1
2/*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#include "SkUtils.h"
11#include "SkLazyFnPtr.h"
12
13#if 0
14#define assign_16_longs(dst, value)             \
15    do {                                        \
16        (dst)[0] = value;   (dst)[1] = value;   \
17        (dst)[2] = value;   (dst)[3] = value;   \
18        (dst)[4] = value;   (dst)[5] = value;   \
19        (dst)[6] = value;   (dst)[7] = value;   \
20        (dst)[8] = value;   (dst)[9] = value;   \
21        (dst)[10] = value;  (dst)[11] = value;  \
22        (dst)[12] = value;  (dst)[13] = value;  \
23        (dst)[14] = value;  (dst)[15] = value;  \
24    } while (0)
25#else
26#define assign_16_longs(dst, value)             \
27    do {                                        \
28        *(dst)++ = value;   *(dst)++ = value;   \
29        *(dst)++ = value;   *(dst)++ = value;   \
30        *(dst)++ = value;   *(dst)++ = value;   \
31        *(dst)++ = value;   *(dst)++ = value;   \
32        *(dst)++ = value;   *(dst)++ = value;   \
33        *(dst)++ = value;   *(dst)++ = value;   \
34        *(dst)++ = value;   *(dst)++ = value;   \
35        *(dst)++ = value;   *(dst)++ = value;   \
36    } while (0)
37#endif
38
39///////////////////////////////////////////////////////////////////////////////
40
41static void sk_memset16_portable(uint16_t dst[], uint16_t value, int count) {
42    SkASSERT(dst != NULL && count >= 0);
43
44    if (count <= 0) {
45        return;
46    }
47
48    // not sure if this helps to short-circuit on small values of count
49    if (count < 8) {
50        do {
51            *dst++ = (uint16_t)value;
52        } while (--count != 0);
53        return;
54    }
55
56    // ensure we're on a long boundary
57    if ((size_t)dst & 2) {
58        *dst++ = (uint16_t)value;
59        count -= 1;
60    }
61
62    uint32_t value32 = ((uint32_t)value << 16) | value;
63
64    // handle the bulk with our unrolled macro
65    {
66        int sixteenlongs = count >> 5;
67        if (sixteenlongs) {
68            uint32_t* dst32 = (uint32_t*)dst;
69            do {
70                assign_16_longs(dst32, value32);
71            } while (--sixteenlongs != 0);
72            dst = (uint16_t*)dst32;
73            count &= 31;
74        }
75    }
76
77    // handle (most) of the rest
78    {
79        int longs = count >> 1;
80        if (longs) {
81            do {
82                *(uint32_t*)dst = value32;
83                dst += 2;
84            } while (--longs != 0);
85        }
86    }
87
88    // cleanup a possible trailing short
89    if (count & 1) {
90        *dst = (uint16_t)value;
91    }
92}
93
94static void sk_memset32_portable(uint32_t dst[], uint32_t value, int count) {
95    SkASSERT(dst != NULL && count >= 0);
96
97    int sixteenlongs = count >> 4;
98    if (sixteenlongs) {
99        do {
100            assign_16_longs(dst, value);
101        } while (--sixteenlongs != 0);
102        count &= 15;
103    }
104
105    if (count) {
106        do {
107            *dst++ = value;
108        } while (--count != 0);
109    }
110}
111
112static void sk_memcpy32_portable(uint32_t dst[], const uint32_t src[], int count) {
113    memcpy(dst, src, count * sizeof(uint32_t));
114}
115
116namespace {
117// These three methods technically need external linkage to be passed as template parameters.
118// Since they can't be static, we hide them in an anonymous namespace instead.
119
120SkMemset16Proc choose_memset16() {
121    SkMemset16Proc proc = SkMemset16GetPlatformProc();
122    return proc ? proc : sk_memset16_portable;
123}
124
125SkMemset32Proc choose_memset32() {
126    SkMemset32Proc proc = SkMemset32GetPlatformProc();
127    return proc ? proc : sk_memset32_portable;
128}
129
130SkMemcpy32Proc choose_memcpy32() {
131    SkMemcpy32Proc proc = SkMemcpy32GetPlatformProc();
132    return proc ? proc : sk_memcpy32_portable;
133}
134
135}  // namespace
136
137void sk_memset16(uint16_t dst[], uint16_t value, int count) {
138    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemset16Proc, proc, choose_memset16);
139    proc.get()(dst, value, count);
140}
141
142void sk_memset32(uint32_t dst[], uint32_t value, int count) {
143    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemset32Proc, proc, choose_memset32);
144    proc.get()(dst, value, count);
145}
146
147void sk_memcpy32(uint32_t dst[], const uint32_t src[], int count) {
148    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemcpy32Proc, proc, choose_memcpy32);
149    proc.get()(dst, src, count);
150}
151
152///////////////////////////////////////////////////////////////////////////////
153
154/*  0xxxxxxx    1 total
155    10xxxxxx    // never a leading byte
156    110xxxxx    2 total
157    1110xxxx    3 total
158    11110xxx    4 total
159
160    11 10 01 01 xx xx xx xx 0...
