rewrite yaz0 (de)compressor interface

z64yaz0.new.c

@@ -0,0 +1,331 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+//version 1.0 (20050707) by shevious
+//Thanks to thakis for yaz0dec 1.0.
+
+#define lament(...) fprintf(stderr, __VA_ARGS__)
+#define error_when(cond, ...) do { \
+        if ((cond) || errno) { \
+            lament(__VA_ARGS__); \
+            lament(": %s\n", strerror(errno)); \
+            goto error; \
+        } \
+    } while (0)
+
+typedef unsigned char u8;
+
+enum {
+    max_runlen = 0xFF + 0x12
+};
+
+// simple and straight encoding scheme for Yaz0
+static long
+simpleEnc(u8 *src, int size, int pos, long *pMatchPos)
+{
+    int startPos = pos - 0x1000;
+    long numBytes = 1;
+    long matchPos = 0;
+
+    int end = size - pos;
+    // maximum runlength for 3 byte encoding
+    if (end > max_runlen)
+        end = max_runlen;
+
+    if (startPos < 0)
+        startPos = 0;
+    for (int i = startPos; i < pos; i++) {
+        int j;
+        for (j = 0; j < end; j++) {
+            if (src[i + j] != src[j + pos])
+                break;
+        }
+        if (j > numBytes) {
+            numBytes = j;
+            matchPos = i;
+        }
+    }
+
+    *pMatchPos = matchPos;
+
+    if (numBytes == 2)
+        numBytes = 1;
+
+    return numBytes;
+}
+
+// a lookahead encoding scheme for ngc Yaz0
+static long
+nintendoEnc(u8 *src, int size, int pos, long *pMatchPos)
+{
+    long numBytes = 1;
+    static long numBytes1;
+    static long matchPos;
+    static int prevFlag = 0;
+
+    // if prevFlag is set, it means that the previous position
+    // was determined by look-ahead try.
+    // so just use it. this is not the best optimization,
+    // but nintendo's choice for speed.
+    if (prevFlag == 1) {
+        *pMatchPos = matchPos;
+        prevFlag = 0;
+        return numBytes1;
+    }
+
+    prevFlag = 0;
+    numBytes = simpleEnc(src, size, pos, &matchPos);
+    *pMatchPos = matchPos;
+
+    // if this position is RLE encoded, then compare to copying 1 byte and next position(pos+1) encoding
+    if (numBytes >= 3) {
+        numBytes1 = simpleEnc(src, size, pos + 1, &matchPos);
+        // if the next position encoding is +2 longer than current position, choose it.
+        // this does not guarantee the best optimization, but fairly good optimization with speed.
+        if (numBytes1 >= numBytes + 2) {
+            numBytes = 1;
+            prevFlag = 1;
+        }
+    }
+    return numBytes;
+}
+
+static int
+encodeYaz0(u8 *src, u8 *dst, int srcSize)
+{
+    int srcPos = 0;
+    int dstPos = 0;
+    int bufPos = 0;
+
+    u8 buf[24]; // 8 codes * 3 bytes maximum
+
+    long validBitCount = 0; // number of valid bits left in "code" byte
+    u8 currCodeByte = 0; // a bitfield, set bits meaning copy, unset meaning RLE
+
+    while (srcPos < srcSize) {
+        long numBytes;
+        long matchPos;
+
+        numBytes = nintendoEnc(src, srcSize, srcPos, &matchPos);
+        if (numBytes < 3) {
+            // straight copy
+            buf[bufPos] = src[srcPos];
+            bufPos++;
+            srcPos++;
+            //set flag for straight copy
+            currCodeByte |= (0x80 >> validBitCount);
+        } else {
+            //RLE part
+            long dist = srcPos - matchPos - 1;
+            u8 byte1, byte2, byte3;
+
+            if (numBytes >= 0x12) { // 3 byte encoding
+                byte1 = 0 | (dist >> 8);
+                byte2 = dist & 0xFF;
+                buf[bufPos++] = byte1;
+                buf[bufPos++] = byte2;
+                // maximum runlength for 3 byte encoding
+                if (numBytes > max_runlen)
+                    numBytes = max_runlen;
+                byte3 = numBytes - 0x12;
+                buf[bufPos++] = byte3;
+            } else { // 2 byte encoding
+                byte1 = ((numBytes - 2) << 4) | (dist >> 8);
+                byte2 = dist & 0xFF;
+                buf[bufPos++] = byte1;
+                buf[bufPos++] = byte2;
+            }
+            srcPos += numBytes;
+        }
+
+        validBitCount++;
+
+        // write eight codes
+        if (validBitCount == 8) {
+            dst[dstPos++] = currCodeByte;
+            for (int j = 0; j < bufPos; j++)
+                dst[dstPos++] = buf[j];
+
+            currCodeByte = 0;
+            validBitCount = 0;
+            bufPos = 0;
+        }
+    }
+
+    if (validBitCount > 0) {
+        dst[dstPos++] = currCodeByte;
+        for (int j = 0; j < bufPos; j++)
+            dst[dstPos++] = buf[j];
+
+        currCodeByte = 0;
+        validBitCount = 0;
+        bufPos = 0;
+    }
+
+    return dstPos;
+}
+
+static void
+decompress(u8 *src, u8 *dst, int uncompressedSize)
