/* Copyright (C) 2001-2018 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* Adobe-based CMap character decoding */
#include "memory_.h"
#include "string_.h"
#include "gx.h"
#include "gserrors.h"
#include "gsstruct.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gxfcmap1.h"

/* Get a big-endian integer. */
static inline ulong
bytes2int(const byte *p, int n)
{
    ulong v = 0;
    int i;

    for (i = 0; i < n; ++i)
        v = (v << 8) + p[i];
    return v;
}

/* ---------------- GC descriptors ---------------- */

public_st_cmap_adobe1();
/* Because lookup ranges can be elements of arrays, */
/* their enum_ptrs procedure must never return 0 prematurely. */
static
ENUM_PTRS_WITH(cmap_lookup_range_enum_ptrs,
               gx_cmap_lookup_range_t *pclr) return 0;
case 0:
    if (pclr->value_type == CODE_VALUE_GLYPH) {
        const byte *pv = pclr->values.data;
        int size = pclr->value_size;
        int k;

        for (k = 0; k < pclr->num_entries; ++k, pv += size) {
            gs_glyph glyph = bytes2int(pv, size);

            pclr->cmap->mark_glyph(mem, glyph, pclr->cmap->mark_glyph_data);
        }
    }
    return ENUM_OBJ(pclr->cmap);
case 1: return ENUM_STRING(&pclr->keys);
case 2: return ENUM_STRING(&pclr->values);
ENUM_PTRS_END
static
RELOC_PTRS_WITH(cmap_lookup_range_reloc_ptrs, gx_cmap_lookup_range_t *pclr)
    RELOC_VAR(pclr->cmap);
    RELOC_STRING_VAR(pclr->keys);
    RELOC_STRING_VAR(pclr->values);
RELOC_PTRS_END
public_st_cmap_lookup_range();
public_st_cmap_lookup_range_element();

/* ---------------- Procedures ---------------- */

    /* ------ Decoding ------ */

/*
 * multi-dimensional range comparator
 */

#ifndef GS_THREADSAFE
#ifdef DEBUG
static void
print_msg_str_in_range(const byte *str,
                       const byte *key_lo, const byte *key_hi,
                       int key_size)
{
    debug_print_string_hex_nomem(str, key_size);
    dlprintf(" in ");
    debug_print_string_hex_nomem(key_lo, key_size);
    dlprintf(" - ");
    debug_print_string_hex_nomem(key_hi, key_size);
    dlprintf("\n");
}
#endif
#endif

static int
gs_cmap_get_shortest_chr(const gx_code_map_t * pcmap, uint *pfidx)
{
    int i;
    int len_shortest = MAX_CMAP_CODE_SIZE;
    uint fidx_shortest = 0; /* font index for this fallback */

    for (i = pcmap->num_lookup - 1; i >= 0; --i) {
        const gx_cmap_lookup_range_t *pclr = &pcmap->lookup[i];
        if ((pclr->key_prefix_size + pclr->key_size) <= len_shortest) {
           len_shortest = (pclr->key_prefix_size + pclr->key_size);
           fidx_shortest = pclr->font_index;
        }
    }

    *pfidx = fidx_shortest;
    return len_shortest;
}

/*
 * multi-dimensional relative position calculator
 *
 * Returns offset of the given CID, considering CID range
 * as array of CIDs (the last index changes fastest).
 */
static int
gs_multidim_CID_offset(const byte *key_str,
                        const byte *key_lo, const byte *key_hi,
                        int key_size)
{

    int i;	/* index for current dimension */
    int CID_offset = 0;

#ifndef GS_THREADSAFE
#ifdef DEBUG
    if (gs_debug_c('J')) {
        dlprintf("[J]gmCo()         calc CID_offset for 0x");
        print_msg_str_in_range(key_str, key_lo, key_hi, key_size);
    }
#endif
#endif

    for (i = 0; i < key_size; i++)
        CID_offset = CID_offset * (key_hi[i] - key_lo[i] + 1) +
            key_str[i] - key_lo[i];

