| 1 | /* SPDX-License-Identifier: MIT */ |
| 2 | /* |
| 3 | * Pixman stride and buffer size helpers. |
| 4 | * Expects PIXMAN_FORMAT_BPP() and pixman_format_code_t to be |
| 5 | * already defined (by either <pixman.h> or "pixman-minimal.h"). |
| 6 | */ |
| 7 | |
| 8 | #ifndef QEMU_PIXMAN_HELPERS_H |
| 9 | #define QEMU_PIXMAN_HELPERS_H |
| 10 | |
| 11 | /* |
| 12 | * Compute the row stride for a pixman image, aligned to sizeof(uint32_t), |
| 13 | * as pixman does. Returns -1 on integer overflow. |
| 14 | */ |
| 15 | static inline int qemu_pixman_stride(pixman_format_code_t format, int width) |
| 16 | { |
| 17 | int stride; |
| 18 | |
| 19 | if (unlikely(__builtin_mul_overflow(width, PIXMAN_FORMAT_BPP(format), |
| 20 | &stride)) || |
| 21 | unlikely(__builtin_add_overflow(stride, 31, &stride))) { |
| 22 | return -1; |
| 23 | } |
| 24 | return (stride / 32) * sizeof(uint32_t); |
| 25 | } |
| 26 | |
| 27 | /* |
| 28 | * Compute stride and buffer size for a pixman image. |
| 29 | * If *rowstride_bytes is 0, compute it from format and width |
| 30 | * (aligned to sizeof(uint32_t), as pixman does). |
| 31 | * Returns false on integer overflow. |
| 32 | */ |
| 33 | static inline bool qemu_pixman_image_calc_size(pixman_format_code_t format, |
| 34 | int width, int height, |
| 35 | int *rowstride_bytes, |
| 36 | size_t *buf_size) |
| 37 | { |
| 38 | if (!*rowstride_bytes) { |
| 39 | *rowstride_bytes = qemu_pixman_stride(format, width); |
| 40 | if (*rowstride_bytes < 0) { |
| 41 | return false; |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | return likely(!__builtin_mul_overflow((size_t)height, |
| 46 | (size_t)*rowstride_bytes, buf_size)); |
| 47 | } |
| 48 | |
| 49 | #endif /* QEMU_PIXMAN_HELPERS_H */ |