From 0db136b1b09232083d99e4315dd4432ed0195d2c Mon Sep 17 00:00:00 2001
From: David Corbett <corbett.dav@northeastern.edu>
Date: Thu, 9 May 2024 11:49:48 -0400
Subject: [PATCH] [subset-cff] Shorten output of `encode_num_tp`

---
 src/hb-subset-cff-common.hh                   |  57 ++++++++++++++++--
 .../api/fonts/AdobeVFPrototype.abc.static.otf | Bin 2576 -> 2576 bytes
 ...Prototype.default.all.wght=650,CNTR=50.otf | Bin 41760 -> 41760 bytes
 .../Cantarell-VF-ABC.default.all.wght=800.otf | Bin 1488 -> 1488 bytes
 ...tarell-VF-ABC.retain-gids.all.wght=800.otf | Bin 1488 -> 1488 bytes
 5 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/src/hb-subset-cff-common.hh b/src/hb-subset-cff-common.hh
index 462e99cf8..4039f9c95 100644
--- a/src/hb-subset-cff-common.hh
+++ b/src/hb-subset-cff-common.hh
@@ -115,7 +115,7 @@ struct str_encoder_t
       encode_byte (OpCode_BCD);
 
       // Based on:
-      // https://github.com/fonttools/fonttools/blob/97ed3a61cde03e17b8be36f866192fbd56f1d1a7/Lib/fontTools/misc/psCharStrings.py#L265-L294
+      // https://github.com/fonttools/fonttools/blob/0738c41dfbcbc213ab9263f486ef0cccc6eb5ce5/Lib/fontTools/misc/psCharStrings.py#L267-L316
 
       char buf[16];
       /* FontTools has the following comment:
@@ -133,6 +133,10 @@ struct str_encoder_t
       (void) hb_uselocale (((void) freelocale (clocale), oldlocale));
 
       char *s = buf;
+      size_t len;
+      char *comma = strchr (s, ',');
+      if (comma) // Comma for some European locales in case no uselocale available.
+	*comma = '.';
       if (s[0] == '0' && s[1] == '.')
 	s++;
       else if (s[0] == '-' && s[1] == '0' && s[2] == '.')
@@ -140,6 +144,45 @@ struct str_encoder_t
 	s[1] = '-';
 	s++;
       }
+      else if ((len = strlen (s)) > 3 && !strcmp (s + len - 3, "000"))
+      {
+	unsigned exponent = len - 3;
+	char *s2 = s + exponent - 1;
+	while (*s2 == '0' && exponent > 1)
+	{
+	  s2--;
+	  exponent++;
+	}
+	snprintf (s2 + 1, sizeof (buf) - (s2 + 1 - buf), "E%u", exponent);
+      }
+      else
+      {
+	char *dot = strchr (s, '.');
+	char *e = strchr (s, 'E');
+	if (dot && e)
+	{
+	  memmove (dot, dot + 1, e - (dot + 1));
+	  int exponent = atoi (e + 1);
+	  int new_exponent = exponent - (e - (dot + 1));
+	  if (new_exponent == 1)
+	  {
+	    e[-1] = '0';
+	    e[0] = '\0';
+	  }
+	  else
+	    snprintf (e - 1, sizeof (buf) - (e - 1 - buf), "E%d", new_exponent);
+	}
+      }
+      if ((s[0] == '.' && s[1] == '0') || (s[0] == '-' && s[1] == '.' && s[2] == '0'))
+      {
+	int sign = s[0] == '-';
+	char *s2 = s + sign + 1;
+	while (*s2 == '0')
+	  s2++;
+	len = strlen (s2);
+	memmove (s + sign, s2, len);
+	snprintf (s + sign + len, sizeof (buf) - (s + sign + len - buf), "E-%u", (unsigned) (strlen (s + sign) - 1));
+      }
       hb_vector_t<char> nibbles;
       while (*s)
       {
@@ -155,20 +198,22 @@ struct str_encoder_t
 	    {
 	      s++;
 	      nibbles.push (0x0C); // E-
-	      continue;
+	    } else {
+	      if (c2 == '+')
+		s++;
+	      nibbles.push (0x0B); // E
 	    }
-	    if (c2 == '+')
+	    if (*s == '0')
 	      s++;
-	    nibbles.push (0x0B); // E
 	    continue;
 	  }
 
-	  case '.': case ',': // Comma for some European locales in case no uselocale available.
+	  case '.':
 	    nibbles.push (0x0A); // .
 	    continue;
 
 	  case '-':
-	    nibbles.push (0x0E); // .
+	    nibbles.push (0x0E); // -
 	    continue;
 	}
 
diff --git a/test/api/fonts/AdobeVFPrototype.abc.static.otf b/test/api/fonts/AdobeVFPrototype.abc.static.otf
index bfce3598fabc460ec8753ca6a1497b6dfbdb149c..0c2e43db4a3a291a37526e19ed5de328ede5d273 100644
GIT binary patch
delta 16
XcmbOrGC^d6J~Oj<jQ?gM=6h@aDaHic

delta 16
XcmbOrGC^d6J~Q(I^Z3n1%=g#;ENcZY

diff --git a/test/subset/data/expected/instantiate_cff2/AdobeVFPrototype.default.all.wght=650,CNTR=50.otf b/test/subset/data/expected/instantiate_cff2/AdobeVFPrototype.default.all.wght=650,CNTR=50.otf
index d00445a9ccd3ace6c4fcabab4da27e6e57553fa8..acf48c3b46b2a5c19bb9b14e9e351cc4ad364767 100644
GIT binary patch
delta 50
zcmZ2*jA_9!CK3OT5Pt?9h6V;^1_x(1H>0l~4is$^;bCNX_d#p&W)((eCuZ{)|IJ#?
G-{JwInGpH_

delta 50
zcmZ2*jA_9!CK3OT5Pt?9h6V;^1_x(1H=~OT2X1c^;bCO4xS)A(vkD`#6Y~P|_|00*
G-{Jv>pbz>0

diff --git a/test/subset/data/expected/instantiate_cff2_update_metrics/Cantarell-VF-ABC.default.all.wght=800.otf b/test/subset/data/expected/instantiate_cff2_update_metrics/Cantarell-VF-ABC.default.all.wght=800.otf
index 2d9bc980645794bd906d87bef4e3e4c4a9d5cc7e..0ce078527c7ff17c4c117a13dad2ef87e91fbe89 100644
GIT binary patch
delta 47
zcmcb>eSurVKP1GTftR6yftew|+0D)9u8ffGMv*s+EYC7iwI;JL9b!(3@!x!siJch$
DJ|qpX

delta 47
zcmcb>eSurVKP1GTftR6yftew|+0D)9txSONMv*s+EXOil%1vfrI>fvnDSq=wCU#~3
DO?(cp

diff --git a/test/subset/data/expected/instantiate_cff2_update_metrics/Cantarell-VF-ABC.retain-gids.all.wght=800.otf b/test/subset/data/expected/instantiate_cff2_update_metrics/Cantarell-VF-ABC.retain-gids.all.wght=800.otf
index 2d9bc980645794bd906d87bef4e3e4c4a9d5cc7e..0ce078527c7ff17c4c117a13dad2ef87e91fbe89 100644
GIT binary patch
delta 47
zcmcb>eSurVKP1GTftR6yftew|+0D)9u8ffGMv*s+EYC7iwI;JL9b!(3@!x!siJch$
DJ|qpX

delta 47
zcmcb>eSurVKP1GTftR6yftew|+0D)9txSONMv*s+EXOil%1vfrI>fvnDSq=wCU#~3
DO?(cp