/* Copyright 2014 Adobe Systems Incorporated (http://www.adobe.com/). All Rights Reserved.
   This software is licensed as OpenSource, under the Apache License, Version 2.0. This license is available at: http://opensource.org/licenses/Apache-2.0. */

/*
 * Shared OpenType Layout support.
 */

#include "otl.h"
#include "feat.h"
#include <stdio.h>

#include <stdlib.h>

/* --------------------------- Context Definition -------------------------- */

struct otlCtx_ {
    hotCtx g; /* Package context */
};

/* -------------------------- Coverage Definition -------------------------- */

/* --- Format --- */

typedef struct {
    unsigned short CoverageFormat; /* =1 */
    unsigned short GlyphCount;
    GID *GlyphArray; /* [GlyphCount] */
} CoverageFormat1;
#define COVERAGE1_SIZE(nGlyphs) (uint16 * 2 + uint16 * (nGlyphs))

typedef struct {
    GID Start;
    GID End;
    unsigned short StartCoverageIndex;
} RangeRecord;
#define RANGE_RECORD_SIZE (uint16 * 3)

typedef struct {
    unsigned short CoverageFormat; /* =2 */
    unsigned short RangeCount;
    RangeRecord *RangeRecord; /* [RangeCount] */
} CoverageFormat2;
#define COVERAGE2_SIZE(nRanges) (uint16 * 2 + RANGE_RECORD_SIZE * (nRanges))

/* --- Build --- */

typedef struct {
    dnaDCL(GID, glyph); /* Covered glyph list */
    Offset offset;      /* Offset to coverage |=> start of coverage section */
    void *tbl;          /* Formatted table */
} CoverageRecord;

typedef struct {
    CoverageRecord *new;            /* Table under construction */
    LOffset offset;                 /* Cumulative size of coverages */
    dnaDCL(CoverageRecord, tables); /* Coverage tables */
} Coverage;

/* ---------------------------- Class Definition --------------------------- */

/* --- Format --- */

typedef struct {
    unsigned short ClassFormat; /* =1 */
    GID StartGlyph;
    unsigned short GlyphCount;
    unsigned short *ClassValueArray; /* [GlyphCount] */
} ClassDefFormat1;
#define CLASS1_SIZE(nGlyphs) (uint16 * 3 + uint16 * (nGlyphs))

typedef struct {
    GID Start;
    GID End;
    unsigned short Class;
} ClassRangeRecord;
#define CLASS_RANGE_RECORD_SIZE (uint16 * 3)

typedef struct {
    unsigned short ClassFormat; /* =2 */
    unsigned short ClassRangeCount;
    ClassRangeRecord *ClassRangeRecord; /* [ClassRangeCount] */
} ClassDefFormat2;
#define CLASS2_SIZE(nRanges) (uint16 * 2 + CLASS_RANGE_RECORD_SIZE * (nRanges))

/* --- Build --- */

typedef struct {
    GID glyph;
    unsigned short class;
} ClassMap;

typedef struct {
    dnaDCL(ClassMap, map); /* Class mappings */
    Offset offset;         /* Offset to class |=> start of class section */
    void *tbl;             /* Formatted table */
} ClassRecord;

typedef struct {
    ClassRecord *new;            /* Table under construction */
    LOffset offset;              /* Cumulative size of classes */
    dnaDCL(ClassRecord, tables); /* Class tables */
} Class;

/* --------------------------- Device Definition --------------------------- */

typedef struct {
    unsigned short StartSize;
    unsigned short EndSize;
    unsigned short DeltaFormat;
#define DeltaBits2 1
#define DeltaBits4 2
#define DeltaBits8 3
    unsigned short *DeltaValue; /* [((EndSize-StartSize+1)* (2^DeltaFormat)+15)/16] */
} DeviceTable;

void otlDeviceBeg(hotCtx g, otlTbl t) {
    /* Todo */
}

void otlDeviceAddEntry(hotCtx g, otlTbl t, unsigned short ppem, short delta) {
    /* Todo */
}

Offset otlDeviceEnd(hotCtx g, otlTbl t) {
    /* Todo */
    return 0;
}

void otlDeviceWrite(hotCtx g, otlTbl t) {
    /* Todo */
}

/* --------------------------------- Table --------------------------------- */

/* --- Format --- */

/* --- ScriptList --- */
typedef struct {
    Offset LookupOrder; /* Reserved=NULL */
    unsigned short ReqFeatureIndex;
    unsigned short FeatureCount;
    unsigned short *FeatureIndex; /* [FeatureCount] */
} LangSys;
#define LANG_SYS_SIZE(nFeatures) (uint16 * 3 + uint16 * (nFeatures))

typedef struct {
    Tag LangSysTag;
    DCL_OFFSET(LangSys, LangSys); /* |-> Script */
} LangSysRecord;
#define LANG_SYS_RECORD_SIZE (uint32 + uint16)

typedef struct {
    DCL_OFFSET(LangSys, DefaultLangSys); /* |-> Script */
    unsigned short LangSysCount;
    LangSysRecord *LangSysRecord; /* [LangSysCount] */
} Script;
#define SCRIPT_SIZE(nLanguages) (uint16 * 2 + LANG_SYS_RECORD_SIZE * (nLanguages))

typedef struct {
    Tag ScriptTag;
    DCL_OFFSET(Script, Script); /* |-> ScriptList */
} ScriptRecord;
#define SCRIPT_RECORD_SIZE (uint32 + uint16)

typedef struct {
    unsigned short ScriptCount;
    ScriptRecord *ScriptRecord; /* [ScriptCount] */
} ScriptList;
#define SCRIPT_LIST_SIZE(nScripts) (uint16 + SCRIPT_RECORD_SIZE * (nScripts))

/* --- FeatureList --- */
typedef struct {
    Offset FeatureParams; /* Reserved=NULL */
    unsigned short LookupCount;
    unsigned short *LookupListIndex; /* [LookupCount] */
} Feature;
#define FEATURE_SIZE(nLookups) (uint16 * 2 + uint16 * (nLookups))
#define IS_FEAT_PARAM(L) (((L) >> 16) == GPOSFeatureParam) /* test otl SubTable->lookup value. */

typedef struct {
    Tag FeatureTag;
    DCL_OFFSET(Feature, Feature); /* |-> FeatureList */
} FeatureRecord;
#define FEATURE_RECORD_SIZE (uint32 + uint16)

typedef struct {
    unsigned short FeatureCount;
    FeatureRecord *FeatureRecord; /* [FeatureCount] */
} FeatureList;
#define FEATURE_LIST_SIZE(nFeatures) (uint16 + FEATURE_RECORD_SIZE * (nFeatures))
#define FEAT_PARAM_ZERO 1 /* a dummy valued, used to differenatiate NULL_OFFSET from a real zero offset for the FeatureParams field.*/
/* --- LookupList --- */
typedef struct {
    unsigned short LookupType;
    unsigned short LookupFlag;
    unsigned short SubTableCount;
    unsigned short UseMarkSetIndex; /* This is not counted in LOOKUP_HDR_SIZE, as it is written only if (LookupFlag & otlUseMarkFilteringSet).*/
    long *SubTable;                 /* [SubTableCount] |-> Lookup                */
                                    /* long instead of Offset for temp -ve value */
} Lookup;
#define LOOKUP_HDR_SIZE (uint16 * 3)
#define LOOKUP_SIZE(nSubtables) (LOOKUP_HDR_SIZE + uint16 * (nSubtables))

typedef struct {
    unsigned short LookupCount;
    DCL_OFFSET_ARRAY(Lookup, Lookup); /* [LookupCount] |-> LookupList */
} LookupList;
#define LOOKUP_LIST_SIZE(nLookups) (uint16 + uint16 * (nLookups))

/* --- Header --- */
typedef struct {
    Fixed Version;
    DCL_OFFSET(ScriptList, ScriptList);   /* |-> Header */
    DCL_OFFSET(FeatureList, FeatureList); /* |-> Header */
    DCL_OFFSET(LookupList, LookupList);   /* |-> Header */
} Header;
#define HEADER_SIZE (uint32 + uint16 * 3)

