Add src and linux binaries for (de)compression code

bin/src/compress.c

@@ -0,0 +1,237 @@
+#include <stdio.h>
+#include <stddef.h>
+#include <sys/stat.h>
+
+const int MAXLENGTH = 0x300;
+
+struct section {
+    int mode;
+    int length;
+    char data[2];
+    int datalength;
+};
+
+int find_duplicate(off_t loc, off_t size, char buf[], struct section *out) {
+    int i, j;
+    struct section result;
+    result.mode = 4;
+    result.length = 0;
+    for (i = 0; i < loc && i < 0x10000; i++) {
+        if (buf[i] != buf[loc]) {
+            continue;
+        }
+        for (j = 0; j < MAXLENGTH; j++) {
+            if (buf[i + j] != buf[loc + j]) {
+                break;
+            }
+        }
+        if (j > result.length) {
+            result.length = j;
+            result.data[0] = i & 0xFF;
+            result.data[1] = (i >> 8) & 0xFF;
+            result.datalength = 2;
+        }
+    }
+    if (result.length < 4) {
+        return -1;
+    }
+    *out = result;
+    return 0;
+}
+
+int find_repeat_byte(off_t loc, off_t size, char buf[], struct section *out) {
+    int i;
+    for (i = 0; i < MAXLENGTH && loc + i < size; i++) {
+        if (buf[loc + i] != buf[loc]) {
+            break;
+        }
+    }
+    if (i > 2) {
+        struct section result;
+        result.mode = 1;
+        result.length = i;
+        result.data[0] = buf[loc];
+        result.datalength = 1;
+        *out = result;
+        return 0;
+    }
+    return -1;
+}
+
+int find_repeat_word(off_t loc, off_t size, char buf[], struct section *out) {
+    int i;
+    for (i = 0; i < MAXLENGTH && loc + i + 1 < size; i += 1) {
+        if (buf[loc + i] != buf[loc + (i & 1)]) {
+            break;
+        }
+    }
+    if (i > 3) {
+        struct section result;
+        result.mode = 2;
+        result.length = i;
+        result.data[0] = buf[loc];
+        result.data[1] = buf[loc + 1];
+        result.datalength = 2;
+        *out = result;
+        return 0;
+    }
+    return -1;
+}
+
+int find_incrementing_byte(off_t loc, off_t size, char buf[], struct section *out) {
+    int i;
+    for (i = 0; i < MAXLENGTH && loc + i < size; i++) {
+        if (buf[loc] + i < i) {
+            break;
+        }
+        if (buf[loc + i] != buf[loc] + i) {
+            break;
+        }
+    }
+    if (i > 2) {
+        struct section result;
+        result.mode = 3;
+        result.length = i;
+        result.data[0] = buf[loc];
+        result.datalength = 1;
+        *out = result;
+        return 0;
+    }
+    return -1;
+}
+
+int get_section(off_t loc, off_t size, char buf[], struct section *out) {
+    struct section best, current;
+    best.length = 0;
+    if (!find_repeat_byte(loc, size, buf, &current)) {
+        if (current.length > best.length) {
+            best = current;
+        }
+    }
+    if (!find_repeat_word(loc, size, buf, &current)) {
+        if (current.length > best.length) {
+            best = current;
+        }
+    }
+    if (!find_incrementing_byte(loc, size, buf, &current)) {
+        if (current.length > best.length) {
+            best = current;
+        }
+    }
+    if (!find_duplicate(loc, size, buf, &current)) {
+        if (current.length > best.length) {
+            best = current;
+        }
+    }
+    if (best.length > 0) {
+        // printf("byte %06X: mode %d length %02X\n", loc, best.mode, best.length);
+        *out = best;
+        return 0;
+    } else {
+        return -1;
+    }
+}
+
+int write_section(struct section section, char data[], char buf[], int loc) {
+    int nloc = loc;
+    int len = section.length - 1;
+    if (len > 0x1F) {
+      buf[nloc++] = 0xE0 | (section.mode << 2) | (len >> 8);
+      buf[nloc++] = len & 0xFF;
+    } else {
+      buf[nloc++] = (section.mode << 5) | len;
+    }
+    for (int i = 0; i < section.datalength; i++) {
+        buf[nloc++] = data[i];
+    }
+    return nloc;
+}
+
+int main(int argc, char *argv[]) {
+    if (argc < 3) {
+        printf("Usage: %s infile outfile\n", argv[0]);
+        return 1;
+    }
+
+    FILE *inptr;
+    if ((inptr = fopen(argv[1], "rb")) == NULL) {
+        printf("%s does not exist.\n", argv[1]);
+        return 1;
+    }
+
+    int fd = fileno(inptr);
+    if (fd < 0) {
+        printf("Error stating file: %s\n", argv[1]);
+        return 1;
+    }
+
+    struct stat buf;
+    if (fstat(fd, &buf) != 0) {
+        printf("Error stating file: %s\n", argv[1]);
+        return 1;
+    }
+    off_t size = buf.st_size;
+
+    char inbuf[size];
+
+    if (fread(inbuf, 1, size, inptr) < size) {
+        printf("Error reading file: %s\n", argv[1]);
+        return 1;
+    }
+
+    fclose(inptr);
+
+
+    char outbuf[size * 2];
+    char m0data[MAXLENGTH];
+
+    int oloc = 0;
+    struct section m0;
+    m0.mode = 0;
+    m0.length = 0;
+    int i;
+
+    off_t loc = 0;
+    while (loc < size) {
+        struct section section;
+        if (!get_section(loc, size, inbuf, &section)) {
+            if (m0.length > 0) {
+                m0.datalength = m0.length;
+                oloc = write_section(m0, m0data, outbuf, oloc);
+                m0.length = 0;
+            }
+            oloc = write_section(section, section.data, outbuf, oloc);
+            loc += section.length;
+        } else {
+            if (m0.length == MAXLENGTH) {
+                m0.datalength = m0.length;
+                oloc = write_section(m0, m0data, outbuf, oloc);
+                m0.length = 0;
+            }
+            m0data[m0.length++] = inbuf[loc];
+            loc += 1;
+        }
+    }
+
+    if (m0.length > 0) {
+        m0.datalength = m0.length;
+        oloc = write_section(m0, m0data, outbuf, oloc);
+        m0.length = 0;
+    }
+
+    outbuf[oloc++] = 0xFF;
+
+    FILE *outptr;
+    if ((outptr = fopen(argv[2], "wb")) == NULL) {
+        printf("Error opening file: %s\n", argv[2]);
+        return 1;
+    }
+
+    if (fwrite(outbuf, 1, oloc, outptr) < oloc) {
+        printf("Error writing to file: %s\n", argv[2]);
+        return 1;
+    }
+
+    fclose(outptr);
+    printf("Input file: %X bytes. Compressed: %X bytes.\n", size, oloc);
+}