161    0xE5XX0000
162    0xE5 << 24
163*/
164
165#ifdef SK_DEBUG
166    static void assert_utf8_leadingbyte(unsigned c) {
167        SkASSERT(c <= 0xF7);    // otherwise leading byte is too big (more than 4 bytes)
168        SkASSERT((c & 0xC0) != 0x80);   // can't begin with a middle char
169    }
170
171    int SkUTF8_LeadByteToCount(unsigned c) {
172        assert_utf8_leadingbyte(c);
173        return (((0xE5 << 24) >> (c >> 4 << 1)) & 3) + 1;
174    }
175#else
176    #define assert_utf8_leadingbyte(c)
177#endif
178
179int SkUTF8_CountUnichars(const char utf8[]) {
180    SkASSERT(utf8);
181
182    int count = 0;
183
184    for (;;) {
185        int c = *(const uint8_t*)utf8;
186        if (c == 0) {
187            break;
188        }
189        utf8 += SkUTF8_LeadByteToCount(c);
190        count += 1;
191    }
192    return count;
193}
194
195int SkUTF8_CountUnichars(const char utf8[], size_t byteLength) {
196    SkASSERT(utf8 || 0 == byteLength);
197
198    int         count = 0;
199    const char* stop = utf8 + byteLength;
200
201    while (utf8 < stop) {
202        utf8 += SkUTF8_LeadByteToCount(*(const uint8_t*)utf8);
203        count += 1;
204    }
205    return count;
206}
207
208SkUnichar SkUTF8_ToUnichar(const char utf8[]) {
209    SkASSERT(utf8);
210
211    const uint8_t*  p = (const uint8_t*)utf8;
212    int             c = *p;
213    int             hic = c << 24;
214
215    assert_utf8_leadingbyte(c);
216
217    if (hic < 0) {
218        uint32_t mask = (uint32_t)~0x3F;
219        hic <<= 1;
220        do {
221            c = (c << 6) | (*++p & 0x3F);
222            mask <<= 5;
223        } while ((hic <<= 1) < 0);
224        c &= ~mask;
225    }
226    return c;
227}
228
229SkUnichar SkUTF8_NextUnichar(const char** ptr) {
230    SkASSERT(ptr && *ptr);
231
232    const uint8_t*  p = (const uint8_t*)*ptr;
233    int             c = *p;
234    int             hic = c << 24;
235
236    assert_utf8_leadingbyte(c);
237
238    if (hic < 0) {
239        uint32_t mask = (uint32_t)~0x3F;
240        hic <<= 1;
241        do {
242            c = (c << 6) | (*++p & 0x3F);
243            mask <<= 5;
244        } while ((hic <<= 1) < 0);
245        c &= ~mask;
246    }
247    *ptr = (char*)p + 1;
248    return c;
249}
250
251SkUnichar SkUTF8_PrevUnichar(const char** ptr) {
252    SkASSERT(ptr && *ptr);
253
254    const char* p = *ptr;
255
256    if (*--p & 0x80) {
257        while (*--p & 0x40) {
258            ;
259        }
260    }
261
262    *ptr = (char*)p;
263    return SkUTF8_NextUnichar(&p);
264}
265
266size_t SkUTF8_FromUnichar(SkUnichar uni, char utf8[]) {
267    if ((uint32_t)uni > 0x10FFFF) {
268        SkDEBUGFAIL("bad unichar");
269        return 0;
270    }
271
272    if (uni <= 127) {
273        if (utf8) {
274            *utf8 = (char)uni;
275        }
276        return 1;
277    }
278
279    char    tmp[4];
280    char*   p = tmp;
281    size_t  count = 1;
282
283    SkDEBUGCODE(SkUnichar orig = uni;)
284
285    while (uni > 0x7F >> count) {
286        *p++ = (char)(0x80 | (uni & 0x3F));
287        uni >>= 6;
288        count += 1;
289    }
290
291    if (utf8) {
292        p = tmp;
293        utf8 += count;
294        while (p < tmp + count - 1) {
295            *--utf8 = *p++;
296        }
297        *--utf8 = (char)(~(0xFF >> count) | uni);
298    }
299
300    SkASSERT(utf8 == NULL || orig == SkUTF8_ToUnichar(utf8));
301    return count;
302}
303
304///////////////////////////////////////////////////////////////////////////////
305
306int SkUTF16_CountUnichars(const uint16_t src[]) {