/* --- Build --- */

typedef struct {
    Tag script;
    Tag language;
    Tag feature;
    unsigned long lookup; /* Lookup type (31-16), lookup flag (15-0) */
    unsigned short extensionLookupType;
    unsigned short offset;
    unsigned short markSetIndex; /* Used and written only of lookupFlag UseMarkEst is set. */
    Label label;
    unsigned short fmt; /* Subtable format (Debug only) */
    int isFeatParam;
    int seenInFeature;
    struct { /* Reference indexes */
        short feature;
        short lookup;
    } index;
    struct { /* Indexes of next different elements in table */
        short script;
        short language;
        short feature;
        short lookup;
    } span;
} Subtable;

typedef struct {
    Label label;
    int lookupInx;
    int used; /* set to 1 if this label is actually referenced */
} LabelInfo;

typedef struct {
    Label baseLabel; /* label of referenced subtable */
    Label refLabel;  /* label of referencing subtable */
} RefLabelInfo;

struct otlTbl_ {
    dnaDCL(Subtable, subtable);     /* Subtable list */
    dnaDCL(LabelInfo, label);       /* maps: label -> lookup index */
    dnaDCL(RefLabelInfo, refLabel); /* used to make sure that all stand-alone lookups actually get referenced. */
    Header tbl;                     /* Formatted table */
    Offset lookupSize;              /* Size of Lookup List + Lookups */
    Coverage coverage;
    Class class;
    short nAnonSubtables;
    short nStandAloneSubtables;
    short nRefLookups; /* number of otl Subtable 's that are only references to look ups*/
    short nFeatParams; /* number of otl Subtable 's that hold feature table parameters.*/
#if HOT_DEBUG
    int nCoverageReused;
    int nClassReused;
#endif
};

#if HOT_DEBUG
/* Initialize subtable. Not needed except for debug dumps */
static void initSubtable(void *ctx, long count, Subtable *sub) {
    long i;
    for (i = 0; i < count; i++) {
        sub->seenInFeature = sub->isFeatParam = 0;
        sub->span.script = sub->span.language = sub->span.feature =
            sub->span.lookup = 0;
        sub->index.feature = sub->index.lookup = -1;
        sub++;
    }
    return;
}

static void valDump(short val, short excep, int isRef) {
    if (val == excep) {
        fprintf(stderr, "   * ");
    } else if (isRef) {
        fprintf(stderr, "   ->%hd ", val);
    } else {
        fprintf(stderr, "%4hd ", val);
    }
}

static void tagDump(Tag tag, char ch) {
    if (tag == TAG_UNDEF) {
        fprintf(stderr, "****");
    } else {
        fprintf(stderr, "%c%c%c%c", TAG_ARG(tag));
    }
    if (ch != 0) {
        fprintf(stderr, "%c", ch);
    }
}

void otlDumpSubtables(hotCtx g, otlTbl t) {
    long i;

    fprintf(stderr,
            "# nCov: %ld, nClass: %ld; nCovReused: %d, nClassReused: %d\n"
            "# [offs relative to start of subtable section]\n",
            t->coverage.tables.cnt, t->class.tables.cnt,
            t->nCoverageReused, t->nClassReused);
    fprintf(stderr,
            "      -----tag------ --look-----            -------span--------  --index--\n"
            "      scri lang feat typ/fmt|flg offs  lab  scri lang feat look  feat look"
            "\n");
    for (i = 0; i < t->subtable.cnt; i++) {
        Subtable *sub = &t->subtable.array[i];
        fprintf(stderr, "[%3ld] ", i);
        tagDump(sub->script, ' ');
        tagDump(sub->language, ' ');
        tagDump(sub->feature, ' ');
        fprintf(stderr, "   %2lu/%hu|%-3lx %4hx ",
                sub->lookup >> 16,
                sub->fmt,
                sub->lookup & 0xffff,
                sub->offset);
        fprintf(stderr, "%4x ", sub->label);

        valDump(sub->span.script, 0, 0);
        valDump(sub->span.language, 0, 0);
        valDump(sub->span.feature, 0, 0);
        valDump(sub->span.lookup, 0, 0);
        fprintf(stderr, " ");
        valDump(sub->index.feature, -1, 0);
        valDump(sub->index.lookup, -1, IS_REF_LAB(sub->label));
        fprintf(stderr, "\n");
    }
}

/* Must call only after otlTableFill(). Returns total length of the Script-,
   Feature-, and Lookup Lists, with all their associated structures (Script,
   LangSys, Feature, Lookup). */
static LOffset otlGetHeaderSize(otlTbl t) {
    return t->tbl.LookupList + t->lookupSize;
}

void otlDumpSizes(hotCtx g, otlTbl t, LOffset subtableSize,
                  LOffset extensionSectionSize) {
    LOffset s, tot = 0;

    s = otlGetHeaderSize(t);
    tot += s;
    DF(1, (stderr, "  Scr,Fea,Lkp lists:     size %5u, tot %5u\n", s, tot));

    s = subtableSize;
    tot += s;
    DF(1, (stderr, "  Main subtable section: size %5u, tot %5u\n", s, tot));

    s = otlGetCoverageSize(t);
    tot += s;
    DF(1, (stderr, "  Main coverage section: size %5u, tot ", s));
    if (s != 0) {
        DF(1, (stderr, "%5u\n", tot));
    } else {
        DF(1, (stderr, "    \"\n"));
    }

    s = otlGetClassSize(t);
    tot += s;
    DF(1, (stderr, "  Main class section:    size %5u, tot ", s));
    if (s != 0) {
        DF(1, (stderr, "%5u\n", tot));
    } else {
        DF(1, (stderr, "    \"\n"));
    }

    s = extensionSectionSize;
    tot += s;
    DF(1, (stderr, "  Extension section:     size %5u, tot ", s));
    if (s != 0) {
        DF(1, (stderr, "%5u\n", tot));
    } else {
        DF(1, (stderr, "    \"\n"));
    }
}

#endif /* HOT_DEBUG */

/* --------------------------- Standard Functions -------------------------- */

void otlNew(hotCtx g) {
    otlCtx h = MEM_NEW(g, sizeof(struct otlCtx_));

    /* Link contexts */
    h->g = g;
    g->ctx.otl = h;
}

void otlFree(hotCtx g) {
    MEM_FREE(g, g->ctx.otl);
}

/* --------------------------- Coverage Functions -------------------------- */

/* Element initializer */
static void coverageRecordInit(void *ctx, long count, CoverageRecord *rec) {
    hotCtx g = ctx;
    long i;
    for (i = 0; i < count; i++) {
        dnaINIT(g->dnaCtx, rec->glyph, 50, 50);
        rec++;
    }
    return;
}

/* Initialize coverage tables */
static void coverageNew(hotCtx g, otlTbl t) {
    t->coverage.offset = 0;
    dnaINIT(g->dnaCtx, t->coverage.tables, 10, 5);
    t->coverage.tables.func = coverageRecordInit;
}

/* Fill format 1 table */
static CoverageFormat1 *fillCoverage1(hotCtx g, unsigned nGlyphs, GID *glyph) {
    unsigned int i;
    unsigned int dstIndex;
    CoverageFormat1 *fmt = MEM_NEW(g, sizeof(CoverageFormat1)); /* This may be more than we need, becuase we skip suplicate glyoh ID;s, but there's no harm in that. */

    fmt->CoverageFormat = 1;
    fmt->GlyphArray = MEM_NEW(g, sizeof(GID) * nGlyphs);
    // COPY(fmt->GlyphArray, glyph, nGlyphs);

    fmt->GlyphArray[0] = glyph[0];
    dstIndex = 1;
    for (i = 1; i < nGlyphs; i++) {
        if (glyph[i - 1] == glyph[i]) {
            /* Skip duplicate glyphs */

#if HOT_DEBUG
            printf("duplicated glyph ['%d']in coverage fmt 1.\n", glyph[i]);
#endif
            continue;
        }
        fmt->GlyphArray[dstIndex] = glyph[i];
        dstIndex++;
    }
    fmt->GlyphCount = dstIndex;
    return fmt;
}

/* Fill format 2 table */
static CoverageFormat2 *fillCoverage2(hotCtx g, int nRanges, long nGlyphs,
                                      GID *glyph) {
    int i;
    int iRange;
    int iStart;
    unsigned int curNGlyph;
    CoverageFormat2 *fmt = MEM_NEW(g, sizeof(CoverageFormat2));

    fmt->CoverageFormat = 2;
    fmt->RangeCount = nRanges;
    fmt->RangeRecord = MEM_NEW(g, sizeof(RangeRecord) * nRanges);

    iRange = 0;
    iStart = 0;
    curNGlyph = 0;

    for (i = 1; i <= nGlyphs; i++) {
        if (i == nGlyphs || glyph[i - 1] != glyph[i] - 1) {
            RangeRecord *rec;

            if ((i != nGlyphs) && (glyph[i - 1] == glyph[i])) {
                /* Skip duplicate glyphs */

#if HOT_DEBUG
                printf("duplicated glyph ['%d']in coverage fmt 2.\n", glyph[i]);
#endif
                continue;
            }
            rec = &fmt->RangeRecord[iRange++];

            rec->Start = glyph[iStart];
            rec->End = glyph[i - 1];
            iStart = i;
            rec->StartCoverageIndex = curNGlyph - (rec->End - rec->Start);
        }
        curNGlyph++;
    }
    return fmt;
}

