79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
#include <assert.h>
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#include "parser_internal.h"
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struct bits_env {
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uint8_t length;
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uint8_t signedp;
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};
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static HParseResult* parse_bits(void* env, HParseState *state) {
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struct bits_env *env_ = env;
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HParsedToken *result = a_new(HParsedToken, 1);
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result->token_type = (env_->signedp ? TT_SINT : TT_UINT);
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if (env_->signedp)
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result->sint = h_read_bits(&state->input_stream, env_->length, true);
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else
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result->uint = h_read_bits(&state->input_stream, env_->length, false);
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return make_result(state, result);
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}
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static bool h_svm_action_bits(HArena *arena, HSVMContext *ctx, void* env) {
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// BUG: relies un undefined behaviour: int64_t is a signed uint64_t; not necessarily true on 32-bit
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struct bits_env *env_ = env;
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HParsedToken *top = ctx->stack[ctx->stack_count-1];
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assert(top->token_type == TT_BYTES);
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uint64_t res = 0;
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for (size_t i = 0; i < top->bytes.len; i++)
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res = (res << 8) | top->bytes.token[i]; // TODO: Handle other endiannesses.
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top->uint = res; // possibly cast to signed through union
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top->token_type = (env_->signedp ? TT_SINT : TT_UINT);
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return true;
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}
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static bool bits_ctrvm(HRVMProg *prog, void* env) {
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struct bits_env *env_ = (struct bits_env*)env;
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h_rvm_insert_insn(prog, RVM_PUSH, 0);
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for (size_t i=0; (i < env_->length)/8; ++i) { // FUTURE: when we can handle non-byte-aligned, the env_->length/8 part will be different
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h_rvm_insert_insn(prog, RVM_MATCH, 0xFF00);
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h_rvm_insert_insn(prog, RVM_STEP, 0);
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}
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h_rvm_insert_insn(prog, RVM_CAPTURE, 0);
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h_rvm_insert_insn(prog, RVM_ACTION, h_rvm_create_action(prog, h_svm_action_bits, env));
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return true;
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}
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static const HParserVtable bits_vt = {
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.parse = parse_bits,
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.isValidRegular = h_true,
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.isValidCF = h_true,
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.compile_to_rvm = bits_ctrvm,
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};
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HParser* h_bits(size_t len, bool sign) {
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return h_bits__m(&system_allocator, len, sign);
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}
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HParser* h_bits__m(HAllocator* mm__, size_t len, bool sign) {
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struct bits_env *env = h_new(struct bits_env, 1);
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env->length = len;
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env->signedp = sign;
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HParser *res = h_new(HParser, 1);
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res->vtable = &bits_vt;
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res->env = env;
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return res;
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}
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#define SIZED_BITS(name_pre, len, signedp) \
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HParser* h_##name_pre##len () { \
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return h_bits__m(&system_allocator, len, signedp); \
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} \
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HParser* h_##name_pre##len##__m(HAllocator* mm__) { \
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return h_bits__m(mm__, len, signedp); \
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}
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SIZED_BITS(int, 8, true)
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SIZED_BITS(int, 16, true)
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SIZED_BITS(int, 32, true)
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SIZED_BITS(int, 64, true)
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SIZED_BITS(uint, 8, false)
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SIZED_BITS(uint, 16, false)
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SIZED_BITS(uint, 32, false)
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SIZED_BITS(uint, 64, false)
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