Document and replace some magic values in sft/ttcr (vcl)

Change-Id: Id9c3f96acb7b93c7ef215ae33d98ad17ef45095c
Reviewed-on: https://gerrit.libreoffice.org/80719
Reviewed-by: Khaled Hosny <khaledhosny@eglug.org>
Tested-by: Jenkins

3 files changed, 293 insertions, 88 deletions

diff --git a/vcl/inc/sft.hxx b/vcl/inc/sft.hxx
index aa81dcd151cb..39bc2ecfd421 100644
--- a/vcl/inc/sft.hxx
+++ b/vcl/inc/sft.hxx
@@ -185,6 +185,222 @@ namespace vcl
 
     struct TrueTypeFont;
 
+/*
+  Some table OS/2 consts
+  quick history:
+  OpenType has been created from TrueType
+  - original TrueType had an OS/2 table with a length of 68 bytes
+  (cf https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6OS2.html)
+  - There have been 6 versions (from version 0 to 5)
+  (cf https://docs.microsoft.com/en-us/typography/opentype/otspec140/os2ver0)
+
+  For the record:
+  // From Initial TrueType version
+  TYPE       NAME                       FROM BYTE
+  uint16     version                    0
+  int16      xAvgCharWidth              2
+  uint16     usWeightClass              4
+  uint16     usWidthClass               6
+  uint16     fsType                     8
+  int16      ySubscriptXSize           10
+  int16      ySubscriptYSize           12
+  int16      ySubscriptXOffset         14
+  int16      ySubscriptYOffset         16
+  int16      ySuperscriptXSize         18
+  int16      ySuperscriptYSize         20
+  int16      ySuperscriptXOffset       22
+  int16      ySuperscriptYOffset       24
+  int16      yStrikeoutSize            26
+  int16      yStrikeoutPosition        28
+  int16      sFamilyClass              30
+  uint8      panose[10]                32
+  uint32     ulUnicodeRange1           42
+  uint32     ulUnicodeRange2           46
+  uint32     ulUnicodeRange3           50
+  uint32     ulUnicodeRange4           54
+  Tag        achVendID                 58
+  uint16     fsSelection               62
+  uint16     usFirstCharIndex          64
+  uint16     usLastCharIndex           66
+
+  // From Version 0 of OpenType
+  int16      sTypoAscender             68
+  int16      sTypoDescender            70
+  int16      sTypoLineGap              72
+  uint16     usWinAscent               74
+  uint16     usWinDescent              76
+
+  => length for OpenType version 0 = 78 bytes
+
+  // From Version 1 of OpenType
+  uint32     ulCodePageRange1          78
+  uint32     ulCodePageRange2          82
+
+  => length for OpenType version 1 = 86 bytes
+
+  // From Version 2 of OpenType
+  // (idem for Versions 3 and 4)
+  int16      sxHeight                  86
+  int16      sCapHeight                88
+  uint16     usDefaultChar             90
+  uint16     usBreakChar               92
+  uint16     usMaxContext              94
+
+  => length for OpenType version 2, 3 and 4 = 96 bytes
+
+  // From Version 5 of OpenType
+  uint16     usLowerOpticalPointSize   96
+  uint16     usUpperOpticalPointSize   98
+  END                                 100
+
+  => length for OS/2 table version 5 = 100 bytes
+
+*/
+static const int OS2_Legacy_length = 68;
+static const int OS2_V0_length = 78;
+static const int OS2_V1_length = 86;
+
+static const int OS2_usWeightClass_offset = 4;
+static const int OS2_usWidthClass_offset = 6;
+static const int OS2_fsType_offset = 8;
+static const int OS2_panose_offset = 32;
+static const int OS2_panoseNbBytes_offset = 10;
+static const int OS2_ulUnicodeRange1_offset = 42;
+static const int OS2_ulUnicodeRange2_offset = 46;
+static const int OS2_ulUnicodeRange3_offset = 50;
+static const int OS2_ulUnicodeRange4_offset = 54;
+static const int OS2_fsSelection_offset = 62;
+static const int OS2_typoAscender_offset = 68;
+static const int OS2_typoDescender_offset = 70;
+static const int OS2_typoLineGap_offset = 72;
+static const int OS2_winAscent_offset = 74;
+static const int OS2_winDescent_offset = 76;
+static const int OS2_ulCodePageRange1_offset = 78;
+static const int OS2_ulCodePageRange2_offset = 82;
+
+/*
+  Some table hhea consts
+  cf https://docs.microsoft.com/fr-fr/typography/opentype/spec/hhea
+  TYPE       NAME                       FROM BYTE
+  uint16     majorVersion               0
+  uint16     minorVersion               2
+  FWORD      ascender                   4
+  FWORD      descender                  6
+  FWORD      lineGap                    8
+  UFWORD     advanceWidthMax           10