/* Fill coverage table */
static Offset fillCoverage(hotCtx g, otlTbl t) {
    int i;
    int nRanges;
    unsigned size1;
    unsigned size2;
    CoverageRecord *new = t->coverage.new;
    long nGlyphs = new->glyph.cnt;
    long nFinalGlyphs;
    GID *glyph = new->glyph.array;

    new->offset = (unsigned short)t->coverage.offset;

    /* Count ranges (assumes glyphs sorted by increasing GID) */
    nRanges = 1;
    nFinalGlyphs = 1;
    for (i = 1; i < nGlyphs; i++) {
        if (glyph[i - 1] == glyph[i]) {
            /* Skip duplicate glyphs */
            continue;
        }
        nFinalGlyphs++;
        if (glyph[i - 1] != glyph[i] - 1) {
            nRanges++;
        }
    }

    size1 = COVERAGE1_SIZE(nFinalGlyphs);
    size2 = COVERAGE2_SIZE(nRanges);

    /* Choose smallest representation */

    if (size1 < size2) {
        new->tbl = fillCoverage1(g, nGlyphs, glyph);
        t->coverage.offset += size1;
    } else {
        new->tbl = fillCoverage2(g, nRanges, nGlyphs, glyph);
        t->coverage.offset += size2;
    }

    if (t->coverage.offset > 0xFFFF) {
        hotMsg(g, hotFATAL, "coverage section too large (%0lx)",
               t->coverage.offset);
    }

    return new->offset; /* Return new table's offset */
}

/* Write format 1 table */
static void writeCoverage1(otlCtx h, CoverageFormat1 *fmt) {
    int i;

    OUT2(fmt->CoverageFormat);
    OUT2(fmt->GlyphCount);
    for (i = 0; i < fmt->GlyphCount; i++) {
        OUT2(fmt->GlyphArray[i]);
    }
}

/* Write format 2 table */
static void writeCoverage2(otlCtx h, CoverageFormat2 *fmt) {
    int i;

    OUT2(fmt->CoverageFormat);
    OUT2(fmt->RangeCount);
    for (i = 0; i < fmt->RangeCount; i++) {
        RangeRecord *rec = &fmt->RangeRecord[i];
        OUT2(rec->Start);
        OUT2(rec->End);
        OUT2(rec->StartCoverageIndex);
    }
}

/* Write all coverage tables */
void otlCoverageWrite(hotCtx g, otlTbl t) {
    int i;
    otlCtx h = g->ctx.otl;

    for (i = 0; i < t->coverage.tables.cnt; i++) {
        void *tbl = t->coverage.tables.array[i].tbl;

        switch (*(unsigned short *)tbl) {
            case 1:
                writeCoverage1(h, tbl);
                break;

            case 2:
                writeCoverage2(h, tbl);
                break;
        }
    }
}

/* Free format 1 table */
static void freeCoverage1(hotCtx g, CoverageFormat1 *fmt) {
    MEM_FREE(g, fmt->GlyphArray);
}

/* Free format 2 table */
static void freeCoverage2(hotCtx g, CoverageFormat2 *fmt) {
    MEM_FREE(g, fmt->RangeRecord);
}

/* Free formated table */
static void freeCoverage(hotCtx g, CoverageRecord *rec) {
    switch (*(unsigned short *)rec->tbl) {
        case 1:
            freeCoverage1(g, rec->tbl);
            break;

        case 2:
            freeCoverage2(g, rec->tbl);
            break;
    }
    MEM_FREE(g, rec->tbl);
}

static void coverageReuse(hotCtx g, otlTbl t) {
    int i;
    for (i = 0; i < t->coverage.tables.cnt; i++) {
        freeCoverage(g, &t->coverage.tables.array[i]);
    }
    t->coverage.tables.cnt = 0;
    t->coverage.offset = 0;
}

/* Free all coverage tables */
static void coverageFree(hotCtx g, otlTbl t) {
    int i;
    for (i = 0; i < t->coverage.tables.size; i++) {
        dnaFREE(t->coverage.tables.array[i].glyph);
    }
    dnaFREE(t->coverage.tables);
}

/* Begin new coverage table */
void otlCoverageBegin(hotCtx g, otlTbl t) {
    t->coverage.new = dnaNEXT(t->coverage.tables);
    t->coverage.new->glyph.cnt = 0;
}

/* Add coverage glyph */
void otlCoverageAddGlyph(hotCtx g, otlTbl t, GID glyph) {
    *dnaNEXT(t->coverage.new->glyph) = glyph;
}

/* Compare glyph ids */
static int CDECL cmpGlyphIds(const void *first, const void *second) {
    GID a = *(GID *)first;
    GID b = *(GID *)second;
    if (a < b) {
        return -1;
    } else if (a > b) {
        return 1;
    }
    return 0;
}

/* End coverage table; uniqueness of GIDs up to client. Sorting done here. */
Offset otlCoverageEnd(hotCtx g, otlTbl t) {
    long i;
    CoverageRecord *new = t->coverage.new;

    /* Sort glyph ids into increasing order */
    qsort(new->glyph.array, new->glyph.cnt, sizeof(GID), cmpGlyphIds);

    /* Check for matching table */
    for (i = 0; i < t->coverage.tables.cnt - 1; i++) {
        CoverageRecord *old = &t->coverage.tables.array[i];

        if (new->glyph.cnt == old->glyph.cnt) {
            long j;
            for (j = 0; j < new->glyph.cnt; j++) {
                if (new->glyph.array[j] != old->glyph.array[j]) {
                    goto next;
                }
            }

            /* Found match */
#if HOT_DEBUG
            t->nCoverageReused++;
#if 0
            if (DF_LEVEL >= 2) {
                fprintf(stderr, "# Using coverage already present:");
                for (j = 0; j < old->glyph.cnt; j++) {
                    gidDump(g, old->glyph.array[j],
                            j != old->glyph.cnt - 1 ? ' ' : 0);
                }
                fprintf(stderr, "\n");
            }
#endif
#endif
            t->coverage.tables.cnt--; /* Remove new table */
            return old->offset;       /* Return matching table's offset */
        }
    next:;
    }

    /* No match; fill table and return its offset  */
    return fillCoverage(g, t);
}

/* Returns total length of the coverage section, for all coverages currently
   defined. */
LOffset otlGetCoverageSize(otlTbl t) {
    return t->coverage.offset;
}

/* Returns total length of the class section, for all classes currently
   defined. */
LOffset otlGetClassSize(otlTbl t) {
    return t->class.offset;
}

/* ---------------------------- Class Functions ---------------------------- */

/* Class record element initializer */
static void classRecordInit(void *ctx, long count, ClassRecord *rec) {
    hotCtx g = ctx;
    long i;
    for (i = 0; i < count; i++) {
        dnaINIT(g->dnaCtx, rec->map, 50, 50);
        rec++;
    }
    return;
}

static void classNew(hotCtx g, otlTbl t) {
    t->class.offset = 0;
    dnaINIT(g->dnaCtx, t->class.tables, 10, 5);
    t->class.tables.func = classRecordInit;
}

/* Fill format 1 table */
static ClassDefFormat1 *fillClass1(hotCtx g,
                                   int nMaps, ClassMap *maps, int nGlyphs) {
    int i;
    ClassDefFormat1 *fmt = MEM_NEW(g, sizeof(ClassDefFormat1));

    fmt->ClassFormat = 1;
    fmt->StartGlyph = nMaps ? maps[0].glyph : GID_NOTDEF;
    fmt->GlyphCount = nGlyphs;
    fmt->ClassValueArray = nMaps ? MEM_NEW(g, sizeof(unsigned short) * nGlyphs)
                                 : NULL;

    /* Initialize to class 0 */
    for (i = 0; i < nGlyphs; i++) {
        fmt->ClassValueArray[i] = 0;
    }

    /* Add explicit glyph classes */
    for (i = 0; i < nMaps; i++) {
        fmt->ClassValueArray[maps[i].glyph - fmt->StartGlyph] = maps[i].class;
    }
    return fmt;
}

/* Fill format 2 table */
static ClassDefFormat2 *fillClass2(hotCtx g,
                                   int nMaps, ClassMap *maps, int nRanges) {
    int i;
    int iRange;
    int iStart;
    ClassDefFormat2 *fmt = MEM_NEW(g, sizeof(ClassDefFormat2));

    fmt->ClassFormat = 2;
    fmt->ClassRangeCount = nRanges;
    fmt->ClassRangeRecord = nRanges ? MEM_NEW(g, sizeof(ClassRangeRecord) * nRanges) : NULL;

    iRange = 0;
    iStart = 0;
    for (i = 1; i <= nMaps; i++) {
        if (i == nMaps ||
            maps[i - 1].glyph != maps[i].glyph - 1 ||
            maps[i - 1].class != maps[i].class) {
            ClassRangeRecord *rec = &fmt->ClassRangeRecord[iRange++];

            rec->Start = maps[iStart].glyph;
            rec->End = maps[i - 1].glyph;
            rec->Class = maps[i - 1].class;

            iStart = i;
        }
    }
    return fmt;
}

/* Fill class table */
static Offset fillClass(hotCtx g, otlTbl t) {
    int i;
    int nRanges;
    unsigned size1;
    unsigned size2;
    ClassRecord *new = t->class.new;
    int nMaps = new->map.cnt;
    ClassMap *maps = new->map.array;
    int nGlyphs = nMaps ? maps[nMaps - 1].glyph - maps[0].glyph + 1
                        : 0;

    new->offset = (unsigned short)t->class.offset;