#ifdef DEBUG
    if_debug1('J', "[J]gmCo()         CID_offset = %d\n", CID_offset);
#endif

    return CID_offset;
}

/*
 * Decode a character from a string using a code map, updating the index.
 * Return 0 for a CID or name, N > 0 for a character code where N is the
 * number of bytes in the code, or an error.  Store the decoded bytes in
 * *pchr.  For undefined characters, set *pglyph = GS_NO_GLYPH and return 0.
 */
static int
code_map_decode_next_multidim_regime(const gx_code_map_t * pcmap,
                     const gs_const_string * pstr,
                     uint * pindex, uint * pfidx,
                     gs_char * pchr, gs_glyph * pglyph)
{
    const byte *str = pstr->data + *pindex;
    uint ssize = pstr->size - *pindex;
    /*
     * The keys are not sorted due to 'usecmap'.  Possible optimization :
     * merge and sort keys in 'zbuildcmap', then use binary search here.
     * This would be valuable for UniJIS-UTF8-H, which contains about 7000
     * keys.
     */
    int i;

    /*
     * In the fallback of CMap decoding procedure, there is "partial matching".
     * For detail, refer PostScript Ref. Manual v3 at the end of Fonts chapter.
     */

    /* "pm" stands for partial match (not pointer), temporal use. */
    int pm_maxlen = 0;		/* partial match: max length */
    int pm_index = *pindex;	/* partial match: ptr index (in str) */
    uint pm_fidx = *pfidx;	/* partial match: ptr font index */
    gs_char pm_chr = *pchr;	/* partial match: ptr character */

    *pchr = '\0';

#ifndef GS_THREADSAFE
#ifdef DEBUG
    if (gs_debug_c('J')) {
        dlprintf("[J]CMDNmr() is called: str=(");
        debug_print_string_hex_nomem(str, ssize);
        dlprintf3(") @ 0x%lx ssize=%d, %d ranges to check\n",
                  (ulong)str, ssize, pcmap->num_lookup);
    }
#endif
#endif

    for (i = pcmap->num_lookup - 1; i >= 0; --i) {
        /* main loop - scan the map passed via pcmap */
        /* reverse scan order due to 'usecmap' */

        const gx_cmap_lookup_range_t *pclr = &pcmap->lookup[i];
        int pre_size = pclr->key_prefix_size, key_size = pclr->key_size,
            chr_size = pre_size + key_size;

        int j = 0;
        /* length of the given byte stream is shorter than
         * chr-length of current range, no need for further check,
         * skip to the next range.
         */
        if (ssize < chr_size)
            continue;

        if (0 < pre_size) {
            const byte * prefix = pclr->key_prefix;
            /* check partial match in prefix */
            for (j = 0; j < pre_size; j++)
               if (prefix[j] != str[j])
                   break;

            if (0 == j)			/* no match, skip to next i */
                continue;
            else if (j < pre_size) {	/* not exact, partial match */
#ifndef GS_THREADSAFE
#ifdef DEBUG
                if (gs_debug_c('J')) {
                    dlprintf("[J]CMDNmr() partial match with prefix:");
                    print_msg_str_in_range(str, prefix,
                                                prefix, pre_size);
                }
#endif
#endif
                if (pm_maxlen < j) {
                    pm_maxlen = chr_size;
                    pm_chr = bytes2int(str, chr_size);
                    pm_index = (*pindex) + chr_size;
                    pm_fidx = pclr->font_index;
                }
                continue ; /* no need to check key, skip to next i */
            }

#ifndef GS_THREADSAFE
#ifdef DEBUG
            if (gs_debug_c('J')) {
                dlprintf("[J]CMDNmr()   full match with prefix:");
                print_msg_str_in_range(str, prefix, prefix, pre_size);
            }
#endif
#endif
        } /* if (0 < pre_size) */

        /* full match in prefix. check key */
        {
            const byte *key = pclr->keys.data;
            int step = key_size;
            int k, l;
            const byte *pvalue = NULL;

            /* when range is "range", 2 keys for lo-end and hi-end
             * are stacked. So twice the step. current "key" points
             * lo-end of current range, and the pointer for hi-end
             * is calculated by (key + step - key_size).
             */

            if (pclr->key_is_range)
                step <<=1; 	/* step = step * 2; */

            for (k = 0; k < pclr->num_entries; ++k, key += step) {

#ifndef GS_THREADSAFE
#ifdef DEBUG
                if_debug0('j', "[j]CMDNmr()     check key:");
                if (gs_debug_c('j'))
                    print_msg_str_in_range(str + pre_size,
                        key, key + step - key_size, key_size) ;
#endif
#endif

                for (l = 0; l < key_size; l++) {
                    byte c = str[l + pre_size];
                    if (c < key[l] || c > key[step - key_size + l])
                        break;
                }

                if (pm_maxlen < pre_size + l) {
                    pm_maxlen = chr_size;
                    pm_chr = bytes2int(str, chr_size);
                    pm_index = (*pindex) + chr_size;
                    pm_fidx = pclr->font_index;
                }
                if (l == key_size)
                        break;
            }

