static int dxv_decompress_dxt5(AVCodecContext *avctx) { DXVContext *ctx = avctx->priv_data; GetByteContext *gbc = &ctx->gbc; uint32_t value, op; int idx, prev, state = 0; int pos = 4; int run = 0; int probe, check; /* Copy the first four elements */ AV_WL32(ctx->tex_data + 0, bytestream2_get_le32(gbc)); AV_WL32(ctx->tex_data + 4, bytestream2_get_le32(gbc)); AV_WL32(ctx->tex_data + 8, bytestream2_get_le32(gbc)); AV_WL32(ctx->tex_data + 12, bytestream2_get_le32(gbc)); /* Process input until the whole texture has been filled */ while (pos + 2 <= ctx->tex_size / 4) { if (run) { run--; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; } else { if (state == 0) { value = bytestream2_get_le32(gbc); state = 16; } op = value & 0x3; value >>= 2; state--; switch (op) { case 0: /* Long copy */ check = bytestream2_get_byte(gbc) + 1; if (check == 256) { do { probe = bytestream2_get_le16(gbc); check += probe; } while (probe == 0xFFFF); } while (check && pos + 4 <= ctx->tex_size / 4) { prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; check--; } /* Restart (or exit) the loop */ continue; break; case 1: /* Load new run value */ run = bytestream2_get_byte(gbc); if (run == 255) { do { probe = bytestream2_get_le16(gbc); run += probe; } while (probe == 0xFFFF); } /* Copy two dwords from previous data */ prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; break; case 2: /* Copy two dwords from a previous index */ idx = 8 + bytestream2_get_le16(gbc); if (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4) prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; break; case 3: /* Copy two dwords from input */ prev = bytestream2_get_le32(gbc); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = bytestream2_get_le32(gbc); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; break; } } CHECKPOINT(4); if (pos + 2 > ctx->tex_size / 4) /* Copy two elements from a previous offset or from the input buffer */ if (op) { if (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4) prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; } else { CHECKPOINT(4); if (op && (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4)) if (op) prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); else prev = bytestream2_get_le32(gbc); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; CHECKPOINT(4); if (op) prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); else prev = bytestream2_get_le32(gbc); AV_WL32(ctx->tex_data + 4 * pos, prev); pos++; } } return 0; }