    /* Count ranges (assumes glyphs sorted by increasing GID) */
    nRanges = nMaps != 0;
    for (i = 1; i < nMaps; i++) {
        if (maps[i - 1].glyph != maps[i].glyph - 1 ||
            maps[i - 1].class != maps[i].class) {
            /* Start new range when break in GID sequence or new class */
            nRanges++;
        }
    }

    size1 = CLASS1_SIZE(nGlyphs);
    size2 = CLASS2_SIZE(nRanges);

    /* Choose smallest representation */
    if (size1 < size2) {
        new->tbl = fillClass1(g, nMaps, maps, nGlyphs);
        t->class.offset += size1;
    } else {
        new->tbl = fillClass2(g, nMaps, maps, nRanges);
        t->class.offset += size2;
    }
    if (t->class.offset > 0xFFFF) {
        hotMsg(g, hotFATAL, "class section too large (%0lx)", t->class.offset);
    }

    return new->offset; /* Return new table's offset */
}

/* Write format 1 table */
static void writeClass1(otlCtx h, ClassDefFormat1 *fmt) {
    int i;

    OUT2(fmt->ClassFormat);
    OUT2(fmt->StartGlyph);
    OUT2(fmt->GlyphCount);
    for (i = 0; i < fmt->GlyphCount; i++) {
        OUT2(fmt->ClassValueArray[i]);
    }
}

/* Write format 2 table */
static void writeClass2(otlCtx h, ClassDefFormat2 *fmt) {
    int i;

    OUT2(fmt->ClassFormat);
    OUT2(fmt->ClassRangeCount);
    for (i = 0; i < fmt->ClassRangeCount; i++) {
        ClassRangeRecord *rec = &fmt->ClassRangeRecord[i];
        OUT2(rec->Start);
        OUT2(rec->End);
        OUT2(rec->Class);
    }
}

/* Write all class tables */
void otlClassWrite(hotCtx g, otlTbl t) {
    int i;
    otlCtx h = g->ctx.otl;

    for (i = 0; i < t->class.tables.cnt; i++) {
        void *tbl = t->class.tables.array[i].tbl;

        switch (*(unsigned short *)tbl) {
            case 1:
                writeClass1(h, tbl);
                break;

            case 2:
                writeClass2(h, tbl);
                break;
        }
    }
}

/* Free format 1 table */
static void freeClass1(hotCtx g, ClassDefFormat1 *fmt) {
    MEM_FREE(g, fmt->ClassValueArray);
}

/* Free format 2 table */
static void freeClass2(hotCtx g, ClassDefFormat2 *fmt) {
    MEM_FREE(g, fmt->ClassRangeRecord);
}

/* Free formated table */
static void freeClass(hotCtx g, ClassRecord *rec) {
    switch (*(unsigned short *)rec->tbl) {
        case 1:
            freeClass1(g, rec->tbl);
            break;

        case 2:
            freeClass2(g, rec->tbl);
            break;
    }
    MEM_FREE(g, rec->tbl);
}

static void classReuse(hotCtx g, otlTbl t) {
    int i;
    for (i = 0; i < t->class.tables.cnt; i++) {
        freeClass(g, &t->class.tables.array[i]);
    }
    t->class.tables.cnt = 0;
    t->class.offset = 0;
}

/* Free all class tables */
static void classFree(hotCtx g, otlTbl t) {
    int i;
    for (i = 0; i < t->class.tables.size; i++) {
        dnaFREE(t->class.tables.array[i].map);
    }
    dnaFREE(t->class.tables);
}

/* Begin new class table */
void otlClassBegin(hotCtx g, otlTbl t) {
    t->class.new = dnaNEXT(t->class.tables);
    t->class.new->map.cnt = 0;
}

/* Add class mapping; ignore class 0's */
void otlClassAddMapping(hotCtx g, otlTbl t, GID glyph, unsigned int class) {
    if (class != 0) {
        ClassMap *map = dnaNEXT(t->class.new->map);
        map->glyph = glyph;
        map->class = class;
    }
}

/* Compare glyph ids */
static int CDECL cmpClassMaps(const void *first, const void *second) {
    unsigned short aClass;
    unsigned short bClass;
    GID a = ((ClassMap *)first)->glyph;
    GID b = ((ClassMap *)second)->glyph;
    if (a < b) {
        return -1;
    } else if (a > b) {
        return 1;
    }
    /* Note that I am sorting the classes in increasing class index. The result is that a higher index */
    /* will overwrite a lower index, when this is written to a class definition..                      */
    aClass = ((ClassMap *)first)->class;
    bClass = ((ClassMap *)second)->class;
    if (aClass < bClass) {
        return -1;
    } else if (aClass > bClass) {
        return 1;
    }
    return 0;
}

/* End class table */
Offset otlClassEnd(hotCtx g, otlTbl t) {
    int i;
    ClassRecord *new = t->class.new;

    /* Sort glyph ids into increasing order */
    qsort(new->map.array, new->map.cnt, sizeof(ClassMap), cmpClassMaps);

    /* Check for matching table */
    for (i = 0; i < t->class.tables.cnt - 1; i++) {
        ClassRecord *old = &t->class.tables.array[i];

        if (new->map.cnt == old->map.cnt) {
            int j;
            for (j = 0; j < new->map.cnt; j++) {
                if (new->map.array[j].glyph != old->map.array[j].glyph ||
                    new->map.array[j].class != old->map.array[j].class) {
                    goto next;
                }
            }

            /* Found match */
#if HOT_DEBUG
            t->nClassReused++;
#if 0
            if (DF_LEVEL >= 2) {
                fprintf(stderr, "# Using class already present:");
                for (j = 0; j < old->map.cnt; j++) {
                    fprintf(stderr, " ");
                    gidDump(g, old->map.array[j].glyph, 0);
                    fprintf(stderr, ":%u", old->map.array[j].class);
                }
                fprintf(stderr, "\n");
            }
#endif
#endif
            t->class.tables.cnt--; /* Remove new table */
            return old->offset;    /* Return matching table's offset */
        }
    next:;
    }

    /* No match; fill table and return its offset  */
    return fillClass(g, t);
}

/* ---------------------------- Device Functions --------------------------- */

/* I don't know if we'll ever need device tables. If we do it would be
   implemented here */

/* ---------------------------- Table Functions ---------------------------- */

/* Create new table context */
otlTbl otlTableNew(hotCtx g) {
    otlTbl t = MEM_NEW(g, sizeof(struct otlTbl_));

    dnaINIT(g->dnaCtx, t->subtable, 10, 5);
    dnaINIT(g->dnaCtx, t->label, 50, 100);
    dnaINIT(g->dnaCtx, t->refLabel, 50, 100);

#if HOT_DEBUG
    t->subtable.func = initSubtable;
    t->nCoverageReused = 0;
    t->nClassReused = 0;
#endif
    coverageNew(g, t);
    classNew(g, t);
    t->nAnonSubtables = t->nStandAloneSubtables = t->nRefLookups = t->nFeatParams = 0;

    return t;
}

/* Compare labels */
static int CDECL cmpLabels(const void *first, const void *second, void *ctx) {
    const LabelInfo *a = first;
    const LabelInfo *b = second;

    if (a->label < b->label) {
        return -1;
    } else if (a->label > b->label) {
        return 1;
    } else if (a != b) {
        hotCtx *g = ctx;
        hotMsg(*g, hotFATAL, "[internal] duplicate subtable label encountered");
    }
    return 0; /* Suppress compiler warning */
}

static int CDECL cmpLabelsByLookup(const void *first, const void *second, void *ctx) {
    const LabelInfo *a = first;
    const LabelInfo *b = second;

    if (a->lookupInx < b->lookupInx) {
        return -1;
    } else if (a->lookupInx > b->lookupInx) {
        return 1;
    } else if (a->label < b->label) {
        return -1;
    } else if (a->label > b->label) {
        return 1;
    } else if (a != b) {
        hotCtx *g = ctx;
        hotMsg(*g, hotFATAL, "[internal] duplicate subtable label encountered");
    }
    return 0; /* Suppress compiler warning */
}

static int CDECL matchLabel(const void *key, const void *value) {
    int a = *(int *)key;
    int b = ((LabelInfo *)value)->label;
    if (a < b) {
        return -1;
    } else if (a > b) {
        return 1;
    } else {
        return 0;
    }
}

static int CDECL matchLabelByLookup(const void *key, const void *value) {
    int a = *(int *)key;
    int b = ((LabelInfo *)value)->lookupInx;
    if (a < b) {
        return -1;
    } else if (a > b) {
        return 1;
    } else {
        return 0;
    }
}