+  FWORD      minLeftSideBearing        12
+  FWORD      minRightSideBearing       14
+  FWORD      xMaxExtent                16
+  int16      caretSlopeRise            18
+  int16      caretSlopeRun             20
+  int16      caretOffset               22
+  int16      (reserved)                24
+  int16      (reserved)                26
+  int16      (reserved)                28
+  int16      (reserved)                30
+  int16      metricDataFormat          32
+  uint16     numberOfHMetrics          34
+  END                                  36
+
+  => length for hhea table = 36 bytes
+
+*/
+static const int HHEA_Length = 36;
+
+static const int HHEA_ascender_offset = 4;
+static const int HHEA_descender_offset = 6;
+static const int HHEA_lineGap_offset = 8;
+static const int HHEA_caretSlopeRise_offset = 18;
+static const int HHEA_caretSlopeRun_offset = 20;
+
+/*
+  Some table post consts
+  cf https://docs.microsoft.com/fr-fr/typography/opentype/spec/post
+  TYPE       NAME                       FROM BYTE
+  Fixed      version                    0
+  Fixed      italicAngle                4
+  FWord      underlinePosition          8
+  FWord      underlineThickness        10
+  uint32     isFixedPitch              12
+  ...
+
+*/
+static const int POST_italicAngle_offset = 4;
+static const int POST_underlinePosition_offset = 8;
+static const int POST_underlineThickness_offset = 10;
+static const int POST_isFixedPitch_offset = 12;
+
+/*
+  Some table head consts
+  cf https://docs.microsoft.com/fr-fr/typography/opentype/spec/head
+  TYPE       NAME                       FROM BYTE
+  uit16      majorVersion               0
+  uit16      minorVersion               2
+  Fixed      fontRevision               4
+  uint32     checkSumAdjustment         8
+  uint32     magicNumber               12 (= 0x5F0F3CF5)
+  uint16     flags                     16
+  uint16     unitsPerEm                18
+  LONGDATETIME created                 20
+  LONGDATETIME modified                28
+  int16      xMin                      36
+  int16      yMin                      38
+  int16      xMax                      40
+  int16      yMax                      42
+  uint16     macStyle                  44
+  uint16     lowestRecPPEM             46
+  int16      fontDirectionHint         48
+  int16      indexToLocFormat          50
+  int16      glyphDataFormat           52
+
+  END                                  54
+
+  => length head table = 54 bytes
+*/
+static const int HEAD_Length_offset = 54;
+
+static const int HEAD_majorVersion_offset = 0;
+static const int HEAD_fontRevision_offset = 4;
+static const int HEAD_magicNumber_offset = 12;
+static const int HEAD_flags_offset = 16;
+static const int HEAD_unitsPerEm_offset = 18;
+static const int HEAD_created_offset = 20;
+static const int HEAD_xMin_offset = 36;
+static const int HEAD_yMin_offset = 38;
+static const int HEAD_xMax_offset = 40;
+static const int HEAD_yMax_offset = 42;
+static const int HEAD_macStyle_offset = 44;
+static const int HEAD_lowestRecPPEM_offset = 46;
+static const int HEAD_fontDirectionHint_offset = 48;
+static const int HEAD_indexToLocFormat_offset = 50;
+static const int HEAD_glyphDataFormat_offset = 52;
+
+/*
+  Some table maxp consts
+  cf https://docs.microsoft.com/fr-fr/typography/opentype/spec/maxp
+  For 0.5 version
+  TYPE       NAME                       FROM BYTE
+  Fixed      version                    0
+  uint16     numGlyphs                  4
+
+  For 1.0 Version
+  Fixed      version                    0
+  uint16     numGlyphs                  4
+  uint16     maxPoints                  6
+  uint16     maxContours                8
+  uint16     maxCompositePoints        10
+  uint16     maxCompositeContours      12
+  ...
+
+*/
+static const int MAXP_Version1Length_offset = 32;
+
+static const int MAXP_numGlyphs_offset = 4;
+static const int MAXP_maxPoints_offset = 6;
+static const int MAXP_maxContours_offset = 8;
+static const int MAXP_maxCompositePoints_offset = 10;
+static const int MAXP_maxCompositeContours_offset = 12;
+
 /**
  * @defgroup sft Sun Font Tools Exported Functions
  */
diff --git a/vcl/source/fontsubset/sft.cxx b/vcl/source/fontsubset/sft.cxx
index 52b2e0360b50..9da262cf4a42 100644
--- a/vcl/source/fontsubset/sft.cxx
+++ b/vcl/source/fontsubset/sft.cxx
@@ -1639,11 +1639,11 @@ static SFErrCodes doOpenTTFont( sal_uInt32 facenum, TrueTypeFont* t )
 