307    SkASSERT(src);
308
309    int count = 0;
310    unsigned c;
311    while ((c = *src++) != 0) {
312        SkASSERT(!SkUTF16_IsLowSurrogate(c));
313        if (SkUTF16_IsHighSurrogate(c)) {
314            c = *src++;
315            SkASSERT(SkUTF16_IsLowSurrogate(c));
316        }
317        count += 1;
318    }
319    return count;
320}
321
322int SkUTF16_CountUnichars(const uint16_t src[], int numberOf16BitValues) {
323    SkASSERT(src);
324
325    const uint16_t* stop = src + numberOf16BitValues;
326    int count = 0;
327    while (src < stop) {
328        unsigned c = *src++;
329        SkASSERT(!SkUTF16_IsLowSurrogate(c));
330        if (SkUTF16_IsHighSurrogate(c)) {
331            SkASSERT(src < stop);
332            c = *src++;
333            SkASSERT(SkUTF16_IsLowSurrogate(c));
334        }
335        count += 1;
336    }
337    return count;
338}
339
340SkUnichar SkUTF16_NextUnichar(const uint16_t** srcPtr) {
341    SkASSERT(srcPtr && *srcPtr);
342
343    const uint16_t* src = *srcPtr;
344    SkUnichar       c = *src++;
345
346    SkASSERT(!SkUTF16_IsLowSurrogate(c));
347    if (SkUTF16_IsHighSurrogate(c)) {
348        unsigned c2 = *src++;
349        SkASSERT(SkUTF16_IsLowSurrogate(c2));
350
351        // c = ((c & 0x3FF) << 10) + (c2 & 0x3FF) + 0x10000
352        // c = (((c & 0x3FF) + 64) << 10) + (c2 & 0x3FF)
353        c = (c << 10) + c2 + (0x10000 - (0xD800 << 10) - 0xDC00);
354    }
355    *srcPtr = src;
356    return c;
357}
358
359SkUnichar SkUTF16_PrevUnichar(const uint16_t** srcPtr) {
360    SkASSERT(srcPtr && *srcPtr);
361
362    const uint16_t* src = *srcPtr;
363    SkUnichar       c = *--src;
364
365    SkASSERT(!SkUTF16_IsHighSurrogate(c));
366    if (SkUTF16_IsLowSurrogate(c)) {
367        unsigned c2 = *--src;
368        SkASSERT(SkUTF16_IsHighSurrogate(c2));
369        c = (c2 << 10) + c + (0x10000 - (0xD800 << 10) - 0xDC00);
370    }
371    *srcPtr = src;
372    return c;
373}
374
375size_t SkUTF16_FromUnichar(SkUnichar uni, uint16_t dst[]) {
376    SkASSERT((unsigned)uni <= 0x10FFFF);
377
378    int extra = (uni > 0xFFFF);
379
380    if (dst) {
381        if (extra) {
382            // dst[0] = SkToU16(0xD800 | ((uni - 0x10000) >> 10));
383            // dst[0] = SkToU16(0xD800 | ((uni >> 10) - 64));
384            dst[0] = SkToU16((0xD800 - 64) + (uni >> 10));
385            dst[1] = SkToU16(0xDC00 | (uni & 0x3FF));
386
387            SkASSERT(SkUTF16_IsHighSurrogate(dst[0]));
388            SkASSERT(SkUTF16_IsLowSurrogate(dst[1]));
389        } else {
390            dst[0] = SkToU16(uni);
391            SkASSERT(!SkUTF16_IsHighSurrogate(dst[0]));
392            SkASSERT(!SkUTF16_IsLowSurrogate(dst[0]));
393        }
394    }
395    return 1 + extra;
396}
397
398size_t SkUTF16_ToUTF8(const uint16_t utf16[], int numberOf16BitValues,
399                      char utf8[]) {
400    SkASSERT(numberOf16BitValues >= 0);
401    if (numberOf16BitValues <= 0) {
402        return 0;
403    }
404
405    SkASSERT(utf16 != NULL);
406
407    const uint16_t* stop = utf16 + numberOf16BitValues;
408    size_t          size = 0;
409
410    if (utf8 == NULL) {    // just count
411        while (utf16 < stop) {
412            size += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), NULL);
413        }
414    } else {
415        char* start = utf8;
416        while (utf16 < stop) {
417            utf8 += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), utf8);
418        }
419        size = utf8 - start;
420    }
421    return size;
422}
423