/* Returns the lookup index associated with baselabel (which should not have
   the reference bit set). May be called from outside this module only after
   otlTableFill() */
int otlLabel2LookupIndex(hotCtx g, otlTbl t, int baselabel) {
    LabelInfo *li =
        (LabelInfo *)bsearch(&baselabel, t->label.array, t->label.cnt,
                             sizeof(LabelInfo), matchLabel);
    if (li == NULL) {
        hotMsg(g, hotFATAL, "(internal) label 0x%x not found", baselabel);
    } else {
        li->used = 1;
    }
    return li->lookupInx;
}

/* Looks through the lable list for the named lookup index Returns 1 if it has been referenced, else
   returns -1. May be called from outside this module only after otlTableFill() */
int findSeenRef(hotCtx g, otlTbl t, int baseLookup) {
    LabelInfo *li =
        (LabelInfo *)bsearch(&baseLookup, t->label.array, t->label.cnt,
                             sizeof(LabelInfo), matchLabelByLookup);
    if (li == NULL) {
        hotMsg(g, hotFATAL, "Base lookup %d not found", baseLookup);
    }

    return li->used;
}

/* Sort in LookupList order: non-reference subtbls by offset (with aalt sorting
   first); then Feat Params; last references. */
static int CDECL cmpLookupList(const void *first, const void *second,
                               void *ctx) {
    const Subtable *a = first;
    const Subtable *b = second;
    Tag aalt_tag = TAG('a', 'a', 'l', 't');

    if (!IS_REF_LAB(a->label) && IS_REF_LAB(b->label)) {
        return -1;
    } else if (IS_REF_LAB(a->label) && !IS_REF_LAB(b->label)) {
        return 1;
    } else if (IS_REF_LAB(a->label) && IS_REF_LAB(b->label)) {
        return 0; /* Don't bother sorting references */
    } else if ((!a->isFeatParam) && b->isFeatParam) {
        return -1;
    } else if (a->isFeatParam && (!b->isFeatParam)) {
        return 1;
    } else if ((a->feature != b->feature) && (a->feature == aalt_tag)) {
        return -1;
    } else if ((a->feature != b->feature) && (b->feature == aalt_tag)) {
        return 1;
    } else if (a->offset < b->offset) {
        return -1;
    } else if (a->offset > b->offset) {
        return 1;
    } else if (a != b) {
        hotCtx *g = ctx;
        hotMsg(*g, hotFATAL, "[internal] subtables have same offset");
    }
    return 0; /* Suppress compiler warning */
}

void sortLabelList(hotCtx g, otlTbl t) {
    ctuQSort(t->label.array, t->label.cnt, sizeof(LabelInfo), cmpLabels, &g);
}

/* Calculate LookupList indexes. Granularity of lookups has already been
   determined by the client of this module by labels. Prepare the label ->
   lkpInx mapping */
static void calcLookupListIndexes(hotCtx g, otlTbl t) {
    long i;
    int indexCnt = 0;

    ctuQSort(t->subtable.array, t->subtable.cnt, sizeof(Subtable),
             cmpLookupList, &g);

    /* Process all regular subtables and subtables with feature parameters.          */
    /* We want the lookups indices to be ordered in the order that they were created */
    /* by feature file definitions.                                                  */
    for (i = 0; i < (t->subtable.cnt - t->nRefLookups); i++) {
        Subtable *sub = &t->subtable.array[i];

        if (i == 0 || sub->label != (sub - 1)->label) {
            /* Label i.e. lookup change. Store lab -> lookupInx info in this first subtable of the span of tables with the same label.  */
            LabelInfo *lab = dnaNEXT(t->label);
            lab->used = 0; /* new label; hasn't been referenced by anything yet. */

            /* sub-tables with feature Params currently don't have any look-ups. */
            if (sub->isFeatParam) {
                sub->index.lookup = -1;
            } else {
                sub->index.lookup = indexCnt++;
            }
            lab->label = sub->label;
            lab->lookupInx = sub->index.lookup;
        } else {
            sub->index.lookup = indexCnt - 1;
        }
    }

    ctuQSort(t->label.array, t->label.cnt, sizeof(LabelInfo), cmpLabels, &g);

    /* Fill the index of any reference subtables (sorted at end) */
    for (; i < t->subtable.cnt; i++) {
        Subtable *sub = &t->subtable.array[i];
        sub->index.lookup = otlLabel2LookupIndex(g, t, sub->label & ~REF_LAB);
    }
}

/* Determine granularity of a Feature */
static int CDECL cmpFeatTmp(const void *first, const void *second) {
    const Subtable *a = first;
    const Subtable *b = second;

    if ((a->feature == TAG_STAND_ALONE) && (b->feature != TAG_STAND_ALONE)) {
        return 1;
    } else if ((b->feature == TAG_STAND_ALONE) && (a->feature != TAG_STAND_ALONE)) {
        return -1;
    } else if (a->script < b->script) {
        /* Make sure that anonymous lookups sort last (script == TAG_UDEF, aka 0cFFFF) */
        return -1;
    } else if (a->script > b->script) {
        return 1;
    } else if (a->language < b->language) {
        /* Test language */
        return -1;
    } else if (a->language > b->language) {
        return 1;
    } else if (a->feature < b->feature) {
        /* Test feature */
        return -1;
    } else if (a->feature > b->feature) {
        return 1;
    } else {
        return 0;
    }
}

/* Sort in FeatureList order */
static int CDECL cmpFeatureList(const void *first, const void *second) {
    const Subtable *a = first;
    const Subtable *b = second;

    if ((a->feature == TAG_STAND_ALONE) && (b->feature != TAG_STAND_ALONE)) {
        return 1;
    } else if ((b->feature == TAG_STAND_ALONE) && (a->feature != TAG_STAND_ALONE)) {
        return -1;
    } else if (a->feature < b->feature) {
        /* Test feature */
        return -1;
    } else if (a->feature > b->feature) {
        return 1;
    } else if (a->feature == TAG_UNDEF) {
        /* Don't bother further checking anon lookups - these are sorted to the end by now. */
        return 0;
    } else if (a->index.feature < b->index.feature) {
        /* Test feature index */
        return -1;
    } else if (a->index.feature > b->index.feature) {
        return 1;
    } else if (a->index.lookup < b->index.lookup) {
        /* Test lookup index */
        return -1;
    } else if (a->index.lookup > b->index.lookup) {
        return 1;
    } else {
        return 0;
    }
}

/* Calculate feature indexes */
static void calcFeatureListIndexes(hotCtx g, otlTbl t) {
    long i;
    int indexCnt;
    int prevIndex;

    /* Determine granularity of features */
    qsort(t->subtable.array, t->subtable.cnt, sizeof(Subtable), cmpFeatTmp);

    /* Assign temporary feature indexes according to feature granularity (i.e. */
    /* same script, language & feature), disregarding whether reference or has */
    /* parameters or not                                                       */
    indexCnt = 0;
    for (i = 0; i < t->subtable.cnt - t->nAnonSubtables; i++) {
        Subtable *sub = &t->subtable.array[i];
        Subtable *prev = sub - 1; /* xxx */

        sub->index.feature = (i == 0 || !(sub->script == prev->script &&
                                          sub->language == prev->language &&
                                          sub->feature == prev->feature))
                                 ? indexCnt++ /* Feature change */
                                 : indexCnt - 1;
    }

    /* Sort in final feature order */
    qsort(t->subtable.array, t->subtable.cnt, sizeof(Subtable), cmpFeatureList);

    /* Assign final feature indexes */
    prevIndex = -1;
    indexCnt = 0;
    for (i = 0; i < t->subtable.cnt - t->nAnonSubtables; i++) {
        Subtable *sub = &t->subtable.array[i];

        if (sub->index.feature != prevIndex) {
            /* -- Feature change --  */
            prevIndex = sub->index.feature;
            sub->index.feature = indexCnt++;
        } else {
            sub->index.feature = indexCnt - 1;
        }
    }
}

