SkUtils.cpp revision 05d1cc23ec8c7c4befa039330c48901f9ff1251c 
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 "SkOnce.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 void choose_memset16(SkMemset16Proc* proc) {
117    *proc = SkMemset16GetPlatformProc();
118    if (NULL == *proc) {
119        *proc = &sk_memset16_portable;
120    }
121}
122
123void sk_memset16(uint16_t dst[], uint16_t value, int count) {
124    SK_DECLARE_STATIC_ONCE(once);
125    static SkMemset16Proc proc = NULL;
126    SkOnce(&once, choose_memset16, &proc);
127    SkASSERT(proc != NULL);
128
129    return proc(dst, value, count);
130}
131
132static void choose_memset32(SkMemset32Proc* proc) {
133    *proc = SkMemset32GetPlatformProc();
134    if (NULL == *proc) {
135        *proc = &sk_memset32_portable;
136    }
137}
138
139void sk_memset32(uint32_t dst[], uint32_t value, int count) {
140    SK_DECLARE_STATIC_ONCE(once);
141    static SkMemset32Proc proc = NULL;
142    SkOnce(&once, choose_memset32, &proc);
143    SkASSERT(proc != NULL);
144
145    return proc(dst, value, count);
146}
147
148static void choose_memcpy32(SkMemcpy32Proc* proc) {
149    *proc = SkMemcpy32GetPlatformProc();
150    if (NULL == *proc) {
151        *proc = &sk_memcpy32_portable;
152    }
153}
154
155void sk_memcpy32(uint32_t dst[], const uint32_t src[], int count) {
156    SK_DECLARE_STATIC_ONCE(once);
157    static SkMemcpy32Proc proc = NULL;
158    SkOnce(&once, choose_memcpy32, &proc);
159    SkASSERT(proc != NULL);
160
161    return proc(dst, src, count);
162}
163
164///////////////////////////////////////////////////////////////////////////////
165
166/*  0xxxxxxx    1 total
167    10xxxxxx    // never a leading byte
168    110xxxxx    2 total
169    1110xxxx    3 total
170    11110xxx    4 total
171
172    11 10 01 01 xx xx xx xx 0...
173    0xE5XX0000
174    0xE5 << 24
175*/
176
177#ifdef SK_DEBUG
178    static void assert_utf8_leadingbyte(unsigned c) {
179        SkASSERT(c <= 0xF7);    // otherwise leading byte is too big (more than 4 bytes)
180        SkASSERT((c & 0xC0) != 0x80);   // can't begin with a middle char
181    }
182
183    int SkUTF8_LeadByteToCount(unsigned c) {
184        assert_utf8_leadingbyte(c);
185        return (((0xE5 << 24) >> (c >> 4 << 1)) & 3) + 1;
186    }
187#else
188    #define assert_utf8_leadingbyte(c)
189#endif
190
191int SkUTF8_CountUnichars(const char utf8[]) {
192    SkASSERT(utf8);
193
194    int count = 0;
195
196    for (;;) {
197        int c = *(const uint8_t*)utf8;
198        if (c == 0) {
199            break;
200        }
201        utf8 += SkUTF8_LeadByteToCount(c);
202        count += 1;
203    }
204    return count;
205}
206
207int SkUTF8_CountUnichars(const char utf8[], size_t byteLength) {
208    SkASSERT(NULL != utf8 || 0 == byteLength);
209
210    int         count = 0;
211    const char* stop = utf8 + byteLength;
212
213    while (utf8 < stop) {
214        utf8 += SkUTF8_LeadByteToCount(*(const uint8_t*)utf8);
215        count += 1;
216    }
217    return count;
218}
219
220SkUnichar SkUTF8_ToUnichar(const char utf8[]) {
221    SkASSERT(NULL != utf8);
222
223    const uint8_t*  p = (const uint8_t*)utf8;
224    int             c = *p;
225    int             hic = c << 24;
226
227    assert_utf8_leadingbyte(c);
228
229    if (hic < 0) {
230        uint32_t mask = (uint32_t)~0x3F;
231        hic <<= 1;
232        do {
233            c = (c << 6) | (*++p & 0x3F);
234            mask <<= 5;
235        } while ((hic <<= 1) < 0);
236        c &= ~mask;
237    }
238    return c;
239}
240
241SkUnichar SkUTF8_NextUnichar(const char** ptr) {
242    SkASSERT(NULL != ptr && NULL != *ptr);
243
244    const uint8_t*  p = (const uint8_t*)*ptr;
245    int             c = *p;
246    int             hic = c << 24;
247
248    assert_utf8_leadingbyte(c);
249
250    if (hic < 0) {
251        uint32_t mask = (uint32_t)~0x3F;
252        hic <<= 1;
253        do {
254            c = (c << 6) | (*++p & 0x3F);
255            mask <<= 5;
256        } while ((hic <<= 1) < 0);
257        c &= ~mask;
258    }
259    *ptr = (char*)p + 1;
260    return c;
261}
262
263SkUnichar SkUTF8_PrevUnichar(const char** ptr) {
264    SkASSERT(NULL != ptr && NULL != *ptr);
265
266    const char* p = *ptr;
267
268    if (*--p & 0x80) {
269        while (*--p & 0x40) {
270            ;
271        }
272    }
273
274    *ptr = (char*)p;
275    return SkUTF8_NextUnichar(&p);
276}
277
278size_t SkUTF8_FromUnichar(SkUnichar uni, char utf8[]) {
