Remove BUILDFIXED and MAKEFIXED. (#375)

Remove BUILDFIXED support.
Split out MAKEFIXED into a separate 'makefixed' util that is easy
to use if we want to regenerate/verify inffixed.h.

1 files changed, 89 insertions, 0 deletions

diff --git a/tools/makefixed.c b/tools/makefixed.c
new file mode 100644
index 0000000..0f983bd
--- /dev/null
+++ b/tools/makefixed.c
@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include "zbuild.h"
+#include "zutil.h"
+#include "inftrees.h"
+#include "inflate.h"
+
+// Build and return state with length and distance decoding tables and index sizes set to fixed code decoding.
+void ZLIB_INTERNAL buildfixedtables(struct inflate_state *state) {
+    static code *lenfix, *distfix;
+    static code fixed[544];
+
+    // build fixed huffman tables
+    unsigned sym, bits;
+    static code *next;
+
+    // literal/length table
+    sym = 0;
+    while (sym < 144) state->lens[sym++] = 8;
+    while (sym < 256) state->lens[sym++] = 9;
+    while (sym < 280) state->lens[sym++] = 7;
+    while (sym < 288) state->lens[sym++] = 8;
+    next = fixed;
+    lenfix = next;
+    bits = 9;
+    zng_inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
+
+    // distance table
+    sym = 0;
+    while (sym < 32) state->lens[sym++] = 5;
+    distfix = next;
+    bits = 5;
+    zng_inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
+
+    state->lencode = lenfix;
+    state->lenbits = 9;
+    state->distcode = distfix;
+    state->distbits = 5;
+}
+
+
+//  Create fixed tables on the fly and write out a inffixed.h file that is #include'd above.
+//  makefixed() writes those tables to stdout, which would be piped to inffixed.h.
+void makefixed(void) {
+    unsigned low, size;
+    struct inflate_state state;
+
+    buildfixedtables(&state);
+    puts("    /* inffixed.h -- table for decoding fixed codes");
+    puts("     * Generated automatically by makefixed().");
+    puts("     */");
+    puts("");
+    puts("    /* WARNING: this file should *not* be used by applications.");
+    puts("       It is part of the implementation of this library and is");
+    puts("       subject to change. Applications should only use zlib.h.");
+    puts("     */");
+    puts("");
+    size = 1U << 9;
+    printf("    static const code lenfix[%u] = {", size);
+    low = 0;
+    for (;;) {
+        if ((low % 7) == 0)
+            printf("\n        ");
+        printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
+            state.lencode[low].bits, state.lencode[low].val);
+        if (++low == size)
+            break;
+        putchar(',');
+    }
+    puts("\n    };");
+    size = 1U << 5;
+    printf("\n    static const code distfix[%u] = {", size);
+    low = 0;
+    for (;;) {
+        if ((low % 6) == 0)
+            printf("\n        ");
+        printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits, state.distcode[low].val);
+        if (++low == size)
+            break;
+        putchar(',');
+    }
+    puts("\n    };");
+}
+
+// The output of this application can be piped out to recreate inffixed.h
+int main(void) {
+    makefixed();
+    return 0;
+}
+