     table = getTable(t, O_head);
     table_size = getTableSize(t, O_head);
-    if (table_size < 52) {
+    if (table_size < HEAD_Length_offset) {
         return SFErrCodes::TtFormat;
     }
-    t->unitsPerEm = GetUInt16(table, 18);
-    int indexfmt = GetInt16(table, 50);
+    t->unitsPerEm = GetUInt16(table, HEAD_unitsPerEm_offset);
+    int indexfmt = GetInt16(table, HEAD_indexToLocFormat_offset);
 
     if( ((indexfmt != 0) && (indexfmt != 1)) || (t->unitsPerEm <= 0) ) {
         return SFErrCodes::TtFormat;
@@ -1937,7 +1937,7 @@ SFErrCodes CreateTTFromTTGlyphs(TrueTypeFont  *ttf,
     /**                       hhea                         **/
     const sal_uInt8* p = getTable(ttf, O_hhea);
     if (p) {
-        hhea = TrueTypeTableNew_hhea(GetUInt16(p, 4), GetUInt16(p, 6), GetUInt16(p, 8), GetUInt16(p, 18), GetUInt16(p, 20));
+        hhea = TrueTypeTableNew_hhea(GetUInt16(p, HHEA_ascender_offset), GetUInt16(p, HHEA_descender_offset), GetUInt16(p, HHEA_lineGap_offset), GetUInt16(p, HHEA_caretSlopeRise_offset), GetUInt16(p, HHEA_caretSlopeRun_offset));
     } else {
         hhea = TrueTypeTableNew_hhea(0, 0, 0, 0, 0);
     }
@@ -1946,13 +1946,13 @@ SFErrCodes CreateTTFromTTGlyphs(TrueTypeFont  *ttf,
 
     p = getTable(ttf, O_head);
     assert(p != nullptr);
-    head = TrueTypeTableNew_head(GetUInt32(p, 4),
-                                 GetUInt16(p, 16),
-                                 GetUInt16(p, 18),
-                                 p+20,
-                                 GetUInt16(p, 44),
-                                 GetUInt16(p, 46),
-                                 GetInt16(p, 48));
+    head = TrueTypeTableNew_head(GetUInt32(p, HEAD_fontRevision_offset),
+                                 GetUInt16(p, HEAD_flags_offset),
+                                 GetUInt16(p, HEAD_unitsPerEm_offset),
+                                 p+HEAD_created_offset,
+                                 GetUInt16(p, HEAD_macStyle_offset),
+                                 GetUInt16(p, HEAD_lowestRecPPEM_offset),
+                                 GetInt16(p, HEAD_fontDirectionHint_offset));
 
