Deduplicate code

2017-07-24 12:40:59 -07:00
parent 8ed9220102
commit 6eefa32911
6 changed files with 153 additions and 452 deletions
@@ -0,0 +1,113 @@
+#include <stdio.h>
+
+#include "ldm.h"
+
+void LDM_outputConfiguration(void) {
+  printf("=====================\n");
+  printf("Configuration\n");
+  printf("LDM_WINDOW_SIZE_LOG: %d\n", LDM_WINDOW_SIZE_LOG);
+  printf("LDM_MIN_MATCH_LENGTH, LDM_HASH_LENGTH: %d, %d\n",
+         LDM_MIN_MATCH_LENGTH, LDM_HASH_LENGTH);
+  printf("LDM_MEMORY_USAGE: %d\n", LDM_MEMORY_USAGE);
+  printf("HASH_ONLY_EVERY_LOG: %d\n", HASH_ONLY_EVERY_LOG);
+  printf("HASH_BUCKET_SIZE_LOG: %d\n", HASH_BUCKET_SIZE_LOG);
+  printf("LDM_LAG %d\n", LDM_LAG);
+  printf("=====================\n");
+}
+
+void LDM_readHeader(const void *src, U64 *compressedSize,
+                    U64 *decompressedSize) {
+  const BYTE *ip = (const BYTE *)src;
+  *compressedSize = MEM_readLE64(ip);
+  ip += sizeof(U64);
+  *decompressedSize = MEM_readLE64(ip);
+  // ip += sizeof(U64);
+}
+
+void LDM_writeHeader(void *memPtr, U64 compressedSize,
+                     U64 decompressedSize) {
+  MEM_write64(memPtr, compressedSize);
+  MEM_write64((BYTE *)memPtr + 8, decompressedSize);
+}
+
+struct LDM_DCtx {
+  size_t compressedSize;
+  size_t maxDecompressedSize;
+
+  const BYTE *ibase;   /* Base of input */
+  const BYTE *ip;      /* Current input position */
+  const BYTE *iend;    /* End of source */
+
+  const BYTE *obase;   /* Base of output */
+  BYTE *op;            /* Current output position */
+  const BYTE *oend;    /* End of output */
+};
+
+void LDM_initializeDCtx(LDM_DCtx *dctx,
+                        const void *src, size_t compressedSize,
+                        void *dst, size_t maxDecompressedSize) {
+  dctx->compressedSize = compressedSize;
+  dctx->maxDecompressedSize = maxDecompressedSize;
+
+  dctx->ibase = src;
+  dctx->ip = (const BYTE *)src;
+  dctx->iend = dctx->ip + dctx->compressedSize;
+  dctx->op = dst;
+  dctx->oend = dctx->op + dctx->maxDecompressedSize;
+}
+
+size_t LDM_decompress(const void *src, size_t compressedSize,
+                      void *dst, size_t maxDecompressedSize) {
+
+  LDM_DCtx dctx;
+  LDM_initializeDCtx(&dctx, src, compressedSize, dst, maxDecompressedSize);
+
+  while (dctx.ip < dctx.iend) {
+    BYTE *cpy;
+    const BYTE *match;
+    size_t length, offset;
+
+    /* Get the literal length. */
+    const unsigned token = *(dctx.ip)++;
+    if ((length = (token >> ML_BITS)) == RUN_MASK) {
+      unsigned s;
+      do {
+        s = *(dctx.ip)++;
+        length += s;
+      } while (s == 255);
+    }
+
+    /* Copy the literals. */
+    cpy = dctx.op + length;
+    memcpy(dctx.op, dctx.ip, length);
+    dctx.ip += length;
+    dctx.op = cpy;
+
+    //TODO : dynamic offset size
+    offset = MEM_read32(dctx.ip);
+    dctx.ip += LDM_OFFSET_SIZE;
+    match = dctx.op - offset;
+
+    /* Get the match length. */
+    length = token & ML_MASK;
+    if (length == ML_MASK) {
+      unsigned s;
+      do {
+        s = *(dctx.ip)++;
+        length += s;
+      } while (s == 255);
+    }
+    length += LDM_MIN_MATCH_LENGTH;
+
+    /* Copy match. */
+    cpy = dctx.op + length;
+
+    // Inefficient for now.
+    while (match < cpy - offset && dctx.op < dctx.oend) {
+      *(dctx.op)++ = *match++;
+    }
+  }
+  return dctx.op - (BYTE *)dst;
+}
+
+