/* Sort in ScriptList order */
static int CDECL cmpScriptList(const void *first, const void *second) {
    const Subtable *a = first;
    const Subtable *b = second;

    if ((a->feature == TAG_STAND_ALONE) && (b->feature != TAG_STAND_ALONE)) {
        return 1;
    } else if ((b->feature == TAG_STAND_ALONE) && (a->feature != TAG_STAND_ALONE)) {
        return -1;
    } else if (a->script < b->script) {
        /* Test script Tag TAG_UNDEF is sorted to the end, as it is 0xFFFF. */
        return -1;
    } else if (a->script > b->script) {
        return 1;
    } else if (a->script == TAG_UNDEF) {
        return 0; /* Don't bother checking anon lkps */
    } else if (a->language < b->language) {
        /* Test language */
        return -1;
    } else if (a->language > b->language) {
        return 1;
    } else if (a->feature < b->feature) {
        /* Test feature index */
        return -1;
    } else if (a->feature > b->feature) {
        return 1;
    } else {
        return 0; /* Further testing not needed for ScriptList */
    }
}

/* Calculate script, language, and index.feature spans */
static void prepScriptList(hotCtx g, otlTbl t) {
    int scr;
    int Scr;
    int spanLimit = t->subtable.cnt - t->nAnonSubtables;

    qsort(t->subtable.array, t->subtable.cnt, sizeof(Subtable), cmpScriptList);

    Scr = 0;
    for (scr = 1; scr <= spanLimit; scr++) {
        if (scr == spanLimit || t->subtable.array[scr].script !=
                                    t->subtable.array[Scr].script) {
            /* -- Script change -- */
            int lan;
            int Lan = Scr;

            t->subtable.array[Scr].span.script = scr;

            for (lan = Lan + 1; lan <= scr; lan++) {
                if (lan == scr || t->subtable.array[lan].language !=
                                      t->subtable.array[Lan].language) {
                    /* -- Language change -- */
                    int fea;
                    int Fea = Lan;

                    t->subtable.array[Lan].span.language = lan;

                    for (fea = Fea + 1; fea <= lan; fea++) {
                        if (fea == lan ||
                            t->subtable.array[fea].index.feature !=
                                t->subtable.array[Fea].index.feature) {
                            /* -- Feature index change -- */
                            t->subtable.array[Fea].span.feature = fea;
                            Fea = fea;
                        }
                    }
                    Lan = lan;
                }
            }
            Scr = scr;
        }
    }
}

/* Fill language system record */
static Offset fillLangSysRecord(hotCtx g, otlTbl t, LangSys *sys,
                                int iLanguage) {
    int i;
    int j;
    int nFeatures;
    Subtable *sub;
    int iNext = t->subtable.array[iLanguage].span.language;

    /* Count features in this language system span: */
    nFeatures = 0;
    for (i = iLanguage; i < iNext; i = t->subtable.array[i].span.feature) {
        nFeatures++;
    }

    /* Fill record */
    sys->LookupOrder = NULL_OFFSET;
    sys->ReqFeatureIndex = 0xffff; /* xxx unsuported at present */
    sys->FeatureCount = nFeatures;
    sys->FeatureIndex = MEM_NEW(g, sizeof(unsigned short) * nFeatures);

    j = 0;
    for (i = iLanguage; i < iNext; i = sub->span.feature) {
        sub = &t->subtable.array[i];
        sys->FeatureIndex[j++] = sub->index.feature;
    }

    return LANG_SYS_SIZE(nFeatures);
}

/* Fill ScriptList */
static Offset fillScriptList(hotCtx g, otlTbl t) {
    int i;
    int nScripts;
    int iScript;
    Offset oScriptList;
    /* This works becuase prepScript has sorted the subtables so that anon subtabes are last, preceded by Stand-Alone subtables */
    int spanLimit = t->subtable.cnt - (t->nAnonSubtables + t->nStandAloneSubtables);

    /* Count scripts */
    nScripts = 0;
    for (i = 0; i < spanLimit; i = t->subtable.array[i].span.script) {
        nScripts++;
    }

    /* Allocate scripts */
    t->tbl.ScriptList_.ScriptCount = nScripts;
    t->tbl.ScriptList_.ScriptRecord =
        MEM_NEW(g, sizeof(ScriptRecord) * nScripts);

    oScriptList = SCRIPT_LIST_SIZE(nScripts);

    /* Build table */
    iScript = 0;
    for (i = 0; i < nScripts; i++) {
        int j;
        int iLanguage;
        int nLanguages;
        Offset oScript;
        Subtable *sub = &t->subtable.array[iScript];
        ScriptRecord *rec = &t->tbl.ScriptList_.ScriptRecord[i];
        Script *script = &rec->Script_;

        /* Fill ScriptRecord */
        rec->ScriptTag = sub->script;
        rec->Script = oScriptList;

        if (sub->language == dflt_) {
            /* Fill default language system record */
            script->DefaultLangSys =
                fillLangSysRecord(g, t, &script->DefaultLangSys_, iScript);
            iLanguage = sub->span.language;
        } else {
            script->DefaultLangSys = NULL_OFFSET;
            iLanguage = iScript;
        }

        /* Count languages for this script */
        nLanguages = 0;
        for (j = iLanguage; j < sub->span.script;
             j = t->subtable.array[j].span.language) {
            nLanguages++;
        }

        /* Allocate Languages */
        script->LangSysCount = nLanguages;
        script->LangSysRecord = (nLanguages == 0) ? NULL : MEM_NEW(g, sizeof(LangSysRecord) * nLanguages);

        oScript = SCRIPT_SIZE(nLanguages);

        if (script->DefaultLangSys != NULL_OFFSET) {
            Offset tmp = script->DefaultLangSys;
            script->DefaultLangSys = oScript;
            oScript += tmp;
        }

        /* Fill languages system records */
        for (j = 0; j < nLanguages; j++) {
            Subtable *sub = &t->subtable.array[iLanguage];
            LangSysRecord *rec = &script->LangSysRecord[j];

            /* Fill langSysRecord */
            rec->LangSysTag = sub->language;
            rec->LangSys = oScript;

            oScript += fillLangSysRecord(g, t,
                                         &script->LangSysRecord[j].LangSys_,
                                         iLanguage);

            /* Advance to next language */
            iLanguage = sub->span.language;
        }

        /* Advance to next script */
        oScriptList += oScript;
        iScript = sub->span.script;
    }

    return oScriptList;
}

/* Sort; span by feature index and lookup index. Caution: overwrites
   span.feature from prepScriptList().
 */
static void prepFeatureList(hotCtx g, otlTbl t) {
    int fea;
    int Fea;
    int spanLimit = t->subtable.cnt - t->nAnonSubtables;

    qsort(t->subtable.array, t->subtable.cnt, sizeof(Subtable), cmpFeatureList);

    Fea = 0;
    for (fea = 1; fea <= spanLimit; fea++) {
        /* This logic steps through the  t->subtable.array.                                                        */
        /* Whenever it encorunters a new feature subtable.array[fea].index.feature index,                          */
        /* it stores the current subtable index in the first subtale of the sequence of subtables that             */
        /* had the previous subtable index. The array is this divided into sequences of subtables with the         */
        /* same index.feature, and the span.featur of the first subtable in the index gives the index of the first */
        /* subtable in the next run.                                                                               */
        /* The same is then done for sequences of subtables with the same index.lookup                             */
        /* within the previous sequence of subtables with the same same index.feature.                             */
        if (fea == spanLimit || t->subtable.array[fea].index.feature !=
                                    t->subtable.array[Fea].index.feature) {
            /* Feature index change */
            int loo;
            int Loo = Fea;

            t->subtable.array[Fea].span.feature = fea;

            for (loo = Loo + 1; loo <= fea; loo++) {
                if (loo == fea || t->subtable.array[loo].index.lookup !=
                                      t->subtable.array[Loo].index.lookup) {
                    /* Lookup index change */
                    t->subtable.array[Loo].span.lookup = loo;
                    Loo = loo;
                }
            }
            Fea = fea;
        }
    }
}

/* Sort; span by lookup index */
static void prepLookupList(hotCtx g, otlTbl t) {
    int loo;
    int Loo;
    int spanLimit = t->subtable.cnt - (t->nRefLookups + t->nFeatParams);

    ctuQSort(t->subtable.array, t->subtable.cnt, sizeof(Subtable),
             cmpLookupList, &g);
    Loo = 0;
    for (loo = 1; loo <= spanLimit; loo++) {
        if (loo == spanLimit || t->subtable.array[loo].index.lookup !=
                                    t->subtable.array[Loo].index.lookup) {
            /* Lookup index change */
            t->subtable.array[Loo].span.lookup = loo;
            Loo = loo;
        }
    }
}