     /**                       glyf                          **/
 
@@ -1988,10 +1988,10 @@ SFErrCodes CreateTTFromTTGlyphs(TrueTypeFont  *ttf,
     /**                       post                          **/
     if ((p = getTable(ttf, O_post)) != nullptr) {
         post = TrueTypeTableNew_post(0x00030000,
-                                     GetUInt32(p, 4),
-                                     GetUInt16(p, 8),
-                                     GetUInt16(p, 10),
-                                     GetUInt16(p, 12));
+                                     GetUInt32(p, POST_italicAngle_offset),
+                                     GetUInt16(p, POST_underlinePosition_offset),
+                                     GetUInt16(p, POST_underlineThickness_offset),
+                                     GetUInt16(p, POST_isFixedPitch_offset));
     } else {
         post = TrueTypeTableNew_post(0x00030000, 0, 0, 0, 0);
     }
@@ -2364,24 +2364,21 @@ void GetTTFontMetrics(const uint8_t *pHhea, size_t nHhea,
     /* There are 3 different versions of OS/2 table: original (68 bytes long),
      * Microsoft old (78 bytes long) and Microsoft new (86 bytes long,)
      * Apple's documentation recommends looking at the table length.
-     *
-     * FIXME: horribly outdated comment and horrible code that uses hard-coded
-     * offsets to read the table.
      */
-    if (nOs2 >= 76 + 2)
+    if (nOs2 >= OS2_V0_length)
     {
-        info->fsSelection   = GetUInt16(pOs2, 62);
-        info->typoAscender  = GetInt16(pOs2,  68);
-        info->typoDescender = GetInt16(pOs2,  70);
-        info->typoLineGap   = GetInt16(pOs2,  72);
-        info->winAscent     = GetUInt16(pOs2, 74);
-        info->winDescent    = GetUInt16(pOs2, 76);
+        info->fsSelection   = GetUInt16(pOs2, OS2_fsSelection_offset);
+        info->typoAscender  = GetInt16(pOs2, OS2_typoAscender_offset);
+        info->typoDescender = GetInt16(pOs2, OS2_typoDescender_offset);
+        info->typoLineGap   = GetInt16(pOs2, OS2_typoLineGap_offset);
+        info->winAscent     = GetUInt16(pOs2, OS2_winAscent_offset);
+        info->winDescent    = GetUInt16(pOs2, OS2_winDescent_offset);
     }
 
-    if (nHhea >= 8 + 2) {
-        info->ascender      = GetInt16(pHhea, 4);
-        info->descender     = GetInt16(pHhea, 6);
-        info->linegap       = GetInt16(pHhea, 8);
+    if (nHhea >= HHEA_lineGap_offset + 2) {
+        info->ascender      = GetInt16(pHhea, HHEA_ascender_offset);
+        info->descender     = GetInt16(pHhea, HHEA_descender_offset);
+        info->linegap       = GetInt16(pHhea, HHEA_lineGap_offset);
     }
 }
 
