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      1 /*
      2  * Copyright 2011 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "SkData.h"
      9 #include "SkFlattenableBuffers.h"
     10 #include "SkOSFile.h"
     11 #include "SkOnce.h"
     12 
     13 SkData::SkData(const void* ptr, size_t size, ReleaseProc proc, void* context) {
     14     fPtr = ptr;
     15     fSize = size;
     16     fReleaseProc = proc;
     17     fReleaseProcContext = context;
     18 }
     19 
     20 SkData::~SkData() {
     21     if (fReleaseProc) {
     22         fReleaseProc(fPtr, fSize, fReleaseProcContext);
     23     }
     24 }
     25 
     26 bool SkData::equals(const SkData* other) const {
     27     if (NULL == other) {
     28         return false;
     29     }
     30 
     31     return fSize == other->fSize && !memcmp(fPtr, other->fPtr, fSize);
     32 }
     33 
     34 size_t SkData::copyRange(size_t offset, size_t length, void* buffer) const {
     35     size_t available = fSize;
     36     if (offset >= available || 0 == length) {
     37         return 0;
     38     }
     39     available -= offset;
     40     if (length > available) {
     41         length = available;
     42     }
     43     SkASSERT(length > 0);
     44 
     45     memcpy(buffer, this->bytes() + offset, length);
     46     return length;
     47 }
     48 
     49 ///////////////////////////////////////////////////////////////////////////////
     50 
     51 void SkData::NewEmptyImpl(SkData** empty) {
     52     *empty = new SkData(NULL, 0, NULL, NULL);
     53 }
     54 
     55 SkData* SkData::NewEmpty() {
     56     static SkData* gEmptyRef;
     57     SK_DECLARE_STATIC_ONCE(once);
     58     SkOnce(&once, SkData::NewEmptyImpl, &gEmptyRef);
     59     gEmptyRef->ref();
     60     return gEmptyRef;
     61 }
     62 
     63 // assumes fPtr was allocated via sk_malloc
     64 static void sk_free_releaseproc(const void* ptr, size_t, void*) {
     65     sk_free((void*)ptr);
     66 }
     67 
     68 SkData* SkData::NewFromMalloc(const void* data, size_t length) {
     69     return new SkData(data, length, sk_free_releaseproc, NULL);
     70 }
     71 
     72 SkData* SkData::NewWithCopy(const void* data, size_t length) {
     73     if (0 == length) {
     74         return SkData::NewEmpty();
     75     }
     76 
     77     void* copy = sk_malloc_throw(length); // balanced in sk_free_releaseproc
     78     memcpy(copy, data, length);
     79     return new SkData(copy, length, sk_free_releaseproc, NULL);
     80 }
     81 
     82 SkData* SkData::NewWithProc(const void* data, size_t length,
     83                             ReleaseProc proc, void* context) {
     84     return new SkData(data, length, proc, context);
     85 }
     86 
     87 // assumes fPtr was allocated with sk_fmmap
     88 static void sk_mmap_releaseproc(const void* addr, size_t length, void*) {
     89     sk_fmunmap(addr, length);
     90 }
     91 
     92 SkData* SkData::NewFromFILE(SkFILE* f) {
     93     size_t size;
     94     void* addr = sk_fmmap(f, &size);
     95     if (NULL == addr) {
     96         return NULL;
     97     }
     98 
     99     return SkData::NewWithProc(addr, size, sk_mmap_releaseproc, NULL);
    100 }
    101 
    102 SkData* SkData::NewFromFileName(const char path[]) {
    103     SkFILE* f = path ? sk_fopen(path, kRead_SkFILE_Flag) : NULL;
    104     if (NULL == f) {
    105         return NULL;
    106     }
    107     SkData* data = NewFromFILE(f);
    108     sk_fclose(f);
    109     return data;
    110 }
    111 
    112 SkData* SkData::NewFromFD(int fd) {
    113     size_t size;
    114     void* addr = sk_fdmmap(fd, &size);
    115     if (NULL == addr) {
    116         return NULL;
    117     }
    118 
    119     return SkData::NewWithProc(addr, size, sk_mmap_releaseproc, NULL);
    120 }
    121 
    122 // assumes context is a SkData
    123 static void sk_dataref_releaseproc(const void*, size_t, void* context) {
    124     SkData* src = reinterpret_cast<SkData*>(context);
    125     src->unref();
    126 }
    127 
    128 SkData* SkData::NewSubset(const SkData* src, size_t offset, size_t length) {
    129     /*
    130         We could, if we wanted/need to, just make a deep copy of src's data,
    131         rather than referencing it. This would duplicate the storage (of the
    132         subset amount) but would possibly allow src to go out of scope sooner.
    133      */
    134 
    135     size_t available = src->size();
    136     if (offset >= available || 0 == length) {
    137         return SkData::NewEmpty();
    138     }
    139     available -= offset;
    140     if (length > available) {
    141         length = available;
    142     }
    143     SkASSERT(length > 0);
    144 
    145     src->ref(); // this will be balanced in sk_dataref_releaseproc
    146     return new SkData(src->bytes() + offset, length, sk_dataref_releaseproc,
    147                          const_cast<SkData*>(src));
    148 }
    149 
    150 SkData* SkData::NewWithCString(const char cstr[]) {
    151     size_t size;
    152     if (NULL == cstr) {
    153         cstr = "";
    154         size = 1;
    155     } else {
    156         size = strlen(cstr) + 1;
    157     }
    158     return NewWithCopy(cstr, size);
    159 }
    160