/* Fill FeatureList */
static Offset findFeatParamOffset(Tag featTag, Label featLabel, Subtable *subArray, int numSubtables) {
    int i;
    Subtable *sub;
    Offset value = 0;
    Label matchlabel = (Label)(featLabel & ~REF_LAB);

    for (i = 0; i < numSubtables; i++) {
        sub = &subArray[i];
        if ((sub->feature == featTag) && (sub->label == matchlabel)) {
            value = sub->offset;
            break;
        }
    }

    return value;
}

static Offset fillFeatureList(hotCtx g, otlTbl t) {
    int i;
    int nFeatures;
    int iFeature;
    Offset oFeatureList;
    /* This works becuase prepFeature has sorted the subtables so that anon subtabes are last, preceded by Stand-Alone subtables */
    int spanLimit = t->subtable.cnt - (t->nAnonSubtables + t->nStandAloneSubtables);

    nFeatures = t->subtable.array[spanLimit - 1].index.feature + 1;
    /* Allocate features */
    t->tbl.FeatureList_.FeatureCount = nFeatures;
    t->tbl.FeatureList_.FeatureRecord =
        MEM_NEW(g, sizeof(FeatureRecord) * nFeatures);

    oFeatureList = FEATURE_LIST_SIZE(nFeatures);

    /* Build table */
    iFeature = 0;
    for (i = 0; i < nFeatures; i++) {
        int j;
        int k;
        int nLookups;
        int nParamSubtables;
        Offset nParamOffset;
        Subtable *sub = &t->subtable.array[iFeature];
        FeatureRecord *rec = &t->tbl.FeatureList_.FeatureRecord[i];
        Feature *feature = &rec->Feature_;
        /* if ( sub->feature == (Tag)TAG_STAND_ALONE) */
        /*     continue;                              */

        /* Fill FeatureRecord */
        rec->FeatureTag = sub->feature;
        rec->Feature = oFeatureList;

        /* Count lookups for this feature. These will include references. */
        nLookups = 0;
        nParamSubtables = 0;
        nParamOffset = 0;
        /* sub is is the first subtable in a run of subtables with the same feature table index.                       */
        /* sub->span.feature is the array index for the first subtable with a different feature table index.           */
        /* This field is NOT set in any of the other subtables in the current run.                                     */
        /* Within the current run, the first subtable of a sequence with the same lookup table index                   */
        /* span.lookup set to the first subtable of the nexte sequence with a different lookup index or deature index. */
        for (j = iFeature; j < sub->span.feature; j = t->subtable.array[j].span.lookup) {
            Subtable *lsub = &t->subtable.array[j];

            if (lsub->isFeatParam) {
                nParamSubtables++;           /* There ought to be only one of these! */
                nParamOffset = lsub->offset; /* Note! this is only the offset from the start of the subtable block that follows the lookupList */
                if (IS_REF_LAB(lsub->label)) {
                    nParamOffset = findFeatParamOffset(lsub->feature, lsub->label, t->subtable.array, spanLimit);
                }
            } else {
                nLookups++;
            }
        }

        /* Allocate Lookups */
        feature->LookupCount = nLookups;

        if (nLookups > 0) {
            feature->LookupListIndex =
                MEM_NEW(g, sizeof(unsigned short) * nLookups);

            /* Fill lookup list */
            k = 0;
            for (j = iFeature; j < sub->span.feature;
                 j = t->subtable.array[j].span.lookup) {
                if (!t->subtable.array[j].isFeatParam) {
                    feature->LookupListIndex[k++] = t->subtable.array[j].index.lookup;
                }
            }
        } else {
            feature->LookupListIndex = (void *)0xFFFFFFFF;
        }
        oFeatureList += FEATURE_SIZE(nLookups);

        /* Add feature parameter */
        if (nParamSubtables > 0) {
            if (nParamSubtables > 1) {
                hotMsg(g, hotFATAL, "GPOS feature '%c%c%c%c' has more than one FeatureParameter subtable! ",
                       TAG_ARG(rec->FeatureTag));
            }

            if (nParamOffset == 0) {
                /* This happens when the 'size' feature is the first GPOS feature in the feature file.*/
                nParamOffset = FEAT_PARAM_ZERO; /* So we can tell the difference between 'undefined' and a real zero value.*/
            }
            feature->FeatureParams = nParamOffset; /* Note! this is only the offset from the start of the subtable block that follows the lookupList */
        } else {
            feature->FeatureParams = NULL_OFFSET;
        }

        /* Advance to next feature */
        iFeature = sub->span.feature;
    }

    return oFeatureList;
}

static void fixFeatureParmOffsets(hotCtx g, otlTbl t, short shortfeatureParamBaseOffset) {
    int nFeatures = t->tbl.FeatureList_.FeatureCount;
    int i;

    for (i = 0; i < nFeatures; i++) {
        FeatureRecord *rec = &t->tbl.FeatureList_.FeatureRecord[i];
        Feature *feature = &rec->Feature_;
        if (feature->FeatureParams != 0) {
            /* Undo fix so we can tell the diff between feature->FeatureParam==NULL_OFFSET, */
            /* and a real 0 offset from the start of the subtable array.                    */
            if (feature->FeatureParams == FEAT_PARAM_ZERO) {
                feature->FeatureParams = 0;
            }
            /* feature->FeatureParams is now: (offset from start of subtable block that follows the LookupList) */
            /* shortfeatureParamBaseOffset is (size of featureList) + (size of LookupList).                     */
            feature->FeatureParams = feature->FeatureParams + shortfeatureParamBaseOffset - rec->Feature;
        }
    }
}

/* Fill LookupList */
static Offset fillLookupList(hotCtx g, otlTbl t) {
    int i;
    Subtable *sub;
    int nLookups = 0;
    Offset oLookupList;
    int lkpInx;
    int spanLimit = t->subtable.cnt - (t->nRefLookups + t->nFeatParams);

    /* Count lookups */
    if (spanLimit > 0) {
        /*can  have 0 lookups when there is only a GPOS 'size' feature, and no other features.*/
        nLookups = t->subtable.array[spanLimit - 1].index.lookup + 1;
    }

    DF(2, (stderr, ">OTL: %d lookup%s allocated (%d ref%s skipped)\n",
           nLookups, nLookups == 1 ? "" : "s",
           t->nRefLookups, t->nRefLookups == 1 ? "" : "s"));

    /* Allocate lookups */
    t->tbl.LookupList_.LookupCount = nLookups;
    t->tbl.LookupList_.Lookup = MEM_NEW(g, sizeof(Offset) * nLookups);
    t->tbl.LookupList_.Lookup_ = MEM_NEW(g, sizeof(Lookup) * nLookups);

    oLookupList = LOOKUP_LIST_SIZE(nLookups);

    /* Build table */
    lkpInx = 0;
    for (i = 0; i < spanLimit; i = sub->span.lookup) {
        Lookup *lookup;
        int nSubtables;
        int j;

        sub = &t->subtable.array[i];
        lookup = &t->tbl.LookupList_.Lookup_[lkpInx];
        nSubtables = sub->span.lookup - i;

        t->tbl.LookupList_.Lookup[lkpInx] = oLookupList;

        lookup->LookupType = (unsigned short)(sub->lookup >> 16);
        lookup->LookupFlag = (unsigned short)(sub->lookup & 0xffff);
        /* Allocate subtables */
        lookup->SubTableCount = nSubtables;
        lookup->SubTable = MEM_NEW(g, sizeof(long) * nSubtables);

        /* Fill subtable array. Offsets may be -ve; will be adjusted later. */
        for (j = 0; j < nSubtables; j++) {
            lookup->SubTable[j] = (sub + j)->offset - oLookupList;
        }

        oLookupList += LOOKUP_SIZE(nSubtables);
        if (lookup->LookupFlag & otlUseMarkFilteringSet) {
            lookup->UseMarkSetIndex = sub->markSetIndex;
            oLookupList += sizeof(lookup->UseMarkSetIndex);
        }
        lkpInx++;
    }

    return oLookupList;
}

void checkStandAloneTablRefs(hotCtx g, otlTbl t) {
    int i;
    /* Now go back through all the real subtables, and check that the stand-alone ones have been referenced. */
    ctuQSort(t->label.array, t->label.cnt, sizeof(LabelInfo), cmpLabelsByLookup, &g);
    for (i = 0; i < (t->subtable.cnt - (t->nAnonSubtables + t->nRefLookups)); i++) {
        Subtable *sub = &t->subtable.array[i];
        if (sub->seenInFeature != 0) {
            continue;
        }
        /* This is a stand-alone lookup */
        sub->seenInFeature = findSeenRef(g, t, sub->index.lookup);
        if (sub->seenInFeature == 0) {
            hotMsg(g, hotWARNING, "Stand-alone lookup with Lookup Index %d was not referenced from within any feature, and will never be used.", sub->index.lookup);
        }
    }
}

void otlTableFill(hotCtx g, otlTbl t) {
    Offset offset = HEADER_SIZE;

    calcLookupListIndexes(g, t);
    calcFeatureListIndexes(g, t);

    t->tbl.Version = VERSION(1, 0);

    prepScriptList(g, t);
    t->tbl.ScriptList = offset;
    offset += fillScriptList(g, t);