            /* all keys are tried, but found no match. */
            /* go to next prefix. */
            if (k == pclr->num_entries)
                continue;

            /* We have a match.  Return the result. */
            *pchr = bytes2int(str, chr_size);
            *pindex += chr_size;
            *pfidx = pclr->font_index;
            pvalue = pclr->values.data + k * pclr->value_size;

#ifndef GS_THREADSAFE
#ifdef DEBUG
            if (gs_debug_c('J')) {
                dlprintf("[J]CMDNmr()     full matched pvalue=(");
                debug_print_string_hex_nomem(pvalue, pclr->value_size);
                dlprintf(")\n");
            }
#endif
#endif

            switch (pclr->value_type) {
            case CODE_VALUE_CID:
                *pglyph = GS_MIN_CID_GLYPH +
                    bytes2int(pvalue, pclr->value_size) +
                    gs_multidim_CID_offset(str + pre_size,
                        key, key + step - key_size, key_size);
                return 0;
            case CODE_VALUE_NOTDEF:
                *pglyph = GS_MIN_CID_GLYPH +
                    bytes2int(pvalue, pclr->value_size);
                return 0;
            case CODE_VALUE_GLYPH:
                *pglyph = bytes2int(pvalue, pclr->value_size);
                return 0;
            case CODE_VALUE_CHARS:
                *pglyph =
                    bytes2int(pvalue, pclr->value_size) +
                    bytes2int(str + pre_size, key_size) -
                    bytes2int(key, key_size);
                return pclr->value_size;
            default:            /* shouldn't happen */
                return_error(gs_error_rangecheck);
            }
        }
    }
    /* No mapping. */
    *pchr = pm_chr;
    *pindex = pm_index;
    *pfidx = pm_fidx;
    *pglyph = GS_NO_GLYPH;

#ifndef GS_THREADSAFE
#ifdef DEBUG
    if (gs_debug_c('J')) {
        dlprintf("[J]CMDNmr()     no full match, use partial match for (");
        debug_print_string_hex_nomem(str, pm_maxlen);
        dlprintf(")\n");
    }
#endif
#endif

    return 0;
}

/*
 * Decode a character from a string using a CMap.
 * Return like code_map_decode_next.
 * At present, the range specification by (begin|end)codespacerange
 * is not used in this function. Therefore, this function accepts
 * some invalid CMap which def & undef maps exceed the codespacerange.
 * It should be checked in this function, or some procedure in gs_cmap.ps.
 */
static int
gs_cmap_adobe1_decode_next(const gs_cmap_t * pcmap_in,
                           const gs_const_string * pstr,
                           uint * pindex, uint * pfidx,
                           gs_char * pchr, gs_glyph * pglyph)
{
    const gs_cmap_adobe1_t *pcmap = (const gs_cmap_adobe1_t *)pcmap_in;
    uint save_index = *pindex;
    int code;

    uint pm_index;
    uint pm_fidx;

    /* For first, check defined map */
    if_debug0('J', "[J]GCDN() check def CMap\n");
    code =
        code_map_decode_next_multidim_regime(&pcmap->def, pstr, pindex, pfidx, pchr, pglyph);

    /* This is defined character */
    if (code != 0 || *pglyph != GS_NO_GLYPH)
        return code;

    /* In here, this is NOT defined character */
    /* save partially matched results */
    pm_index = *pindex;
    pm_fidx = *pfidx;

    /* check notdef map. */
    if_debug0('J', "[J]GCDN() check notdef CMap\n");
    *pindex = save_index;
    code =
        code_map_decode_next_multidim_regime(&pcmap->notdef, pstr, pindex, pfidx, pchr, pglyph);

    /* This is defined "notdef" character. */
    if (code != 0 || *pglyph != GS_NO_GLYPH)
        return code;

    /*
     * This is undefined in def & undef maps,
     * use partially matched result with default notdef (CID = 0).
     */
    if (save_index < pm_index) {

        /* there was some partially matched */

        *pglyph = GS_MIN_CID_GLYPH;	/* CID = 0 */
        *pindex = pm_index;
        *pfidx = pm_fidx;
        *pchr = '\0';
         return 0; /* should return some error for partial matched .notdef? */
    }
    else {
        /* no match */