@@ -2401,50 +2398,46 @@ void GetTTGlobalFontInfo(TrueTypeFont *ttf, TTGlobalFontInfo *info)
     const sal_uInt8* table = getTable(ttf, O_OS2);
     sal_uInt32 table_size = getTableSize(ttf, O_OS2);
     if (table && table_size >= 42) {
-        info->weight = GetUInt16(table, 4);
-        info->width  = GetUInt16(table, 6);
-
-        /* There are 3 different versions of OS/2 table: original (68 bytes long),
-         * Microsoft old (78 bytes long) and Microsoft new (86 bytes long,)
-         * Apple's documentation recommends looking at the table length.
-         */
-        if (table_size >= 78) {
-            info->typoAscender = XUnits(UPEm,GetInt16(table, 68));
-            info->typoDescender = XUnits(UPEm, GetInt16(table, 70));
-            info->typoLineGap = XUnits(UPEm, GetInt16(table, 72));
-            info->winAscent = XUnits(UPEm, GetUInt16(table, 74));
-            info->winDescent = XUnits(UPEm, GetUInt16(table, 76));
+        info->weight = GetUInt16(table, OS2_usWeightClass_offset);
+        info->width  = GetUInt16(table, OS2_usWidthClass_offset);
+
+        if (table_size >= OS2_V0_length) {
+            info->typoAscender = XUnits(UPEm,GetInt16(table, OS2_typoAscender_offset));
+            info->typoDescender = XUnits(UPEm, GetInt16(table, OS2_typoDescender_offset));
+            info->typoLineGap = XUnits(UPEm, GetInt16(table, OS2_typoLineGap_offset));
+            info->winAscent = XUnits(UPEm, GetUInt16(table, OS2_winAscent_offset));
+            info->winDescent = XUnits(UPEm, GetUInt16(table, OS2_winDescent_offset));
             /* sanity check; some fonts treat winDescent as signed
            * violating the standard */
             if( info->winDescent > 5*UPEm )
-                info->winDescent = XUnits(UPEm, GetInt16(table, 76));
+                info->winDescent = XUnits(UPEm, GetInt16(table, OS2_winDescent_offset));
         }
-        memcpy(info->panose, table + 32, 10);
-        info->typeFlags = GetUInt16( table, 8 );
+        memcpy(info->panose, table + OS2_panose_offset, OS2_panoseNbBytes_offset);
+        info->typeFlags = GetUInt16( table, OS2_fsType_offset );
     }
 
     table = getTable(ttf, O_post);
     if (table && getTableSize(ttf, O_post) >= 12+sizeof(sal_uInt32)) {
-        info->pitch  = GetUInt32(table, 12);
-        info->italicAngle = GetInt32(table, 4);
+        info->pitch  = GetUInt32(table, POST_isFixedPitch_offset);
+        info->italicAngle = GetInt32(table, POST_italicAngle_offset);
     }
 
     table = getTable(ttf, O_head);      /* 'head' tables is always there */
     table_size = getTableSize(ttf, O_head);
     if (table_size >= 46) {
-        info->xMin = XUnits(UPEm, GetInt16(table, 36));
-        info->yMin = XUnits(UPEm, GetInt16(table, 38));
-        info->xMax = XUnits(UPEm, GetInt16(table, 40));
-        info->yMax = XUnits(UPEm, GetInt16(table, 42));
-        info->macStyle = GetInt16(table, 44);
+        info->xMin = XUnits(UPEm, GetInt16(table, HEAD_xMin_offset));
+        info->yMin = XUnits(UPEm, GetInt16(table, HEAD_yMin_offset));
+        info->xMax = XUnits(UPEm, GetInt16(table, HEAD_xMax_offset));
+        info->yMax = XUnits(UPEm, GetInt16(table, HEAD_yMax_offset));
+        info->macStyle = GetInt16(table, HEAD_macStyle_offset);
     }
 
     table = getTable(ttf, O_hhea);
     table_size = getTableSize(ttf, O_hhea);
     if (table && table_size >= 10) {
-        info->ascender  = XUnits(UPEm, GetInt16(table, 4));
-        info->descender = XUnits(UPEm, GetInt16(table, 6));
-        info->linegap   = XUnits(UPEm, GetInt16(table, 8));
+        info->ascender  = XUnits(UPEm, GetInt16(table, HHEA_ascender_offset));
+        info->descender = XUnits(UPEm, GetInt16(table, HHEA_descender_offset));
+        info->linegap   = XUnits(UPEm, GetInt16(table, HHEA_lineGap_offset));
     }
 
