comparison: src/buffer.c
src/buffer.c
- changeset 1516
- 95b094472e9a
- parent 1515
- f024313c08f1
equal
deleted
inserted
replaced
| 1515:f024313c08f1 | 1516:95b094472e9a |
|---|---|
| 259 } else { | 259 } else { |
| 260 return -1; // LCOV_EXCL_LINE | 260 return -1; // LCOV_EXCL_LINE |
| 261 } | 261 } |
| 262 } | 262 } |
| 263 | 263 |
| 264 int cxBufferMinimumCapacity(CxBuffer *buffer, size_t newcap) { | 264 static size_t cx_buffer_calculate_minimum_capacity(size_t mincap) { |
| 265 if (newcap <= buffer->capacity) { | |
| 266 return 0; | |
| 267 } | |
| 268 | |
| 269 unsigned long pagesize = system_page_size(); | 265 unsigned long pagesize = system_page_size(); |
| 270 // if page size is larger than 64 KB - for some reason - truncate to 64 KB | 266 // if page size is larger than 64 KB - for some reason - truncate to 64 KB |
| 271 if (pagesize > 65536) pagesize = 65536; | 267 if (pagesize > 65536) pagesize = 65536; |
| 272 if (newcap < pagesize) { | 268 if (mincap < pagesize) { |
| 273 // when smaller as one page, map to the next power of two | 269 // when smaller as one page, map to the next power of two |
| 274 newcap--; | 270 mincap--; |
| 275 newcap |= newcap >> 1; | 271 mincap |= mincap >> 1; |
| 276 newcap |= newcap >> 2; | 272 mincap |= mincap >> 2; |
| 277 newcap |= newcap >> 4; | 273 mincap |= mincap >> 4; |
| 278 // last operation only needed for pages larger 4096 bytes | 274 // last operation only needed for pages larger 4096 bytes |
| 279 // but if/else would be more expensive than just doing this | 275 // but if/else would be more expensive than just doing this |
| 280 newcap |= newcap >> 8; | 276 mincap |= mincap >> 8; |
| 281 newcap++; | 277 mincap++; |
| 282 } else { | 278 } else { |
| 283 // otherwise, map to a multiple of the page size | 279 // otherwise, map to a multiple of the page size |
| 284 newcap -= newcap % pagesize; | 280 mincap -= mincap % pagesize; |
| 285 newcap += pagesize; | 281 mincap += pagesize; |
| 286 // note: if newcap is already page aligned, | 282 // note: if newcap is already page aligned, |
| 287 // this gives a full additional page (which is good) | 283 // this gives a full additional page (which is good) |
| 288 } | 284 } |
| 289 | 285 return mincap; |
| 286 } | |
| 287 | |
| 288 int cxBufferMinimumCapacity(CxBuffer *buffer, size_t newcap) { | |
| 289 if (newcap <= buffer->capacity) { | |
| 290 return 0; | |
| 291 } | |
| 292 newcap = cx_buffer_calculate_minimum_capacity(newcap); | |
| 290 return cxBufferReserve(buffer, newcap); | 293 return cxBufferReserve(buffer, newcap); |
| 291 } | 294 } |
| 292 | 295 |
| 293 void cxBufferShrink( | 296 void cxBufferShrink( |
| 294 CxBuffer *buffer, | 297 CxBuffer *buffer, |
| 390 | 393 |
| 391 size_t required = buffer->pos + len; | 394 size_t required = buffer->pos + len; |
| 392 bool perform_flush = false; | 395 bool perform_flush = false; |
| 393 if (required > buffer->capacity) { | 396 if (required > buffer->capacity) { |
| 394 if (buffer->flags & CX_BUFFER_AUTO_EXTEND) { | 397 if (buffer->flags & CX_BUFFER_AUTO_EXTEND) { |
| 395 if (buffer->flush != NULL && required > buffer->flush->threshold) { | 398 if (buffer->flush != NULL) { |
| 396 perform_flush = true; | 399 size_t newcap = cx_buffer_calculate_minimum_capacity(required); |
| 400 if (newcap > buffer->flush->threshold) { | |
| 401 newcap = buffer->flush->threshold; | |
| 402 } | |
| 403 if (cxBufferReserve(buffer, newcap)) { | |
| 404 return total_flushed; // LCOV_EXCL_LINE | |
| 405 } | |
| 406 if (required > newcap) { | |
| 407 perform_flush = true; | |
| 408 } | |
| 397 } else { | 409 } else { |
| 398 if (cxBufferMinimumCapacity(buffer, required)) { | 410 if (cxBufferMinimumCapacity(buffer, required)) { |
| 399 return total_flushed; // LCOV_EXCL_LINE | 411 return total_flushed; // LCOV_EXCL_LINE |
| 400 } | 412 } |
| 401 } | 413 } |
