SkUtils.cpp revision 3fdc7d6dd13b510de09cf29ffd3fe36adf89d541 
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
116static SkMemset16Proc choose_memset16() {
117    SkMemset16Proc proc = SkMemset16GetPlatformProc();
118    return proc ? proc : sk_memset16_portable;
119}
120
121void sk_memset16(uint16_t dst[], uint16_t value, int count) {
122    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemset16Proc, choice);
123    return choice.get(choose_memset16)(dst, value, count);
124}
125
126static SkMemset32Proc choose_memset32() {
127    SkMemset32Proc proc = SkMemset32GetPlatformProc();
128    return proc ? proc : sk_memset32_portable;
129}
130
131void sk_memset32(uint32_t dst[], uint32_t value, int count) {
132    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemset32Proc, choice);
133    return choice.get(choose_memset32)(dst, value, count);
134}
135
136static SkMemcpy32Proc choose_memcpy32() {
137    SkMemcpy32Proc proc = SkMemcpy32GetPlatformProc();
138    return proc ? proc : sk_memcpy32_portable;
139}
140
141void sk_memcpy32(uint32_t dst[], const uint32_t src[], int count) {
142    SK_DECLARE_STATIC_LAZY_FN_PTR(SkMemcpy32Proc, choice);
143    return choice.get(choose_memcpy32)(dst, src, count);
144}
145
146///////////////////////////////////////////////////////////////////////////////
147
148/*  0xxxxxxx    1 total
149    10xxxxxx    // never a leading byte
150    110xxxxx    2 total
151    1110xxxx    3 total
152    11110xxx    4 total
153
154    11 10 01 01 xx xx xx xx 0...
155    0xE5XX0000
156    0xE5 << 24
157*/
158
159#ifdef SK_DEBUG
160    static void assert_utf8_leadingbyte(unsigned c) {
161        SkASSERT(c <= 0xF7);    // otherwise leading byte is too big (more than 4 bytes)
162        SkASSERT((c & 0xC0) != 0x80);   // can't begin with a middle char
163    }
164
165    int SkUTF8_LeadByteToCount(unsigned c) {
166        assert_utf8_leadingbyte(c);
167        return (((0xE5 << 24) >> (c >> 4 << 1)) & 3) + 1;
168    }
169#else
170    #define assert_utf8_leadingbyte(c)
171#endif
172
173int SkUTF8_CountUnichars(const char utf8[]) {
174    SkASSERT(utf8);
175
176    int count = 0;
177
178    for (;;) {
179        int c = *(const uint8_t*)utf8;
180        if (c == 0) {
181            break;
182        }
183        utf8 += SkUTF8_LeadByteToCount(c);
184        count += 1;
185    }
186    return count;
187}
188
189int SkUTF8_CountUnichars(const char utf8[], size_t byteLength) {
190    SkASSERT(NULL != utf8 || 0 == byteLength);
191
192    int         count = 0;
193    const char* stop = utf8 + byteLength;
194
195    while (utf8 < stop) {
196        utf8 += SkUTF8_LeadByteToCount(*(const uint8_t*)utf8);
197        count += 1;
198    }
199    return count;
200}
201
202SkUnichar SkUTF8_ToUnichar(const char utf8[]) {
203    SkASSERT(NULL != utf8);
204
205    const uint8_t*  p = (const uint8_t*)utf8;
206    int             c = *p;
207    int             hic = c << 24;
208
209    assert_utf8_leadingbyte(c);
210
211    if (hic < 0) {
212        uint32_t mask = (uint32_t)~0x3F;
213        hic <<= 1;
214        do {
215            c = (c << 6) | (*++p & 0x3F);
216            mask <<= 5;
217        } while ((hic <<= 1) < 0);
218        c &= ~mask;
219    }
220    return c;
221}
222
223SkUnichar SkUTF8_NextUnichar(const char** ptr) {
224    SkASSERT(NULL != ptr && NULL != *ptr);
225
226    const uint8_t*  p = (const uint8_t*)*ptr;
227    int             c = *p;
228    int             hic = c << 24;
229
230    assert_utf8_leadingbyte(c);
231
232    if (hic < 0) {
233        uint32_t mask = (uint32_t)~0x3F;
234        hic <<= 1;
235        do {
236            c = (c << 6) | (*++p & 0x3F);
237            mask <<= 5;
238        } while ((hic <<= 1) < 0);
239        c &= ~mask;
240    }
241    *ptr = (char*)p + 1;
242    return c;
243}
244
245SkUnichar SkUTF8_PrevUnichar(const char** ptr) {
246    SkASSERT(NULL != ptr && NULL != *ptr);
247
248    const char* p = *ptr;
249
250    if (*--p & 0x80) {
251        while (*--p & 0x40) {
252            ;
253        }
254    }
255
256    *ptr = (char*)p;
257    return SkUTF8_NextUnichar(&p);
258}
259
260size_t SkUTF8_FromUnichar(SkUnichar uni, char utf8[]) {
261    if ((uint32_t)uni > 0x10FFFF) {
262        SkDEBUGFAIL("bad unichar");
263        return 0;
264    }
265
266    if (uni <= 127) {
267        if (utf8) {