     table = getTable(ttf, O_vhea);
@@ -2623,19 +2616,19 @@ bool getTTCoverage(
 {
     bool bRet = false;
     // parse OS/2 header
-    if (nLength >= 58)
+    if (nLength >= OS2_Legacy_length)
     {
         rUnicodeRange = std::bitset<UnicodeCoverage::MAX_UC_ENUM>();
-        append(rUnicodeRange.get(),  0, GetUInt32(pTable, 42));
-        append(rUnicodeRange.get(), 32, GetUInt32(pTable, 46));
-        append(rUnicodeRange.get(), 64, GetUInt32(pTable, 50));
-        append(rUnicodeRange.get(), 96, GetUInt32(pTable, 54));
+        append(rUnicodeRange.get(),  0, GetUInt32(pTable, OS2_ulUnicodeRange1_offset));
+        append(rUnicodeRange.get(), 32, GetUInt32(pTable, OS2_ulUnicodeRange2_offset));
+        append(rUnicodeRange.get(), 64, GetUInt32(pTable, OS2_ulUnicodeRange3_offset));
+        append(rUnicodeRange.get(), 96, GetUInt32(pTable, OS2_ulUnicodeRange4_offset));
         bRet = true;
-        if (nLength >= 86)
+        if (nLength >= OS2_V1_length)
         {
             rCodePageRange = std::bitset<CodePageCoverage::MAX_CP_ENUM>();
-            append(rCodePageRange.get(),  0, GetUInt32(pTable, 78));
-            append(rCodePageRange.get(), 32, GetUInt32(pTable, 82));
+            append(rCodePageRange.get(),  0, GetUInt32(pTable, OS2_ulCodePageRange1_offset));
+            append(rCodePageRange.get(), 32, GetUInt32(pTable, OS2_ulCodePageRange2_offset));
         }
     }
     return bRet;
diff --git a/vcl/source/fontsubset/ttcr.cxx b/vcl/source/fontsubset/ttcr.cxx
index b4074203d316..a52f8fda08b0 100644
--- a/vcl/source/fontsubset/ttcr.cxx
+++ b/vcl/source/fontsubset/ttcr.cxx
@@ -300,17 +300,13 @@ SFErrCodes StreamToFile(TrueTypeCreator *_this, const char* fname)
  * TrueTypeTable private methods
  */
 
-#define TABLESIZE_head 54
-#define TABLESIZE_hhea 36
-#define TABLESIZE_maxp 32
-
 /*    Table         data points to
  * --------------------------------------------
  *    generic       tdata_generic struct
- *    'head'        TABLESIZE_head bytes of memory
- *    'hhea'        TABLESIZE_hhea bytes of memory
+ *    'head'        HEAD_Length_offset bytes of memory
+ *    'hhea'        HHEA_Length bytes of memory
  *    'loca'        tdata_loca struct
- *    'maxp'        TABLESIZE_maxp bytes of memory
+ *    'maxp'        MAXP_Version1Length_offset bytes of memory
  *    'glyf'        list of GlyphData structs (defined in sft.h)
  *    'name'        list of NameRecord structs (defined in sft.h)
  *    'post'        tdata_post struct
@@ -507,7 +503,7 @@ static int GetRawData_generic(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32
 
 static int GetRawData_head(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32 *len, sal_uInt32 *tag)
 {
-    *len = TABLESIZE_head;
+    *len = HEAD_Length_offset;
     *ptr = static_cast<sal_uInt8 *>(_this->data);
     *tag = T_head;
 
@@ -516,7 +512,7 @@ static int GetRawData_head(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32 *le
 
 static int GetRawData_hhea(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32 *len, sal_uInt32 *tag)
 {
-    *len = TABLESIZE_hhea;
+    *len = HHEA_Length;
     *ptr = static_cast<sal_uInt8 *>(_this->data);
     *tag = T_hhea;
 
@@ -542,7 +538,7 @@ static int GetRawData_loca(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32 *le
 
 static int GetRawData_maxp(TrueTypeTable *_this, sal_uInt8 **ptr, sal_uInt32 *len, sal_uInt32 *tag)
 {
-    *len = TABLESIZE_maxp;
+    *len = MAXP_Version1Length_offset;
     *ptr = static_cast<sal_uInt8 *>(_this->data);
     *tag = T_maxp;
 