        /* Even partial match is failed.
         * Getting the shortest length from defined characters,
         * and take the leading bytes (with same length of the shortest
         * defined chr) as an unidentified character: CID = 0.
         * Also this procedure is specified in PS Ref. Manual v3,
         * at the end of Fonts chapter.
         */

        uint ssize = pstr->size - save_index;
        int chr_size_shortest =
                gs_cmap_get_shortest_chr(&pcmap->def, pfidx);

        if (chr_size_shortest <= ssize) {
            *pglyph = GS_MIN_CID_GLYPH;	/* CID = 0, this is CMap fallback */
            *pindex = save_index + chr_size_shortest;
            *pchr = '\0';
#ifndef GS_THREADSAFE
#ifdef DEBUG
            if (gs_debug_c('J')) {
                const byte *str = pstr->data + save_index;
                dlprintf1("[J]GCDN() no partial match, skip %d byte (",
                                               chr_size_shortest);
                debug_print_string_hex_nomem(str, chr_size_shortest);
                dlprintf(")\n");
            }
#endif
#endif
            return 0; /* should return some error for fallback .notdef? */
        }
        else {
            /* Undecodable string is shorter than the shortest character,
             * return 'GS_NO_GLYPH' and update index to end-of-string
             */
#ifndef GS_THREADSAFE
#ifdef DEBUG
            if (gs_debug_c('J')) {
                dlprintf2("[J]GCDN() left data in buffer (%d) is shorter than shortest defined character (%d)\n",
                  ssize, chr_size_shortest);
            }
#endif
#endif
            *pglyph = GS_NO_GLYPH;
            *pindex += ssize;
            return 0;			/* fixme: should return a code != 0 if caller needs to know */
        }
    }
}

    /* ------ Initialization/creation ------ */

/*
 * Allocate and initialize an Adobe1 CMap.  The caller must still fill in
 * the code space ranges, lookup tables, keys, and values.
 */

static int
adobe1_next_range(gs_cmap_ranges_enum_t *penum)
{
    const gs_cmap_adobe1_t *const pcmap =
        (const gs_cmap_adobe1_t *)penum->cmap;

    if (penum->index >= pcmap->code_space.num_ranges)
        return 1;
    penum->range = pcmap->code_space.ranges[penum->index++];
    return 0;
}
static const gs_cmap_ranges_enum_procs_t adobe1_range_procs = {
    adobe1_next_range
};
static void
gs_cmap_adobe1_enum_ranges(const gs_cmap_t *pcmap, gs_cmap_ranges_enum_t *pre)
{
    gs_cmap_ranges_enum_setup(pre, pcmap, &adobe1_range_procs);
}
static int
adobe1_next_lookup(gs_cmap_lookups_enum_t *penum, const gx_code_map_t *pcm)
{
    const gx_cmap_lookup_range_t *lookup = &pcm->lookup[penum->index[0]];

    penum->entry.value.data = 0L;
    if (penum->index[0] >= pcm->num_lookup)
        return 1;
    penum->entry.key_size = lookup->key_prefix_size + lookup->key_size;
    penum->entry.key_is_range = lookup->key_is_range;
    penum->entry.value_type = lookup->value_type;
    penum->entry.value.size = lookup->value_size;
    penum->entry.font_index = lookup->font_index;
    penum->index[0]++;
    penum->index[1] = 0;
    return 0;
}
static int
adobe1_next_lookup_def(gs_memory_t *mem, gs_cmap_lookups_enum_t *penum)
{
    return adobe1_next_lookup(penum,
                        &((const gs_cmap_adobe1_t *)penum->cmap)->def);
}
static int
adobe1_next_lookup_notdef(gs_memory_t *mem, gs_cmap_lookups_enum_t *penum)
{
    return adobe1_next_lookup(penum,
                        &((const gs_cmap_adobe1_t *)penum->cmap)->notdef);
}
static int
adobe1_next_entry(gs_cmap_lookups_enum_t *penum, const gx_code_map_t *pcm)
{
    const gx_cmap_lookup_range_t *lookup = &pcm->lookup[penum->index[0] - 1];
    int psize = lookup->key_prefix_size;
    int ksize = lookup->key_size;
    const byte *key =
        lookup->keys.data + penum->index[1] * ksize *
        (lookup->key_is_range ? 2 : 1);
    int i;

