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comparison tools/lib64gfx.c @ 1542:69fa95707e65

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Implement dmGenericRLEAnalyze() and use it where appropriate.
author Matti Hamalainen <ccr@tnsp.org>
date Sat, 12 May 2018 05:31:40 +0300
parents 776aa43b2c57
children 20cd589366d7
comparison
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1541:203e00a4dfc0 1542:69fa95707e65
242 } 242 }
243 243
244 244
245 void dmGenericRLEAnalyze(const DMGrowBuf *buf, Uint8 *rleMarker, const int rleType) 245 void dmGenericRLEAnalyze(const DMGrowBuf *buf, Uint8 *rleMarker, const int rleType)
246 { 246 {
247 247 #define DM_STAT_MAX 256
248 size_t *stats;
249
250 // Allocate statistics counts buffer
251 if ((stats = dmMalloc0(DM_STAT_MAX * sizeof(size_t))) == NULL)
252 return;
253
254 // Get statistics on the data
255 for (size_t offs = 0; offs < buf->len; offs++)
256 stats[buf->data[offs]]++;
257
258 // According to compression type ..
259 if (rleType == DM_COMP_RLE_MARKER)
260 {
261 size_t selected = 0,
262 smallest = buf->len;
263
264 // Find least used byte value
265 for (size_t n = 0; n < DM_STAT_MAX; n++)
266 {
267 if (stats[n] < smallest)
268 {
269 selected = n;
270 smallest = stats[n];
271 }
272 }
273
274 *rleMarker = selected;
275 }
276 else
277 *rleMarker = 0xC0;
278
279 dmFree(stats);
248 } 280 }
249 281
250 282
251 int dmDecodeGenericRLE(DMGrowBuf *dst, const Uint8 *src, const Uint8 *srcEnd, const DMCompParams *cfg) 283 int dmDecodeGenericRLE(DMGrowBuf *dst, const Uint8 *src, const Uint8 *srcEnd, const DMCompParams *cfg)
252 { 284 {