268            *utf8 = (char)uni;
269        }
270        return 1;
271    }
272
273    char    tmp[4];
274    char*   p = tmp;
275    size_t  count = 1;
276
277    SkDEBUGCODE(SkUnichar orig = uni;)
278
279    while (uni > 0x7F >> count) {
280        *p++ = (char)(0x80 | (uni & 0x3F));
281        uni >>= 6;
282        count += 1;
283    }
284
285    if (utf8) {
286        p = tmp;
287        utf8 += count;
288        while (p < tmp + count - 1) {
289            *--utf8 = *p++;
290        }
291        *--utf8 = (char)(~(0xFF >> count) | uni);
292    }
293
294    SkASSERT(utf8 == NULL || orig == SkUTF8_ToUnichar(utf8));
295    return count;
296}
297
298///////////////////////////////////////////////////////////////////////////////
299
300int SkUTF16_CountUnichars(const uint16_t src[]) {
301    SkASSERT(src);
302
303    int count = 0;
304    unsigned c;
305    while ((c = *src++) != 0) {
306        SkASSERT(!SkUTF16_IsLowSurrogate(c));
307        if (SkUTF16_IsHighSurrogate(c)) {
308            c = *src++;
309            SkASSERT(SkUTF16_IsLowSurrogate(c));
310        }
311        count += 1;
312    }
313    return count;
314}
315
316int SkUTF16_CountUnichars(const uint16_t src[], int numberOf16BitValues) {
317    SkASSERT(src);
318
319    const uint16_t* stop = src + numberOf16BitValues;
320    int count = 0;
321    while (src < stop) {
322        unsigned c = *src++;
323        SkASSERT(!SkUTF16_IsLowSurrogate(c));
324        if (SkUTF16_IsHighSurrogate(c)) {
325            SkASSERT(src < stop);
326            c = *src++;
327            SkASSERT(SkUTF16_IsLowSurrogate(c));
328        }
329        count += 1;
330    }
331    return count;
332}
333
334SkUnichar SkUTF16_NextUnichar(const uint16_t** srcPtr) {
335    SkASSERT(srcPtr && *srcPtr);
336
337    const uint16_t* src = *srcPtr;
338    SkUnichar       c = *src++;
339
340    SkASSERT(!SkUTF16_IsLowSurrogate(c));
341    if (SkUTF16_IsHighSurrogate(c)) {
342        unsigned c2 = *src++;
343        SkASSERT(SkUTF16_IsLowSurrogate(c2));
344
345        // c = ((c & 0x3FF) << 10) + (c2 & 0x3FF) + 0x10000
346        // c = (((c & 0x3FF) + 64) << 10) + (c2 & 0x3FF)
347        c = (c << 10) + c2 + (0x10000 - (0xD800 << 10) - 0xDC00);
348    }
349    *srcPtr = src;
350    return c;
351}
352
353SkUnichar SkUTF16_PrevUnichar(const uint16_t** srcPtr) {
354    SkASSERT(srcPtr && *srcPtr);
355
356    const uint16_t* src = *srcPtr;
357    SkUnichar       c = *--src;
358
359    SkASSERT(!SkUTF16_IsHighSurrogate(c));
360    if (SkUTF16_IsLowSurrogate(c)) {
361        unsigned c2 = *--src;
362        SkASSERT(SkUTF16_IsHighSurrogate(c2));
363        c = (c2 << 10) + c + (0x10000 - (0xD800 << 10) - 0xDC00);
364    }
365    *srcPtr = src;
366    return c;
367}
368
369size_t SkUTF16_FromUnichar(SkUnichar uni, uint16_t dst[]) {
370    SkASSERT((unsigned)uni <= 0x10FFFF);
371
372    int extra = (uni > 0xFFFF);
373
374    if (dst) {
375        if (extra) {
376            // dst[0] = SkToU16(0xD800 | ((uni - 0x10000) >> 10));
377            // dst[0] = SkToU16(0xD800 | ((uni >> 10) - 64));
378            dst[0] = SkToU16((0xD800 - 64) + (uni >> 10));
379            dst[1] = SkToU16(0xDC00 | (uni & 0x3FF));
380
381            SkASSERT(SkUTF16_IsHighSurrogate(dst[0]));
382            SkASSERT(SkUTF16_IsLowSurrogate(dst[1]));
383        } else {
384            dst[0] = SkToU16(uni);
385            SkASSERT(!SkUTF16_IsHighSurrogate(dst[0]));
386            SkASSERT(!SkUTF16_IsLowSurrogate(dst[0]));
387        }
388    }
389    return 1 + extra;
390}
391
392size_t SkUTF16_ToUTF8(const uint16_t utf16[], int numberOf16BitValues,
393                      char utf8[]) {
394    SkASSERT(numberOf16BitValues >= 0);
395    if (numberOf16BitValues <= 0) {
396        return 0;
397    }
398
399    SkASSERT(utf16 != NULL);
400
401    const uint16_t* stop = utf16 + numberOf16BitValues;
402    size_t          size = 0;
403
404    if (utf8 == NULL) {    // just count
405        while (utf16 < stop) {
406            size += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), NULL);
407        }
408    } else {
409        char* start = utf8;
410        while (utf16 < stop) {
411            utf8 += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), utf8);
412        }
413        size = utf8 - start;
414    }
415    return size;
416}
417