    if (penum->index[1] >= lookup->num_entries)
        return 1;
    if (psize + ksize > MAX_CMAP_CODE_SIZE)
        return_error(gs_error_rangecheck);
    for (i = 0; i < 2; ++i, key += ksize) {
        memcpy(penum->entry.key[i], lookup->key_prefix, psize);
        memcpy(penum->entry.key[i] + psize, key, ksize);
    }
    penum->entry.value.data =
        lookup->values.data + penum->index[1] * lookup->value_size;
    penum->entry.value.size = lookup->value_size;
    penum->index[1]++;
    return 0;
}
static int
adobe1_next_entry_def(gs_cmap_lookups_enum_t *penum)
{
    return adobe1_next_entry(penum,
                        &((const gs_cmap_adobe1_t *)penum->cmap)->def);
}
static int
adobe1_next_entry_notdef(gs_cmap_lookups_enum_t *penum)
{
    return adobe1_next_entry(penum,
                        &((const gs_cmap_adobe1_t *)penum->cmap)->notdef);
}
static const gs_cmap_lookups_enum_procs_t adobe1_lookup_def_procs = {
    adobe1_next_lookup_def, adobe1_next_entry_def
};
static const gs_cmap_lookups_enum_procs_t adobe1_lookup_notdef_procs = {
    adobe1_next_lookup_notdef, adobe1_next_entry_notdef
};
static void
gs_cmap_adobe1_enum_lookups(const gs_cmap_t *pcmap, int which,
                            gs_cmap_lookups_enum_t *pre)
{
    gs_cmap_lookups_enum_setup(pre, pcmap,
                               (which ? &adobe1_lookup_notdef_procs :
                                &adobe1_lookup_def_procs));
}

static const gs_cmap_procs_t cmap_adobe1_procs = {
    gs_cmap_adobe1_decode_next,
    gs_cmap_adobe1_enum_ranges,
    gs_cmap_adobe1_enum_lookups,
    gs_cmap_compute_identity
};

int
gs_cmap_adobe1_alloc(gs_cmap_adobe1_t **ppcmap, int wmode,
                     const byte *map_name, uint name_size,
                     uint num_fonts, uint num_ranges, uint num_lookups,
                     uint keys_size, uint values_size,
                     const gs_cid_system_info_t *pcidsi_in, gs_memory_t *mem)
{
    gs_cmap_t *pcmap;
    gs_cmap_adobe1_t *pcmap1;
    gx_code_space_range_t *ranges = (gx_code_space_range_t *)
        gs_alloc_byte_array(mem, num_ranges, sizeof(gx_code_space_range_t),
                            "gs_cmap_alloc(code space ranges)");
    gx_cmap_lookup_range_t *lookups =
        (num_lookups == 0 ? NULL :
         gs_alloc_struct_array(mem, num_lookups, gx_cmap_lookup_range_t,
                               &st_cmap_lookup_range,
                               "gs_cmap_alloc(lookup ranges)"));
    byte *keys =
        (keys_size == 0 ? NULL :
         gs_alloc_string(mem, keys_size, "gs_cmap_alloc(keys)"));
    byte *values =
        (values_size == 0 ? NULL :
         gs_alloc_string(mem, values_size, "gs_cmap_alloc(values)"));
    int code =
        gs_cmap_alloc(&pcmap, &st_cmap_adobe1, wmode, map_name, name_size,
                      pcidsi_in, num_fonts, &cmap_adobe1_procs, mem);
    uint i;

    if (code < 0 || ranges == 0 || (num_lookups != 0 && lookups == 0) ||
        (keys_size != 0 && keys == 0) || (values_size != 0 && values == 0)) {
        gs_free_string(mem, values, values_size, "gs_cmap_alloc(values)");
        gs_free_string(mem, keys, keys_size, "gs_cmap_alloc(keys)");
        gs_free_object(mem, lookups, "gs_cmap_alloc(lookup ranges)");
        gs_free_object(mem, ranges, "gs_cmap_alloc(code space ranges)");
        return_error(gs_error_VMerror);
    }
    *ppcmap = pcmap1 = (gs_cmap_adobe1_t *)pcmap;
    pcmap1->code_space.ranges = ranges;
    pcmap1->code_space.num_ranges = num_ranges;
    if (num_lookups > 0) {
        for (i = 0; i < num_lookups; ++i) {
            memset(&lookups[i], 0, sizeof(*lookups));
            lookups[i].cmap = pcmap1;
        }
        lookups[0].keys.data = keys;
        lookups[0].keys.size = keys_size;
        lookups[0].values.data = values;
        lookups[0].values.size = values_size;
    }
    pcmap1->def.lookup = lookups;
    pcmap1->def.num_lookup = num_lookups;
    pcmap1->notdef.lookup = 0;
    pcmap1->notdef.num_lookup = 0;
    /* no mark_glyph, mark_glyph_data, glyph_name, glyph_name_data */
    return 0;
}
