157 |
157 |
158 |
158 |
159 /*! HUF_readStats() : |
159 /*! HUF_readStats() : |
160 Read compact Huffman tree, saved by HUF_writeCTable(). |
160 Read compact Huffman tree, saved by HUF_writeCTable(). |
161 `huffWeight` is destination buffer. |
161 `huffWeight` is destination buffer. |
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162 `rankStats` is assumed to be a table of at least HUF_TABLELOG_MAX U32. |
162 @return : size read from `src` , or an error Code . |
163 @return : size read from `src` , or an error Code . |
163 Note : Needed by HUF_readCTable() and HUF_readDTableX?() . |
164 Note : Needed by HUF_readCTable() and HUF_readDTableX?() . |
164 */ |
165 */ |
165 size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, |
166 size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats, |
166 U32* nbSymbolsPtr, U32* tableLogPtr, |
167 U32* nbSymbolsPtr, U32* tableLogPtr, |
185 for (n=0; n<oSize; n+=2) { |
186 for (n=0; n<oSize; n+=2) { |
186 huffWeight[n] = ip[n/2] >> 4; |
187 huffWeight[n] = ip[n/2] >> 4; |
187 huffWeight[n+1] = ip[n/2] & 15; |
188 huffWeight[n+1] = ip[n/2] & 15; |
188 } } } |
189 } } } |
189 else { /* header compressed with FSE (normal case) */ |
190 else { /* header compressed with FSE (normal case) */ |
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191 FSE_DTable fseWorkspace[FSE_DTABLE_SIZE_U32(6)]; /* 6 is max possible tableLog for HUF header (maybe even 5, to be tested) */ |
190 if (iSize+1 > srcSize) return ERROR(srcSize_wrong); |
192 if (iSize+1 > srcSize) return ERROR(srcSize_wrong); |
191 oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize); /* max (hwSize-1) values decoded, as last one is implied */ |
193 oSize = FSE_decompress_wksp(huffWeight, hwSize-1, ip+1, iSize, fseWorkspace, 6); /* max (hwSize-1) values decoded, as last one is implied */ |
192 if (FSE_isError(oSize)) return oSize; |
194 if (FSE_isError(oSize)) return oSize; |
193 } |
195 } |
194 |
196 |
195 /* collect weight stats */ |
197 /* collect weight stats */ |
196 memset(rankStats, 0, (HUF_TABLELOG_ABSOLUTEMAX + 1) * sizeof(U32)); |
198 memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32)); |
197 weightTotal = 0; |
199 weightTotal = 0; |
198 { U32 n; for (n=0; n<oSize; n++) { |
200 { U32 n; for (n=0; n<oSize; n++) { |
199 if (huffWeight[n] >= HUF_TABLELOG_ABSOLUTEMAX) return ERROR(corruption_detected); |
201 if (huffWeight[n] >= HUF_TABLELOG_MAX) return ERROR(corruption_detected); |
200 rankStats[huffWeight[n]]++; |
202 rankStats[huffWeight[n]]++; |
201 weightTotal += (1 << huffWeight[n]) >> 1; |
203 weightTotal += (1 << huffWeight[n]) >> 1; |
202 } } |
204 } } |
203 if (weightTotal == 0) return ERROR(corruption_detected); |
205 if (weightTotal == 0) return ERROR(corruption_detected); |
204 |
206 |
205 /* get last non-null symbol weight (implied, total must be 2^n) */ |
207 /* get last non-null symbol weight (implied, total must be 2^n) */ |
206 { U32 const tableLog = BIT_highbit32(weightTotal) + 1; |
208 { U32 const tableLog = BIT_highbit32(weightTotal) + 1; |
207 if (tableLog > HUF_TABLELOG_ABSOLUTEMAX) return ERROR(corruption_detected); |
209 if (tableLog > HUF_TABLELOG_MAX) return ERROR(corruption_detected); |
208 *tableLogPtr = tableLog; |
210 *tableLogPtr = tableLog; |
209 /* determine last weight */ |
211 /* determine last weight */ |
210 { U32 const total = 1 << tableLog; |
212 { U32 const total = 1 << tableLog; |
211 U32 const rest = total - weightTotal; |
213 U32 const rest = total - weightTotal; |
212 U32 const verif = 1 << BIT_highbit32(rest); |
214 U32 const verif = 1 << BIT_highbit32(rest); |