#if HOT_DEBUG
    if (DF_LEVEL >= 1) {
        otlDumpSubtables(g, t);
    }
#endif

    prepFeatureList(g, t);
    t->tbl.FeatureList = offset;
    offset += fillFeatureList(g, t);

    prepLookupList(g, t);
    t->tbl.LookupList = offset;
    t->lookupSize = fillLookupList(g, t);

    if (t->nFeatParams > 0) {
        /* The feature table FeatureParam offsets are currently from the start of the subtable block.*/
        /* featureParamBaseOffset is the (size of the feature list + feature record array) + size of the lookup list. */
        short featureParamBaseOffset = (t->tbl.LookupList - t->tbl.FeatureList) + t->lookupSize;
        fixFeatureParmOffsets(g, t, featureParamBaseOffset);
    }
}

void otlTableFillStub(hotCtx g, otlTbl t) {
    Header *hdr = &t->tbl;

    t->tbl.Version = VERSION(1, 0);

    t->tbl.ScriptList = 0;
    t->tbl.FeatureList = 0;
    t->tbl.LookupList = 0;

    hdr->ScriptList_.ScriptCount = 0;
    hdr->FeatureList_.FeatureCount = 0;
    hdr->LookupList_.LookupCount = 0;
}

/* Write language system record */
static void writeLangSys(otlCtx h, LangSys *rec) {
    int i;

    OUT2(rec->LookupOrder);
    OUT2(rec->ReqFeatureIndex);
    OUT2(rec->FeatureCount);

    for (i = 0; i < rec->FeatureCount; i++) {
        OUT2(rec->FeatureIndex[i]);
    }
}

void otlTableWrite(hotCtx g, otlTbl t) {
    int i;
    int j;
    otlCtx h = g->ctx.otl;
    Header *hdr = &t->tbl;

    /* Write header */
    OUT4(hdr->Version);
    OUT2(hdr->ScriptList);
    OUT2(hdr->FeatureList);
    OUT2(hdr->LookupList);

    if (hdr->ScriptList == 0) {
        return;
    }

    /* Write script list */
    OUT2(hdr->ScriptList_.ScriptCount);
    for (i = 0; i < hdr->ScriptList_.ScriptCount; i++) {
        ScriptRecord *rec = &hdr->ScriptList_.ScriptRecord[i];

        OUT4(rec->ScriptTag);
        OUT2(rec->Script);
    }
    for (i = 0; i < hdr->ScriptList_.ScriptCount; i++) {
        Script *script = &hdr->ScriptList_.ScriptRecord[i].Script_;

        OUT2(script->DefaultLangSys);
        OUT2(script->LangSysCount);

        for (j = 0; j < script->LangSysCount; j++) {
            LangSysRecord *rec = &script->LangSysRecord[j];

            OUT4(rec->LangSysTag);
            OUT2(rec->LangSys);
        }

        if (script->DefaultLangSys != 0) {
            writeLangSys(h, &script->DefaultLangSys_);
        }

        for (j = 0; j < script->LangSysCount; j++) {
            writeLangSys(h, &script->LangSysRecord[j].LangSys_);
        }
    }

    /* Write feature list */
    OUT2(hdr->FeatureList_.FeatureCount);
    for (i = 0; i < hdr->FeatureList_.FeatureCount; i++) {
        FeatureRecord *rec = &hdr->FeatureList_.FeatureRecord[i];

        OUT4(rec->FeatureTag);
        OUT2(rec->Feature);
    }
    for (i = 0; i < hdr->FeatureList_.FeatureCount; i++) {
        Feature *feature = &hdr->FeatureList_.FeatureRecord[i].Feature_;

        OUT2(feature->FeatureParams);
        OUT2(feature->LookupCount);

        for (j = 0; j < feature->LookupCount; j++) {
            OUT2(feature->LookupListIndex[j]);
        }
    }

    /* Write lookup list */
    OUT2(hdr->LookupList_.LookupCount);
    for (i = 0; i < hdr->LookupList_.LookupCount; i++) {
        OUT2(hdr->LookupList_.Lookup[i]);
    }
    for (i = 0; i < hdr->LookupList_.LookupCount; i++) {
        Lookup *lookup = &hdr->LookupList_.Lookup_[i];

        OUT2(lookup->LookupType);
        OUT2(lookup->LookupFlag);
        OUT2(lookup->SubTableCount);
        for (j = 0; j < lookup->SubTableCount; j++) {
            OUT2((short)(lookup->SubTable[j] + t->lookupSize));
        }
        if (lookup->LookupFlag & otlUseMarkFilteringSet) {
            OUT2(lookup->UseMarkSetIndex);
        }
    }
}

/* Free language system record */
static void freeLangSys(hotCtx g, LangSys *rec) {
    MEM_FREE(g, rec->FeatureIndex);
}

static void freeTable(hotCtx g, otlTbl t) {
    int i;
    int j;
    Header *hdr = &t->tbl;

    /* Free script list */
    for (i = 0; i < hdr->ScriptList_.ScriptCount; i++) {
        Script *script = &hdr->ScriptList_.ScriptRecord[i].Script_;

        if (script->DefaultLangSys != 0) {
            freeLangSys(g, &script->DefaultLangSys_);
        }

        for (j = 0; j < script->LangSysCount; j++) {
            freeLangSys(g, &script->LangSysRecord[j].LangSys_);
        }

        script->LangSysCount = 0;
        MEM_FREE(g, script->LangSysRecord);
    }
    MEM_FREE(g, hdr->ScriptList_.ScriptRecord);

    /* Free feature list */
    for (i = 0; i < hdr->FeatureList_.FeatureCount; i++) {
        Feature *feature = &hdr->FeatureList_.FeatureRecord[i].Feature_;
        if (feature->LookupCount > 0) {
            MEM_FREE(g, feature->LookupListIndex);
        }
    }
    MEM_FREE(g, hdr->FeatureList_.FeatureRecord);

    /* Free lookup list */
    for (i = 0; i < hdr->LookupList_.LookupCount; i++) {
        Lookup *lookup = &hdr->LookupList_.Lookup_[i];

        MEM_FREE(g, lookup->SubTable);
    }
    MEM_FREE(g, hdr->LookupList_.Lookup);
    MEM_FREE(g, hdr->LookupList_.Lookup_);
}

void otlTableReuse(hotCtx g, otlTbl t) {
    if (t->subtable.cnt != 0) {
        freeTable(g, t);
    }
    t->subtable.cnt = 0;
    t->label.cnt = 0;
    t->refLabel.cnt = 0;

#if HOT_DEBUG
    t->subtable.func = initSubtable;
    t->nCoverageReused = 0;
    t->nClassReused = 0;
#endif
    coverageReuse(g, t);
    classReuse(g, t);
    t->nStandAloneSubtables = t->nAnonSubtables = t->nRefLookups = t->nFeatParams = 0;
}

void otlTableFree(hotCtx g, otlTbl t) {
    if (t == NULL) {
        return;
    }
    dnaFREE(t->subtable);
    dnaFREE(t->label);
    dnaFREE(t->refLabel);
    coverageFree(g, t);
    classFree(g, t);
    MEM_FREE(g, t);
}

/* Add subtable to list. Assumes label has been set for intended granularity of
   lookups (i.e. all subtables of the same lookup should have the same
   label). */
void otlSubtableAdd(hotCtx g, otlTbl t, Tag script, Tag language, Tag feature,
                    int lkpType, int lkpFlag, unsigned short markSetIndex, unsigned extensionLookupType,
                    unsigned offset, Label label, unsigned short fmt,
                    int isFeatParam) {
    Subtable *sub = dnaNEXT(t->subtable);

    sub->script = script;
    sub->language = language;
    sub->feature = feature;
    sub->lookup = (unsigned long)lkpType << 16 | lkpFlag;
    sub->markSetIndex = markSetIndex;
    sub->extensionLookupType = extensionLookupType;
    sub->offset = offset;
    sub->label = label;
    sub->fmt = fmt;
    sub->isFeatParam = isFeatParam;
    if (feature == (Tag)TAG_STAND_ALONE) {
        sub->seenInFeature = 0;
    } else {
        sub->seenInFeature = 1;
    }

    if (script == TAG_UNDEF) {
        t->nAnonSubtables++;
    }
    if (feature == (Tag)TAG_STAND_ALONE) {
        t->nStandAloneSubtables++;
    }

    /* FeatParam subtables may be labelled, but should NOT be added */
    /* to the list of real look ups.                                */
    if (IS_REF_LAB(label)) {
        t->nRefLookups++;
    } else if (isFeatParam) {
        t->nFeatParams++;
    }
}