@@ -862,7 +858,7 @@ TrueTypeTable *TrueTypeTableNew_head(sal_uInt32 fontRevision,
     assert(created != nullptr);
 
     TrueTypeTable* table  = static_cast<TrueTypeTable*>(smalloc(sizeof(TrueTypeTable)));
-    sal_uInt8* ptr = ttmalloc(TABLESIZE_head);
+    sal_uInt8* ptr = ttmalloc(HEAD_Length_offset);
 
     PutUInt32(0x00010000, ptr, 0);             /* version */
     PutUInt32(fontRevision, ptr, 4);
@@ -890,7 +886,7 @@ TrueTypeTable *TrueTypeTableNew_hhea(sal_Int16  ascender,
                                      sal_Int16  caretSlopeRun)
 {
     TrueTypeTable* table = static_cast<TrueTypeTable*>(smalloc(sizeof(TrueTypeTable)));
-    sal_uInt8* ptr = ttmalloc(TABLESIZE_hhea);
+    sal_uInt8* ptr = ttmalloc(HHEA_Length);
 
     PutUInt32(0x00010000, ptr, 0);             /* version */
     PutUInt16(ascender, ptr, 4);
@@ -929,10 +925,10 @@ TrueTypeTable *TrueTypeTableNew_loca()
 TrueTypeTable *TrueTypeTableNew_maxp( const sal_uInt8* maxp, int size)
 {
     TrueTypeTable* table = static_cast<TrueTypeTable*>(smalloc(sizeof(TrueTypeTable)));
-    table->data = ttmalloc(TABLESIZE_maxp);
+    table->data = ttmalloc(MAXP_Version1Length_offset);
 
-    if (maxp && size == TABLESIZE_maxp) {
-        memcpy(table->data, maxp, TABLESIZE_maxp);
+    if (maxp && size == MAXP_Version1Length_offset) {
+        memcpy(table->data, maxp, MAXP_Version1Length_offset);
     }
 
     table->tag = T_maxp;
@@ -1374,20 +1370,20 @@ static void ProcessTables(TrueTypeCreator *tt)
 
     head = FindTable(tt, T_head);
     sal_uInt8* const pHeadData = static_cast<sal_uInt8*>(head->data);
-    PutInt16(xMin, pHeadData, 36);
-    PutInt16(yMin, pHeadData, 38);
-    PutInt16(xMax, pHeadData, 40);
-    PutInt16(yMax, pHeadData, 42);
-    PutInt16(indexToLocFormat, pHeadData, 50);
+    PutInt16(xMin, pHeadData, HEAD_xMin_offset);
+    PutInt16(yMin, pHeadData, HEAD_yMin_offset);
+    PutInt16(xMax, pHeadData, HEAD_xMax_offset);
+    PutInt16(yMax, pHeadData, HEAD_yMax_offset);
+    PutInt16(indexToLocFormat, pHeadData, HEAD_indexToLocFormat_offset);
 
     maxp = FindTable(tt, T_maxp);
 
     sal_uInt8* const pMaxpData = static_cast<sal_uInt8*>(maxp->data);
-    PutUInt16(static_cast<sal_uInt16>(nGlyphs), pMaxpData, 4);
-    PutUInt16(maxPoints, pMaxpData, 6);
-    PutUInt16(maxContours, pMaxpData, 8);
-    PutUInt16(maxCompositePoints, pMaxpData, 10);
-    PutUInt16(maxCompositeContours, pMaxpData, 12);
+    PutUInt16(static_cast<sal_uInt16>(nGlyphs), pMaxpData, MAXP_numGlyphs_offset);
+    PutUInt16(maxPoints, pMaxpData, MAXP_maxPoints_offset);
+    PutUInt16(maxContours, pMaxpData, MAXP_maxContours_offset);
+    PutUInt16(maxCompositePoints, pMaxpData, MAXP_maxCompositePoints_offset);
+    PutUInt16(maxCompositeContours, pMaxpData, MAXP_maxCompositeContours_offset);
 
     /*
      * Generate an htmx table and update hhea table