+{
+    int srcPlace = 0, dstPlace = 0; // current read/write positions
+
+    long validBitCount = 0; // number of valid bits left in "code" byte
+    u8 currCodeByte = 0;
+
+    while (dstPlace < uncompressedSize) {
+        // read new "code" byte if the current one is used up
+        if (validBitCount == 0) {
+            currCodeByte = src[srcPlace++];
+            validBitCount = 8;
+        }
+
+        if ((currCodeByte & 0x80) != 0) {
+            // straight copy
+            dst[dstPlace++] = src[srcPlace++];
+        } else {
+            // RLE part
+            u8 byte1 = src[srcPlace++];
+            u8 byte2 = src[srcPlace++];
+
+            long dist = ((byte1 & 0xF) << 8) | byte2;
+            long copySource = dstPlace - (dist + 1);
+
+            long numBytes = byte1 >> 4;
+            if (numBytes == 0) {
+                numBytes = src[srcPlace++] + 0x12;
+            } else {
+                numBytes += 2;
+            }
+
+            // copy run
+            for(int i = 0; i < numBytes; ++i) {
+                dst[dstPlace++] = dst[copySource++];
+            }
+        }
+
+        // use next bit from "code" byte
+        currCodeByte <<= 1;
+        validBitCount--;
+    }
+}
+
+int
+process(const char *fpi, const char *fpo)
+{
+    u8 *bufi = NULL;
+    u8 *bufo = NULL;
+    FILE *fi = NULL;
+    FILE *fo = NULL;
+    long isize;
+    long csize;
+    long outsize;
+    long i;
+
+    fi = fopen(fpi, "rb");
+    error_when(fi == NULL, "Error opening file for reading: %s", fpi);
+
+    error_when(fseek(fi, 0, SEEK_END) != 0, "Error seeking in file: %s", fpi);
+    isize = ftell(fi);
+    error_when(isize < 0, "Error telling in file: %s", fpi);
+    error_when(fseek(fi, 0, SEEK_SET) != 0, "Error seeking in file: %s", fpi);
+
+    if (isize > 0) {
+        bufi = malloc(isize);
+        error_when(bufi == NULL, "Error allocating %li bytes", isize);
+        error_when(fread(bufi, 1, isize, fi) != (size_t)isize,
+                   "Error reading %li bytes from file: %s", isize, fpi);
+    }
+
+    error_when(fclose(fi) != 0, "Error closing file: %s", fpi);
+
+    if (isize < 5) {
+        // FIXME: encodeYaz0 segfaults in this case.
+        lament("Error: input file must be at least 5 bytes.\n");
+        goto error;
+    }
+
+    if (isize > 0x10
+        && bufi[0] == 'Y'
+        && bufi[1] == 'a'
+        && bufi[2] == 'z'
+        && bufi[3] == '0') {
+        outsize = (bufi[4] << 24)
+                | (bufi[5] << 16)
+                | (bufi[6] << 8)
+                |  bufi[7];
+        bufo = malloc(outsize);
+        error_when(bufo == NULL, "Error allocating %li bytes", outsize);
+        decompress(bufi + 16, bufo, outsize);
+
+    } else {
+        // we don't know how big the "compressed" file could get,
+        // so over-allocate!
+        // modern systems have more RAM than the largest Yaz0 file, so...
+        csize = 0x10 + isize * 2;
+        bufo = malloc(csize);
+        error_when(bufo == NULL, "Error allocating %li bytes", csize);
+
+        // write 4 bytes yaz0 header
+        bufo[0] = 'Y';
+        bufo[1] = 'a';
+        bufo[2] = 'z';
+        bufo[3] = '0';
+
+        // write 4 bytes uncompressed size
+        bufo[4] = (isize >> 24) & 0xFF;
+        bufo[5] = (isize >> 16) & 0xFF;
+        bufo[6] = (isize >> 8) & 0xFF;
+        bufo[7] = (isize >> 0) & 0xFF;
+
+        // write 8 bytes unused dummy
+        bufo[8] = 0;
+        bufo[9] = 0;
+        bufo[10] = 0;
+        bufo[11] = 0;
+        bufo[12] = 0;
+        bufo[13] = 0;
+        bufo[14] = 0;
+        bufo[15] = 0;
+
+        csize = encodeYaz0(bufi, bufo + 16, isize) + 16;
+
+        // pad compressed file to be a multiple of 16 bytes.
+        outsize = (csize + 15) & ~0xF;
+        for (i = csize; i < outsize; i++) bufo[i] = 0;
+    }
+
+    fo = fopen(fpo, "wb");
+    error_when(fo == NULL, "Error opening file for writing: %s", fpo);
+    error_when(fwrite(bufo, 1, outsize, fo) != (size_t)outsize,
+               "Error writing %li bytes to file: %s", outsize, fpo);
+    error_when(fclose(fo) != 0, "Error closing file: %s", fpo);
+
+    free(bufi);
+    free(bufo);
+    return 0;
+
+error:
+    if (bufi != NULL) free(bufi);
+    if (bufo != NULL) free(bufo);
+    if (fi != NULL) fclose(fi);
+    if (fo != NULL) fclose(fo);
+    return 1;
+}
+
+int
+main(int argc, char *argv[])
+{
+    if (argc <= 0 || argv == NULL || argv[0] == NULL) {
+        lament("You've met with a terrible fate.\n");
+        return 1;
+    }
+
+    if (argc != 3) {
+        lament("usage: %s {input file} {output file}\n", argv[0]);
+        return 1;
+    }
+
+    return process(argv[1], argv[2]);
+}