279    if ((uint32_t)uni > 0x10FFFF) {
280        SkDEBUGFAIL("bad unichar");
281        return 0;
282    }
283
284    if (uni <= 127) {
285        if (utf8) {
286            *utf8 = (char)uni;
287        }
288        return 1;
289    }
290
291    char    tmp[4];
292    char*   p = tmp;
293    size_t  count = 1;
294
295    SkDEBUGCODE(SkUnichar orig = uni;)
296
297    while (uni > 0x7F >> count) {
298        *p++ = (char)(0x80 | (uni & 0x3F));
299        uni >>= 6;
300        count += 1;
301    }
302
303    if (utf8) {
304        p = tmp;
305        utf8 += count;
306        while (p < tmp + count - 1) {
307            *--utf8 = *p++;
308        }
309        *--utf8 = (char)(~(0xFF >> count) | uni);
310    }
311
312    SkASSERT(utf8 == NULL || orig == SkUTF8_ToUnichar(utf8));
313    return count;
314}
315
316///////////////////////////////////////////////////////////////////////////////
317
318int SkUTF16_CountUnichars(const uint16_t src[]) {
319    SkASSERT(src);
320
321    int count = 0;
322    unsigned c;
323    while ((c = *src++) != 0) {
324        SkASSERT(!SkUTF16_IsLowSurrogate(c));
325        if (SkUTF16_IsHighSurrogate(c)) {
326            c = *src++;
327            SkASSERT(SkUTF16_IsLowSurrogate(c));
328        }
329        count += 1;
330    }
331    return count;
332}
333
334int SkUTF16_CountUnichars(const uint16_t src[], int numberOf16BitValues) {
335    SkASSERT(src);
336
337    const uint16_t* stop = src + numberOf16BitValues;
338    int count = 0;
339    while (src < stop) {
340        unsigned c = *src++;
341        SkASSERT(!SkUTF16_IsLowSurrogate(c));
342        if (SkUTF16_IsHighSurrogate(c)) {
343            SkASSERT(src < stop);
344            c = *src++;
345            SkASSERT(SkUTF16_IsLowSurrogate(c));
346        }
347        count += 1;
348    }
349    return count;
350}
351
352SkUnichar SkUTF16_NextUnichar(const uint16_t** srcPtr) {
353    SkASSERT(srcPtr && *srcPtr);
354
355    const uint16_t* src = *srcPtr;
356    SkUnichar       c = *src++;
357
358    SkASSERT(!SkUTF16_IsLowSurrogate(c));
359    if (SkUTF16_IsHighSurrogate(c)) {
360        unsigned c2 = *src++;
361        SkASSERT(SkUTF16_IsLowSurrogate(c2));
362
363        // c = ((c & 0x3FF) << 10) + (c2 & 0x3FF) + 0x10000
364        // c = (((c & 0x3FF) + 64) << 10) + (c2 & 0x3FF)
365        c = (c << 10) + c2 + (0x10000 - (0xD800 << 10) - 0xDC00);
366    }
367    *srcPtr = src;
368    return c;
369}
370
371SkUnichar SkUTF16_PrevUnichar(const uint16_t** srcPtr) {
372    SkASSERT(srcPtr && *srcPtr);
373
374    const uint16_t* src = *srcPtr;
375    SkUnichar       c = *--src;
376
377    SkASSERT(!SkUTF16_IsHighSurrogate(c));
378    if (SkUTF16_IsLowSurrogate(c)) {
379        unsigned c2 = *--src;
380        SkASSERT(SkUTF16_IsHighSurrogate(c2));
381        c = (c2 << 10) + c + (0x10000 - (0xD800 << 10) - 0xDC00);
382    }
383    *srcPtr = src;
384    return c;
385}
386
387size_t SkUTF16_FromUnichar(SkUnichar uni, uint16_t dst[]) {
388    SkASSERT((unsigned)uni <= 0x10FFFF);
389
390    int extra = (uni > 0xFFFF);
391
392    if (dst) {
393        if (extra) {
394            // dst[0] = SkToU16(0xD800 | ((uni - 0x10000) >> 10));
395            // dst[0] = SkToU16(0xD800 | ((uni >> 10) - 64));
396            dst[0] = SkToU16((0xD800 - 64) + (uni >> 10));
397            dst[1] = SkToU16(0xDC00 | (uni & 0x3FF));
398
399            SkASSERT(SkUTF16_IsHighSurrogate(dst[0]));
400            SkASSERT(SkUTF16_IsLowSurrogate(dst[1]));
401        } else {
402            dst[0] = SkToU16(uni);
403            SkASSERT(!SkUTF16_IsHighSurrogate(dst[0]));
404            SkASSERT(!SkUTF16_IsLowSurrogate(dst[0]));
405        }
406    }
407    return 1 + extra;
408}
409
410size_t SkUTF16_ToUTF8(const uint16_t utf16[], int numberOf16BitValues,
411                      char utf8[]) {
412    SkASSERT(numberOf16BitValues >= 0);
413    if (numberOf16BitValues <= 0) {
414        return 0;
415    }
416
417    SkASSERT(utf16 != NULL);
418
419    const uint16_t* stop = utf16 + numberOf16BitValues;
420    size_t          size = 0;
421
422    if (utf8 == NULL) {    // just count
423        while (utf16 < stop) {
424            size += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), NULL);
425        }
426    } else {
427        char* start = utf8;
428        while (utf16 < stop) {
429            utf8 += SkUTF8_FromUnichar(SkUTF16_NextUnichar(&utf16), utf8);
430        }
431        size = utf8 - start;
432    }
433    return size;
434}
435