bin/src/decompress.c

@@ -0,0 +1,145 @@
+#include <stdio.h>
+#include <stddef.h>
+#include <sys/stat.h>
+
+struct section {
+    int mode;
+    int length;
+    char data[2];
+    int datalength;
+};
+
+int read_section(char buf[], int loc, struct section *out) {
+    int nloc = loc;
+    char header = buf[nloc++];
+
+    printf("%x: ", header & 0xff);
+
+    if (header == -1) {
+      return -1;
+    }
+
+    struct section result;
+    result.data[0] = buf[loc];
+    result.datalength = 1;
+
+    if ((header & 0xE0) == 0xE0) {
+      result.mode = (header & 0x1C) >> 2;
+      result.length = (((header & 0x03) << 8) | buf[nloc++]) + 1;
+    } else {
+      result.mode = (header & 0xE0) >> 5;
+      result.length = (header & 0x1F) + 1;
+    }
+
+    printf("%d: %x\n", result.mode, result.length);
+
+    switch (result.mode) {
+      case 0:
+        result.datalength = 0;
+        break;
+      case 1:
+        result.datalength = 1;
+        break;
+      case 2:
+        result.datalength = 2;
+        break;
+      case 3:
+        result.datalength = 1;
+        break;
+      case 4:
+        result.datalength = 2;
+        break;
+    }
+
+    for (int i = 0; i < result.datalength; i++) {
+      result.data[i] = buf[nloc++];
+    }
+
+    *out = result;
+    return nloc;
+}
+
+int main(int argc, char *argv[]) {
+    if (argc < 3) {
+        printf("Usage: %s infile outfile\n", argv[0]);
+        return 1;
+    }
+
+    FILE *inptr;
+    if ((inptr = fopen(argv[1], "rb")) == NULL) {
+        printf("%s does not exist.\n", argv[1]);
+        return 1;
+    }
+
+    int fd = fileno(inptr);
+    if (fd < 0) {
+        printf("Error stating file: %s\n", argv[1]);
+        return 1;
+    }
+
+    struct stat buf;
+    if (fstat(fd, &buf) != 0) {
+        printf("Error stating file: %s\n", argv[1]);
+        return 1;
+    }
+    off_t size = buf.st_size;
+
+    char inbuf[size];
+
+    if (fread(inbuf, 1, size, inptr) < size) {
+        printf("Error reading file: %s\n", argv[1]);
+        return 1;
+    }
+
+    fclose(inptr);
+
+    char outbuf[size * 256];
+
+    int oloc = 0;
+    struct section section;
+    int i;
+
+    off_t loc = 0;
+
+    while ((loc = read_section(inbuf, loc, &section)) >= 0) {
+      if (section.mode == 0) {
+        for (i = 0; i < section.length; i++) {
+          outbuf[oloc++] = inbuf[loc++];
+        }
+      } else if (section.mode == 1) {
+        for (i = 0; i < section.length; i++) {
+          outbuf[oloc++] = section.data[0];
+        }
+      } else if (section.mode == 2) {
+        for (i = 0; i < section.length; i++) {
+          outbuf[oloc++] = section.data[0];
+          if (++i < section.length) {
+            outbuf[oloc++] = section.data[1];
+          }
+        }
+      } else if (section.mode == 3) {
+        for (i = 0; i < section.length; i++) {
+          outbuf[oloc++] = (section.data[0] + i) & 0xff;
+        }
+      } else if (section.mode == 4) {
+        int offset = section.data[0] | (section.data[1] << 8);
+        for (i = 0; i < section.length; i++) {
+          outbuf[oloc++] = outbuf[offset + i];
+        }
+      }
+    }
+
+    FILE *outptr;
+    if ((outptr = fopen(argv[2], "wb")) == NULL) {
+        printf("Error opening file: %s\n", argv[2]);
+        return 1;
+    }
+
+    if (fwrite(outbuf, 1, oloc, outptr) < oloc) {
+        printf("Error writing to file: %s\n", argv[2]);
+        return 1;
+    }
+
+    fclose(outptr);
+    printf("Input file: %X bytes. Decompressed: %X bytes.\n", size, oloc);
+}