
+		do {
+			ul /= 1024;
+			idx++;
+		} while (ul >= 100000);
+	}
+	v = ul; // ullong divisions are expensive, avoid them
+
+	fmt = " 123456789";
+	u = v / 10;
+	v = v % 10;
+	if (!idx) {
+		// 99999 or less: use "12345" format
+		// u is value/10, v is last digit
+		c = buf[0] = " 123456789"[u/1000];
+		if (c != ' ') fmt = "0123456789";
+		c = buf[1] = fmt[u/100%10];
+		if (c != ' ') fmt = "0123456789";
+		c = buf[2] = fmt[u/10%10];
+		if (c != ' ') fmt = "0123456789";
+		buf[3] = fmt[u%10];
+		buf[4] = "0123456789"[v];
+	} else {
+		// value has been scaled into 0..9999.9 range
+		// u is value, v is 1/10ths (allows for 92.1M format)
+		if (u >= 100) {
+			// value is >= 100: use "1234M', " 123M" formats
+			c = buf[0] = " 123456789"[u/1000];
+			if (c != ' ') fmt = "0123456789";
+			c = buf[1] = fmt[u/100%10];
+			if (c != ' ') fmt = "0123456789";
+			v = u % 10;
+			u = u / 10;
+			buf[2] = fmt[u%10];
+		} else {
+			// value is < 100: use "92.1M" format
+			c = buf[0] = " 123456789"[u/10];
+			if (c != ' ') fmt = "0123456789";
+			buf[1] = fmt[u%10];
+			buf[2] = '.';
+		}
+		buf[3] = "0123456789"[v];
+		buf[4] = scale[idx]; /* typically scale = " kmgt..." */
+	}
+}
+
+/* Convert unsigned long long value into compact 4-char
+ * representation. Examples: "1234", "1.2k", " 27M", "123T"
+ * String is not terminated (buf[4] is untouched) */
+void FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[5], const char *scale)
+{
+	const char *fmt;
+	char c;
+	unsigned v, u, idx = 0;
+
+	if (ul > 9999) { // do not scale if 9999 or less
+		ul *= 10;
+		do {
+			ul /= 1024;
+			idx++;
+		} while (ul >= 10000);
+	}
+	v = ul; // ullong divisions are expensive, avoid them
+
+	fmt = " 123456789";
+	u = v / 10;
+	v = v % 10;
+	if (!idx) {
+		// 9999 or less: use "1234" format
+		// u is value/10, v is last digit
+		c = buf[0] = " 123456789"[u/100];
+		if (c != ' ') fmt = "0123456789";
+		c = buf[1] = fmt[u/10%10];
+		if (c != ' ') fmt = "0123456789";
+		buf[2] = fmt[u%10];
+		buf[3] = "0123456789"[v];
+	} else {
+		// u is value, v is 1/10ths (allows for 9.2M format)
+		if (u >= 10) {
+			// value is >= 10: use "123M', " 12M" formats
+			c = buf[0] = " 123456789"[u/100];
+			if (c != ' ') fmt = "0123456789";
+			v = u % 10;
+			u = u / 10;
+			buf[1] = fmt[u%10];
+		} else {
+			// value is < 10: use "9.2M" format
+			buf[0] = "0123456789"[u];
+			buf[1] = '.';
+		}
+		buf[2] = "0123456789"[v];
+		buf[3] = scale[idx]; /* typically scale = " kmgt..." */
+	}
+}
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index a86efc2..aa08129 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -48,110 +48,6 @@ char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
 	return strncpy(dst, src, IFNAMSIZ);
 }
 
-/* Convert unsigned long long value into compact 4-char
- * representation. Examples: "1234", "1.2k", " 27M", "123T"
- * String is not terminated (buf[4] is untouched) */
-void FAST_FUNC smart_ulltoa4(unsigned long long ul, char buf[5], const char *scale)
-{
-	const char *fmt;
-	char c;
-	unsigned v, u, idx = 0;
-
-	if (ul > 9999) { // do not scale if 9999 or less
-		ul *= 10;
-		do {
-			ul /= 1024;
-			idx++;
-		} while (ul >= 10000);
-	}
-	v = ul; // ullong divisions are expensive, avoid them
-
-	fmt = " 123456789";
-	u = v / 10;
-	v = v % 10;
-	if (!idx) {
-		// 9999 or less: use "1234" format
-		// u is value/10, v is last digit
-		c = buf[0] = " 123456789"[u/100];
-		if (c != ' ') fmt = "0123456789";
-		c = buf[1] = fmt[u/10%10];
-		if (c != ' ') fmt = "0123456789";
-		buf[2] = fmt[u%10];
-		buf[3] = "0123456789"[v];
-	} else {
-		// u is value, v is 1/10ths (allows for 9.2M format)
-		if (u >= 10) {
-			// value is >= 10: use "123M', " 12M" formats
-			c = buf[0] = " 123456789"[u/100];
-			if (c != ' ') fmt = "0123456789";
-			v = u % 10;
-			u = u / 10;
-			buf[1] = fmt[u%10];
-		} else {
-			// value is < 10: use "9.2M" format
-			buf[0] = "0123456789"[u];
-			buf[1] = '.';
-		}
-		buf[2] = "0123456789"[v];
-		buf[3] = scale[idx]; /* typically scale = " kmgt..." */
-	}
-}
-
-/* Convert unsigned long long value into compact 5-char representation.
- * String is not terminated (buf[5] is untouched) */
-void FAST_FUNC smart_ulltoa5(unsigned long long ul, char buf[6], const char *scale)
-{
-	const char *fmt;
-	char c;
-	unsigned v, u, idx = 0;
-
-	if (ul > 99999) { // do not scale if 99999 or less
-		ul *= 10;
-		do {
-			ul /= 1024;
-			idx++;
-		} while (ul >= 100000);
-	}
-	v = ul; // ullong divisions are expensive, avoid them
-
-	fmt = " 123456789";
-	u = v / 10;
-	v = v % 10;
-	if (!idx) {
-		// 99999 or less: use "12345" format
-		// u is value/10, v is last digit
-		c = buf[0] = " 123456789"[u/1000];
-		if (c != ' ') fmt = "0123456789";
-		c = buf[1] = fmt[u/100%10];
-		if (c != ' ') fmt = "0123456789";
-		c = buf[2] = fmt[u/10%10];
-		if (c != ' ') fmt = "0123456789";
-		buf[3] = fmt[u%10];
-		buf[4] = "0123456789"[v];
-	} else {
-		// value has been scaled into 0..9999.9 range
-		// u is value, v is 1/10ths (allows for 92.1M format)
-		if (u >= 100) {
-			// value is >= 100: use "1234M', " 123M" formats
-			c = buf[0] = " 123456789"[u/1000];
-			if (c != ' ') fmt = "0123456789";
-			c = buf[1] = fmt[u/100%10];
-			if (c != ' ') fmt = "0123456789";
-			v = u % 10;
-			u = u / 10;
-			buf[2] = fmt[u%10];
-		} else {
-			// value is < 100: use "92.1M" format
-			c = buf[0] = " 123456789"[u/10];
-			if (c != ' ') fmt = "0123456789";
-			buf[1] = fmt[u%10];
-			buf[2] = '.';
-		}
-		buf[3] = "0123456789"[v];
-		buf[4] = scale[idx]; /* typically scale = " kmgt..." */
-	}
-}
-
 
 // Convert unsigned integer to ascii, writing into supplied buffer.
 // A truncated result contains the first few digits of the result ala strncpy.